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8713 lines
213 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
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<HTML
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><HEAD
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><TITLE
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> NCURSES Programming HOWTO </TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.79"></HEAD
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CLASS="ARTICLE"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="ARTICLE"
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><DIV
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CLASS="TITLEPAGE"
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><H1
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CLASS="TITLE"
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><A
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NAME="AEN2"
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>NCURSES Programming HOWTO</A
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></H1
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><H3
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CLASS="AUTHOR"
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><A
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NAME="AEN4"
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> Pradeep Padala </A
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></H3
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><DIV
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CLASS="AFFILIATION"
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><DIV
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CLASS="ADDRESS"
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><P
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CLASS="ADDRESS"
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><CODE
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CLASS="EMAIL"
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><<A
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HREF="mailto:ppadala@gmail.com"
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>ppadala@gmail.com</A
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>></CODE
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></P
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></DIV
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></DIV
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><P
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CLASS="PUBDATE"
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>v1.9, 2005-06-20<BR></P
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><DIV
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CLASS="REVHISTORY"
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><TABLE
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WIDTH="100%"
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BORDER="0"
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><TR
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><TH
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ALIGN="LEFT"
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VALIGN="TOP"
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COLSPAN="3"
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><B
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>Revision History</B
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></TH
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.9</TD
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><TD
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ALIGN="LEFT"
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>2005-06-20</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>The license has been changed to the MIT-style license used
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by NCURSES. Note that the programs are also re-licensed under this.</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.8</TD
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><TD
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ALIGN="LEFT"
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>2005-06-17</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Lots of updates. Added references and perl examples.
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Changes to examples. Many grammatical and stylistic changes to the
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content. Changes to NCURSES history.</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.7.1</TD
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><TD
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ALIGN="LEFT"
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>2002-06-25</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Added a README file for building and instructions
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for building from source.</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.7</TD
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><TD
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ALIGN="LEFT"
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>2002-06-25</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Added "Other formats" section and made a lot of fancy
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changes to the programs. Inlining of programs is gone.</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.6.1</TD
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><TD
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ALIGN="LEFT"
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>2002-02-24</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Removed the old Changelog section, cleaned the makefiles</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.6</TD
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><TD
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ALIGN="LEFT"
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>2002-02-16</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Corrected a lot of spelling mistakes, added ACS variables
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section</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.5</TD
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><TD
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ALIGN="LEFT"
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>2002-01-05</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Changed structure to present proper TOC</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.3.1</TD
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><TD
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ALIGN="LEFT"
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>2001-07-26</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Corrected maintainers paragraph, Corrected stable release number</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.3</TD
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><TD
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ALIGN="LEFT"
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>2001-07-24</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Added copyright notices to main document (LDP license)
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and programs (GPL), Corrected
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printw_example.</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.2</TD
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><TD
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ALIGN="LEFT"
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>2001-06-05</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Incorporated ravi's changes. Mainly to introduction, menu,
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form, justforfun sections</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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>Revision 1.1</TD
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><TD
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ALIGN="LEFT"
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>2001-05-22</TD
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><TD
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ALIGN="LEFT"
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>Revised by: ppadala</TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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COLSPAN="3"
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>Added "a word about window" section, Added scanw_example.</TD
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></TR
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></TABLE
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></DIV
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><DIV
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><DIV
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CLASS="ABSTRACT"
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><P
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></P
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><A
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NAME="AEN67"
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></A
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><P
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> <SPAN
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CLASS="emphasis"
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><I
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CLASS="EMPHASIS"
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>This document is intended to be an "All in One" guide for programming with
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ncurses and its sister libraries. We graduate from a simple "Hello World"
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program to more complex form manipulation. No prior experience in ncurses is
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assumed. Send comments to <A
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HREF="mailto:ppadala@gmail.com"
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TARGET="_top"
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>this address</A
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>
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</I
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></SPAN
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>
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</P
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><P
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></P
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></DIV
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></DIV
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><HR></DIV
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><DIV
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CLASS="TOC"
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><DL
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><DT
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><B
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>Table of Contents</B
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></DT
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><DT
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>1. <A
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HREF="#INTRO"
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>Introduction</A
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></DT
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><DD
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><DL
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><DT
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>1.1. <A
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HREF="#WHATIS"
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>What is NCURSES?</A
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></DT
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><DT
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>1.2. <A
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|
HREF="#WHATCANWEDO"
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|
>What we can do with NCURSES</A
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|
></DT
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|
><DT
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|
>1.3. <A
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|
HREF="#WHERETOGETIT"
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|
>Where to get it</A
|
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></DT
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><DT
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|
>1.4. <A
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|
HREF="#PURPOSE"
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|
>Purpose/Scope of the document</A
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></DT
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><DT
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|
>1.5. <A
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HREF="#ABOUTPROGRAMS"
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>About the Programs</A
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></DT
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><DT
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|
>1.6. <A
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HREF="#OTHERFORMATS"
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|
>Other Formats of the document</A
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></DT
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><DD
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><DL
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><DT
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|
>1.6.1. <A
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HREF="#LISTFORMATS"
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|
>Readily available formats from tldp.org</A
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></DT
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><DT
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|
>1.6.2. <A
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HREF="#BUILDSOURCE"
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>Building from source</A
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></DT
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></DL
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></DD
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><DT
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|
>1.7. <A
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HREF="#CREDITS"
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>Credits</A
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></DT
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><DT
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|
>1.8. <A
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HREF="#WISHLIST"
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|
>Wish List</A
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></DT
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><DT
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|
>1.9. <A
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HREF="#COPYRIGHT"
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>Copyright</A
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></DT
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></DL
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></DD
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><DT
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|
>2. <A
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HREF="#HELLOWORLD"
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|
>Hello World !!!</A
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></DT
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><DD
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><DL
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><DT
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|
>2.1. <A
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HREF="#COMPILECURSES"
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|
>Compiling With the NCURSES Library</A
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></DT
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><DT
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|
>2.2. <A
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HREF="#DISSECTION"
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>Dissection</A
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></DT
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><DD
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><DL
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><DT
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|
>2.2.1. <A
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HREF="#ABOUT-INITSCR"
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|
>About initscr()</A
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></DT
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><DT
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|
>2.2.2. <A
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HREF="#MYST-REFRESH"
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|
>The mysterious refresh()</A
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></DT
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|
><DT
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|
>2.2.3. <A
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|
HREF="#ABOUT-ENDWIN"
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|
>About endwin()</A
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></DT
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></DL
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></DD
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></DL
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></DD
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><DT
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>3. <A
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HREF="#GORY"
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|
>The Gory Details</A
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></DT
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><DT
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|
>4. <A
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HREF="#INIT"
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>Initialization</A
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></DT
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><DD
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><DL
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><DT
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>4.1. <A
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HREF="#ABOUTINIT"
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>Initialization functions</A
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></DT
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><DT
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>4.2. <A
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HREF="#RAWCBREAK"
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>raw() and cbreak()</A
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></DT
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><DT
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|
>4.3. <A
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HREF="#ECHONOECHO"
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>echo() and noecho()</A
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></DT
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><DT
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>4.4. <A
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HREF="#KEYPAD"
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>keypad()</A
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></DT
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><DT
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|
>4.5. <A
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HREF="#HALFDELAY"
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>halfdelay()</A
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></DT
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><DT
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|
>4.6. <A
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|
HREF="#MISCINIT"
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|
>Miscellaneous Initialization functions</A
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></DT
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><DT
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>4.7. <A
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HREF="#INITEX"
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|
>An Example</A
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></DT
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></DL
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></DD
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><DT
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|
>5. <A
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HREF="#AWORDWINDOWS"
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|
>A Word about Windows</A
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></DT
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><DT
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|
>6. <A
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HREF="#PRINTW"
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>Output functions</A
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></DT
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><DD
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><DL
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><DT
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>6.1. <A
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HREF="#ADDCHCLASS"
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>addch() class of functions</A
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></DT
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><DT
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>6.2. <A
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HREF="#AEN298"
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>mvaddch(), waddch() and mvwaddch()</A
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></DT
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><DT
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>6.3. <A
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HREF="#PRINTWCLASS"
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>printw() class of functions</A
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></DT
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><DD
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><DL
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><DT
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|
>6.3.1. <A
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HREF="#PRINTWMVPRINTW"
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|
>printw() and mvprintw</A
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></DT
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><DT
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|
>6.3.2. <A
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HREF="#WPRINTWMVWPRINTW"
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|
>wprintw() and mvwprintw</A
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|
></DT
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><DT
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|
>6.3.3. <A
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HREF="#VWPRINTW"
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|
>vwprintw()</A
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|
></DT
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><DT
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|
>6.3.4. <A
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|
HREF="#SIMPLEPRINTWEX"
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|
>A Simple printw example</A
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></DT
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></DL
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|
></DD
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><DT
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|
>6.4. <A
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HREF="#ADDSTRCLASS"
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>addstr() class of functions</A
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></DT
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><DT
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|
>6.5. <A
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|
HREF="#ACAUTION"
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|
>A word of caution</A
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></DT
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></DL
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|
></DD
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><DT
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|
>7. <A
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|
HREF="#SCANW"
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|
>Input functions</A
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></DT
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><DD
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|
><DL
|
|
><DT
|
|
>7.1. <A
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|
HREF="#GETCHCLASS"
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|
>getch() class of functions</A
|
|
></DT
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|
><DT
|
|
>7.2. <A
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|
HREF="#SCANWCLASS"
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|
>scanw() class of functions</A
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></DT
|
|
><DD
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|
><DL
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|
><DT
|
|
>7.2.1. <A
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|
HREF="#SCANWMVSCANW"
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|
>scanw() and mvscanw</A
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|
></DT
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|
><DT
|
|
>7.2.2. <A
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|
HREF="#WSCANWMVWSCANW"
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|
>wscanw() and mvwscanw()</A
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|
></DT
|
|
><DT
|
|
>7.2.3. <A
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|
HREF="#VWSCANW"
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|
>vwscanw()</A
|
|
></DT
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|
></DL
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|
></DD
|
|
><DT
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|
>7.3. <A
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|
HREF="#GETSTRCLASS"
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|
>getstr() class of functions</A
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|
></DT
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|
><DT
|
|
>7.4. <A
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|
HREF="#GETSTREX"
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|
>Some examples</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>8. <A
|
|
HREF="#ATTRIB"
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|
>Attributes</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>8.1. <A
|
|
HREF="#ATTRIBDETAILS"
|
|
>The details</A
|
|
></DT
|
|
><DT
|
|
>8.2. <A
|
|
HREF="#ATTRONVSATTRSET"
|
|
>attron() vs attrset()</A
|
|
></DT
|
|
><DT
|
|
>8.3. <A
|
|
HREF="#ATTR_GET"
|
|
>attr_get()</A
|
|
></DT
|
|
><DT
|
|
>8.4. <A
|
|
HREF="#ATTR_FUNCS"
|
|
>attr_ functions</A
|
|
></DT
|
|
><DT
|
|
>8.5. <A
|
|
HREF="#WATTRFUNCS"
|
|
>wattr functions</A
|
|
></DT
|
|
><DT
|
|
>8.6. <A
|
|
HREF="#CHGAT"
|
|
>chgat() functions</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>9. <A
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|
HREF="#WINDOWS"
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|
>Windows</A
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></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>9.1. <A
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|
HREF="#WINDOWBASICS"
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|
>The basics</A
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></DT
|
|
><DT
|
|
>9.2. <A
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|
HREF="#LETBEWINDOW"
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|
>Let there be a Window !!!</A
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|
></DT
|
|
><DT
|
|
>9.3. <A
|
|
HREF="#BORDEREXEXPL"
|
|
>Explanation</A
|
|
></DT
|
|
><DT
|
|
>9.4. <A
|
|
HREF="#OTHERSTUFF"
|
|
>The other stuff in the example</A
|
|
></DT
|
|
><DT
|
|
>9.5. <A
|
|
HREF="#OTHERBORDERFUNCS"
|
|
>Other Border functions</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>10. <A
|
|
HREF="#COLOR"
|
|
>Colors</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>10.1. <A
|
|
HREF="#COLORBASICS"
|
|
>The basics</A
|
|
></DT
|
|
><DT
|
|
>10.2. <A
|
|
HREF="#CHANGECOLORDEFS"
|
|
>Changing Color Definitions</A
|
|
></DT
|
|
><DT
|
|
>10.3. <A
|
|
HREF="#COLORCONTENT"
|
|
>Color Content</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>11. <A
|
|
HREF="#KEYS"
|
|
>Interfacing with the key board</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>11.1. <A
|
|
HREF="#KEYSBASICS"
|
|
>The Basics</A
|
|
></DT
|
|
><DT
|
|
>11.2. <A
|
|
HREF="#SIMPLEKEYEX"
|
|
>A Simple Key Usage example</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>12. <A
|
|
HREF="#MOUSE"
|
|
>Interfacing with the mouse</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>12.1. <A
|
|
HREF="#MOUSEBASICS"
|
|
>The Basics</A
|
|
></DT
|
|
><DT
|
|
>12.2. <A
|
|
HREF="#GETTINGEVENTS"
|
|
>Getting the events</A
|
|
></DT
|
|
><DT
|
|
>12.3. <A
|
|
HREF="#MOUSETOGETHER"
|
|
>Putting it all Together</A
|
|
></DT
|
|
><DT
|
|
>12.4. <A
|
|
HREF="#MISCMOUSEFUNCS"
|
|
>Miscellaneous Functions</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>13. <A
|
|
HREF="#SCREEN"
|
|
>Screen Manipulation</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>13.1. <A
|
|
HREF="#GETYX"
|
|
>getyx() functions</A
|
|
></DT
|
|
><DT
|
|
>13.2. <A
|
|
HREF="#SCREENDUMP"
|
|
>Screen Dumping</A
|
|
></DT
|
|
><DT
|
|
>13.3. <A
|
|
HREF="#WINDOWDUMP"
|
|
>Window Dumping</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>14. <A
|
|
HREF="#MISC"
|
|
>Miscellaneous features</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>14.1. <A
|
|
HREF="#CURSSET"
|
|
>curs_set()</A
|
|
></DT
|
|
><DT
|
|
>14.2. <A
|
|
HREF="#TEMPLEAVE"
|
|
>Temporarily Leaving Curses mode</A
|
|
></DT
|
|
><DT
|
|
>14.3. <A
|
|
HREF="#ACSVARS"
|
|
>ACS_ variables</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>15. <A
|
|
HREF="#OTHERLIB"
|
|
>Other libraries</A
|
|
></DT
|
|
><DT
|
|
>16. <A
|
|
HREF="#PANELS"
|
|
>Panel Library</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>16.1. <A
|
|
HREF="#PANELBASICS"
|
|
>The Basics</A
|
|
></DT
|
|
><DT
|
|
>16.2. <A
|
|
HREF="#COMPILEPANELS"
|
|
>Compiling With the Panels Library</A
|
|
></DT
|
|
><DT
|
|
>16.3. <A
|
|
HREF="#PANELBROWSING"
|
|
>Panel Window Browsing</A
|
|
></DT
|
|
><DT
|
|
>16.4. <A
|
|
HREF="#USERPTRUSING"
|
|
>Using User Pointers</A
|
|
></DT
|
|
><DT
|
|
>16.5. <A
|
|
HREF="#PANELMOVERESIZE"
|
|
>Moving and Resizing Panels</A
|
|
></DT
|
|
><DT
|
|
>16.6. <A
|
|
HREF="#PANELSHOWHIDE"
|
|
>Hiding and Showing Panels</A
|
|
></DT
|
|
><DT
|
|
>16.7. <A
|
|
HREF="#PANELABOVE"
|
|
>panel_above() and panel_below() Functions</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>17. <A
|
|
HREF="#MENUS"
|
|
>Menus Library</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>17.1. <A
|
|
HREF="#MENUBASICS"
|
|
>The Basics</A
|
|
></DT
|
|
><DT
|
|
>17.2. <A
|
|
HREF="#COMPILEMENUS"
|
|
>Compiling With the Menu Library</A
|
|
></DT
|
|
><DT
|
|
>17.3. <A
|
|
HREF="#MENUDRIVER"
|
|
>Menu Driver: The work horse of the menu system</A
|
|
></DT
|
|
><DT
|
|
>17.4. <A
|
|
HREF="#MENUWINDOWS"
|
|
>Menu Windows</A
|
|
></DT
|
|
><DT
|
|
>17.5. <A
|
|
HREF="#SCROLLMENUS"
|
|
>Scrolling Menus</A
|
|
></DT
|
|
><DT
|
|
>17.6. <A
|
|
HREF="#MULTICOLUMN"
|
|
>Multi Columnar Menus</A
|
|
></DT
|
|
><DT
|
|
>17.7. <A
|
|
HREF="#MULTIVALUEMENUS"
|
|
>Multi Valued Menus</A
|
|
></DT
|
|
><DT
|
|
>17.8. <A
|
|
HREF="#MENUOPT"
|
|
>Menu Options</A
|
|
></DT
|
|
><DT
|
|
>17.9. <A
|
|
HREF="#MENUUSERPTR"
|
|
>The useful User Pointer</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>18. <A
|
|
HREF="#FORMS"
|
|
>Forms Library</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>18.1. <A
|
|
HREF="#FORMBASICS"
|
|
>The Basics</A
|
|
></DT
|
|
><DT
|
|
>18.2. <A
|
|
HREF="#COMPILEFORMS"
|
|
>Compiling With the Forms Library</A
|
|
></DT
|
|
><DT
|
|
>18.3. <A
|
|
HREF="#PLAYFIELDS"
|
|
>Playing with Fields</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>18.3.1. <A
|
|
HREF="#FETCHINFO"
|
|
>Fetching Size and Location of Field</A
|
|
></DT
|
|
><DT
|
|
>18.3.2. <A
|
|
HREF="#MOVEFIELD"
|
|
>Moving the field</A
|
|
></DT
|
|
><DT
|
|
>18.3.3. <A
|
|
HREF="#JUSTIFYFIELD"
|
|
>Field Justification</A
|
|
></DT
|
|
><DT
|
|
>18.3.4. <A
|
|
HREF="#FIELDDISPATTRIB"
|
|
>Field Display Attributes</A
|
|
></DT
|
|
><DT
|
|
>18.3.5. <A
|
|
HREF="#FIELDOPTIONBITS"
|
|
>Field Option Bits</A
|
|
></DT
|
|
><DT
|
|
>18.3.6. <A
|
|
HREF="#FIELDSTATUS"
|
|
>Field Status</A
|
|
></DT
|
|
><DT
|
|
>18.3.7. <A
|
|
HREF="#FIELDUSERPTR"
|
|
>Field User Pointer</A
|
|
></DT
|
|
><DT
|
|
>18.3.8. <A
|
|
HREF="#VARIABLESIZEFIELDS"
|
|
>Variable-Sized Fields</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>18.4. <A
|
|
HREF="#FORMWINDOWS"
|
|
>Form Windows</A
|
|
></DT
|
|
><DT
|
|
>18.5. <A
|
|
HREF="#FILEDVALIDATE"
|
|
>Field Validation</A
|
|
></DT
|
|
><DT
|
|
>18.6. <A
|
|
HREF="#FORMDRIVER"
|
|
>Form Driver: The work horse of the forms system</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>18.6.1. <A
|
|
HREF="#PAGENAVREQ"
|
|
>Page Navigation Requests</A
|
|
></DT
|
|
><DT
|
|
>18.6.2. <A
|
|
HREF="#INTERFIELDNAVREQ"
|
|
>Inter-Field Navigation Requests</A
|
|
></DT
|
|
><DT
|
|
>18.6.3. <A
|
|
HREF="#INTRAFIELDNAVREQ"
|
|
>Intra-Field Navigation Requests</A
|
|
></DT
|
|
><DT
|
|
>18.6.4. <A
|
|
HREF="#SCROLLREQ"
|
|
>Scrolling Requests</A
|
|
></DT
|
|
><DT
|
|
>18.6.5. <A
|
|
HREF="#EDITREQ"
|
|
>Editing Requests</A
|
|
></DT
|
|
><DT
|
|
>18.6.6. <A
|
|
HREF="#ORDERREQ"
|
|
>Order Requests</A
|
|
></DT
|
|
><DT
|
|
>18.6.7. <A
|
|
HREF="#APPLICCOMMANDS"
|
|
>Application Commands</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>19. <A
|
|
HREF="#TOOLS"
|
|
>Tools and Widget Libraries</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>19.1. <A
|
|
HREF="#CDK"
|
|
>CDK (Curses Development Kit)</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>19.1.1. <A
|
|
HREF="#WIDGETLIST"
|
|
>Widget List</A
|
|
></DT
|
|
><DT
|
|
>19.1.2. <A
|
|
HREF="#CDKATTRACT"
|
|
>Some Attractive Features</A
|
|
></DT
|
|
><DT
|
|
>19.1.3. <A
|
|
HREF="#CDKCONCLUSION"
|
|
>Conclusion</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>19.2. <A
|
|
HREF="#DIALOG"
|
|
>The dialog</A
|
|
></DT
|
|
><DT
|
|
>19.3. <A
|
|
HREF="#PERLCURSES"
|
|
>Perl Curses Modules CURSES::FORM and CURSES::WIDGETS</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>20. <A
|
|
HREF="#JUSTFORFUN"
|
|
>Just For Fun !!!</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>20.1. <A
|
|
HREF="#GAMEOFLIFE"
|
|
>The Game of Life</A
|
|
></DT
|
|
><DT
|
|
>20.2. <A
|
|
HREF="#MAGIC"
|
|
>Magic Square</A
|
|
></DT
|
|
><DT
|
|
>20.3. <A
|
|
HREF="#HANOI"
|
|
>Towers of Hanoi</A
|
|
></DT
|
|
><DT
|
|
>20.4. <A
|
|
HREF="#QUEENS"
|
|
>Queens Puzzle</A
|
|
></DT
|
|
><DT
|
|
>20.5. <A
|
|
HREF="#SHUFFLE"
|
|
>Shuffle</A
|
|
></DT
|
|
><DT
|
|
>20.6. <A
|
|
HREF="#TT"
|
|
>Typing Tutor</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>21. <A
|
|
HREF="#REF"
|
|
>References</A
|
|
></DT
|
|
></DL
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="INTRO"
|
|
>1. Introduction</A
|
|
></H2
|
|
><P
|
|
>In the olden days of teletype terminals, terminals were away from computers and
|
|
were connected to them through serial cables. The terminals could be configured
|
|
by sending a series of bytes. All the capabilities (such as
|
|
moving the cursor to a new location, erasing part of the screen, scrolling the
|
|
screen, changing modes etc.) of terminals could be accessed through these
|
|
series of bytes. These control seeuqnces are usually called escape sequences,
|
|
because they start
|
|
with an escape(0x1B) character. Even today, with proper emulation, we can send
|
|
escape sequences to the emulator and achieve the same effect on a terminal
|
|
window.</P
|
|
><P
|
|
>Suppose you wanted to print a line in color. Try typing this on your console.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>echo "^[[0;31;40mIn Color"</PRE
|
|
><P
|
|
>The first character is an escape character, which looks like two characters ^
|
|
and [. To be able to print it, you have to press CTRL+V and then the ESC key.
|
|
All the others are normal printable characters. You should be able to see the
|
|
string "In Color" in red. It stays that way and to revert back to the original
|
|
mode type this.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>echo "^[[0;37;40m"</PRE
|
|
><P
|
|
>Now, what do these magic characters mean? Difficult to comprehend? They might
|
|
even be different for different terminals. So the designers of UNIX invented a
|
|
mechanism named <TT
|
|
CLASS="LITERAL"
|
|
>termcap</TT
|
|
>. It is a file that
|
|
lists all the capabilities of a particular terminal, along with the escape
|
|
sequences needed to achieve a particular effect. In the later years, this was
|
|
replaced by <TT
|
|
CLASS="LITERAL"
|
|
>terminfo</TT
|
|
>. Without delving too
|
|
much into details, this mechanism allows application
|
|
programs to query the terminfo database and obtain the control characters to be
|
|
sent to a terminal or terminal emulator.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="WHATIS"
|
|
>1.1. What is NCURSES?</A
|
|
></H3
|
|
><P
|
|
>
|
|
You might be wondering, what the import of all this technical gibberish is. In
|
|
the above scenario, every application program is supposed to query the terminfo
|
|
and perform the necessary stuff (sending control characters etc.). It soon became
|
|
difficult to manage this complexity and this gave birth to 'CURSES'. Curses is
|
|
a pun on the name "cursor optimization". The Curses library forms a wrapper
|
|
over working with raw terminal codes, and provides highly flexible and
|
|
efficient API (Application Programming Interface). It provides functions to
|
|
move the cursor, create windows, produce colors, play with mouse etc. The
|
|
application programs need not worry about the underlying terminal capabilities.</P
|
|
><P
|
|
>So what is NCURSES? NCURSES is a clone of the original System V Release 4.0
|
|
(SVr4) curses. It is a freely distributable library, fully compatible with
|
|
older version of curses. In short, it is a library of functions that manages
|
|
an application's display on character-cell terminals. In the remainder of the
|
|
document, the terms curses and ncurses are used interchangeably. </P
|
|
><P
|
|
>A detailed history of NCURSES can be found in the NEWS file from the source
|
|
distribution. The current package is maintained by
|
|
<A
|
|
HREF="mailto:dickey@his.com"
|
|
TARGET="_top"
|
|
>Thomas Dickey</A
|
|
>.
|
|
You can contact the maintainers at <A
|
|
HREF="mailto:bug-ncurses@gnu.org"
|
|
TARGET="_top"
|
|
>bug-ncurses@gnu.org</A
|
|
>.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="WHATCANWEDO"
|
|
>1.2. What we can do with NCURSES</A
|
|
></H3
|
|
><P
|
|
>NCURSES not only creates a wrapper over terminal capabilities, but also gives a
|
|
robust framework to create nice looking UI (User Interface)s in text mode. It
|
|
provides functions to create windows etc. Its sister libraries panel, menu and
|
|
form provide an extension to the basic curses library. These libraries usually
|
|
come along with curses. One can create applications that contain multiple
|
|
windows, menus, panels and forms. Windows can be managed independently, can
|
|
provide 'scrollability' and even can be hidden.</P
|
|
><P
|
|
>
|
|
Menus provide the user with an easy command selection option. Forms allow the
|
|
creation of easy-to-use data entry and display windows. Panels extend the
|
|
capabilities of ncurses to deal with overlapping and stacked windows.</P
|
|
><P
|
|
>These are just some of the basic things we can do with ncurses. As we move
|
|
along, We will see all the capabilities of these libraries. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="WHERETOGETIT"
|
|
>1.3. Where to get it</A
|
|
></H3
|
|
><P
|
|
>All right, now that you know what you can do with ncurses, you must be rearing
|
|
to get started. NCURSES is usually shipped with your installation. In case
|
|
you don't have the library or want to compile it on your own, read on.</P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>Compiling the package</I
|
|
></SPAN
|
|
> </P
|
|
><P
|
|
>NCURSES can be obtained from <A
|
|
HREF="ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz"
|
|
TARGET="_top"
|
|
>ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz</A
|
|
> or any of the ftp
|
|
sites mentioned in <A
|
|
HREF="http://www.gnu.org/order/ftp.html"
|
|
TARGET="_top"
|
|
>http://www.gnu.org/order/ftp.html</A
|
|
>. </P
|
|
><P
|
|
>Read the README and INSTALL files for details on to how to install it. It
|
|
usually involves the following operations.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> tar zxvf ncurses<version>.tar.gz # unzip and untar the archive
|
|
cd ncurses<version> # cd to the directory
|
|
./configure # configure the build according to your
|
|
# environment
|
|
make # make it
|
|
su root # become root
|
|
make install # install it</PRE
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>Using the RPM </I
|
|
></SPAN
|
|
></P
|
|
><P
|
|
>NCURSES RPM can be found and downloaded from <A
|
|
HREF="http://rpmfind.net"
|
|
TARGET="_top"
|
|
>http://rpmfind.net </A
|
|
>. The RPM can be installed with the following
|
|
command after becoming root.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> rpm -i <downloaded rpm></PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PURPOSE"
|
|
>1.4. Purpose/Scope of the document</A
|
|
></H3
|
|
><P
|
|
>This document is intended to be a "All in One" guide for programming with
|
|
ncurses and its sister libraries. We graduate from a simple "Hello World"
|
|
program to more complex form manipulation. No prior experience in ncurses is
|
|
assumed. The writing is informal, but a lot of detail is provided for
|
|
each of the examples.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ABOUTPROGRAMS"
|
|
>1.5. About the Programs</A
|
|
></H3
|
|
><P
|
|
>All the programs in the document are available in zipped form
|
|
<A
|
|
HREF="http://www.tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs.tar.gz"
|
|
TARGET="_top"
|
|
>here</A
|
|
>. Unzip and untar it. The directory structure looks like this.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>ncurses
|
|
|
|
|
|----> JustForFun -- just for fun programs
|
|
|----> basics -- basic programs
|
|
|----> demo -- output files go into this directory after make
|
|
| |
|
|
| |----> exe -- exe files of all example programs
|
|
|----> forms -- programs related to form library
|
|
|----> menus -- programs related to menus library
|
|
|----> panels -- programs related to panels library
|
|
|----> perl -- perl equivalents of the examples (contributed
|
|
| by Anuradha Ratnaweera)
|
|
|----> Makefile -- the top level Makefile
|
|
|----> README -- the top level README file. contains instructions
|
|
|----> COPYING -- copyright notice</PRE
|
|
><P
|
|
>The individual directories contain the following files.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>Description of files in each directory
|
|
--------------------------------------
|
|
JustForFun
|
|
|
|
|
|----> hanoi.c -- The Towers of Hanoi Solver
|
|
|----> life.c -- The Game of Life demo
|
|
|----> magic.c -- An Odd Order Magic Square builder
|
|
|----> queens.c -- The famous N-Queens Solver
|
|
|----> shuffle.c -- A fun game, if you have time to kill
|
|
|----> tt.c -- A very trivial typing tutor
|
|
|
|
basics
|
|
|
|
|
|----> acs_vars.c -- ACS_ variables example
|
|
|----> hello_world.c -- Simple "Hello World" Program
|
|
|----> init_func_example.c -- Initialization functions example
|
|
|----> key_code.c -- Shows the scan code of the key pressed
|
|
|----> mouse_menu.c -- A menu accessible by mouse
|
|
|----> other_border.c -- Shows usage of other border functions apa
|
|
| -- rt from box()
|
|
|----> printw_example.c -- A very simple printw() example
|
|
|----> scanw_example.c -- A very simple getstr() example
|
|
|----> simple_attr.c -- A program that can print a c file with
|
|
| -- comments in attribute
|
|
|----> simple_color.c -- A simple example demonstrating colors
|
|
|----> simple_key.c -- A menu accessible with keyboard UP, DOWN
|
|
| -- arrows
|
|
|----> temp_leave.c -- Demonstrates temporarily leaving curses mode
|
|
|----> win_border.c -- Shows Creation of windows and borders
|
|
|----> with_chgat.c -- chgat() usage example
|
|
|
|
forms
|
|
|
|
|
|----> form_attrib.c -- Usage of field attributes
|
|
|----> form_options.c -- Usage of field options
|
|
|----> form_simple.c -- A simple form example
|
|
|----> form_win.c -- Demo of windows associated with forms
|
|
|
|
menus
|
|
|
|
|
|----> menu_attrib.c -- Usage of menu attributes
|
|
|----> menu_item_data.c -- Usage of item_name() etc.. functions
|
|
|----> menu_multi_column.c -- Creates multi columnar menus
|
|
|----> menu_scroll.c -- Demonstrates scrolling capability of menus
|
|
|----> menu_simple.c -- A simple menu accessed by arrow keys
|
|
|----> menu_toggle.c -- Creates multi valued menus and explains
|
|
| -- REQ_TOGGLE_ITEM
|
|
|----> menu_userptr.c -- Usage of user pointer
|
|
|----> menu_win.c -- Demo of windows associated with menus
|
|
|
|
panels
|
|
|
|
|
|----> panel_browse.c -- Panel browsing through tab. Usage of user
|
|
| -- pointer
|
|
|----> panel_hide.c -- Hiding and Un hiding of panels
|
|
|----> panel_resize.c -- Moving and resizing of panels
|
|
|----> panel_simple.c -- A simple panel example
|
|
|
|
perl
|
|
|----> 01-10.pl -- Perl equivalents of first ten example programs</PRE
|
|
><P
|
|
>There is a top level Makefile included in the main directory. It builds all the
|
|
files and puts the ready-to-use exes in demo/exe directory. You can also
|
|
do selective make by going into the corresponding directory. Each directory
|
|
contains a README file explaining the purpose of each c file in the directory.</P
|
|
><P
|
|
>For every example, I have included path name for the file relative to the
|
|
examples directory. </P
|
|
><P
|
|
> If you prefer browsing individual programs, point your browser to
|
|
<A
|
|
HREF="http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/"
|
|
TARGET="_top"
|
|
>http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/</A
|
|
></P
|
|
><P
|
|
>All the programs are released under the same license that is used by ncurses
|
|
(MIT-style). This gives you the ability to do pretty much anything other than
|
|
claiming them as yours. Feel free to use them in your programs as appropriate.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="OTHERFORMATS"
|
|
>1.6. Other Formats of the document</A
|
|
></H3
|
|
><P
|
|
>This howto is also availabe in various other formats on the tldp.org site.
|
|
Here are the links to other formats of this document.</P
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="LISTFORMATS"
|
|
>1.6.1. Readily available formats from tldp.org</A
|
|
></H4
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><A
|
|
HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/pdf/NCURSES-Programming-HOWTO.pdf"
|
|
TARGET="_top"
|
|
>Acrobat PDF Format</A
|
|
></P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><A
|
|
HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/ps/NCURSES-Programming-HOWTO.ps.gz"
|
|
TARGET="_top"
|
|
>PostScript Format</A
|
|
></P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><A
|
|
HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html/NCURSES-Programming-HOWTO-html.tar.gz"
|
|
TARGET="_top"
|
|
>In Multiple HTML pages</A
|
|
></P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><A
|
|
HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/NCURSES-Programming-HOWTO.html"
|
|
TARGET="_top"
|
|
>In One big HTML format</A
|
|
></P
|
|
></LI
|
|
></UL
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="BUILDSOURCE"
|
|
>1.6.2. Building from source</A
|
|
></H4
|
|
><P
|
|
>If above links are broken or if you want to experiment with sgml read on.
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> Get both the source and the tar,gzipped programs, available at
|
|
http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
|
|
NCURSES-HOWTO/NCURSES-Programming-HOWTO.sgml
|
|
http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
|
|
NCURSES-HOWTO/ncurses_programs.tar.gz
|
|
|
|
Unzip ncurses_programs.tar.gz with
|
|
tar zxvf ncurses_programs.tar.gz
|
|
|
|
Use jade to create various formats. For example if you just want to create
|
|
the multiple html files, you would use
|
|
jade -t sgml -i html -d <path to docbook html stylesheet>
|
|
NCURSES-Programming-HOWTO.sgml
|
|
to get pdf, first create a single html file of the HOWTO with
|
|
jade -t sgml -i html -d <path to docbook html stylesheet> -V nochunks
|
|
NCURSES-Programming-HOWTO.sgml > NCURSES-ONE-BIG-FILE.html
|
|
then use htmldoc to get pdf file with
|
|
htmldoc --size universal -t pdf --firstpage p1 -f <output file name.pdf>
|
|
NCURSES-ONE-BIG-FILE.html
|
|
for ps, you would use
|
|
htmldoc --size universal -t ps --firstpage p1 -f <output file name.ps>
|
|
NCURSES-ONE-BIG-FILE.html</PRE
|
|
></P
|
|
><P
|
|
>See <A
|
|
HREF="http://www.tldp.org/LDP/LDP-Author-Guide/"
|
|
TARGET="_top"
|
|
>LDP Author guide</A
|
|
> for more details. If all else failes, mail me at
|
|
<A
|
|
HREF="ppadala@gmail.com"
|
|
TARGET="_top"
|
|
>ppadala@gmail.com</A
|
|
></P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="CREDITS"
|
|
>1.7. Credits</A
|
|
></H3
|
|
><P
|
|
>I thank <A
|
|
HREF="mailto:sharath_1@usa.net"
|
|
TARGET="_top"
|
|
>Sharath</A
|
|
> and Emre Akbas for
|
|
helping me with few sections. The introduction was initially written by sharath.
|
|
I rewrote it with few excerpts taken from his initial work. Emre helped in
|
|
writing printw and scanw sections.</P
|
|
><P
|
|
>Perl equivalents of the example programs are contributed by <A
|
|
HREF="mailto:Aratnaweera@virtusa.com"
|
|
TARGET="_top"
|
|
>Anuradha Ratnaweera</A
|
|
>. </P
|
|
><P
|
|
>Then comes <A
|
|
HREF="mailto:parimi@ece.arizona.edu"
|
|
TARGET="_top"
|
|
>Ravi Parimi</A
|
|
>, my
|
|
dearest friend, who has been on this project before even one line was written.
|
|
He constantly bombarded me with suggestions and patiently reviewed the whole
|
|
text. He also checked each program on Linux and Solaris. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="WISHLIST"
|
|
>1.8. Wish List</A
|
|
></H3
|
|
><P
|
|
>This is the wish list, in the order of priority. If you have a wish or you want
|
|
to work on completing the wish, mail <A
|
|
HREF="mailto:ppadala@gmail.com"
|
|
TARGET="_top"
|
|
>me</A
|
|
>. </P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
>Add examples to last parts of forms section.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Prepare a Demo showing all the programs and allow the user to browse through
|
|
description of each program. Let the user compile and see the program in action.
|
|
A dialog based interface is preferred.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Add debug info. _tracef, _tracemouse stuff.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Accessing termcap, terminfo using functions provided by ncurses
|
|
package.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Working on two terminals simultaneously.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Add more stuff to miscellaneous section.</P
|
|
></LI
|
|
></UL
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="COPYRIGHT"
|
|
>1.9. Copyright</A
|
|
></H3
|
|
><P
|
|
>Copyright © 2001 by Pradeep Padala. </P
|
|
><P
|
|
>Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
of this software and associated documentation files (the "Software"), to deal
|
|
in the Software without restriction, including without limitation the rights
|
|
to use, copy, modify, merge, publish, distribute, distribute with
|
|
modifications, sublicense, and/or sell copies of the Software, and to permit
|
|
persons to whom the Software is furnished to do so, subject to the following
|
|
conditions:</P
|
|
><P
|
|
>The above copyright notice and this permission notice shall be included in all
|
|
copies or substantial portions of the Software.</P
|
|
><P
|
|
>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
|
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
|
|
IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.</P
|
|
><P
|
|
>Except as contained in this notice, the name(s) of the above copyright holders
|
|
shall not be used in advertising or otherwise to promote the sale, use or
|
|
other dealings in this Software without prior written authorization. </P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="HELLOWORLD"
|
|
>2. Hello World !!!</A
|
|
></H2
|
|
><P
|
|
>Welcome to the world of curses. Before we plunge into the library and look into
|
|
its various features, let's write a simple program and say
|
|
hello to the world. </P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="COMPILECURSES"
|
|
>2.1. Compiling With the NCURSES Library</A
|
|
></H3
|
|
><P
|
|
>To use ncurses library functions, you have to include ncurses.h in your
|
|
programs. To link the
|
|
program with ncurses the flag -lncurses should be added.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> #include <ncurses.h>
|
|
.
|
|
.
|
|
.
|
|
|
|
compile and link: gcc <program file> -lncurses</PRE
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BHW"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 1. The Hello World !!! Program </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
int main()
|
|
{
|
|
initscr(); /* Start curses mode */
|
|
printw("Hello World !!!"); /* Print Hello World */
|
|
refresh(); /* Print it on to the real screen */
|
|
getch(); /* Wait for user input */
|
|
endwin(); /* End curses mode */
|
|
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="DISSECTION"
|
|
>2.2. Dissection</A
|
|
></H3
|
|
><P
|
|
>
|
|
The above program prints "Hello World !!!" to the screen and exits. This
|
|
program shows how to initialize curses and do screen manipulation and
|
|
end curses mode. Let's dissect it line by line. </P
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="ABOUT-INITSCR"
|
|
>2.2.1. About initscr()</A
|
|
></H4
|
|
><P
|
|
>The function initscr() initializes the terminal in curses mode. In some
|
|
implementations, it clears the screen and presents a blank screen. To do any
|
|
screen manipulation using curses package this has to be called first. This
|
|
function initializes the curses system and allocates memory for our present
|
|
window (called <TT
|
|
CLASS="LITERAL"
|
|
>stdscr</TT
|
|
>) and some other data-structures. Under extreme
|
|
cases this function might fail due to insufficient memory to allocate memory
|
|
for curses library's data structures. </P
|
|
><P
|
|
>
|
|
After this is done, we can do a variety of initializations to customize
|
|
our curses settings. These details will be explained <A
|
|
HREF="#INIT"
|
|
>later </A
|
|
>.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="MYST-REFRESH"
|
|
>2.2.2. The mysterious refresh()</A
|
|
></H4
|
|
><P
|
|
>The next line printw prints the string "Hello World !!!" on to the screen. This
|
|
function is analogous to normal printf in all respects except that it prints
|
|
the data on a window called stdscr at the current (y,x) co-ordinates. Since our
|
|
present co-ordinates are at 0,0 the string is printed at the left hand corner
|
|
of the window.</P
|
|
><P
|
|
>This brings us to that mysterious refresh(). Well, when we called printw
|
|
the data is actually written to an imaginary window, which is not updated
|
|
on the screen yet. The job of printw is to update a few flags
|
|
and data structures and write the data to a buffer corresponding to stdscr.
|
|
In order to show it on the screen, we need to call refresh() and tell the
|
|
curses system to dump the contents on the screen.</P
|
|
><P
|
|
>The philosophy behind all this is to allow the programmer to do multiple updates
|
|
on the imaginary screen or windows and do a refresh once all his screen update
|
|
is done. refresh() checks the window and updates only the portion which has been
|
|
changed. This improves performance and offers greater flexibility too. But, it is
|
|
sometimes frustrating to beginners. A common mistake committed by beginners is
|
|
to forget to call refresh() after they did some update through printw() class of
|
|
functions. I still forget to add it sometimes :-) </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="ABOUT-ENDWIN"
|
|
>2.2.3. About endwin()</A
|
|
></H4
|
|
><P
|
|
>And finally don't forget to end the curses mode. Otherwise your terminal might
|
|
behave strangely after the program quits. endwin() frees the memory taken by
|
|
curses sub-system and its data structures and puts the terminal in normal
|
|
mode. This function must be called after you are done with the curses mode. </P
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="GORY"
|
|
>3. The Gory Details</A
|
|
></H2
|
|
><P
|
|
>Now that we have seen how to write a simple curses program let's get into the
|
|
details. There are many functions that help customize what you see on screen and
|
|
many features which can be put to full use. </P
|
|
><P
|
|
>Here we go...</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="INIT"
|
|
>4. Initialization</A
|
|
></H2
|
|
><P
|
|
>We now know that to initialize curses system the function initscr() has to be
|
|
called. There are functions which can be called after this initialization to
|
|
customize our curses session. We may ask the curses system to set the terminal
|
|
in raw mode or initialize color or initialize the mouse etc.. Let's discuss some
|
|
of the functions that are normally called immediately after initscr();</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ABOUTINIT"
|
|
>4.1. Initialization functions</A
|
|
></H3
|
|
><P
|
|
> </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="RAWCBREAK"
|
|
>4.2. raw() and cbreak()</A
|
|
></H3
|
|
><P
|
|
>Normally the terminal driver buffers the characters a user types until a new
|
|
line or carriage return is encountered. But most programs require that the
|
|
characters be available as soon as the user types them. The above two functions
|
|
are used to disable line buffering. The difference between these two functions
|
|
is in the way control characters like suspend (CTRL-Z), interrupt and quit
|
|
(CTRL-C) are passed to the program. In the raw() mode these characters are
|
|
directly passed to the program without generating a signal. In the
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>cbreak()</TT
|
|
> mode these control characters are
|
|
interpreted as any other character by the terminal driver. I personally prefer
|
|
to use raw() as I can exercise greater control over what the user does.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ECHONOECHO"
|
|
>4.3. echo() and noecho()</A
|
|
></H3
|
|
><P
|
|
>
|
|
These functions control the echoing of characters typed by the user to the
|
|
terminal. <TT
|
|
CLASS="LITERAL"
|
|
>noecho()</TT
|
|
> switches off echoing. The
|
|
reason you might want to do this is to gain more control over echoing or to
|
|
suppress unnecessary echoing while taking input from the user through the
|
|
getch() etc. functions. Most of the interactive programs call
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>noecho()</TT
|
|
> at initialization and do the echoing
|
|
of characters in a controlled manner. It gives the programmer the flexibility
|
|
of echoing characters at any place in the window without updating current (y,x)
|
|
co-ordinates. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="KEYPAD"
|
|
>4.4. keypad()</A
|
|
></H3
|
|
><P
|
|
>This is my favorite initialization function. It enables the reading of function
|
|
keys like F1, F2, arrow keys etc. Almost every interactive program enables this,
|
|
as arrow keys are a major part of any User Interface. Do
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>keypad(stdscr, TRUE) </TT
|
|
> to enable this feature
|
|
for the regular screen (stdscr). You will learn more about key management in
|
|
later sections of this document.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="HALFDELAY"
|
|
>4.5. halfdelay()</A
|
|
></H3
|
|
><P
|
|
>This function, though not used very often, is a useful one at times.
|
|
halfdelay()is called to enable the half-delay mode, which is similar to the
|
|
cbreak() mode in that characters typed are immediately available to program.
|
|
However, it waits for 'X' tenths of a second for input and then returns ERR, if
|
|
no input is available. 'X' is the timeout value passed to the function
|
|
halfdelay(). This function is useful when you want to ask the user for input,
|
|
and if he doesn't respond with in certain time, we can do some thing else. One
|
|
possible example is a timeout at the password prompt. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MISCINIT"
|
|
>4.6. Miscellaneous Initialization functions</A
|
|
></H3
|
|
><P
|
|
>There are few more functions which are called at initialization to
|
|
customize curses behavior. They are not used as extensively as those mentioned
|
|
above. Some of them are explained where appropriate.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="INITEX"
|
|
>4.7. An Example</A
|
|
></H3
|
|
><P
|
|
>Let's write a program which will clarify the usage of these functions.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BINFU"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 2. Initialization Function Usage example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
int main()
|
|
{ int ch;
|
|
|
|
initscr(); /* Start curses mode */
|
|
raw(); /* Line buffering disabled */
|
|
keypad(stdscr, TRUE); /* We get F1, F2 etc.. */
|
|
noecho(); /* Don't echo() while we do getch */
|
|
|
|
printw("Type any character to see it in bold\n");
|
|
ch = getch(); /* If raw() hadn't been called
|
|
* we have to press enter before it
|
|
* gets to the program */
|
|
if(ch == KEY_F(1)) /* Without keypad enabled this will */
|
|
printw("F1 Key pressed");/* not get to us either */
|
|
/* Without noecho() some ugly escape
|
|
* charachters might have been printed
|
|
* on screen */
|
|
else
|
|
{ printw("The pressed key is ");
|
|
attron(A_BOLD);
|
|
printw("%c", ch);
|
|
attroff(A_BOLD);
|
|
}
|
|
refresh(); /* Print it on to the real screen */
|
|
getch(); /* Wait for user input */
|
|
endwin(); /* End curses mode */
|
|
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>This program is self-explanatory. But I used functions which aren't explained
|
|
yet. The function <TT
|
|
CLASS="LITERAL"
|
|
>getch()</TT
|
|
> is used to get a
|
|
character from user. It is equivalent to normal
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getchar()</TT
|
|
> except that we can disable the line
|
|
buffering to avoid <enter> after input. Look for more about
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getch()</TT
|
|
>and reading keys in the <A
|
|
HREF="#KEYS"
|
|
> key management section </A
|
|
>. The functions attron and attroff
|
|
are used to switch some attributes on and off respectively. In the example I
|
|
used them to print the character in bold. These functions are explained in detail
|
|
later.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="AWORDWINDOWS"
|
|
>5. A Word about Windows</A
|
|
></H2
|
|
><P
|
|
>
|
|
Before we plunge into the myriad ncurses functions, let me clear few things
|
|
about windows. Windows are explained in detail in following <A
|
|
HREF="#WINDOWS"
|
|
> sections </A
|
|
></P
|
|
><P
|
|
>A Window is an imaginary screen defined by curses system. A window does not mean
|
|
a bordered window which you usually see on Win9X platforms. When curses is
|
|
initialized, it creates a default window named
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>stdscr</TT
|
|
> which represents your 80x25 (or the size
|
|
of window in which you are running) screen. If you are doing simple tasks like
|
|
printing few strings, reading input etc., you can safely use this single window
|
|
for all of your purposes. You can also create windows and call functions which
|
|
explicitly work on the specified window.</P
|
|
><P
|
|
>For example, if you call</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> printw("Hi There !!!");
|
|
refresh();</PRE
|
|
><P
|
|
>It prints the string on stdscr at the present cursor position. Similarly the
|
|
call to refresh(), works on stdscr only. </P
|
|
><P
|
|
>Say you have created <A
|
|
HREF="#WINDOWS"
|
|
>windows</A
|
|
> then you have to
|
|
call a function with a 'w' added to the usual function.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> wprintw(win, "Hi There !!!");
|
|
wrefresh(win);</PRE
|
|
><P
|
|
>As you will see in the rest of the document, naming of functions follow the
|
|
same convention. For each function there usually are three more functions.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> printw(string); /* Print on stdscr at present cursor position */
|
|
mvprintw(y, x, string);/* Move to (y, x) then print string */
|
|
wprintw(win, string); /* Print on window win at present cursor position */
|
|
/* in the window */
|
|
mvwprintw(win, y, x, string); /* Move to (y, x) relative to window */
|
|
/* co-ordinates and then print */</PRE
|
|
><P
|
|
>Usually the w-less functions are macros which expand to corresponding w-function
|
|
with stdscr as the window parameter.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="PRINTW"
|
|
>6. Output functions</A
|
|
></H2
|
|
><P
|
|
>I guess you can't wait any more to see some action. Back to our odyssey of
|
|
curses functions. Now that curses is initialized, let's interact with
|
|
world.</P
|
|
><P
|
|
>There are three classes of functions which you can use to do output on screen.
|
|
<P
|
|
></P
|
|
><OL
|
|
TYPE="1"
|
|
><LI
|
|
><P
|
|
>addch() class: Print single character with attributes </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>printw() class: Print formatted output similar to printf()</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>addstr() class: Print strings</P
|
|
></LI
|
|
></OL
|
|
></P
|
|
><P
|
|
>These functions can be used interchangeably and it's a matter of style as to
|
|
which class is used. Let's see each one in detail.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ADDCHCLASS"
|
|
>6.1. addch() class of functions</A
|
|
></H3
|
|
><P
|
|
>These functions put a single character into the current cursor location and
|
|
advance the position of the cursor. You can give the character to be printed but
|
|
they usually are used to print a character with some attributes. Attributes are
|
|
explained in detail in later <A
|
|
HREF="#ATTRIB"
|
|
> sections </A
|
|
> of the
|
|
document. If a character is associated with an attribute(bold, reverse video
|
|
etc.), when curses prints the character, it is printed in that attribute.</P
|
|
><P
|
|
>In order to combine a character with some attributes, you have two options:</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
>By OR'ing a single character with the desired attribute macros. These attribute
|
|
macros could be found in the header file
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>ncurses.h</TT
|
|
>. For example, you want to print a
|
|
character ch(of type char) bold and underlined, you would call addch() as below.
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> addch(ch | A_BOLD | A_UNDERLINE);</PRE
|
|
></P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>By using functions like <TT
|
|
CLASS="LITERAL"
|
|
>attrset(),attron(),attroff()</TT
|
|
>. These functions are explained in the <A
|
|
HREF="#ATTRIB"
|
|
>Attributes</A
|
|
> section. Briefly, they manipulate the current attributes of
|
|
the given window. Once set, the character printed in the window are associated
|
|
with the attributes until it is turned off.</P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>Additionally, <TT
|
|
CLASS="LITERAL"
|
|
>curses</TT
|
|
> provides some special
|
|
characters for character-based graphics. You can draw tables, horizontal or
|
|
vertical lines, etc. You can find all avaliable characters in the header file
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>ncurses.h</TT
|
|
>. Try looking for macros beginning
|
|
with <TT
|
|
CLASS="LITERAL"
|
|
>ACS_</TT
|
|
> in this file. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="AEN298"
|
|
>6.2. mvaddch(), waddch() and mvwaddch()</A
|
|
></H3
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>mvaddch()</TT
|
|
> is used to move the cursor to a
|
|
given point, and then print. Thus, the calls:
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> move(row,col); /* moves the cursor to row<SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>th</I
|
|
></SPAN
|
|
> row and col<SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>th</I
|
|
></SPAN
|
|
> column */
|
|
addch(ch);</PRE
|
|
>
|
|
can be replaced by
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> mvaddch(row,col,ch);</PRE
|
|
></P
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>waddch()</TT
|
|
> is similar to
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>addch()</TT
|
|
>, except that it adds a character into
|
|
the given window. (Note that <TT
|
|
CLASS="LITERAL"
|
|
>addch()</TT
|
|
> adds a
|
|
character into the window <TT
|
|
CLASS="LITERAL"
|
|
>stdscr</TT
|
|
>.)</P
|
|
><P
|
|
>In a similar fashion <TT
|
|
CLASS="LITERAL"
|
|
>mvwaddch()</TT
|
|
> function is
|
|
used to add a character into the given window at the given coordinates.</P
|
|
><P
|
|
>Now, we are familiar with the basic output function
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>addch()</TT
|
|
>. But, if we want to print a string, it
|
|
would be very annoying to print it character by character. Fortunately,
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>ncurses</TT
|
|
> provides <TT
|
|
CLASS="LITERAL"
|
|
>printf</TT
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>-like</I
|
|
></SPAN
|
|
> or
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>puts</TT
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>-like</I
|
|
></SPAN
|
|
> functions.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PRINTWCLASS"
|
|
>6.3. printw() class of functions</A
|
|
></H3
|
|
><P
|
|
>These functions are similar to <TT
|
|
CLASS="LITERAL"
|
|
>printf()</TT
|
|
> with
|
|
the added capability of printing at any position on the screen. </P
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="PRINTWMVPRINTW"
|
|
>6.3.1. printw() and mvprintw</A
|
|
></H4
|
|
><P
|
|
>These two functions work much like <TT
|
|
CLASS="LITERAL"
|
|
>printf()</TT
|
|
>.
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>mvprintw()</TT
|
|
> can be used to move the cursor to a
|
|
position and then print. If you want to move the cursor first and then print
|
|
using <TT
|
|
CLASS="LITERAL"
|
|
>printw()</TT
|
|
> function, use
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>move() </TT
|
|
> first and then use
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>printw()</TT
|
|
> though I see no point why one should
|
|
avoid using <TT
|
|
CLASS="LITERAL"
|
|
>mvprintw()</TT
|
|
>, you have the
|
|
flexibility to manipulate. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="WPRINTWMVWPRINTW"
|
|
>6.3.2. wprintw() and mvwprintw</A
|
|
></H4
|
|
><P
|
|
>These two functions are similar to above two except that they print in the
|
|
corresponding window given as argument. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="VWPRINTW"
|
|
>6.3.3. vwprintw()</A
|
|
></H4
|
|
><P
|
|
>This function is similar to <TT
|
|
CLASS="LITERAL"
|
|
>vprintf()</TT
|
|
>. This can
|
|
be used when variable number of arguments are to be printed.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="SIMPLEPRINTWEX"
|
|
>6.3.4. A Simple printw example</A
|
|
></H4
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BPREX"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 3. A Simple printw example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h> /* ncurses.h includes stdio.h */
|
|
#include <string.h>
|
|
|
|
int main()
|
|
{
|
|
char mesg[]="Just a string"; /* message to be appeared on the screen */
|
|
int row,col; /* to store the number of rows and *
|
|
* the number of colums of the screen */
|
|
initscr(); /* start the curses mode */
|
|
getmaxyx(stdscr,row,col); /* get the number of rows and columns */
|
|
mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
|
|
/* print the message at the center of the screen */
|
|
mvprintw(row-2,0,"This screen has %d rows and %d columns\n",row,col);
|
|
printw("Try resizing your window(if possible) and then run this program again");
|
|
refresh();
|
|
getch();
|
|
endwin();
|
|
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>Above program demonstrates how easy it is to use <TT
|
|
CLASS="LITERAL"
|
|
>printw</TT
|
|
>. You just feed the coordinates and the message to be appeared
|
|
on the screen, then it does what you want.</P
|
|
><P
|
|
>The above program introduces us to a new function
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getmaxyx()</TT
|
|
>, a macro defined in
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>ncurses.h</TT
|
|
>. It gives the number of columns and
|
|
the number of rows in a given window.
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getmaxyx()</TT
|
|
> does this by updating the variables
|
|
given to it. Since <TT
|
|
CLASS="LITERAL"
|
|
>getmaxyx()</TT
|
|
> is not a function
|
|
we don't pass pointers to it, we just give two integer variables. </P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ADDSTRCLASS"
|
|
>6.4. addstr() class of functions</A
|
|
></H3
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>addstr()</TT
|
|
> is used to put a character string into
|
|
a given window. This function is similar to calling
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>addch()</TT
|
|
> once for each character in a given
|
|
string. This is true for all output functions. There are other functions from
|
|
this family such as <TT
|
|
CLASS="LITERAL"
|
|
>mvaddstr(),mvwaddstr()</TT
|
|
> and
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>waddstr()</TT
|
|
>, which obey the naming convention of
|
|
curses.(e.g. mvaddstr() is similar to the respective calls move() and then
|
|
addstr().) Another function of this family is addnstr(), which takes an integer
|
|
parameter(say n) additionally. This function puts at most n characters into the
|
|
screen. If n is negative, then the entire string will be added. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ACAUTION"
|
|
>6.5. A word of caution</A
|
|
></H3
|
|
><P
|
|
>All these functions take y co-ordinate first and then x in their arguments.
|
|
A common mistake by beginners is to pass x,y in that order. If you are
|
|
doing too many manipulations of (y,x) co-ordinates, think of dividing the
|
|
screen into windows and manipulate each one separately. Windows are explained
|
|
in the <A
|
|
HREF="#WINDOWS"
|
|
> windows </A
|
|
> section.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="SCANW"
|
|
>7. Input functions</A
|
|
></H2
|
|
><P
|
|
>Well, printing without taking input, is boring. Let's see functions which
|
|
allow us to get input from user. These functions also can be divided into
|
|
three categories.</P
|
|
><P
|
|
></P
|
|
><OL
|
|
TYPE="1"
|
|
><LI
|
|
><P
|
|
>getch() class: Get a character</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>scanw() class: Get formatted input</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>getstr() class: Get strings</P
|
|
></LI
|
|
></OL
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="GETCHCLASS"
|
|
>7.1. getch() class of functions</A
|
|
></H3
|
|
><P
|
|
>These functions read a single character from the terminal. But there are several
|
|
subtle facts to consider. For example if you don't use the function cbreak(),
|
|
curses will not read your input characters contiguously but will begin read them
|
|
only after a new line or an EOF is encountered. In order to avoid this, the
|
|
cbreak() function must used so that characters are immediately available to your
|
|
program. Another widely used function is noecho(). As the name suggests, when
|
|
this function is set (used), the characters that are keyed in by the user will
|
|
not show up on the screen. The two functions cbreak() and noecho() are typical
|
|
examples of key management. Functions of this genre are explained in the
|
|
<A
|
|
HREF="#KEYS"
|
|
>key management section </A
|
|
>.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="SCANWCLASS"
|
|
>7.2. scanw() class of functions</A
|
|
></H3
|
|
><P
|
|
>These functions are similar to <TT
|
|
CLASS="LITERAL"
|
|
>scanf()</TT
|
|
> with the
|
|
added capability of getting the input from any location on the screen.</P
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="SCANWMVSCANW"
|
|
>7.2.1. scanw() and mvscanw</A
|
|
></H4
|
|
><P
|
|
>The usage of these functions is similar to that of
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>sscanf()</TT
|
|
>, where the line to be scanned is
|
|
provided by <TT
|
|
CLASS="LITERAL"
|
|
>wgetstr()</TT
|
|
> function. That is, these
|
|
functions call to <TT
|
|
CLASS="LITERAL"
|
|
>wgetstr()</TT
|
|
> function(explained
|
|
below) and uses the resulting line for a scan. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="WSCANWMVWSCANW"
|
|
>7.2.2. wscanw() and mvwscanw()</A
|
|
></H4
|
|
><P
|
|
>These are similar to above two functions except that they read from a window,
|
|
which is supplied as one of the arguments to these functions. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="VWSCANW"
|
|
>7.2.3. vwscanw()</A
|
|
></H4
|
|
><P
|
|
>This function is similar to <TT
|
|
CLASS="LITERAL"
|
|
>vscanf()</TT
|
|
>. This can
|
|
be used when a variable number of arguments are to be scanned.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="GETSTRCLASS"
|
|
>7.3. getstr() class of functions</A
|
|
></H3
|
|
><P
|
|
>These functions are used to get strings from the terminal. In essence, this
|
|
function performs the same task as would be achieved by a series of calls to
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getch()</TT
|
|
> until a newline, carriage return, or
|
|
end-of-file is received. The resulting string of characters are pointed to by
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>str</TT
|
|
>, which is a character pointer provided by
|
|
the user.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="GETSTREX"
|
|
>7.4. Some examples</A
|
|
></H3
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BSCEX"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 4. A Simple scanw example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h> /* ncurses.h includes stdio.h */
|
|
#include <string.h>
|
|
|
|
int main()
|
|
{
|
|
char mesg[]="Enter a string: "; /* message to be appeared on the screen */
|
|
char str[80];
|
|
int row,col; /* to store the number of rows and *
|
|
* the number of colums of the screen */
|
|
initscr(); /* start the curses mode */
|
|
getmaxyx(stdscr,row,col); /* get the number of rows and columns */
|
|
mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
|
|
/* print the message at the center of the screen */
|
|
getstr(str);
|
|
mvprintw(LINES - 2, 0, "You Entered: %s", str);
|
|
getch();
|
|
endwin();
|
|
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="ATTRIB"
|
|
>8. Attributes</A
|
|
></H2
|
|
><P
|
|
>We have seen an example of how attributes can be used to print characters with
|
|
some special effects. Attributes, when set prudently, can present information in
|
|
an easy, understandable manner. The following program takes a C file as input
|
|
and prints the file with comments in bold. Scan through the code. </P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BSIAT"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 5. A Simple Attributes example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>/* pager functionality by Joseph Spainhour" <spainhou@bellsouth.net> */
|
|
#include <ncurses.h>
|
|
#include <stdlib.h>
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
int ch, prev, row, col;
|
|
prev = EOF;
|
|
FILE *fp;
|
|
int y, x;
|
|
|
|
if(argc != 2)
|
|
{
|
|
printf("Usage: %s <a c file name>\n", argv[0]);
|
|
exit(1);
|
|
}
|
|
fp = fopen(argv[1], "r");
|
|
if(fp == NULL)
|
|
{
|
|
perror("Cannot open input file");
|
|
exit(1);
|
|
}
|
|
initscr(); /* Start curses mode */
|
|
getmaxyx(stdscr, row, col); /* find the boundaries of the screeen */
|
|
while((ch = fgetc(fp)) != EOF) /* read the file till we reach the end */
|
|
{
|
|
getyx(stdscr, y, x); /* get the current curser position */
|
|
if(y == (row - 1)) /* are we are at the end of the screen */
|
|
{
|
|
printw("<-Press Any Key->"); /* tell the user to press a key */
|
|
getch();
|
|
clear(); /* clear the screen */
|
|
move(0, 0); /* start at the beginning of the screen */
|
|
}
|
|
if(prev == '/' && ch == '*') /* If it is / and * then only
|
|
* switch bold on */
|
|
{
|
|
attron(A_BOLD); /* cut bold on */
|
|
getyx(stdscr, y, x); /* get the current curser position */
|
|
move(y, x - 1); /* back up one space */
|
|
printw("%c%c", '/', ch); /* The actual printing is done here */
|
|
}
|
|
else
|
|
printw("%c", ch);
|
|
refresh();
|
|
if(prev == '*' && ch == '/')
|
|
attroff(A_BOLD); /* Switch it off once we got *
|
|
* and then / */
|
|
prev = ch;
|
|
}
|
|
endwin(); /* End curses mode */
|
|
fclose(fp);
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>
|
|
Don't worry about all those initialization and other crap. Concentrate on
|
|
the while loop. It reads each character in the file and searches for the
|
|
pattern /*. Once it spots the pattern, it switches the BOLD attribute on with
|
|
<TT
|
|
CLASS="LITERAL"
|
|
> attron()</TT
|
|
> . When we get the pattern */ it is
|
|
switched off by <TT
|
|
CLASS="LITERAL"
|
|
> attroff()</TT
|
|
> .</P
|
|
><P
|
|
>
|
|
The above program also introduces us to two useful functions
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getyx() </TT
|
|
> and
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>move()</TT
|
|
>. The first function gets the
|
|
co-ordinates of the present cursor into the variables y, x. Since getyx() is a
|
|
macro we don't have to pass pointers to variables. The function
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>move()</TT
|
|
> moves the cursor to the co-ordinates
|
|
given to it. </P
|
|
><P
|
|
>
|
|
The above program is really a simple one which doesn't do much. On these lines
|
|
one could write a more useful program which reads a C file, parses it and prints
|
|
it in different colors. One could even extend it to other languages as well.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ATTRIBDETAILS"
|
|
>8.1. The details</A
|
|
></H3
|
|
><P
|
|
>Let's get into more details of attributes. The functions <TT
|
|
CLASS="LITERAL"
|
|
>attron(), attroff(), attrset() </TT
|
|
>, and their sister functions
|
|
<TT
|
|
CLASS="LITERAL"
|
|
> attr_get()</TT
|
|
> etc.. can be used to switch
|
|
attributes on/off , get attributes and produce a colorful display.</P
|
|
><P
|
|
>The functions attron and attroff take a bit-mask of attributes and switch them
|
|
on or off, respectively. The following video attributes, which are defined in
|
|
<curses.h> can be passed to these functions. </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>
|
|
A_NORMAL Normal display (no highlight)
|
|
A_STANDOUT Best highlighting mode of the terminal.
|
|
A_UNDERLINE Underlining
|
|
A_REVERSE Reverse video
|
|
A_BLINK Blinking
|
|
A_DIM Half bright
|
|
A_BOLD Extra bright or bold
|
|
A_PROTECT Protected mode
|
|
A_INVIS Invisible or blank mode
|
|
A_ALTCHARSET Alternate character set
|
|
A_CHARTEXT Bit-mask to extract a character
|
|
COLOR_PAIR(n) Color-pair number n
|
|
</PRE
|
|
><P
|
|
>
|
|
The last one is the most colorful one :-) Colors are explained in the
|
|
<A
|
|
HREF="#color"
|
|
TARGET="_top"
|
|
>next sections</A
|
|
>.</P
|
|
><P
|
|
>We can OR(|) any number of above attributes to get a combined effect. If you
|
|
wanted reverse video with blinking characters you can use</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> attron(A_REVERSE | A_BLINK);</PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ATTRONVSATTRSET"
|
|
>8.2. attron() vs attrset()</A
|
|
></H3
|
|
><P
|
|
>Then what is the difference between attron() and attrset()? attrset sets the
|
|
attributes of window whereas attron just switches on the attribute given to it.
|
|
So attrset() fully overrides whatever attributes the window previously had and
|
|
sets it to the new attribute(s). Similarly attroff() just switches off the
|
|
attribute(s) given to it as an argument. This gives us the flexibility of
|
|
managing attributes easily.But if you use them carelessly you may loose track of
|
|
what attributes the window has and garble the display. This is especially true
|
|
while managing menus with colors and highlighting. So decide on a consistent
|
|
policy and stick to it. You can always use <TT
|
|
CLASS="LITERAL"
|
|
> standend()</TT
|
|
> which is equivalent to <TT
|
|
CLASS="LITERAL"
|
|
> attrset(A_NORMAL)</TT
|
|
> which turns off all attributes and brings you to normal mode.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ATTR_GET"
|
|
>8.3. attr_get()</A
|
|
></H3
|
|
><P
|
|
> The function attr_get() gets the current attributes and color pair of the
|
|
window. Though we might not use this as often as the above functions, this is
|
|
useful in scanning areas of screen. Say we wanted to do some complex update on
|
|
screen and we are not sure what attribute each character is associated with.
|
|
Then this function can be used with either attrset or attron to produce the
|
|
desired effect. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ATTR_FUNCS"
|
|
>8.4. attr_ functions</A
|
|
></H3
|
|
><P
|
|
>There are series of functions like attr_set(), attr_on etc.. These are similar
|
|
to above functions except that they take parameters of type
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>attr_t</TT
|
|
>.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="WATTRFUNCS"
|
|
>8.5. wattr functions</A
|
|
></H3
|
|
><P
|
|
>For each of the above functions we have a corresponding function with 'w' which
|
|
operates on a particular window. The above functions operate on stdscr. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="CHGAT"
|
|
>8.6. chgat() functions</A
|
|
></H3
|
|
><P
|
|
>The function chgat() is listed in the end of the man page curs_attr. It actually
|
|
is a useful one. This function can be used to set attributes for a group of
|
|
characters without moving. I mean it !!! without moving the cursor :-) It
|
|
changes the attributes of a given number of characters starting at the current
|
|
cursor location.</P
|
|
><P
|
|
>We can give -1 as the character count to update till end of line. If you want to
|
|
change attributes of characters from current position to end of line, just use
|
|
this.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> chgat(-1, A_REVERSE, 0, NULL);</PRE
|
|
><P
|
|
>
|
|
This function is useful when changing attributes for characters that are
|
|
already on the screen. Move to the character from which you want to change and
|
|
change the attribute. </P
|
|
><P
|
|
>Other functions wchgat(), mvchgat(), wchgat() behave similarly except that the w
|
|
functions operate on the particular window. The mv functions first move the
|
|
cursor then perform the work given to them. Actually chgat is a macro which is
|
|
replaced by a wchgat() with stdscr as the window. Most of the "w-less" functions
|
|
are macros.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BWICH"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 6. Chgat() Usage example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
int main(int argc, char *argv[])
|
|
{ initscr(); /* Start curses mode */
|
|
start_color(); /* Start color functionality */
|
|
|
|
init_pair(1, COLOR_CYAN, COLOR_BLACK);
|
|
printw("A Big string which i didn't care to type fully ");
|
|
mvchgat(0, 0, -1, A_BLINK, 1, NULL);
|
|
/*
|
|
* First two parameters specify the position at which to start
|
|
* Third parameter number of characters to update. -1 means till
|
|
* end of line
|
|
* Forth parameter is the normal attribute you wanted to give
|
|
* to the charcter
|
|
* Fifth is the color index. It is the index given during init_pair()
|
|
* use 0 if you didn't want color
|
|
* Sixth one is always NULL
|
|
*/
|
|
refresh();
|
|
getch();
|
|
endwin(); /* End curses mode */
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>This example also introduces us to the color world of curses. Colors will be
|
|
explained in detail later. Use 0 for no color.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="WINDOWS"
|
|
>9. Windows</A
|
|
></H2
|
|
><P
|
|
>Windows form the most important concept in curses. You have seen the standard
|
|
window stdscr above where all the functions implicitly operated on this window.
|
|
Now to make design even a simplest GUI, you need to resort to windows. The main
|
|
reason you may want to use windows is to manipulate parts of the screen
|
|
separately, for better efficiency, by updating only the windows that need to be
|
|
changed and for a better design. I would say the last reason is the most
|
|
important in going for windows. You should always strive for a better and
|
|
easy-to-manage design in your programs. If you are writing big, complex GUIs
|
|
this is of pivotal importance before you start doing anything.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="WINDOWBASICS"
|
|
>9.1. The basics</A
|
|
></H3
|
|
><P
|
|
>A Window can be created by calling the function
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>newwin()</TT
|
|
>. It doesn't create any thing on the
|
|
screen actually. It allocates memory for a structure to manipulate the window
|
|
and updates the structure with data regarding the window like it's size, beginy,
|
|
beginx etc.. Hence in curses, a window is just an abstraction of an imaginary
|
|
window, which can be manipulated independent of other parts of screen. The
|
|
function newwin() returns a pointer to structure WINDOW, which can be passed to
|
|
window related functions like wprintw() etc.. Finally the window can be
|
|
destroyed with delwin(). It will deallocate the memory associated with the
|
|
window structure.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="LETBEWINDOW"
|
|
>9.2. Let there be a Window !!!</A
|
|
></H3
|
|
><P
|
|
>What fun is it, if a window is created and we can't see it. So the fun part
|
|
begins by displaying the window. The function
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>box()</TT
|
|
> can be used to draw a border around the
|
|
window. Let's explore these functions in more detail in this example.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BWIBO"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 7. Window Border example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
|
|
WINDOW *create_newwin(int height, int width, int starty, int startx);
|
|
void destroy_win(WINDOW *local_win);
|
|
|
|
int main(int argc, char *argv[])
|
|
{ WINDOW *my_win;
|
|
int startx, starty, width, height;
|
|
int ch;
|
|
|
|
initscr(); /* Start curses mode */
|
|
cbreak(); /* Line buffering disabled, Pass on
|
|
* everty thing to me */
|
|
keypad(stdscr, TRUE); /* I need that nifty F1 */
|
|
|
|
height = 3;
|
|
width = 10;
|
|
starty = (LINES - height) / 2; /* Calculating for a center placement */
|
|
startx = (COLS - width) / 2; /* of the window */
|
|
printw("Press F1 to exit");
|
|
refresh();
|
|
my_win = create_newwin(height, width, starty, startx);
|
|
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case KEY_LEFT:
|
|
destroy_win(my_win);
|
|
my_win = create_newwin(height, width, starty,--startx);
|
|
break;
|
|
case KEY_RIGHT:
|
|
destroy_win(my_win);
|
|
my_win = create_newwin(height, width, starty,++startx);
|
|
break;
|
|
case KEY_UP:
|
|
destroy_win(my_win);
|
|
my_win = create_newwin(height, width, --starty,startx);
|
|
break;
|
|
case KEY_DOWN:
|
|
destroy_win(my_win);
|
|
my_win = create_newwin(height, width, ++starty,startx);
|
|
break;
|
|
}
|
|
}
|
|
|
|
endwin(); /* End curses mode */
|
|
return 0;
|
|
}
|
|
|
|
WINDOW *create_newwin(int height, int width, int starty, int startx)
|
|
{ WINDOW *local_win;
|
|
|
|
local_win = newwin(height, width, starty, startx);
|
|
box(local_win, 0 , 0); /* 0, 0 gives default characters
|
|
* for the vertical and horizontal
|
|
* lines */
|
|
wrefresh(local_win); /* Show that box */
|
|
|
|
return local_win;
|
|
}
|
|
|
|
void destroy_win(WINDOW *local_win)
|
|
{
|
|
/* box(local_win, ' ', ' '); : This won't produce the desired
|
|
* result of erasing the window. It will leave it's four corners
|
|
* and so an ugly remnant of window.
|
|
*/
|
|
wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' ');
|
|
/* The parameters taken are
|
|
* 1. win: the window on which to operate
|
|
* 2. ls: character to be used for the left side of the window
|
|
* 3. rs: character to be used for the right side of the window
|
|
* 4. ts: character to be used for the top side of the window
|
|
* 5. bs: character to be used for the bottom side of the window
|
|
* 6. tl: character to be used for the top left corner of the window
|
|
* 7. tr: character to be used for the top right corner of the window
|
|
* 8. bl: character to be used for the bottom left corner of the window
|
|
* 9. br: character to be used for the bottom right corner of the window
|
|
*/
|
|
wrefresh(local_win);
|
|
delwin(local_win);
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="BORDEREXEXPL"
|
|
>9.3. Explanation</A
|
|
></H3
|
|
><P
|
|
>Don't scream. I know it's a big example. But I have to explain some important
|
|
things here :-). This program creates a rectangular window that can be moved
|
|
with left, right, up, down arrow keys. It repeatedly creates and destroys
|
|
windows as user press a key. Don't go beyond the screen limits. Checking for
|
|
those limits is left as an exercise for the reader. Let's dissect it by line by line.</P
|
|
><P
|
|
>The <TT
|
|
CLASS="LITERAL"
|
|
>create_newwin()</TT
|
|
> function creates a window
|
|
with <TT
|
|
CLASS="LITERAL"
|
|
>newwin() </TT
|
|
> and displays a border around it
|
|
with box. The function <TT
|
|
CLASS="LITERAL"
|
|
> destroy_win()</TT
|
|
> first
|
|
erases the window from screen by painting a border with ' ' character and then
|
|
calling <TT
|
|
CLASS="LITERAL"
|
|
>delwin()</TT
|
|
> to deallocate memory related
|
|
to it. Depending on the key the user presses, starty or startx is changed and a
|
|
new window is created.</P
|
|
><P
|
|
>In the destroy_win, as you can see, I used wborder instead of box. The reason is
|
|
written in the comments (You missed it. I know. Read the code :-)). wborder
|
|
draws a border around the window with the characters given to it as the 4 corner
|
|
points and the 4 lines. To put it clearly, if you have called wborder as below:
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> wborder(win, '|', '|', '-', '-', '+', '+', '+', '+');</PRE
|
|
></P
|
|
><P
|
|
>it produces some thing like </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> +------------+
|
|
| |
|
|
| |
|
|
| |
|
|
| |
|
|
| |
|
|
| |
|
|
+------------+</PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="OTHERSTUFF"
|
|
>9.4. The other stuff in the example</A
|
|
></H3
|
|
><P
|
|
>You can also see in the above examples, that I have used the variables COLS,
|
|
LINES which are initialized to the screen sizes after initscr(). They can be
|
|
useful in finding screen dimensions and finding the center co-ordinate of the
|
|
screen as above. The function <TT
|
|
CLASS="LITERAL"
|
|
>getch()</TT
|
|
> as usual
|
|
gets the key from keyboard and according to the key it does the corresponding
|
|
work. This type of switch- case is very common in any GUI based programs.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="OTHERBORDERFUNCS"
|
|
>9.5. Other Border functions</A
|
|
></H3
|
|
><P
|
|
>Above program is grossly inefficient in that with each press of a key, a window
|
|
is destroyed and another is created. So let's write a more efficient program
|
|
which uses other border related functions.</P
|
|
><P
|
|
>The following program uses <TT
|
|
CLASS="LITERAL"
|
|
>mvhline()</TT
|
|
> and
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>mvvline()</TT
|
|
> to achieve similar effect. These two
|
|
functions are simple. They create a horizontal or vertical line of the specified
|
|
length at the specified position.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BOTBO"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 8. More border functions</B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
typedef struct _win_border_struct {
|
|
chtype ls, rs, ts, bs,
|
|
tl, tr, bl, br;
|
|
}WIN_BORDER;
|
|
|
|
typedef struct _WIN_struct {
|
|
|
|
int startx, starty;
|
|
int height, width;
|
|
WIN_BORDER border;
|
|
}WIN;
|
|
|
|
void init_win_params(WIN *p_win);
|
|
void print_win_params(WIN *p_win);
|
|
void create_box(WIN *win, bool flag);
|
|
|
|
int main(int argc, char *argv[])
|
|
{ WIN win;
|
|
int ch;
|
|
|
|
initscr(); /* Start curses mode */
|
|
start_color(); /* Start the color functionality */
|
|
cbreak(); /* Line buffering disabled, Pass on
|
|
* everty thing to me */
|
|
keypad(stdscr, TRUE); /* I need that nifty F1 */
|
|
noecho();
|
|
init_pair(1, COLOR_CYAN, COLOR_BLACK);
|
|
|
|
/* Initialize the window parameters */
|
|
init_win_params(&win);
|
|
print_win_params(&win);
|
|
|
|
attron(COLOR_PAIR(1));
|
|
printw("Press F1 to exit");
|
|
refresh();
|
|
attroff(COLOR_PAIR(1));
|
|
|
|
create_box(&win, TRUE);
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case KEY_LEFT:
|
|
create_box(&win, FALSE);
|
|
--win.startx;
|
|
create_box(&win, TRUE);
|
|
break;
|
|
case KEY_RIGHT:
|
|
create_box(&win, FALSE);
|
|
++win.startx;
|
|
create_box(&win, TRUE);
|
|
break;
|
|
case KEY_UP:
|
|
create_box(&win, FALSE);
|
|
--win.starty;
|
|
create_box(&win, TRUE);
|
|
break;
|
|
case KEY_DOWN:
|
|
create_box(&win, FALSE);
|
|
++win.starty;
|
|
create_box(&win, TRUE);
|
|
break;
|
|
}
|
|
}
|
|
endwin(); /* End curses mode */
|
|
return 0;
|
|
}
|
|
void init_win_params(WIN *p_win)
|
|
{
|
|
p_win->height = 3;
|
|
p_win->width = 10;
|
|
p_win->starty = (LINES - p_win->height)/2;
|
|
p_win->startx = (COLS - p_win->width)/2;
|
|
|
|
p_win->border.ls = '|';
|
|
p_win->border.rs = '|';
|
|
p_win->border.ts = '-';
|
|
p_win->border.bs = '-';
|
|
p_win->border.tl = '+';
|
|
p_win->border.tr = '+';
|
|
p_win->border.bl = '+';
|
|
p_win->border.br = '+';
|
|
|
|
}
|
|
void print_win_params(WIN *p_win)
|
|
{
|
|
#ifdef _DEBUG
|
|
mvprintw(25, 0, "%d %d %d %d", p_win->startx, p_win->starty,
|
|
p_win->width, p_win->height);
|
|
refresh();
|
|
#endif
|
|
}
|
|
void create_box(WIN *p_win, bool flag)
|
|
{ int i, j;
|
|
int x, y, w, h;
|
|
|
|
x = p_win->startx;
|
|
y = p_win->starty;
|
|
w = p_win->width;
|
|
h = p_win->height;
|
|
|
|
if(flag == TRUE)
|
|
{ mvaddch(y, x, p_win->border.tl);
|
|
mvaddch(y, x + w, p_win->border.tr);
|
|
mvaddch(y + h, x, p_win->border.bl);
|
|
mvaddch(y + h, x + w, p_win->border.br);
|
|
mvhline(y, x + 1, p_win->border.ts, w - 1);
|
|
mvhline(y + h, x + 1, p_win->border.bs, w - 1);
|
|
mvvline(y + 1, x, p_win->border.ls, h - 1);
|
|
mvvline(y + 1, x + w, p_win->border.rs, h - 1);
|
|
|
|
}
|
|
else
|
|
for(j = y; j <= y + h; ++j)
|
|
for(i = x; i <= x + w; ++i)
|
|
mvaddch(j, i, ' ');
|
|
|
|
refresh();
|
|
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="COLOR"
|
|
>10. Colors</A
|
|
></H2
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="COLORBASICS"
|
|
>10.1. The basics</A
|
|
></H3
|
|
><P
|
|
>Life seems dull with no colors. Curses has a nice mechanism to handle colors.
|
|
Let's get into the thick of the things with a small program.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BSICO"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 9. A Simple Color example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string);
|
|
int main(int argc, char *argv[])
|
|
{ initscr(); /* Start curses mode */
|
|
if(has_colors() == FALSE)
|
|
{ endwin();
|
|
printf("Your terminal does not support color\n");
|
|
exit(1);
|
|
}
|
|
start_color(); /* Start color */
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
|
|
attron(COLOR_PAIR(1));
|
|
print_in_middle(stdscr, LINES / 2, 0, 0, "Viola !!! In color ...");
|
|
attroff(COLOR_PAIR(1));
|
|
getch();
|
|
endwin();
|
|
}
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string)
|
|
{ int length, x, y;
|
|
float temp;
|
|
|
|
if(win == NULL)
|
|
win = stdscr;
|
|
getyx(win, y, x);
|
|
if(startx != 0)
|
|
x = startx;
|
|
if(starty != 0)
|
|
y = starty;
|
|
if(width == 0)
|
|
width = 80;
|
|
|
|
length = strlen(string);
|
|
temp = (width - length)/ 2;
|
|
x = startx + (int)temp;
|
|
mvwprintw(win, y, x, "%s", string);
|
|
refresh();
|
|
}
|
|
</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>As you can see, to start using color, you should first call the function
|
|
<TT
|
|
CLASS="LITERAL"
|
|
> start_color()</TT
|
|
>. After that, you can use color
|
|
capabilities of your terminals using various functions. To find out whether a
|
|
terminal has color capabilities or not, you can use
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>has_colors()</TT
|
|
> function, which returns FALSE if
|
|
the terminal does not support color. </P
|
|
><P
|
|
>Curses initializes all the colors supported by terminal when start_color() is
|
|
called. These can be accessed by the define constants like
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>COLOR_BLACK </TT
|
|
> etc. Now to actually start using
|
|
colors, you have to define pairs. Colors are always used in pairs. That means
|
|
you have to use the function <TT
|
|
CLASS="LITERAL"
|
|
>init_pair() </TT
|
|
> to
|
|
define the foreground and background for the pair number you give. After that
|
|
that pair number can be used as a normal attribute with <TT
|
|
CLASS="LITERAL"
|
|
>COLOR_PAIR()</TT
|
|
>function. This may seem to be cumbersome at first.
|
|
But this elegant solution allows us to manage color pairs very easily. To
|
|
appreciate it, you have to look into the the source code of "dialog", a utility
|
|
for displaying dialog boxes from shell scripts. The developers have defined
|
|
foreground and background combinations for all the colors they might need and
|
|
initialized at the beginning. This makes it very easy to set attributes just by
|
|
accessing a pair which we already have defined as a constant.</P
|
|
><P
|
|
>The following colors are defined in <TT
|
|
CLASS="LITERAL"
|
|
>curses.h</TT
|
|
>.
|
|
You can use these as parameters for various color functions.
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> COLOR_BLACK 0
|
|
COLOR_RED 1
|
|
COLOR_GREEN 2
|
|
COLOR_YELLOW 3
|
|
COLOR_BLUE 4
|
|
COLOR_MAGENTA 5
|
|
COLOR_CYAN 6
|
|
COLOR_WHITE 7</PRE
|
|
></P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="CHANGECOLORDEFS"
|
|
>10.2. Changing Color Definitions</A
|
|
></H3
|
|
><P
|
|
>The function <TT
|
|
CLASS="LITERAL"
|
|
>init_color()</TT
|
|
>can be used to change
|
|
the rgb values for the colors defined by curses initially. Say you wanted to
|
|
lighten the intensity of red color by a minuscule. Then you can use this
|
|
function as</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> init_color(COLOR_RED, 700, 0, 0);
|
|
/* param 1 : color name
|
|
* param 2, 3, 4 : rgb content min = 0, max = 1000 */</PRE
|
|
><P
|
|
>If your terminal cannot change the color definitions, the function returns ERR.
|
|
The function <TT
|
|
CLASS="LITERAL"
|
|
>can_change_color()</TT
|
|
> can be used to
|
|
find out whether the terminal has the capability of changing color content or
|
|
not. The rgb content is scaled from 0 to 1000. Initially RED color is defined
|
|
with content 1000(r), 0(g), 0(b). </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="COLORCONTENT"
|
|
>10.3. Color Content</A
|
|
></H3
|
|
><P
|
|
>The functions <TT
|
|
CLASS="LITERAL"
|
|
>color_content()</TT
|
|
> and
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>pair_content()</TT
|
|
> can be used to find the color
|
|
content and foreground, background combination for the pair. </P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="KEYS"
|
|
>11. Interfacing with the key board</A
|
|
></H2
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="KEYSBASICS"
|
|
>11.1. The Basics</A
|
|
></H3
|
|
><P
|
|
>No GUI is complete without a strong user interface and to interact with the
|
|
user, a curses program should be sensitive to key presses or the mouse actions
|
|
done by the user. Let's deal with the keys first.</P
|
|
><P
|
|
>As you have seen in almost all of the above examples, it's very easy to get key
|
|
input from the user. A simple way of getting key presses is to use
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getch()</TT
|
|
> function. The cbreak mode should be
|
|
enabled to read keys when you are interested in reading individual key hits
|
|
rather than complete lines of text (which usually end with a carriage return).
|
|
keypad should be enabled to get the Functions keys, arrow keys etc. See the
|
|
initialization section for details.</P
|
|
><P
|
|
><TT
|
|
CLASS="LITERAL"
|
|
>getch()</TT
|
|
> returns an integer corresponding to the
|
|
key pressed. If it is a normal character, the integer value will be equivalent
|
|
to the character. Otherwise it returns a number which can be matched with the
|
|
constants defined in <TT
|
|
CLASS="LITERAL"
|
|
>curses.h</TT
|
|
>. For example if
|
|
the user presses F1, the integer returned is 265. This can be checked using the
|
|
macro KEY_F() defined in curses.h. This makes reading keys portable and easy to
|
|
manage.</P
|
|
><P
|
|
>For example, if you call getch() like this</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> int ch;
|
|
|
|
ch = getch();</PRE
|
|
><P
|
|
>getch() will wait for the user to press a key, (unless you specified a timeout)
|
|
and when user presses a key, the corresponding integer is returned. Then you can
|
|
check the value returned with the constants defined in curses.h to match against
|
|
the keys you want.</P
|
|
><P
|
|
>The following code piece will do that job.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> if(ch == KEY_LEFT)
|
|
printw("Left arrow is pressed\n");</PRE
|
|
><P
|
|
>Let's write a small program which creates a menu which can be navigated by up
|
|
and down arrows.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="SIMPLEKEYEX"
|
|
>11.2. A Simple Key Usage example</A
|
|
></H3
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BSIKE"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 10. A Simple Key Usage example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <stdio.h>
|
|
#include <ncurses.h>
|
|
|
|
#define WIDTH 30
|
|
#define HEIGHT 10
|
|
|
|
int startx = 0;
|
|
int starty = 0;
|
|
|
|
char *choices[] = {
|
|
"Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Exit",
|
|
};
|
|
int n_choices = sizeof(choices) / sizeof(char *);
|
|
void print_menu(WINDOW *menu_win, int highlight);
|
|
|
|
int main()
|
|
{ WINDOW *menu_win;
|
|
int highlight = 1;
|
|
int choice = 0;
|
|
int c;
|
|
|
|
initscr();
|
|
clear();
|
|
noecho();
|
|
cbreak(); /* Line buffering disabled. pass on everything */
|
|
startx = (80 - WIDTH) / 2;
|
|
starty = (24 - HEIGHT) / 2;
|
|
|
|
menu_win = newwin(HEIGHT, WIDTH, starty, startx);
|
|
keypad(menu_win, TRUE);
|
|
mvprintw(0, 0, "Use arrow keys to go up and down, Press enter to select a choice");
|
|
refresh();
|
|
print_menu(menu_win, highlight);
|
|
while(1)
|
|
{ c = wgetch(menu_win);
|
|
switch(c)
|
|
{ case KEY_UP:
|
|
if(highlight == 1)
|
|
highlight = n_choices;
|
|
else
|
|
--highlight;
|
|
break;
|
|
case KEY_DOWN:
|
|
if(highlight == n_choices)
|
|
highlight = 1;
|
|
else
|
|
++highlight;
|
|
break;
|
|
case 10:
|
|
choice = highlight;
|
|
break;
|
|
default:
|
|
mvprintw(24, 0, "Charcter pressed is = %3d Hopefully it can be printed as '%c'", c, c);
|
|
refresh();
|
|
break;
|
|
}
|
|
print_menu(menu_win, highlight);
|
|
if(choice != 0) /* User did a choice come out of the infinite loop */
|
|
break;
|
|
}
|
|
mvprintw(23, 0, "You chose choice %d with choice string %s\n", choice, choices[choice - 1]);
|
|
clrtoeol();
|
|
refresh();
|
|
endwin();
|
|
return 0;
|
|
}
|
|
|
|
|
|
void print_menu(WINDOW *menu_win, int highlight)
|
|
{
|
|
int x, y, i;
|
|
|
|
x = 2;
|
|
y = 2;
|
|
box(menu_win, 0, 0);
|
|
for(i = 0; i < n_choices; ++i)
|
|
{ if(highlight == i + 1) /* High light the present choice */
|
|
{ wattron(menu_win, A_REVERSE);
|
|
mvwprintw(menu_win, y, x, "%s", choices[i]);
|
|
wattroff(menu_win, A_REVERSE);
|
|
}
|
|
else
|
|
mvwprintw(menu_win, y, x, "%s", choices[i]);
|
|
++y;
|
|
}
|
|
wrefresh(menu_win);
|
|
}
|
|
</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="MOUSE"
|
|
>12. Interfacing with the mouse</A
|
|
></H2
|
|
><P
|
|
>Now that you have seen how to get keys, lets do the same thing from mouse.
|
|
Usually each UI allows the user to interact with both keyboard and mouse. </P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MOUSEBASICS"
|
|
>12.1. The Basics</A
|
|
></H3
|
|
><P
|
|
>Before you do any thing else, the events you want to receive have to be enabled
|
|
with <TT
|
|
CLASS="LITERAL"
|
|
>mousemask()</TT
|
|
>.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> mousemask( mmask_t newmask, /* The events you want to listen to */
|
|
mmask_t *oldmask) /* The old events mask */</PRE
|
|
><P
|
|
>The first parameter to above function is a bit mask of events you would like to
|
|
listen. By default, all the events are turned off. The bit mask <TT
|
|
CLASS="LITERAL"
|
|
> ALL_MOUSE_EVENTS</TT
|
|
> can be used to get all the events.</P
|
|
><P
|
|
>The following are all the event masks:</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> Name Description
|
|
---------------------------------------------------------------------
|
|
BUTTON1_PRESSED mouse button 1 down
|
|
BUTTON1_RELEASED mouse button 1 up
|
|
BUTTON1_CLICKED mouse button 1 clicked
|
|
BUTTON1_DOUBLE_CLICKED mouse button 1 double clicked
|
|
BUTTON1_TRIPLE_CLICKED mouse button 1 triple clicked
|
|
BUTTON2_PRESSED mouse button 2 down
|
|
BUTTON2_RELEASED mouse button 2 up
|
|
BUTTON2_CLICKED mouse button 2 clicked
|
|
BUTTON2_DOUBLE_CLICKED mouse button 2 double clicked
|
|
BUTTON2_TRIPLE_CLICKED mouse button 2 triple clicked
|
|
BUTTON3_PRESSED mouse button 3 down
|
|
BUTTON3_RELEASED mouse button 3 up
|
|
BUTTON3_CLICKED mouse button 3 clicked
|
|
BUTTON3_DOUBLE_CLICKED mouse button 3 double clicked
|
|
BUTTON3_TRIPLE_CLICKED mouse button 3 triple clicked
|
|
BUTTON4_PRESSED mouse button 4 down
|
|
BUTTON4_RELEASED mouse button 4 up
|
|
BUTTON4_CLICKED mouse button 4 clicked
|
|
BUTTON4_DOUBLE_CLICKED mouse button 4 double clicked
|
|
BUTTON4_TRIPLE_CLICKED mouse button 4 triple clicked
|
|
BUTTON_SHIFT shift was down during button state change
|
|
BUTTON_CTRL control was down during button state change
|
|
BUTTON_ALT alt was down during button state change
|
|
ALL_MOUSE_EVENTS report all button state changes
|
|
REPORT_MOUSE_POSITION report mouse movement</PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="GETTINGEVENTS"
|
|
>12.2. Getting the events</A
|
|
></H3
|
|
><P
|
|
>Once a class of mouse events have been enabled, getch() class of functions
|
|
return KEY_MOUSE every time some mouse event happens. Then the mouse event can
|
|
be retrieved with <TT
|
|
CLASS="LITERAL"
|
|
>getmouse()</TT
|
|
>.</P
|
|
><P
|
|
>The code approximately looks like this:</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> MEVENT event;
|
|
|
|
ch = getch();
|
|
if(ch == KEY_MOUSE)
|
|
if(getmouse(&event) == OK)
|
|
. /* Do some thing with the event */
|
|
.
|
|
.</PRE
|
|
><P
|
|
>
|
|
getmouse() returns the event into the pointer given to it. It's a structure
|
|
which contains</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> typedef struct
|
|
{
|
|
short id; /* ID to distinguish multiple devices */
|
|
int x, y, z; /* event coordinates */
|
|
mmask_t bstate; /* button state bits */
|
|
} </PRE
|
|
><P
|
|
>The <TT
|
|
CLASS="LITERAL"
|
|
>bstate</TT
|
|
> is the main variable we are
|
|
interested in. It tells the button state of the mouse.</P
|
|
><P
|
|
>Then with a code snippet like the following, we can find out what happened.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> if(event.bstate & BUTTON1_PRESSED)
|
|
printw("Left Button Pressed");</PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MOUSETOGETHER"
|
|
>12.3. Putting it all Together</A
|
|
></H3
|
|
><P
|
|
>That's pretty much interfacing with mouse. Let's create the same menu and enable
|
|
mouse interaction. To make things simpler, key handling is removed.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BMOME"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 11. Access the menu with mouse !!! </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
#define WIDTH 30
|
|
#define HEIGHT 10
|
|
|
|
int startx = 0;
|
|
int starty = 0;
|
|
|
|
char *choices[] = { "Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Exit",
|
|
};
|
|
|
|
int n_choices = sizeof(choices) / sizeof(char *);
|
|
|
|
void print_menu(WINDOW *menu_win, int highlight);
|
|
void report_choice(int mouse_x, int mouse_y, int *p_choice);
|
|
|
|
int main()
|
|
{ int c, choice = 0;
|
|
WINDOW *menu_win;
|
|
MEVENT event;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
clear();
|
|
noecho();
|
|
cbreak(); //Line buffering disabled. pass on everything
|
|
|
|
/* Try to put the window in the middle of screen */
|
|
startx = (80 - WIDTH) / 2;
|
|
starty = (24 - HEIGHT) / 2;
|
|
|
|
attron(A_REVERSE);
|
|
mvprintw(23, 1, "Click on Exit to quit (Works best in a virtual console)");
|
|
refresh();
|
|
attroff(A_REVERSE);
|
|
|
|
/* Print the menu for the first time */
|
|
menu_win = newwin(HEIGHT, WIDTH, starty, startx);
|
|
print_menu(menu_win, 1);
|
|
/* Get all the mouse events */
|
|
mousemask(ALL_MOUSE_EVENTS, NULL);
|
|
|
|
while(1)
|
|
{ c = wgetch(menu_win);
|
|
switch(c)
|
|
{ case KEY_MOUSE:
|
|
if(getmouse(&event) == OK)
|
|
{ /* When the user clicks left mouse button */
|
|
if(event.bstate & BUTTON1_PRESSED)
|
|
{ report_choice(event.x + 1, event.y + 1, &choice);
|
|
if(choice == -1) //Exit chosen
|
|
goto end;
|
|
mvprintw(22, 1, "Choice made is : %d String Chosen is \"%10s\"", choice, choices[choice - 1]);
|
|
refresh();
|
|
}
|
|
}
|
|
print_menu(menu_win, choice);
|
|
break;
|
|
}
|
|
}
|
|
end:
|
|
endwin();
|
|
return 0;
|
|
}
|
|
|
|
|
|
void print_menu(WINDOW *menu_win, int highlight)
|
|
{
|
|
int x, y, i;
|
|
|
|
x = 2;
|
|
y = 2;
|
|
box(menu_win, 0, 0);
|
|
for(i = 0; i < n_choices; ++i)
|
|
{ if(highlight == i + 1)
|
|
{ wattron(menu_win, A_REVERSE);
|
|
mvwprintw(menu_win, y, x, "%s", choices[i]);
|
|
wattroff(menu_win, A_REVERSE);
|
|
}
|
|
else
|
|
mvwprintw(menu_win, y, x, "%s", choices[i]);
|
|
++y;
|
|
}
|
|
wrefresh(menu_win);
|
|
}
|
|
|
|
/* Report the choice according to mouse position */
|
|
void report_choice(int mouse_x, int mouse_y, int *p_choice)
|
|
{ int i,j, choice;
|
|
|
|
i = startx + 2;
|
|
j = starty + 3;
|
|
|
|
for(choice = 0; choice < n_choices; ++choice)
|
|
if(mouse_y == j + choice && mouse_x >= i && mouse_x <= i + strlen(choices[choice]))
|
|
{ if(choice == n_choices - 1)
|
|
*p_choice = -1;
|
|
else
|
|
*p_choice = choice + 1;
|
|
break;
|
|
}
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MISCMOUSEFUNCS"
|
|
>12.4. Miscellaneous Functions</A
|
|
></H3
|
|
><P
|
|
>The functions mouse_trafo() and wmouse_trafo() can be used to convert to mouse
|
|
co-ordinates to screen relative co-ordinates. See curs_mouse(3X) man page for details.</P
|
|
><P
|
|
>The mouseinterval function sets the maximum time (in thousands of a
|
|
second) that can elapse between press and release events in order for
|
|
them to be recognized as a click. This function returns the previous
|
|
interval value. The default is one fifth of a second.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="SCREEN"
|
|
>13. Screen Manipulation</A
|
|
></H2
|
|
><P
|
|
>In this section, we will look into some functions, which allow us to manage the
|
|
screen efficiently and to write some fancy programs. This is especially
|
|
important in writing games. </P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="GETYX"
|
|
>13.1. getyx() functions</A
|
|
></H3
|
|
><P
|
|
> The function <TT
|
|
CLASS="LITERAL"
|
|
>getyx()</TT
|
|
> can be used to find out
|
|
the present cursor co-ordinates. It will fill the values of x and y co-ordinates
|
|
in the arguments given to it. Since getyx() is a macro you don't have to pass
|
|
the address of the variables. It can be called as</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> getyx(win, y, x);
|
|
/* win: window pointer
|
|
* y, x: y, x co-ordinates will be put into this variables
|
|
*/</PRE
|
|
><P
|
|
>The function getparyx() gets the beginning co-ordinates of the sub window
|
|
relative to the main window. This is some times useful to update a sub window.
|
|
When designing fancy stuff like writing multiple menus, it becomes difficult to
|
|
store the menu positions, their first option co-ordinates etc. A simple solution
|
|
to this problem, is to create menus in sub windows and later find the starting
|
|
co-ordinates of the menus by using getparyx().</P
|
|
><P
|
|
>The functions getbegyx() and getmaxyx() store current window's beginning and
|
|
maximum co-ordinates. These functions are useful in the same way as above in
|
|
managing the windows and sub windows effectively.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="SCREENDUMP"
|
|
>13.2. Screen Dumping</A
|
|
></H3
|
|
><P
|
|
>While writing games, some times it becomes necessary to store the state of the
|
|
screen and restore it back to the same state. The function scr_dump() can be
|
|
used to dump the screen contents to a file given as an argument. Later it can be
|
|
restored by scr_restore function. These two simple functions can be used
|
|
effectively to maintain a fast moving game with changing scenarios. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="WINDOWDUMP"
|
|
>13.3. Window Dumping</A
|
|
></H3
|
|
><P
|
|
>To store and restore windows, the functions
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>putwin()</TT
|
|
> and <TT
|
|
CLASS="LITERAL"
|
|
>getwin()</TT
|
|
> can be used. <TT
|
|
CLASS="LITERAL"
|
|
>putwin()</TT
|
|
> puts
|
|
the present window state into a file, which can be later restored by
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>getwin()</TT
|
|
>.</P
|
|
><P
|
|
>
|
|
The function <TT
|
|
CLASS="LITERAL"
|
|
>copywin()</TT
|
|
> can be used to copy a
|
|
window completely onto another window. It takes the source and destination
|
|
windows as parameters and according to the rectangle specified, it copies the
|
|
rectangular region from source to destination window. It's last parameter
|
|
specifies whether to overwrite or just overlay the contents on to the
|
|
destination window. If this argument is true, then the copying is
|
|
non-destructive.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="MISC"
|
|
>14. Miscellaneous features</A
|
|
></H2
|
|
><P
|
|
>Now you know enough features to write a good curses program, with all bells and
|
|
whistles. There are some miscellaneous functions which are useful in various
|
|
cases. Let's go headlong into some of those.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="CURSSET"
|
|
>14.1. curs_set()</A
|
|
></H3
|
|
><P
|
|
>This function can be used to make the cursor invisible. The parameter to this
|
|
function should be </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> 0 : invisible or
|
|
1 : normal or
|
|
2 : very visible.</PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="TEMPLEAVE"
|
|
>14.2. Temporarily Leaving Curses mode</A
|
|
></H3
|
|
><P
|
|
>Some times you may want to get back to cooked mode (normal line buffering mode)
|
|
temporarily. In such a case you will first need to save the tty modes with a
|
|
call to <TT
|
|
CLASS="LITERAL"
|
|
>def_prog_mode()</TT
|
|
> and then call
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>endwin()</TT
|
|
> to end the curses mode. This will
|
|
leave you in the original tty mode. To get back to curses once you are done,
|
|
call <TT
|
|
CLASS="LITERAL"
|
|
>reset_prog_mode() </TT
|
|
>. This function returns
|
|
the tty to the state stored by <TT
|
|
CLASS="LITERAL"
|
|
>def_prog_mode()</TT
|
|
>. Then do refresh(), and you are back to the curses mode. Here
|
|
is an example showing the sequence of things to be done.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BTELE"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 12. Temporarily Leaving Curses Mode </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
int main()
|
|
{
|
|
initscr(); /* Start curses mode */
|
|
printw("Hello World !!!\n"); /* Print Hello World */
|
|
refresh(); /* Print it on to the real screen */
|
|
def_prog_mode(); /* Save the tty modes */
|
|
endwin(); /* End curses mode temporarily */
|
|
system("/bin/sh"); /* Do whatever you like in cooked mode */
|
|
reset_prog_mode(); /* Return to the previous tty mode*/
|
|
/* stored by def_prog_mode() */
|
|
refresh(); /* Do refresh() to restore the */
|
|
/* Screen contents */
|
|
printw("Another String\n"); /* Back to curses use the full */
|
|
refresh(); /* capabilities of curses */
|
|
endwin(); /* End curses mode */
|
|
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="ACSVARS"
|
|
>14.3. ACS_ variables</A
|
|
></H3
|
|
><P
|
|
>If you have ever programmed in DOS, you know about those nifty characters in
|
|
extended character set. They are printable only on some terminals. NCURSES
|
|
functions like <TT
|
|
CLASS="LITERAL"
|
|
>box()</TT
|
|
> use these characters. All
|
|
these variables start with ACS meaning alternative character set. You might have
|
|
noticed me using these characters in some of the programs above. Here's an example
|
|
showing all the characters.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="BACSVARS"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 13. ACS Variables Example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <ncurses.h>
|
|
|
|
int main()
|
|
{
|
|
initscr();
|
|
|
|
printw("Upper left corner "); addch(ACS_ULCORNER); printw("\n");
|
|
printw("Lower left corner "); addch(ACS_LLCORNER); printw("\n");
|
|
printw("Lower right corner "); addch(ACS_LRCORNER); printw("\n");
|
|
printw("Tee pointing right "); addch(ACS_LTEE); printw("\n");
|
|
printw("Tee pointing left "); addch(ACS_RTEE); printw("\n");
|
|
printw("Tee pointing up "); addch(ACS_BTEE); printw("\n");
|
|
printw("Tee pointing down "); addch(ACS_TTEE); printw("\n");
|
|
printw("Horizontal line "); addch(ACS_HLINE); printw("\n");
|
|
printw("Vertical line "); addch(ACS_VLINE); printw("\n");
|
|
printw("Large Plus or cross over "); addch(ACS_PLUS); printw("\n");
|
|
printw("Scan Line 1 "); addch(ACS_S1); printw("\n");
|
|
printw("Scan Line 3 "); addch(ACS_S3); printw("\n");
|
|
printw("Scan Line 7 "); addch(ACS_S7); printw("\n");
|
|
printw("Scan Line 9 "); addch(ACS_S9); printw("\n");
|
|
printw("Diamond "); addch(ACS_DIAMOND); printw("\n");
|
|
printw("Checker board (stipple) "); addch(ACS_CKBOARD); printw("\n");
|
|
printw("Degree Symbol "); addch(ACS_DEGREE); printw("\n");
|
|
printw("Plus/Minus Symbol "); addch(ACS_PLMINUS); printw("\n");
|
|
printw("Bullet "); addch(ACS_BULLET); printw("\n");
|
|
printw("Arrow Pointing Left "); addch(ACS_LARROW); printw("\n");
|
|
printw("Arrow Pointing Right "); addch(ACS_RARROW); printw("\n");
|
|
printw("Arrow Pointing Down "); addch(ACS_DARROW); printw("\n");
|
|
printw("Arrow Pointing Up "); addch(ACS_UARROW); printw("\n");
|
|
printw("Board of squares "); addch(ACS_BOARD); printw("\n");
|
|
printw("Lantern Symbol "); addch(ACS_LANTERN); printw("\n");
|
|
printw("Solid Square Block "); addch(ACS_BLOCK); printw("\n");
|
|
printw("Less/Equal sign "); addch(ACS_LEQUAL); printw("\n");
|
|
printw("Greater/Equal sign "); addch(ACS_GEQUAL); printw("\n");
|
|
printw("Pi "); addch(ACS_PI); printw("\n");
|
|
printw("Not equal "); addch(ACS_NEQUAL); printw("\n");
|
|
printw("UK pound sign "); addch(ACS_STERLING); printw("\n");
|
|
|
|
refresh();
|
|
getch();
|
|
endwin();
|
|
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="OTHERLIB"
|
|
>15. Other libraries</A
|
|
></H2
|
|
><P
|
|
>Apart from the curses library, there are few text mode libraries, which provide
|
|
more functionality and a lot of features. The following sections explain three
|
|
standard libraries which are usually distributed along with curses. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="PANELS"
|
|
>16. Panel Library</A
|
|
></H2
|
|
><P
|
|
>Now that you are proficient in curses, you wanted to do some thing big. You
|
|
created a lot of overlapping windows to give a professional windows-type look.
|
|
Unfortunately, it soon becomes difficult to manage these. The multiple
|
|
refreshes, updates plunge you into a nightmare. The overlapping windows create
|
|
blotches, whenever you forget to refresh the windows in the proper order. </P
|
|
><P
|
|
>Don't despair. There's an elegant solution provided in panels library. In the
|
|
words of developers of ncurses </P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>When your interface design is such that windows may dive deeper into the
|
|
visibility stack or pop to the top at runtime, the resulting book-keeping can be
|
|
tedious and difficult to get right. Hence the panels library.</I
|
|
></SPAN
|
|
></P
|
|
><P
|
|
>If you have lot of overlapping windows, then panels library is the way to go. It
|
|
obviates the need of doing series of wnoutrefresh(), doupdate() and relieves the
|
|
burden of doing it correctly(bottom up). The library maintains information about
|
|
the order of windows, their overlapping and update the screen properly. So why
|
|
wait? Let's take a close peek into panels.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PANELBASICS"
|
|
>16.1. The Basics</A
|
|
></H3
|
|
><P
|
|
>Panel object is a window that is implicitly treated as part of a deck including
|
|
all other panel objects. The deck is treated as a stack with the top panel being
|
|
completely visible and the other panels may or may not be obscured according to
|
|
their positions. So the basic idea is to create a stack of overlapping panels
|
|
and use panels library to display them correctly. There is a function similar to
|
|
refresh() which, when called , displays panels in the correct order. Functions
|
|
are provided to hide or show panels, move panels, change its size etc.. The
|
|
overlapping problem is managed by the panels library during all the calls to
|
|
these functions. </P
|
|
><P
|
|
>The general flow of a panel program goes like this:
|
|
|
|
<P
|
|
></P
|
|
><OL
|
|
TYPE="1"
|
|
><LI
|
|
><P
|
|
>Create the windows (with newwin()) to be attached to the panels.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Create panels with the chosen visibility order. Stack them up according to the
|
|
desired visibility. The function new_panel() is used to created panels.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Call update_panels() to write the panels to the virtual screen in correct
|
|
visibility order. Do a doupdate() to show it on the screen. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Mainpulate the panels with show_panel(), hide_panel(), move_panel() etc. Make
|
|
use of helper functions like panel_hidden() and panel_window(). Make use of user
|
|
pointer to store custom data for a panel. Use the functions set_panel_userptr()
|
|
and panel_userptr() to set and get the user pointer for a panel.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>When you are done with the panel use del_panel() to delete the panel.</P
|
|
></LI
|
|
></OL
|
|
></P
|
|
><P
|
|
>Let's make the concepts clear, with some programs. The following is a simple
|
|
program which creates 3 overlapping panels and shows them on the screen. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="COMPILEPANELS"
|
|
>16.2. Compiling With the Panels Library</A
|
|
></H3
|
|
><P
|
|
>To use panels library functions, you have to include panel.h and to link the
|
|
program with panels library the flag -lpanel should be added along with
|
|
-lncurses in that order.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> #include <panel.h>
|
|
.
|
|
.
|
|
.
|
|
|
|
compile and link: gcc <program file> -lpanel -lncurses</PRE
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="PPASI"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 14. Panel basics</B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <panel.h>
|
|
|
|
int main()
|
|
{ WINDOW *my_wins[3];
|
|
PANEL *my_panels[3];
|
|
int lines = 10, cols = 40, y = 2, x = 4, i;
|
|
|
|
initscr();
|
|
cbreak();
|
|
noecho();
|
|
|
|
/* Create windows for the panels */
|
|
my_wins[0] = newwin(lines, cols, y, x);
|
|
my_wins[1] = newwin(lines, cols, y + 1, x + 5);
|
|
my_wins[2] = newwin(lines, cols, y + 2, x + 10);
|
|
|
|
/*
|
|
* Create borders around the windows so that you can see the effect
|
|
* of panels
|
|
*/
|
|
for(i = 0; i < 3; ++i)
|
|
box(my_wins[i], 0, 0);
|
|
|
|
/* Attach a panel to each window */ /* Order is bottom up */
|
|
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
|
|
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
|
|
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
|
|
|
|
/* Update the stacking order. 2nd panel will be on top */
|
|
update_panels();
|
|
|
|
/* Show it on the screen */
|
|
doupdate();
|
|
|
|
getch();
|
|
endwin();
|
|
}
|
|
</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>As you can see, above program follows a simple flow as explained. The windows
|
|
are created with newwin() and then they are attached to panels with new_panel().
|
|
As we attach one panel after another, the stack of panels gets updated. To put
|
|
them on screen update_panels() and doupdate() are called.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PANELBROWSING"
|
|
>16.3. Panel Window Browsing</A
|
|
></H3
|
|
><P
|
|
>A slightly complicated example is given below. This program creates 3
|
|
windows which can be cycled through using tab. Have a look at the code.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="PPABR"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 15. Panel Window Browsing Example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <panel.h>
|
|
|
|
#define NLINES 10
|
|
#define NCOLS 40
|
|
|
|
void init_wins(WINDOW **wins, int n);
|
|
void win_show(WINDOW *win, char *label, int label_color);
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
|
|
|
|
int main()
|
|
{ WINDOW *my_wins[3];
|
|
PANEL *my_panels[3];
|
|
PANEL *top;
|
|
int ch;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize all the colors */
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
init_pair(2, COLOR_GREEN, COLOR_BLACK);
|
|
init_pair(3, COLOR_BLUE, COLOR_BLACK);
|
|
init_pair(4, COLOR_CYAN, COLOR_BLACK);
|
|
|
|
init_wins(my_wins, 3);
|
|
|
|
/* Attach a panel to each window */ /* Order is bottom up */
|
|
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
|
|
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
|
|
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
|
|
|
|
/* Set up the user pointers to the next panel */
|
|
set_panel_userptr(my_panels[0], my_panels[1]);
|
|
set_panel_userptr(my_panels[1], my_panels[2]);
|
|
set_panel_userptr(my_panels[2], my_panels[0]);
|
|
|
|
/* Update the stacking order. 2nd panel will be on top */
|
|
update_panels();
|
|
|
|
/* Show it on the screen */
|
|
attron(COLOR_PAIR(4));
|
|
mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
|
|
attroff(COLOR_PAIR(4));
|
|
doupdate();
|
|
|
|
top = my_panels[2];
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case 9:
|
|
top = (PANEL *)panel_userptr(top);
|
|
top_panel(top);
|
|
break;
|
|
}
|
|
update_panels();
|
|
doupdate();
|
|
}
|
|
endwin();
|
|
return 0;
|
|
}
|
|
|
|
/* Put all the windows */
|
|
void init_wins(WINDOW **wins, int n)
|
|
{ int x, y, i;
|
|
char label[80];
|
|
|
|
y = 2;
|
|
x = 10;
|
|
for(i = 0; i < n; ++i)
|
|
{ wins[i] = newwin(NLINES, NCOLS, y, x);
|
|
sprintf(label, "Window Number %d", i + 1);
|
|
win_show(wins[i], label, i + 1);
|
|
y += 3;
|
|
x += 7;
|
|
}
|
|
}
|
|
|
|
/* Show the window with a border and a label */
|
|
void win_show(WINDOW *win, char *label, int label_color)
|
|
{ int startx, starty, height, width;
|
|
|
|
getbegyx(win, starty, startx);
|
|
getmaxyx(win, height, width);
|
|
|
|
box(win, 0, 0);
|
|
mvwaddch(win, 2, 0, ACS_LTEE);
|
|
mvwhline(win, 2, 1, ACS_HLINE, width - 2);
|
|
mvwaddch(win, 2, width - 1, ACS_RTEE);
|
|
|
|
print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
|
|
}
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
|
|
{ int length, x, y;
|
|
float temp;
|
|
|
|
if(win == NULL)
|
|
win = stdscr;
|
|
getyx(win, y, x);
|
|
if(startx != 0)
|
|
x = startx;
|
|
if(starty != 0)
|
|
y = starty;
|
|
if(width == 0)
|
|
width = 80;
|
|
|
|
length = strlen(string);
|
|
temp = (width - length)/ 2;
|
|
x = startx + (int)temp;
|
|
wattron(win, color);
|
|
mvwprintw(win, y, x, "%s", string);
|
|
wattroff(win, color);
|
|
refresh();
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="USERPTRUSING"
|
|
>16.4. Using User Pointers</A
|
|
></H3
|
|
><P
|
|
>In the above example I used user pointers to find out the next window in the
|
|
cycle. We can attach custom information to the panel by specifying a user
|
|
pointer, which can point to any information you want to store. In this case I
|
|
stored the pointer to the next panel in the cycle. User pointer for a panel can
|
|
be set with the function <TT
|
|
CLASS="LITERAL"
|
|
> set_panel_userptr()</TT
|
|
>.
|
|
It can be accessed using the function <TT
|
|
CLASS="LITERAL"
|
|
>panel_userptr()</TT
|
|
> which will return the user pointer for the panel given as
|
|
argument. After finding the next panel in the cycle It's brought to the top by
|
|
the function top_panel(). This function brings the panel given as argument to
|
|
the top of the panel stack. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PANELMOVERESIZE"
|
|
>16.5. Moving and Resizing Panels</A
|
|
></H3
|
|
><P
|
|
>The function <TT
|
|
CLASS="LITERAL"
|
|
>move_panel()</TT
|
|
> can be used to move a
|
|
panel to the desired location. It does not change the position of the panel in
|
|
the stack. Make sure that you use move_panel() instead mvwin() on the window
|
|
associated with the panel.</P
|
|
><P
|
|
>Resizing a panel is slightly complex. There is no straight forward function
|
|
just to resize the window associated with a panel. A solution to resize a panel
|
|
is to create a new window with the desired sizes, change the window associated
|
|
with the panel using replace_panel(). Don't forget to delete the old window. The
|
|
window associated with a panel can be found by using the function
|
|
panel_window().</P
|
|
><P
|
|
>The following program shows these concepts, in supposedly simple program. You
|
|
can cycle through the window with <TAB> as usual. To resize or move the
|
|
active panel press 'r' for resize 'm' for moving. Then use arrow keys to resize
|
|
or move it to the desired way and press enter to end your resizing or moving.
|
|
This example makes use of user data to get the required data to do the
|
|
operations. </P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="PPARE"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 16. Panel Moving and Resizing example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <panel.h>
|
|
|
|
typedef struct _PANEL_DATA {
|
|
int x, y, w, h;
|
|
char label[80];
|
|
int label_color;
|
|
PANEL *next;
|
|
}PANEL_DATA;
|
|
|
|
#define NLINES 10
|
|
#define NCOLS 40
|
|
|
|
void init_wins(WINDOW **wins, int n);
|
|
void win_show(WINDOW *win, char *label, int label_color);
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
|
|
void set_user_ptrs(PANEL **panels, int n);
|
|
|
|
int main()
|
|
{ WINDOW *my_wins[3];
|
|
PANEL *my_panels[3];
|
|
PANEL_DATA *top;
|
|
PANEL *stack_top;
|
|
WINDOW *temp_win, *old_win;
|
|
int ch;
|
|
int newx, newy, neww, newh;
|
|
int size = FALSE, move = FALSE;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize all the colors */
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
init_pair(2, COLOR_GREEN, COLOR_BLACK);
|
|
init_pair(3, COLOR_BLUE, COLOR_BLACK);
|
|
init_pair(4, COLOR_CYAN, COLOR_BLACK);
|
|
|
|
init_wins(my_wins, 3);
|
|
|
|
/* Attach a panel to each window */ /* Order is bottom up */
|
|
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
|
|
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
|
|
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
|
|
|
|
set_user_ptrs(my_panels, 3);
|
|
/* Update the stacking order. 2nd panel will be on top */
|
|
update_panels();
|
|
|
|
/* Show it on the screen */
|
|
attron(COLOR_PAIR(4));
|
|
mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
|
|
mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
|
|
attroff(COLOR_PAIR(4));
|
|
doupdate();
|
|
|
|
stack_top = my_panels[2];
|
|
top = (PANEL_DATA *)panel_userptr(stack_top);
|
|
newx = top->x;
|
|
newy = top->y;
|
|
neww = top->w;
|
|
newh = top->h;
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case 9: /* Tab */
|
|
top = (PANEL_DATA *)panel_userptr(stack_top);
|
|
top_panel(top->next);
|
|
stack_top = top->next;
|
|
top = (PANEL_DATA *)panel_userptr(stack_top);
|
|
newx = top->x;
|
|
newy = top->y;
|
|
neww = top->w;
|
|
newh = top->h;
|
|
break;
|
|
case 'r': /* Re-Size*/
|
|
size = TRUE;
|
|
attron(COLOR_PAIR(4));
|
|
mvprintw(LINES - 4, 0, "Entered Resizing :Use Arrow Keys to resize and press <ENTER> to end resizing");
|
|
refresh();
|
|
attroff(COLOR_PAIR(4));
|
|
break;
|
|
case 'm': /* Move */
|
|
attron(COLOR_PAIR(4));
|
|
mvprintw(LINES - 4, 0, "Entered Moving: Use Arrow Keys to Move and press <ENTER> to end moving");
|
|
refresh();
|
|
attroff(COLOR_PAIR(4));
|
|
move = TRUE;
|
|
break;
|
|
case KEY_LEFT:
|
|
if(size == TRUE)
|
|
{ --newx;
|
|
++neww;
|
|
}
|
|
if(move == TRUE)
|
|
--newx;
|
|
break;
|
|
case KEY_RIGHT:
|
|
if(size == TRUE)
|
|
{ ++newx;
|
|
--neww;
|
|
}
|
|
if(move == TRUE)
|
|
++newx;
|
|
break;
|
|
case KEY_UP:
|
|
if(size == TRUE)
|
|
{ --newy;
|
|
++newh;
|
|
}
|
|
if(move == TRUE)
|
|
--newy;
|
|
break;
|
|
case KEY_DOWN:
|
|
if(size == TRUE)
|
|
{ ++newy;
|
|
--newh;
|
|
}
|
|
if(move == TRUE)
|
|
++newy;
|
|
break;
|
|
case 10: /* Enter */
|
|
move(LINES - 4, 0);
|
|
clrtoeol();
|
|
refresh();
|
|
if(size == TRUE)
|
|
{ old_win = panel_window(stack_top);
|
|
temp_win = newwin(newh, neww, newy, newx);
|
|
replace_panel(stack_top, temp_win);
|
|
win_show(temp_win, top->label, top->label_color);
|
|
delwin(old_win);
|
|
size = FALSE;
|
|
}
|
|
if(move == TRUE)
|
|
{ move_panel(stack_top, newy, newx);
|
|
move = FALSE;
|
|
}
|
|
break;
|
|
|
|
}
|
|
attron(COLOR_PAIR(4));
|
|
mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
|
|
mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
|
|
attroff(COLOR_PAIR(4));
|
|
refresh();
|
|
update_panels();
|
|
doupdate();
|
|
}
|
|
endwin();
|
|
return 0;
|
|
}
|
|
|
|
/* Put all the windows */
|
|
void init_wins(WINDOW **wins, int n)
|
|
{ int x, y, i;
|
|
char label[80];
|
|
|
|
y = 2;
|
|
x = 10;
|
|
for(i = 0; i < n; ++i)
|
|
{ wins[i] = newwin(NLINES, NCOLS, y, x);
|
|
sprintf(label, "Window Number %d", i + 1);
|
|
win_show(wins[i], label, i + 1);
|
|
y += 3;
|
|
x += 7;
|
|
}
|
|
}
|
|
|
|
/* Set the PANEL_DATA structures for individual panels */
|
|
void set_user_ptrs(PANEL **panels, int n)
|
|
{ PANEL_DATA *ptrs;
|
|
WINDOW *win;
|
|
int x, y, w, h, i;
|
|
char temp[80];
|
|
|
|
ptrs = (PANEL_DATA *)calloc(n, sizeof(PANEL_DATA));
|
|
|
|
for(i = 0;i < n; ++i)
|
|
{ win = panel_window(panels[i]);
|
|
getbegyx(win, y, x);
|
|
getmaxyx(win, h, w);
|
|
ptrs[i].x = x;
|
|
ptrs[i].y = y;
|
|
ptrs[i].w = w;
|
|
ptrs[i].h = h;
|
|
sprintf(temp, "Window Number %d", i + 1);
|
|
strcpy(ptrs[i].label, temp);
|
|
ptrs[i].label_color = i + 1;
|
|
if(i + 1 == n)
|
|
ptrs[i].next = panels[0];
|
|
else
|
|
ptrs[i].next = panels[i + 1];
|
|
set_panel_userptr(panels[i], &ptrs[i]);
|
|
}
|
|
}
|
|
|
|
/* Show the window with a border and a label */
|
|
void win_show(WINDOW *win, char *label, int label_color)
|
|
{ int startx, starty, height, width;
|
|
|
|
getbegyx(win, starty, startx);
|
|
getmaxyx(win, height, width);
|
|
|
|
box(win, 0, 0);
|
|
mvwaddch(win, 2, 0, ACS_LTEE);
|
|
mvwhline(win, 2, 1, ACS_HLINE, width - 2);
|
|
mvwaddch(win, 2, width - 1, ACS_RTEE);
|
|
|
|
print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
|
|
}
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
|
|
{ int length, x, y;
|
|
float temp;
|
|
|
|
if(win == NULL)
|
|
win = stdscr;
|
|
getyx(win, y, x);
|
|
if(startx != 0)
|
|
x = startx;
|
|
if(starty != 0)
|
|
y = starty;
|
|
if(width == 0)
|
|
width = 80;
|
|
|
|
length = strlen(string);
|
|
temp = (width - length)/ 2;
|
|
x = startx + (int)temp;
|
|
wattron(win, color);
|
|
mvwprintw(win, y, x, "%s", string);
|
|
wattroff(win, color);
|
|
refresh();
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>Concentrate on the main while loop. Once it finds out the type of key pressed,
|
|
it takes appropriate action. If 'r' is pressed resizing mode is started. After
|
|
this the new sizes are updated as the user presses the arrow keys. When the user
|
|
presses <ENTER> present selection ends and panel is resized by using the
|
|
concept explained. While in resizing mode the program doesn't show how the
|
|
window is getting resized. It's left as an exercise to the reader to print a
|
|
dotted border while it gets resized to a new position. </P
|
|
><P
|
|
>When the user presses 'm' the move mode starts. This is a bit simpler than
|
|
resizing. As the arrow keys are pressed the new position is updated and
|
|
pressing of <ENTER> causes the panel to be moved by calling the function
|
|
move_panel().</P
|
|
><P
|
|
>In this program the user data which is represented as PANEL_DATA, plays very
|
|
important role in finding the associated information with a panel. As written in
|
|
the comments, the PANEL_DATA stores the panel sizes, label, label color and a
|
|
pointer to the next panel in the cycle.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PANELSHOWHIDE"
|
|
>16.6. Hiding and Showing Panels</A
|
|
></H3
|
|
><P
|
|
>A Panel can be hidden by using the function hide_panel(). This function merely
|
|
removes it form the stack of panels, thus hiding it on the screen once you do
|
|
update_panels() and doupdate(). It doesn't destroy the PANEL structure
|
|
associated with the hidden panel. It can be shown again by using the
|
|
show_panel() function.</P
|
|
><P
|
|
>The following program shows the hiding of panels. Press 'a' or 'b' or 'c' to
|
|
show or hide first, second and third windows respectively. It uses a user data
|
|
with a small variable hide, which keeps track of whether the window is hidden or
|
|
not. For some reason the function
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>panel_hidden()</TT
|
|
> which tells whether a panel is
|
|
hidden or not is not working. A bug report was also presented by Michael Andres
|
|
<A
|
|
HREF="http://www.geocrawler.com/archives/3/344/1999/9/0/2643549/"
|
|
TARGET="_top"
|
|
> here</A
|
|
></P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="PPAHI"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 17. Panel Hiding and Showing example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <panel.h>
|
|
|
|
typedef struct _PANEL_DATA {
|
|
int hide; /* TRUE if panel is hidden */
|
|
}PANEL_DATA;
|
|
|
|
#define NLINES 10
|
|
#define NCOLS 40
|
|
|
|
void init_wins(WINDOW **wins, int n);
|
|
void win_show(WINDOW *win, char *label, int label_color);
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
|
|
|
|
int main()
|
|
{ WINDOW *my_wins[3];
|
|
PANEL *my_panels[3];
|
|
PANEL_DATA panel_datas[3];
|
|
PANEL_DATA *temp;
|
|
int ch;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize all the colors */
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
init_pair(2, COLOR_GREEN, COLOR_BLACK);
|
|
init_pair(3, COLOR_BLUE, COLOR_BLACK);
|
|
init_pair(4, COLOR_CYAN, COLOR_BLACK);
|
|
|
|
init_wins(my_wins, 3);
|
|
|
|
/* Attach a panel to each window */ /* Order is bottom up */
|
|
my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
|
|
my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
|
|
my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
|
|
|
|
/* Initialize panel datas saying that nothing is hidden */
|
|
panel_datas[0].hide = FALSE;
|
|
panel_datas[1].hide = FALSE;
|
|
panel_datas[2].hide = FALSE;
|
|
|
|
set_panel_userptr(my_panels[0], &panel_datas[0]);
|
|
set_panel_userptr(my_panels[1], &panel_datas[1]);
|
|
set_panel_userptr(my_panels[2], &panel_datas[2]);
|
|
|
|
/* Update the stacking order. 2nd panel will be on top */
|
|
update_panels();
|
|
|
|
/* Show it on the screen */
|
|
attron(COLOR_PAIR(4));
|
|
mvprintw(LINES - 3, 0, "Show or Hide a window with 'a'(first window) 'b'(Second Window) 'c'(Third Window)");
|
|
mvprintw(LINES - 2, 0, "F1 to Exit");
|
|
|
|
attroff(COLOR_PAIR(4));
|
|
doupdate();
|
|
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case 'a':
|
|
temp = (PANEL_DATA *)panel_userptr(my_panels[0]);
|
|
if(temp->hide == FALSE)
|
|
{ hide_panel(my_panels[0]);
|
|
temp->hide = TRUE;
|
|
}
|
|
else
|
|
{ show_panel(my_panels[0]);
|
|
temp->hide = FALSE;
|
|
}
|
|
break;
|
|
case 'b':
|
|
temp = (PANEL_DATA *)panel_userptr(my_panels[1]);
|
|
if(temp->hide == FALSE)
|
|
{ hide_panel(my_panels[1]);
|
|
temp->hide = TRUE;
|
|
}
|
|
else
|
|
{ show_panel(my_panels[1]);
|
|
temp->hide = FALSE;
|
|
}
|
|
break;
|
|
case 'c':
|
|
temp = (PANEL_DATA *)panel_userptr(my_panels[2]);
|
|
if(temp->hide == FALSE)
|
|
{ hide_panel(my_panels[2]);
|
|
temp->hide = TRUE;
|
|
}
|
|
else
|
|
{ show_panel(my_panels[2]);
|
|
temp->hide = FALSE;
|
|
}
|
|
break;
|
|
}
|
|
update_panels();
|
|
doupdate();
|
|
}
|
|
endwin();
|
|
return 0;
|
|
}
|
|
|
|
/* Put all the windows */
|
|
void init_wins(WINDOW **wins, int n)
|
|
{ int x, y, i;
|
|
char label[80];
|
|
|
|
y = 2;
|
|
x = 10;
|
|
for(i = 0; i < n; ++i)
|
|
{ wins[i] = newwin(NLINES, NCOLS, y, x);
|
|
sprintf(label, "Window Number %d", i + 1);
|
|
win_show(wins[i], label, i + 1);
|
|
y += 3;
|
|
x += 7;
|
|
}
|
|
}
|
|
|
|
/* Show the window with a border and a label */
|
|
void win_show(WINDOW *win, char *label, int label_color)
|
|
{ int startx, starty, height, width;
|
|
|
|
getbegyx(win, starty, startx);
|
|
getmaxyx(win, height, width);
|
|
|
|
box(win, 0, 0);
|
|
mvwaddch(win, 2, 0, ACS_LTEE);
|
|
mvwhline(win, 2, 1, ACS_HLINE, width - 2);
|
|
mvwaddch(win, 2, width - 1, ACS_RTEE);
|
|
|
|
print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
|
|
}
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
|
|
{ int length, x, y;
|
|
float temp;
|
|
|
|
if(win == NULL)
|
|
win = stdscr;
|
|
getyx(win, y, x);
|
|
if(startx != 0)
|
|
x = startx;
|
|
if(starty != 0)
|
|
y = starty;
|
|
if(width == 0)
|
|
width = 80;
|
|
|
|
length = strlen(string);
|
|
temp = (width - length)/ 2;
|
|
x = startx + (int)temp;
|
|
wattron(win, color);
|
|
mvwprintw(win, y, x, "%s", string);
|
|
wattroff(win, color);
|
|
refresh();
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PANELABOVE"
|
|
>16.7. panel_above() and panel_below() Functions</A
|
|
></H3
|
|
><P
|
|
>The functions <TT
|
|
CLASS="LITERAL"
|
|
>panel_above()</TT
|
|
> and
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>panel_below()</TT
|
|
> can be used to find out the panel
|
|
above and below a panel. If the argument to these functions is NULL, then they
|
|
return a pointer to bottom panel and top panel respectively.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="MENUS"
|
|
>17. Menus Library</A
|
|
></H2
|
|
><P
|
|
>The menus library provides a nice extension to basic curses, through which you
|
|
can create menus. It provides a set of functions to create menus. But they have
|
|
to be customized to give a nicer look, with colors etc. Let's get into the
|
|
details.</P
|
|
><P
|
|
>A menu is a screen display that assists the user to choose some subset of a
|
|
given set of items. To put it simple, a menu is a collection of items from which
|
|
one or more items can be chosen. Some readers might not be aware of multiple
|
|
item selection capability. Menu library provides functionality to write menus
|
|
from which the user can chose more than one item as the preferred choice. This
|
|
is dealt with in a later section. Now it is time for some rudiments.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MENUBASICS"
|
|
>17.1. The Basics</A
|
|
></H3
|
|
><P
|
|
>To create menus, you first create items, and then post the menu to the display.
|
|
After that, all the processing of user responses is done in an elegant function
|
|
menu_driver() which is the work horse of any menu program. </P
|
|
><P
|
|
>The general flow of control of a menu program looks like this.
|
|
<P
|
|
></P
|
|
><OL
|
|
TYPE="1"
|
|
><LI
|
|
><P
|
|
>Initialize curses</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Create items using new_item(). You can specify a name and description for the
|
|
items.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Create the menu with new_menu() by specifying the items to be attached with.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Post the menu with menu_post() and refresh the screen.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Process the user requests with a loop and do necessary updates to menu with
|
|
menu_driver.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Unpost the menu with menu_unpost()</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Free the memory allocated to menu by free_menu()</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Free the memory allocated to the items with free_item() </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>End curses </P
|
|
></LI
|
|
></OL
|
|
></P
|
|
><P
|
|
>Let's see a program which prints a simple menu and updates the current selection
|
|
with up, down arrows. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="COMPILEMENUS"
|
|
>17.2. Compiling With the Menu Library</A
|
|
></H3
|
|
><P
|
|
>To use menu library functions, you have to include menu.h and to link the
|
|
program with menu library the flag -lmenu should be added along with -lncurses
|
|
in that order.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> #include <menu.h>
|
|
.
|
|
.
|
|
.
|
|
|
|
compile and link: gcc <program file> -lmenu -lncurses</PRE
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="MMESI"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 18. Menu Basics </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <curses.h>
|
|
#include <menu.h>
|
|
|
|
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
|
|
#define CTRLD 4
|
|
|
|
char *choices[] = {
|
|
"Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Exit",
|
|
};
|
|
|
|
int main()
|
|
{ ITEM **my_items;
|
|
int c;
|
|
MENU *my_menu;
|
|
int n_choices, i;
|
|
ITEM *cur_item;
|
|
|
|
|
|
initscr();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
n_choices = ARRAY_SIZE(choices);
|
|
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
|
|
|
|
for(i = 0; i < n_choices; ++i)
|
|
my_items[i] = new_item(choices[i], choices[i]);
|
|
my_items[n_choices] = (ITEM *)NULL;
|
|
|
|
my_menu = new_menu((ITEM **)my_items);
|
|
mvprintw(LINES - 2, 0, "F1 to Exit");
|
|
post_menu(my_menu);
|
|
refresh();
|
|
|
|
while((c = getch()) != KEY_F(1))
|
|
{ switch(c)
|
|
{ case KEY_DOWN:
|
|
menu_driver(my_menu, REQ_DOWN_ITEM);
|
|
break;
|
|
case KEY_UP:
|
|
menu_driver(my_menu, REQ_UP_ITEM);
|
|
break;
|
|
}
|
|
}
|
|
|
|
free_item(my_items[0]);
|
|
free_item(my_items[1]);
|
|
free_menu(my_menu);
|
|
endwin();
|
|
}
|
|
</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>This program demonstrates the basic concepts involved in creating a menu using
|
|
menus library. First we create the items using new_item() and then attach them
|
|
to the menu with new_menu() function. After posting the menu and refreshing the
|
|
screen, the main processing loop starts. It reads user input and takes
|
|
corresponding action. The function menu_driver() is the main work horse of the
|
|
menu system. The second parameter to this function tells what's to be done with
|
|
the menu. According to the parameter, menu_driver() does the corresponding task.
|
|
The value can be either a menu navigational request, an ascii character, or a
|
|
KEY_MOUSE special key associated with a mouse event.</P
|
|
><P
|
|
>The menu_driver accepts following navigational requests.
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> REQ_LEFT_ITEM Move left to an item.
|
|
REQ_RIGHT_ITEM Move right to an item.
|
|
REQ_UP_ITEM Move up to an item.
|
|
REQ_DOWN_ITEM Move down to an item.
|
|
REQ_SCR_ULINE Scroll up a line.
|
|
REQ_SCR_DLINE Scroll down a line.
|
|
REQ_SCR_DPAGE Scroll down a page.
|
|
REQ_SCR_UPAGE Scroll up a page.
|
|
REQ_FIRST_ITEM Move to the first item.
|
|
REQ_LAST_ITEM Move to the last item.
|
|
REQ_NEXT_ITEM Move to the next item.
|
|
REQ_PREV_ITEM Move to the previous item.
|
|
REQ_TOGGLE_ITEM Select/deselect an item.
|
|
REQ_CLEAR_PATTERN Clear the menu pattern buffer.
|
|
REQ_BACK_PATTERN Delete the previous character from the pattern buffer.
|
|
REQ_NEXT_MATCH Move to the next item matching the pattern match.
|
|
REQ_PREV_MATCH Move to the previous item matching the pattern match. </PRE
|
|
></P
|
|
><P
|
|
>Don't get overwhelmed by the number of options. We will see them slowly one
|
|
after another. The options of interest in this example are REQ_UP_ITEM and
|
|
REQ_DOWN_ITEM. These two options when passed to menu_driver, menu driver
|
|
updates the current item to one item up or down respectively.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MENUDRIVER"
|
|
>17.3. Menu Driver: The work horse of the menu system</A
|
|
></H3
|
|
><P
|
|
>As you have seen in the above example, menu_driver plays an important role in
|
|
updating the menu. It is very important to understand various options it takes
|
|
and what they do. As explained above, the second parameter to menu_driver() can
|
|
be either a navigational request, a printable character or a KEY_MOUSE key.
|
|
Let's dissect the different navigational requests.</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_LEFT_ITEM and REQ_RIGHT_ITEM</I
|
|
></SPAN
|
|
></P
|
|
><P
|
|
>A Menu can be displayed with multiple columns for more than one item. This can
|
|
be done by using the <TT
|
|
CLASS="LITERAL"
|
|
>menu_format()</TT
|
|
>function.
|
|
When a multi columnar menu is displayed these requests cause the menu driver to
|
|
move the current selection to left or right.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_UP_ITEM and REQ_DOWN_ITEM </I
|
|
></SPAN
|
|
> </P
|
|
><P
|
|
>These two options you have seen in the above example. These options when given,
|
|
makes the menu_driver to move the current selection to an item up or down.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
> <SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_* options</I
|
|
></SPAN
|
|
> </P
|
|
><P
|
|
>The four options REQ_SCR_ULINE, REQ_SCR_DLINE, REQ_SCR_DPAGE, REQ_SCR_UPAGE are
|
|
related to scrolling. If all the items in the menu cannot be displayed in the
|
|
menu sub window, then the menu is scrollable. These requests can be given to the
|
|
menu_driver to do the scrolling either one line up, down or one page down or up
|
|
respectively. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_NEXT_ITEM and
|
|
REQ_PREV_ITEM </I
|
|
></SPAN
|
|
> </P
|
|
><P
|
|
>These requests are self explanatory.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
> <SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_TOGGLE_ITEM</I
|
|
></SPAN
|
|
> </P
|
|
><P
|
|
>This request when given, toggles the present selection. This option is to be
|
|
used only in a multi valued menu. So to use this request the option O_ONEVALUE
|
|
must be off. This option can be made off or on with set_menu_opts().</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
> <SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>Pattern Requests </I
|
|
></SPAN
|
|
></P
|
|
><P
|
|
>Every menu has an associated pattern buffer, which is used to find the nearest
|
|
match to the ascii characters entered by the user. Whenever ascii characters are
|
|
given to menu_driver, it puts in to the pattern buffer. It also tries to find
|
|
the nearest match to the pattern in the items list and moves current selection
|
|
to that item. The request REQ_CLEAR_PATTERN clears the pattern buffer. The
|
|
request REQ_BACK_PATTERN deletes the previous character in the pattern buffer.
|
|
In case the pattern matches more than one item then the matched items can be
|
|
cycled through REQ_NEXT_MATCH and REQ_PREV_MATCH which move the current
|
|
selection to the next and previous matches respectively.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
> <SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>Mouse Requests</I
|
|
></SPAN
|
|
></P
|
|
><P
|
|
>In case of KEY_MOUSE requests, according to the mouse position an action is
|
|
taken accordingly. The action to be taken is explained in the man page as, </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
> If the second argument is the KEY_MOUSE special key, the
|
|
associated mouse event is translated into one of the above
|
|
pre-defined requests. Currently only clicks in the user
|
|
window (e.g. inside the menu display area or the decora­
|
|
tion window) are handled. If you click above the display
|
|
region of the menu, a REQ_SCR_ULINE is generated, if you
|
|
doubleclick a REQ_SCR_UPAGE is generated and if you
|
|
tripleclick a REQ_FIRST_ITEM is generated. If you click
|
|
below the display region of the menu, a REQ_SCR_DLINE is
|
|
generated, if you doubleclick a REQ_SCR_DPAGE is generated
|
|
and if you tripleclick a REQ_LAST_ITEM is generated. If
|
|
you click at an item inside the display area of the menu,
|
|
the menu cursor is positioned to that item.</I
|
|
></SPAN
|
|
></PRE
|
|
></LI
|
|
></UL
|
|
><P
|
|
>Each of the above requests will be explained in the following lines with several
|
|
examples whenever appropriate.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MENUWINDOWS"
|
|
>17.4. Menu Windows</A
|
|
></H3
|
|
><P
|
|
>Every menu created is associated with a window and a sub window. The menu window
|
|
displays any title or border associated with the menu. The menu sub window
|
|
displays the menu items currently available for selection. But we didn't specify
|
|
any window or sub window in the simple example. When a window is not specified,
|
|
stdscr is taken as the main window, and then menu system calculates the sub
|
|
window size required for the display of items. Then items are displayed in the
|
|
calculated sub window. So let's play with these windows and display a menu with
|
|
a border and a title.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="MMEWI"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 19. Menu Windows Usage example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <menu.h>
|
|
|
|
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
|
|
#define CTRLD 4
|
|
|
|
char *choices[] = {
|
|
"Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Exit",
|
|
(char *)NULL,
|
|
};
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
|
|
|
|
int main()
|
|
{ ITEM **my_items;
|
|
int c;
|
|
MENU *my_menu;
|
|
WINDOW *my_menu_win;
|
|
int n_choices, i;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
|
|
/* Create items */
|
|
n_choices = ARRAY_SIZE(choices);
|
|
my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
|
|
for(i = 0; i < n_choices; ++i)
|
|
my_items[i] = new_item(choices[i], choices[i]);
|
|
|
|
/* Crate menu */
|
|
my_menu = new_menu((ITEM **)my_items);
|
|
|
|
/* Create the window to be associated with the menu */
|
|
my_menu_win = newwin(10, 40, 4, 4);
|
|
keypad(my_menu_win, TRUE);
|
|
|
|
/* Set main window and sub window */
|
|
set_menu_win(my_menu, my_menu_win);
|
|
set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
|
|
|
|
/* Set menu mark to the string " * " */
|
|
set_menu_mark(my_menu, " * ");
|
|
|
|
/* Print a border around the main window and print a title */
|
|
box(my_menu_win, 0, 0);
|
|
print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
|
|
mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
|
|
mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
|
|
mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
|
|
mvprintw(LINES - 2, 0, "F1 to exit");
|
|
refresh();
|
|
|
|
/* Post the menu */
|
|
post_menu(my_menu);
|
|
wrefresh(my_menu_win);
|
|
|
|
while((c = wgetch(my_menu_win)) != KEY_F(1))
|
|
{ switch(c)
|
|
{ case KEY_DOWN:
|
|
menu_driver(my_menu, REQ_DOWN_ITEM);
|
|
break;
|
|
case KEY_UP:
|
|
menu_driver(my_menu, REQ_UP_ITEM);
|
|
break;
|
|
}
|
|
wrefresh(my_menu_win);
|
|
}
|
|
|
|
/* Unpost and free all the memory taken up */
|
|
unpost_menu(my_menu);
|
|
free_menu(my_menu);
|
|
for(i = 0; i < n_choices; ++i)
|
|
free_item(my_items[i]);
|
|
endwin();
|
|
}
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
|
|
{ int length, x, y;
|
|
float temp;
|
|
|
|
if(win == NULL)
|
|
win = stdscr;
|
|
getyx(win, y, x);
|
|
if(startx != 0)
|
|
x = startx;
|
|
if(starty != 0)
|
|
y = starty;
|
|
if(width == 0)
|
|
width = 80;
|
|
|
|
length = strlen(string);
|
|
temp = (width - length)/ 2;
|
|
x = startx + (int)temp;
|
|
wattron(win, color);
|
|
mvwprintw(win, y, x, "%s", string);
|
|
wattroff(win, color);
|
|
refresh();
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>This example creates a menu with a title, border, a fancy line separating title
|
|
and the items. As you can see, in order to attach a window to a menu the
|
|
function set_menu_win() has to be used. Then we attach the sub window also. This
|
|
displays the items in the sub window. You can also set the mark string which
|
|
gets displayed to the left of the selected item with set_menu_mark().</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="SCROLLMENUS"
|
|
>17.5. Scrolling Menus</A
|
|
></H3
|
|
><P
|
|
>If the sub window given for a window is not big enough to show all the items,
|
|
then the menu will be scrollable. When you are on the last item in the present
|
|
list, if you send REQ_DOWN_ITEM, it gets translated into REQ_SCR_DLINE and the
|
|
menu scrolls by one item. You can manually give REQ_SCR_ operations to do
|
|
scrolling. Let's see how it can be done.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="MMESC"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 20. Scrolling Menus example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <curses.h>
|
|
#include <menu.h>
|
|
|
|
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
|
|
#define CTRLD 4
|
|
|
|
char *choices[] = {
|
|
"Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Choice 5",
|
|
"Choice 6",
|
|
"Choice 7",
|
|
"Choice 8",
|
|
"Choice 9",
|
|
"Choice 10",
|
|
"Exit",
|
|
(char *)NULL,
|
|
};
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
|
|
|
|
int main()
|
|
{ ITEM **my_items;
|
|
int c;
|
|
MENU *my_menu;
|
|
WINDOW *my_menu_win;
|
|
int n_choices, i;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
init_pair(2, COLOR_CYAN, COLOR_BLACK);
|
|
|
|
/* Create items */
|
|
n_choices = ARRAY_SIZE(choices);
|
|
my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
|
|
for(i = 0; i < n_choices; ++i)
|
|
my_items[i] = new_item(choices[i], choices[i]);
|
|
|
|
/* Crate menu */
|
|
my_menu = new_menu((ITEM **)my_items);
|
|
|
|
/* Create the window to be associated with the menu */
|
|
my_menu_win = newwin(10, 40, 4, 4);
|
|
keypad(my_menu_win, TRUE);
|
|
|
|
/* Set main window and sub window */
|
|
set_menu_win(my_menu, my_menu_win);
|
|
set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
|
|
set_menu_format(my_menu, 5, 1);
|
|
|
|
/* Set menu mark to the string " * " */
|
|
set_menu_mark(my_menu, " * ");
|
|
|
|
/* Print a border around the main window and print a title */
|
|
box(my_menu_win, 0, 0);
|
|
print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
|
|
mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
|
|
mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
|
|
mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
|
|
|
|
/* Post the menu */
|
|
post_menu(my_menu);
|
|
wrefresh(my_menu_win);
|
|
|
|
attron(COLOR_PAIR(2));
|
|
mvprintw(LINES - 2, 0, "Use PageUp and PageDown to scoll down or up a page of items");
|
|
mvprintw(LINES - 1, 0, "Arrow Keys to navigate (F1 to Exit)");
|
|
attroff(COLOR_PAIR(2));
|
|
refresh();
|
|
|
|
while((c = wgetch(my_menu_win)) != KEY_F(1))
|
|
{ switch(c)
|
|
{ case KEY_DOWN:
|
|
menu_driver(my_menu, REQ_DOWN_ITEM);
|
|
break;
|
|
case KEY_UP:
|
|
menu_driver(my_menu, REQ_UP_ITEM);
|
|
break;
|
|
case KEY_NPAGE:
|
|
menu_driver(my_menu, REQ_SCR_DPAGE);
|
|
break;
|
|
case KEY_PPAGE:
|
|
menu_driver(my_menu, REQ_SCR_UPAGE);
|
|
break;
|
|
}
|
|
wrefresh(my_menu_win);
|
|
}
|
|
|
|
/* Unpost and free all the memory taken up */
|
|
unpost_menu(my_menu);
|
|
free_menu(my_menu);
|
|
for(i = 0; i < n_choices; ++i)
|
|
free_item(my_items[i]);
|
|
endwin();
|
|
}
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
|
|
{ int length, x, y;
|
|
float temp;
|
|
|
|
if(win == NULL)
|
|
win = stdscr;
|
|
getyx(win, y, x);
|
|
if(startx != 0)
|
|
x = startx;
|
|
if(starty != 0)
|
|
y = starty;
|
|
if(width == 0)
|
|
width = 80;
|
|
|
|
length = strlen(string);
|
|
temp = (width - length)/ 2;
|
|
x = startx + (int)temp;
|
|
wattron(win, color);
|
|
mvwprintw(win, y, x, "%s", string);
|
|
wattroff(win, color);
|
|
refresh();
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>This program is self-explanatory. In this example the number of choices has been
|
|
increased to ten, which is larger than our sub window size which can hold 6
|
|
items. This message has to be explicitly conveyed to the menu system with the
|
|
function set_menu_format(). In here we specify the number of rows and columns we
|
|
want to be displayed for a single page. We can specify any number of items to be
|
|
shown, in the rows variables, if it is less than the height of the sub window.
|
|
If the key pressed by the user is a PAGE UP or PAGE DOWN, the menu is scrolled a
|
|
page due to the requests (REQ_SCR_DPAGE and REQ_SCR_UPAGE) given to
|
|
menu_driver().</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MULTICOLUMN"
|
|
>17.6. Multi Columnar Menus</A
|
|
></H3
|
|
><P
|
|
>In the above example you have seen how to use the function set_menu_format(). I
|
|
didn't mention what the cols variable (third parameter) does. Well, If your sub
|
|
window is wide enough, you can opt to display more than one item per row. This
|
|
can be specified in the cols variable. To make things simpler, the following
|
|
example doesn't show descriptions for the items.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="MMEMUCO"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 21. Milt Columnar Menus Example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <curses.h>
|
|
#include <menu.h>
|
|
|
|
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
|
|
#define CTRLD 4
|
|
|
|
char *choices[] = {
|
|
"Choice 1", "Choice 2", "Choice 3", "Choice 4", "Choice 5",
|
|
"Choice 6", "Choice 7", "Choice 8", "Choice 9", "Choice 10",
|
|
"Choice 11", "Choice 12", "Choice 13", "Choice 14", "Choice 15",
|
|
"Choice 16", "Choice 17", "Choice 18", "Choice 19", "Choice 20",
|
|
"Exit",
|
|
(char *)NULL,
|
|
};
|
|
|
|
int main()
|
|
{ ITEM **my_items;
|
|
int c;
|
|
MENU *my_menu;
|
|
WINDOW *my_menu_win;
|
|
int n_choices, i;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
init_pair(2, COLOR_CYAN, COLOR_BLACK);
|
|
|
|
/* Create items */
|
|
n_choices = ARRAY_SIZE(choices);
|
|
my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
|
|
for(i = 0; i < n_choices; ++i)
|
|
my_items[i] = new_item(choices[i], choices[i]);
|
|
|
|
/* Crate menu */
|
|
my_menu = new_menu((ITEM **)my_items);
|
|
|
|
/* Set menu option not to show the description */
|
|
menu_opts_off(my_menu, O_SHOWDESC);
|
|
|
|
/* Create the window to be associated with the menu */
|
|
my_menu_win = newwin(10, 70, 4, 4);
|
|
keypad(my_menu_win, TRUE);
|
|
|
|
/* Set main window and sub window */
|
|
set_menu_win(my_menu, my_menu_win);
|
|
set_menu_sub(my_menu, derwin(my_menu_win, 6, 68, 3, 1));
|
|
set_menu_format(my_menu, 5, 3);
|
|
set_menu_mark(my_menu, " * ");
|
|
|
|
/* Print a border around the main window and print a title */
|
|
box(my_menu_win, 0, 0);
|
|
|
|
attron(COLOR_PAIR(2));
|
|
mvprintw(LINES - 3, 0, "Use PageUp and PageDown to scroll");
|
|
mvprintw(LINES - 2, 0, "Use Arrow Keys to navigate (F1 to Exit)");
|
|
attroff(COLOR_PAIR(2));
|
|
refresh();
|
|
|
|
/* Post the menu */
|
|
post_menu(my_menu);
|
|
wrefresh(my_menu_win);
|
|
|
|
while((c = wgetch(my_menu_win)) != KEY_F(1))
|
|
{ switch(c)
|
|
{ case KEY_DOWN:
|
|
menu_driver(my_menu, REQ_DOWN_ITEM);
|
|
break;
|
|
case KEY_UP:
|
|
menu_driver(my_menu, REQ_UP_ITEM);
|
|
break;
|
|
case KEY_LEFT:
|
|
menu_driver(my_menu, REQ_LEFT_ITEM);
|
|
break;
|
|
case KEY_RIGHT:
|
|
menu_driver(my_menu, REQ_RIGHT_ITEM);
|
|
break;
|
|
case KEY_NPAGE:
|
|
menu_driver(my_menu, REQ_SCR_DPAGE);
|
|
break;
|
|
case KEY_PPAGE:
|
|
menu_driver(my_menu, REQ_SCR_UPAGE);
|
|
break;
|
|
}
|
|
wrefresh(my_menu_win);
|
|
}
|
|
|
|
/* Unpost and free all the memory taken up */
|
|
unpost_menu(my_menu);
|
|
free_menu(my_menu);
|
|
for(i = 0; i < n_choices; ++i)
|
|
free_item(my_items[i]);
|
|
endwin();
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>Watch the function call to set_menu_format(). It specifies the number of columns
|
|
to be 3, thus displaying 3 items per row. We have also switched off the showing
|
|
descriptions with the function menu_opts_off(). There are couple of functions
|
|
set_menu_opts(), menu_opts_on() and menu_opts() which can be used to manipulate
|
|
menu options. The following menu options can be specified.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> O_ONEVALUE
|
|
Only one item can be selected for this menu.
|
|
|
|
O_SHOWDESC
|
|
Display the item descriptions when the menu is
|
|
posted.
|
|
|
|
O_ROWMAJOR
|
|
Display the menu in row-major order.
|
|
|
|
O_IGNORECASE
|
|
Ignore the case when pattern-matching.
|
|
|
|
O_SHOWMATCH
|
|
Move the cursor to within the item name while pat­
|
|
tern-matching.
|
|
|
|
O_NONCYCLIC
|
|
Don't wrap around next-item and previous-item,
|
|
requests to the other end of the menu.</PRE
|
|
><P
|
|
>All options are on by default. You can switch specific attributes on or off with
|
|
menu_opts_on() and menu_opts_off() functions. You can also use set_menu_opts()
|
|
to directly specify the options. The argument to this function should be a OR ed
|
|
value of some of those above constants. The function menu_opts() can be used to
|
|
find out a menu's present options. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MULTIVALUEMENUS"
|
|
>17.7. Multi Valued Menus</A
|
|
></H3
|
|
><P
|
|
>You might be wondering what if you switch off the option O_ONEVALUE. Then the
|
|
menu becomes multi-valued. That means you can select more than one item. This
|
|
brings us to the request REQ_TOGGLE_ITEM. Let's see it in action.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="MMETO"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 22. Multi Valued Menus example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <curses.h>
|
|
#include <menu.h>
|
|
|
|
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
|
|
#define CTRLD 4
|
|
|
|
char *choices[] = {
|
|
"Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Choice 5",
|
|
"Choice 6",
|
|
"Choice 7",
|
|
"Exit",
|
|
};
|
|
|
|
int main()
|
|
{ ITEM **my_items;
|
|
int c;
|
|
MENU *my_menu;
|
|
int n_choices, i;
|
|
ITEM *cur_item;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize items */
|
|
n_choices = ARRAY_SIZE(choices);
|
|
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
|
|
for(i = 0; i < n_choices; ++i)
|
|
my_items[i] = new_item(choices[i], choices[i]);
|
|
my_items[n_choices] = (ITEM *)NULL;
|
|
|
|
my_menu = new_menu((ITEM **)my_items);
|
|
|
|
/* Make the menu multi valued */
|
|
menu_opts_off(my_menu, O_ONEVALUE);
|
|
|
|
mvprintw(LINES - 3, 0, "Use <SPACE> to select or unselect an item.");
|
|
mvprintw(LINES - 2, 0, "<ENTER> to see presently selected items(F1 to Exit)");
|
|
post_menu(my_menu);
|
|
refresh();
|
|
|
|
while((c = getch()) != KEY_F(1))
|
|
{ switch(c)
|
|
{ case KEY_DOWN:
|
|
menu_driver(my_menu, REQ_DOWN_ITEM);
|
|
break;
|
|
case KEY_UP:
|
|
menu_driver(my_menu, REQ_UP_ITEM);
|
|
break;
|
|
case ' ':
|
|
menu_driver(my_menu, REQ_TOGGLE_ITEM);
|
|
break;
|
|
case 10: /* Enter */
|
|
{ char temp[200];
|
|
ITEM **items;
|
|
|
|
items = menu_items(my_menu);
|
|
temp[0] = '\0';
|
|
for(i = 0; i < item_count(my_menu); ++i)
|
|
if(item_value(items[i]) == TRUE)
|
|
{ strcat(temp, item_name(items[i]));
|
|
strcat(temp, " ");
|
|
}
|
|
move(20, 0);
|
|
clrtoeol();
|
|
mvprintw(20, 0, temp);
|
|
refresh();
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
free_item(my_items[0]);
|
|
free_item(my_items[1]);
|
|
free_menu(my_menu);
|
|
endwin();
|
|
}
|
|
</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>Whew, A lot of new functions. Let's take them one after another. Firstly, the
|
|
REQ_TOGGLE_ITEM. In a multi-valued menu, the user should be allowed to select
|
|
or un select more than one item. The request REQ_TOGGLE_ITEM toggles the present
|
|
selection. In this case when space is pressed REQ_TOGGLE_ITEM request is sent to
|
|
menu_driver to achieve the result.</P
|
|
><P
|
|
>Now when the user presses <ENTER> we show the items he presently selected.
|
|
First we find out the items associated with the menu using the function
|
|
menu_items(). Then we loop through the items to find out if the item is selected
|
|
or not. The function item_value() returns TRUE if an item is selected. The
|
|
function item_count() returns the number of items in the menu. The item name can
|
|
be found with item_name(). You can also find the description associated with an
|
|
item using item_description().</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MENUOPT"
|
|
>17.8. Menu Options</A
|
|
></H3
|
|
><P
|
|
>Well, by this time you must be itching for some difference in your menu, with
|
|
lots of functionality. I know. You want Colors !!!. You want to create nice
|
|
menus similar to those text mode <A
|
|
HREF="http://www.jersey.net/~debinjoe/games/"
|
|
TARGET="_top"
|
|
>dos games</A
|
|
>. The functions
|
|
set_menu_fore() and set_menu_back() can be used to change the attribute of the
|
|
selected item and unselected item. The names are misleading. They don't change
|
|
menu's foreground or background which would have been useless. </P
|
|
><P
|
|
>The function set_menu_grey() can be used to set the display attribute for the
|
|
non-selectable items in the menu. This brings us to the interesting option for
|
|
an item the one and only O_SELECTABLE. We can turn it off by the function
|
|
item_opts_off() and after that that item is not selectable. It's like a grayed
|
|
item in those fancy windows menus. Let's put these concepts in practice with
|
|
this example</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="MMEAT"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 23. Menu Options example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <menu.h>
|
|
|
|
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
|
|
#define CTRLD 4
|
|
|
|
char *choices[] = {
|
|
"Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Choice 5",
|
|
"Choice 6",
|
|
"Choice 7",
|
|
"Exit",
|
|
};
|
|
|
|
int main()
|
|
{ ITEM **my_items;
|
|
int c;
|
|
MENU *my_menu;
|
|
int n_choices, i;
|
|
ITEM *cur_item;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
init_pair(2, COLOR_GREEN, COLOR_BLACK);
|
|
init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
|
|
|
|
/* Initialize items */
|
|
n_choices = ARRAY_SIZE(choices);
|
|
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
|
|
for(i = 0; i < n_choices; ++i)
|
|
my_items[i] = new_item(choices[i], choices[i]);
|
|
my_items[n_choices] = (ITEM *)NULL;
|
|
item_opts_off(my_items[3], O_SELECTABLE);
|
|
item_opts_off(my_items[6], O_SELECTABLE);
|
|
|
|
/* Create menu */
|
|
my_menu = new_menu((ITEM **)my_items);
|
|
|
|
/* Set fore ground and back ground of the menu */
|
|
set_menu_fore(my_menu, COLOR_PAIR(1) | A_REVERSE);
|
|
set_menu_back(my_menu, COLOR_PAIR(2));
|
|
set_menu_grey(my_menu, COLOR_PAIR(3));
|
|
|
|
/* Post the menu */
|
|
mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected");
|
|
mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
|
|
post_menu(my_menu);
|
|
refresh();
|
|
|
|
while((c = getch()) != KEY_F(1))
|
|
{ switch(c)
|
|
{ case KEY_DOWN:
|
|
menu_driver(my_menu, REQ_DOWN_ITEM);
|
|
break;
|
|
case KEY_UP:
|
|
menu_driver(my_menu, REQ_UP_ITEM);
|
|
break;
|
|
case 10: /* Enter */
|
|
move(20, 0);
|
|
clrtoeol();
|
|
mvprintw(20, 0, "Item selected is : %s",
|
|
item_name(current_item(my_menu)));
|
|
pos_menu_cursor(my_menu);
|
|
break;
|
|
}
|
|
}
|
|
unpost_menu(my_menu);
|
|
for(i = 0; i < n_choices; ++i)
|
|
free_item(my_items[i]);
|
|
free_menu(my_menu);
|
|
endwin();
|
|
}
|
|
</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MENUUSERPTR"
|
|
>17.9. The useful User Pointer</A
|
|
></H3
|
|
><P
|
|
>We can associate a user pointer with each item in the menu. It works the same
|
|
way as user pointer in panels. It's not touched by menu system. You can store
|
|
any thing you like in that. I usually use it to store the function to be
|
|
executed when the menu option is chosen (It's selected and may be the user
|
|
pressed <ENTER>);</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="MMEUS"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 24. Menu User Pointer Usage </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <curses.h>
|
|
#include <menu.h>
|
|
|
|
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
|
|
#define CTRLD 4
|
|
|
|
char *choices[] = {
|
|
"Choice 1",
|
|
"Choice 2",
|
|
"Choice 3",
|
|
"Choice 4",
|
|
"Choice 5",
|
|
"Choice 6",
|
|
"Choice 7",
|
|
"Exit",
|
|
};
|
|
void func(char *name);
|
|
|
|
int main()
|
|
{ ITEM **my_items;
|
|
int c;
|
|
MENU *my_menu;
|
|
int n_choices, i;
|
|
ITEM *cur_item;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
init_pair(2, COLOR_GREEN, COLOR_BLACK);
|
|
init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
|
|
|
|
/* Initialize items */
|
|
n_choices = ARRAY_SIZE(choices);
|
|
my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
|
|
for(i = 0; i < n_choices; ++i)
|
|
{ my_items[i] = new_item(choices[i], choices[i]);
|
|
/* Set the user pointer */
|
|
set_item_userptr(my_items[i], func);
|
|
}
|
|
my_items[n_choices] = (ITEM *)NULL;
|
|
|
|
/* Create menu */
|
|
my_menu = new_menu((ITEM **)my_items);
|
|
|
|
/* Post the menu */
|
|
mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected");
|
|
mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
|
|
post_menu(my_menu);
|
|
refresh();
|
|
|
|
while((c = getch()) != KEY_F(1))
|
|
{ switch(c)
|
|
{ case KEY_DOWN:
|
|
menu_driver(my_menu, REQ_DOWN_ITEM);
|
|
break;
|
|
case KEY_UP:
|
|
menu_driver(my_menu, REQ_UP_ITEM);
|
|
break;
|
|
case 10: /* Enter */
|
|
{ ITEM *cur;
|
|
void (*p)(char *);
|
|
|
|
cur = current_item(my_menu);
|
|
p = item_userptr(cur);
|
|
p((char *)item_name(cur));
|
|
pos_menu_cursor(my_menu);
|
|
break;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
unpost_menu(my_menu);
|
|
for(i = 0; i < n_choices; ++i)
|
|
free_item(my_items[i]);
|
|
free_menu(my_menu);
|
|
endwin();
|
|
}
|
|
|
|
void func(char *name)
|
|
{ move(20, 0);
|
|
clrtoeol();
|
|
mvprintw(20, 0, "Item selected is : %s", name);
|
|
} </SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="FORMS"
|
|
>18. Forms Library</A
|
|
></H2
|
|
><P
|
|
>Well. If you have seen those forms on web pages which take input from users and
|
|
do various kinds of things, you might be wondering how would any one create such
|
|
forms in text mode display. It's quite difficult to write those nifty forms in
|
|
plain ncurses. Forms library tries to provide a basic frame work to build and
|
|
maintain forms with ease. It has lot of features(functions) which manage
|
|
validation, dynamic expansion of fields etc.. Let's see it in full flow.</P
|
|
><P
|
|
>A form is a collection of fields; each field can be either a label(static text)
|
|
or a data-entry location. The forms also library provides functions to divide
|
|
forms into multiple pages. </P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="FORMBASICS"
|
|
>18.1. The Basics</A
|
|
></H3
|
|
><P
|
|
>Forms are created in much the same way as menus. First the fields related to the
|
|
form are created with new_field(). You can set options for the fields, so that
|
|
they can be displayed with some fancy attributes, validated before the field
|
|
looses focus etc.. Then the fields are attached to form. After this, the form
|
|
can be posted to display and is ready to receive inputs. On the similar lines to
|
|
menu_driver(), the form is manipulated with form_driver(). We can send requests
|
|
to form_driver to move focus to a certain field, move cursor to end of the field
|
|
etc.. After the user enters values in the fields and validation done, form can
|
|
be unposted and memory allocated can be freed.</P
|
|
><P
|
|
>The general flow of control of a forms program looks like this.
|
|
|
|
<P
|
|
></P
|
|
><OL
|
|
TYPE="1"
|
|
><LI
|
|
><P
|
|
>Initialize curses</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Create fields using new_field(). You can specify the height and
|
|
width of the field, and its position on the form.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Create the forms with new_form() by specifying the fields to be
|
|
attached with.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Post the form with form_post() and refresh the screen.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Process the user requests with a loop and do necessary updates
|
|
to form with form_driver.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Unpost the menu with form_unpost()</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Free the memory allocated to menu by free_form()</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Free the memory allocated to the items with free_field()</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>End curses</P
|
|
></LI
|
|
></OL
|
|
></P
|
|
><P
|
|
>As you can see, working with forms library is much similar to handling menu
|
|
library. The following examples will explore various aspects of form
|
|
processing. Let's start the journey with a simple example. first.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="COMPILEFORMS"
|
|
>18.2. Compiling With the Forms Library</A
|
|
></H3
|
|
><P
|
|
>To use forms library functions, you have to include form.h and to link the
|
|
program with forms library the flag -lform should be added along with -lncurses
|
|
in that order.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> #include <form.h>
|
|
.
|
|
.
|
|
.
|
|
|
|
compile and link: gcc <program file> -lform -lncurses</PRE
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="FFOSI"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 25. Forms Basics </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <form.h>
|
|
|
|
int main()
|
|
{ FIELD *field[3];
|
|
FORM *my_form;
|
|
int ch;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize the fields */
|
|
field[0] = new_field(1, 10, 4, 18, 0, 0);
|
|
field[1] = new_field(1, 10, 6, 18, 0, 0);
|
|
field[2] = NULL;
|
|
|
|
/* Set field options */
|
|
set_field_back(field[0], A_UNDERLINE); /* Print a line for the option */
|
|
field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
|
|
/* Field is filled up */
|
|
set_field_back(field[1], A_UNDERLINE);
|
|
field_opts_off(field[1], O_AUTOSKIP);
|
|
|
|
/* Create the form and post it */
|
|
my_form = new_form(field);
|
|
post_form(my_form);
|
|
refresh();
|
|
|
|
mvprintw(4, 10, "Value 1:");
|
|
mvprintw(6, 10, "Value 2:");
|
|
refresh();
|
|
|
|
/* Loop through to get user requests */
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case KEY_DOWN:
|
|
/* Go to next field */
|
|
form_driver(my_form, REQ_NEXT_FIELD);
|
|
/* Go to the end of the present buffer */
|
|
/* Leaves nicely at the last character */
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
case KEY_UP:
|
|
/* Go to previous field */
|
|
form_driver(my_form, REQ_PREV_FIELD);
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
default:
|
|
/* If this is a normal character, it gets */
|
|
/* Printed */
|
|
form_driver(my_form, ch);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Un post form and free the memory */
|
|
unpost_form(my_form);
|
|
free_form(my_form);
|
|
free_field(field[0]);
|
|
free_field(field[1]);
|
|
|
|
endwin();
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>Above example is pretty straight forward. It creates two fields with
|
|
<TT
|
|
CLASS="LITERAL"
|
|
>new_field()</TT
|
|
>. new_field() takes height, width,
|
|
starty, startx, number of offscreen rows and number of additional working
|
|
buffers. The fifth argument number of offscreen rows specifies how much of the
|
|
field to be shown. If it is zero, the entire field is always displayed otherwise
|
|
the form will be scrollable when the user accesses not displayed parts of the
|
|
field. The forms library allocates one buffer per field to store the data user
|
|
enters. Using the last parameter to new_field() we can specify it to allocate
|
|
some additional buffers. These can be used for any purpose you like.</P
|
|
><P
|
|
>After creating the fields, back ground attribute of both of them is set to an
|
|
underscore with set_field_back(). The AUTOSKIP option is turned off using
|
|
field_opts_off(). If this option is turned on, focus will move to the next
|
|
field in the form once the active field is filled up completely.</P
|
|
><P
|
|
>After attaching the fields to the form, it is posted. Here on, user inputs are
|
|
processed in the while loop, by making corresponding requests to form_driver.
|
|
The details of all the requests to the form_driver() are explained later.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PLAYFIELDS"
|
|
>18.3. Playing with Fields</A
|
|
></H3
|
|
><P
|
|
>Each form field is associated with a lot of attributes. They can be manipulated
|
|
to get the required effect and to have fun !!!. So why wait? </P
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="FETCHINFO"
|
|
>18.3.1. Fetching Size and Location of Field</A
|
|
></H4
|
|
><P
|
|
>The parameters we have given at the time of creation of a field can be retrieved
|
|
with field_info(). It returns height, width, starty, startx, number of offscreen
|
|
rows, and number of additional buffers into the parameters given to it. It is a
|
|
sort of inverse of new_field().</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int field_info( FIELD *field, /* field from which to fetch */
|
|
int *height, *int width, /* field size */
|
|
int *top, int *left, /* upper left corner */
|
|
int *offscreen, /* number of offscreen rows */
|
|
int *nbuf); /* number of working buffers */</PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="MOVEFIELD"
|
|
>18.3.2. Moving the field</A
|
|
></H4
|
|
><P
|
|
>The location of the field can be moved to a different position with
|
|
move_field().</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int move_field( FIELD *field, /* field to alter */
|
|
int top, int left); /* new upper-left corner */</PRE
|
|
><P
|
|
>As usual, the changed position can be queried with field_infor().</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="JUSTIFYFIELD"
|
|
>18.3.3. Field Justification</A
|
|
></H4
|
|
><P
|
|
>The justification to be done for the field can be fixed using the function
|
|
set_field_just().</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> int set_field_just(FIELD *field, /* field to alter */
|
|
int justmode); /* mode to set */
|
|
int field_just(FIELD *field); /* fetch justify mode of field */</PRE
|
|
><P
|
|
>The justification mode valued accepted and returned by these functions are
|
|
NO_JUSTIFICATION, JUSTIFY_RIGHT, JUSTIFY_LEFT, or JUSTIFY_CENTER.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="FIELDDISPATTRIB"
|
|
>18.3.4. Field Display Attributes</A
|
|
></H4
|
|
><P
|
|
>As you have seen, in the above example, display attribute for the fields can be
|
|
set with set_field_fore() and setfield_back(). These functions set foreground
|
|
and background attribute of the fields. You can also specify a pad character
|
|
which will be filled in the unfilled portion of the field. The pad character is
|
|
set with a call to set_field_pad(). Default pad value is a space. The functions
|
|
field_fore(), field_back, field_pad() can be used to query the present
|
|
foreground, background attributes and pad character for the field. The following
|
|
list gives the usage of functions.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> int set_field_fore(FIELD *field, /* field to alter */
|
|
chtype attr); /* attribute to set */
|
|
|
|
chtype field_fore(FIELD *field); /* field to query */
|
|
/* returns foreground attribute */
|
|
|
|
int set_field_back(FIELD *field, /* field to alter */
|
|
chtype attr); /* attribute to set */
|
|
|
|
chtype field_back(FIELD *field); /* field to query */
|
|
/* returns background attribute */
|
|
|
|
int set_field_pad(FIELD *field, /* field to alter */
|
|
int pad); /* pad character to set */
|
|
|
|
chtype field_pad(FIELD *field); /* field to query */
|
|
/* returns present pad character */ </PRE
|
|
><P
|
|
>Though above functions seem quite simple, using colors with set_field_fore() may
|
|
be frustrating in the beginning. Let me first explain about foreground and
|
|
background attributes of a field. The foreground attribute is associated with
|
|
the character. That means a character in the field is printed with the attribute
|
|
you have set with set_field_fore(). Background attribute is the attribute used
|
|
to fill background of field, whether any character is there or not. So what
|
|
about colors? Since colors are always defined in pairs, what is the right way to
|
|
display colored fields? Here's an example clarifying color attributes.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="FFOAT"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 26. Form Attributes example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <form.h>
|
|
|
|
int main()
|
|
{ FIELD *field[3];
|
|
FORM *my_form;
|
|
int ch;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize few color pairs */
|
|
init_pair(1, COLOR_WHITE, COLOR_BLUE);
|
|
init_pair(2, COLOR_WHITE, COLOR_BLUE);
|
|
|
|
/* Initialize the fields */
|
|
field[0] = new_field(1, 10, 4, 18, 0, 0);
|
|
field[1] = new_field(1, 10, 6, 18, 0, 0);
|
|
field[2] = NULL;
|
|
|
|
/* Set field options */
|
|
set_field_fore(field[0], COLOR_PAIR(1));/* Put the field with blue background */
|
|
set_field_back(field[0], COLOR_PAIR(2));/* and white foreground (characters */
|
|
/* are printed in white */
|
|
field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
|
|
/* Field is filled up */
|
|
set_field_back(field[1], A_UNDERLINE);
|
|
field_opts_off(field[1], O_AUTOSKIP);
|
|
|
|
/* Create the form and post it */
|
|
my_form = new_form(field);
|
|
post_form(my_form);
|
|
refresh();
|
|
|
|
set_current_field(my_form, field[0]); /* Set focus to the colored field */
|
|
mvprintw(4, 10, "Value 1:");
|
|
mvprintw(6, 10, "Value 2:");
|
|
mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
|
|
refresh();
|
|
|
|
/* Loop through to get user requests */
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case KEY_DOWN:
|
|
/* Go to next field */
|
|
form_driver(my_form, REQ_NEXT_FIELD);
|
|
/* Go to the end of the present buffer */
|
|
/* Leaves nicely at the last character */
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
case KEY_UP:
|
|
/* Go to previous field */
|
|
form_driver(my_form, REQ_PREV_FIELD);
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
default:
|
|
/* If this is a normal character, it gets */
|
|
/* Printed */
|
|
form_driver(my_form, ch);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Un post form and free the memory */
|
|
unpost_form(my_form);
|
|
free_form(my_form);
|
|
free_field(field[0]);
|
|
free_field(field[1]);
|
|
|
|
endwin();
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>Play with the color pairs and try to understand the foreground and background
|
|
attributes. In my programs using color attributes, I usually set only the
|
|
background with set_field_back(). Curses simply doesn't allow defining
|
|
individual color attributes. </P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="FIELDOPTIONBITS"
|
|
>18.3.5. Field Option Bits</A
|
|
></H4
|
|
><P
|
|
>There is also a large collection of field option bits you can set to control
|
|
various aspects of forms processing. You can manipulate them with these
|
|
functions:</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_opts(FIELD *field, /* field to alter */
|
|
int attr); /* attribute to set */
|
|
|
|
int field_opts_on(FIELD *field, /* field to alter */
|
|
int attr); /* attributes to turn on */
|
|
|
|
int field_opts_off(FIELD *field, /* field to alter */
|
|
int attr); /* attributes to turn off */
|
|
|
|
int field_opts(FIELD *field); /* field to query */ </PRE
|
|
><P
|
|
>The function set_field_opts() can be used to directly set attributes of a field
|
|
or you can choose to switch a few attributes on and off with field_opts_on() and
|
|
field_opts_off() selectively. Anytime you can query the attributes of a field
|
|
with field_opts(). The following is the list of available options. By default,
|
|
all options are on.</P
|
|
><P
|
|
></P
|
|
><DIV
|
|
CLASS="VARIABLELIST"
|
|
><DL
|
|
><DT
|
|
>O_VISIBLE</DT
|
|
><DD
|
|
><P
|
|
>Controls whether the field is visible on the screen. Can be used
|
|
during form processing to hide or pop up fields depending on the value
|
|
of parent fields.</P
|
|
></DD
|
|
><DT
|
|
>O_ACTIVE</DT
|
|
><DD
|
|
><P
|
|
>Controls whether the field is active during forms processing (i.e.
|
|
visited by form navigation keys). Can be used to make labels or derived
|
|
fields with buffer values alterable by the forms application, not the user.</P
|
|
></DD
|
|
><DT
|
|
>O_PUBLIC</DT
|
|
><DD
|
|
><P
|
|
>Controls whether data is displayed during field entry. If this option is
|
|
turned off on a field, the library will accept and edit data in that field,
|
|
but it will not be displayed and the visible field cursor will not move.
|
|
You can turn off the O_PUBLIC bit to define password fields.</P
|
|
></DD
|
|
><DT
|
|
>O_EDIT</DT
|
|
><DD
|
|
><P
|
|
>Controls whether the field's data can be modified. When this option is
|
|
off, all editing requests except <TT
|
|
CLASS="LITERAL"
|
|
>REQ_PREV_CHOICE</TT
|
|
> and <TT
|
|
CLASS="LITERAL"
|
|
>REQ_NEXT_CHOICE</TT
|
|
>will
|
|
fail. Such read-only fields may be useful for help messages.</P
|
|
></DD
|
|
><DT
|
|
>O_WRAP</DT
|
|
><DD
|
|
><P
|
|
>Controls word-wrapping in multi-line fields. Normally, when any
|
|
character of a (blank-separated) word reaches the end of the current line, the
|
|
entire word is wrapped to the next line (assuming there is one). When this
|
|
option is off, the word will be split across the line break.</P
|
|
></DD
|
|
><DT
|
|
>O_BLANK</DT
|
|
><DD
|
|
><P
|
|
>Controls field blanking. When this option is on, entering a character at
|
|
the first field position erases the entire field (except for the just-entered
|
|
character).</P
|
|
></DD
|
|
><DT
|
|
>O_AUTOSKIP</DT
|
|
><DD
|
|
><P
|
|
>Controls automatic skip to next field when this one fills. Normally,
|
|
when the forms user tries to type more data into a field than will fit,
|
|
the editing location jumps to next field. When this option is off, the
|
|
user's cursor will hang at the end of the field. This option is ignored
|
|
in dynamic fields that have not reached their size limit.</P
|
|
></DD
|
|
><DT
|
|
>O_NULLOK</DT
|
|
><DD
|
|
><P
|
|
>Controls whether validation is applied to
|
|
blank fields. Normally, it is not; the user can leave a field blank
|
|
without invoking the usual validation check on exit. If this option is
|
|
off on a field, exit from it will invoke a validation check.</P
|
|
></DD
|
|
><DT
|
|
>O_PASSOK</DT
|
|
><DD
|
|
><P
|
|
>Controls whether validation occurs on every exit, or only after
|
|
the field is modified. Normally the latter is true. Setting O_PASSOK
|
|
may be useful if your field's validation function may change during
|
|
forms processing.</P
|
|
></DD
|
|
><DT
|
|
>O_STATIC</DT
|
|
><DD
|
|
><P
|
|
>Controls whether the field is fixed to its initial dimensions. If you
|
|
turn this off, the field becomes dynamic and will
|
|
stretch to fit entered data.</P
|
|
></DD
|
|
></DL
|
|
></DIV
|
|
><P
|
|
>A field's options cannot be changed while the field is currently selected.
|
|
However, options may be changed on posted fields that are not current. </P
|
|
><P
|
|
>The option values are bit-masks and can be composed with logical-or in
|
|
the obvious way. You have seen the usage of switching off O_AUTOSKIP option.
|
|
The following example clarifies usage of some more options. Other options
|
|
are explained where appropriate.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="FFOOP"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 27. Field Options Usage example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <form.h>
|
|
|
|
#define STARTX 15
|
|
#define STARTY 4
|
|
#define WIDTH 25
|
|
|
|
#define N_FIELDS 3
|
|
|
|
int main()
|
|
{ FIELD *field[N_FIELDS];
|
|
FORM *my_form;
|
|
int ch, i;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize the fields */
|
|
for(i = 0; i < N_FIELDS - 1; ++i)
|
|
field[i] = new_field(1, WIDTH, STARTY + i * 2, STARTX, 0, 0);
|
|
field[N_FIELDS - 1] = NULL;
|
|
|
|
/* Set field options */
|
|
set_field_back(field[1], A_UNDERLINE); /* Print a line for the option */
|
|
|
|
field_opts_off(field[0], O_ACTIVE); /* This field is a static label */
|
|
field_opts_off(field[1], O_PUBLIC); /* This filed is like a password field*/
|
|
field_opts_off(field[1], O_AUTOSKIP); /* To avoid entering the same field */
|
|
/* after last character is entered */
|
|
|
|
/* Create the form and post it */
|
|
my_form = new_form(field);
|
|
post_form(my_form);
|
|
refresh();
|
|
|
|
set_field_just(field[0], JUSTIFY_CENTER); /* Center Justification */
|
|
set_field_buffer(field[0], 0, "This is a static Field");
|
|
/* Initialize the field */
|
|
mvprintw(STARTY, STARTX - 10, "Field 1:");
|
|
mvprintw(STARTY + 2, STARTX - 10, "Field 2:");
|
|
refresh();
|
|
|
|
/* Loop through to get user requests */
|
|
while((ch = getch()) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case KEY_DOWN:
|
|
/* Go to next field */
|
|
form_driver(my_form, REQ_NEXT_FIELD);
|
|
/* Go to the end of the present buffer */
|
|
/* Leaves nicely at the last character */
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
case KEY_UP:
|
|
/* Go to previous field */
|
|
form_driver(my_form, REQ_PREV_FIELD);
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
default:
|
|
/* If this is a normal character, it gets */
|
|
/* Printed */
|
|
form_driver(my_form, ch);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Un post form and free the memory */
|
|
unpost_form(my_form);
|
|
free_form(my_form);
|
|
free_field(field[0]);
|
|
free_field(field[1]);
|
|
|
|
endwin();
|
|
return 0;
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
><P
|
|
>This example, though useless, shows the usage of options. If used properly, they
|
|
can present information very effectively in a form. The second field being not
|
|
O_PUBLIC, does not show the characters you are typing.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="FIELDSTATUS"
|
|
>18.3.6. Field Status</A
|
|
></H4
|
|
><P
|
|
>The field status specifies whether the field has got edited or not. It is
|
|
initially set to FALSE and when user enters something and the data buffer gets
|
|
modified it becomes TRUE. So a field's status can be queried to find out whether
|
|
it has been modified or not. The following functions can assist in those
|
|
operations.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_status(FIELD *field, /* field to alter */
|
|
int status); /* status to set */
|
|
|
|
int field_status(FIELD *field); /* fetch status of field */</PRE
|
|
><P
|
|
>It's better to check the field's status only after after leaving the field, as
|
|
data buffer might not have been updated yet as the validation is still due. To
|
|
guarantee that right status is returned, call field_status() either (1) in the
|
|
field's exit validation check routine, (2) from the field's or form's
|
|
initialization or termination hooks, or (3) just after a REQ_VALIDATION request
|
|
has been processed by the forms driver</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="FIELDUSERPTR"
|
|
>18.3.7. Field User Pointer</A
|
|
></H4
|
|
><P
|
|
>Every field structure contains one pointer that can be used by the user for
|
|
various purposes. It is not touched by forms library and can be used for any
|
|
purpose by the user. The following functions set and fetch user pointer.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_userptr(FIELD *field,
|
|
char *userptr); /* the user pointer you wish to associate */
|
|
/* with the field */
|
|
|
|
char *field_userptr(FIELD *field); /* fetch user pointer of the field */</PRE
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="VARIABLESIZEFIELDS"
|
|
>18.3.8. Variable-Sized Fields</A
|
|
></H4
|
|
><P
|
|
>If you want a dynamically changing field with variable width, this is the
|
|
feature you want to put to full use. This will allow the user to enter more data
|
|
than the original size of the field and let the field grow. According to the
|
|
field orientation it will scroll horizontally or vertically to incorporate the
|
|
new data.</P
|
|
><P
|
|
>To make a field dynamically growable, the option O_STATIC should be turned off.
|
|
This can be done with a
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
> field_opts_off(field_pointer, O_STATIC);</PRE
|
|
></P
|
|
><P
|
|
>But it's usually not advisable to allow a field to grow infinitely. You can set
|
|
a maximum limit to the growth of the field with
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_max_field(FIELD *field, /* Field on which to operate */
|
|
int max_growth); /* maximum growth allowed for the field */</PRE
|
|
></P
|
|
><P
|
|
>The field info for a dynamically growable field can be retrieved by
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int dynamic_field_info( FIELD *field, /* Field on which to operate */
|
|
int *prows, /* number of rows will be filled in this */
|
|
int *pcols, /* number of columns will be filled in this*/
|
|
int *pmax) /* maximum allowable growth will be filled */
|
|
/* in this */</PRE
|
|
>
|
|
Though field_info work as usual, it is advisable to use this function to get the
|
|
proper attributes of a dynamically growable field.</P
|
|
><P
|
|
>Recall the library routine new_field; a new field created with height set to one
|
|
will be defined to be a one line field. A new field created with height greater
|
|
than one will be defined to be a multi line field. </P
|
|
><P
|
|
>A one line field with O_STATIC turned off (dynamically growable field) will
|
|
contain a single fixed row, but the number of columns can increase if the user
|
|
enters more data than the initial field will hold. The number of columns
|
|
displayed will remain fixed and the additional data will scroll horizontally. </P
|
|
><P
|
|
>A multi line field with O_STATIC turned off (dynamically growable field) will
|
|
contain a fixed number of columns, but the number of rows can increase if the
|
|
user enters more data than the initial field will hold. The number of rows
|
|
displayed will remain fixed and the additional data will scroll vertically.</P
|
|
><P
|
|
>The above two paragraphs pretty much describe a dynamically growable field's
|
|
behavior. The way other parts of forms library behaves is described below:</P
|
|
><P
|
|
></P
|
|
><OL
|
|
TYPE="1"
|
|
><LI
|
|
><P
|
|
>The field option O_AUTOSKIP will be ignored if the option O_STATIC is off and
|
|
there is no maximum growth specified for the field. Currently, O_AUTOSKIP
|
|
generates an automatic REQ_NEXT_FIELD form driver request when the user types in
|
|
the last character position of a field. On a growable field with no maximum
|
|
growth specified, there is no last character position. If a maximum growth is
|
|
specified, the O_AUTOSKIP option will work as normal if the field has grown to
|
|
its maximum size. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>The field justification will be ignored if the option O_STATIC is off.
|
|
Currently, set_field_just can be used to JUSTIFY_LEFT, JUSTIFY_RIGHT,
|
|
JUSTIFY_CENTER the contents of a one line field. A growable one line field will,
|
|
by definition, grow and scroll horizontally and may contain more data than can
|
|
be justified. The return from field_just will be unchanged. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>The overloaded form driver request REQ_NEW_LINE will operate the same way
|
|
regardless of the O_NL_OVERLOAD form option if the field option O_STATIC is off
|
|
and there is no maximum growth specified for the field. Currently, if the form
|
|
option O_NL_OVERLOAD is on, REQ_NEW_LINE implicitly generates a REQ_NEXT_FIELD
|
|
if called from the last line of a field. If a field can grow without bound,
|
|
there is no last line, so REQ_NEW_LINE will never implicitly generate a
|
|
REQ_NEXT_FIELD. If a maximum growth limit is specified and the O_NL_OVERLOAD
|
|
form option is on, REQ_NEW_LINE will only implicitly generate REQ_NEXT_FIELD if
|
|
the field has grown to its maximum size and the user is on the last line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>The library call dup_field will work as usual; it will duplicate the field,
|
|
including the current buffer size and contents of the field being duplicated.
|
|
Any specified maximum growth will also be duplicated. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>The library call link_field will work as usual; it will duplicate all field
|
|
attributes and share buffers with the field being linked. If the O_STATIC field
|
|
option is subsequently changed by a field sharing buffers, how the system reacts
|
|
to an attempt to enter more data into the field than the buffer will currently
|
|
hold will depend on the setting of the option in the current field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>The library call field_info will work as usual; the variable nrow will contain
|
|
the value of the original call to new_field. The user should use
|
|
dynamic_field_info, described above, to query the current size of the buffer.</P
|
|
></LI
|
|
></OL
|
|
><P
|
|
>Some of the above points make sense only after explaining form driver. We will
|
|
be looking into that in next few sections.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="FORMWINDOWS"
|
|
>18.4. Form Windows</A
|
|
></H3
|
|
><P
|
|
>The form windows concept is pretty much similar to menu windows. Every form is
|
|
associated with a main window and a sub window. The form main window displays
|
|
any title or border associated or whatever the user wishes. Then the sub window
|
|
contains all the fields and displays them according to their position. This
|
|
gives the flexibility of manipulating fancy form displaying very easily. </P
|
|
><P
|
|
>Since this is pretty much similar to menu windows, I am providing an example
|
|
with out much explanation. The functions are similar and they work the same way.</P
|
|
><DIV
|
|
CLASS="EXAMPLE"
|
|
><A
|
|
NAME="FFOWI"
|
|
></A
|
|
><P
|
|
><B
|
|
>Example 28. Form Windows Example </B
|
|
></P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="INLINEMEDIAOBJECT"
|
|
>#include <form.h>
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
|
|
|
|
int main()
|
|
{
|
|
FIELD *field[3];
|
|
FORM *my_form;
|
|
WINDOW *my_form_win;
|
|
int ch, rows, cols;
|
|
|
|
/* Initialize curses */
|
|
initscr();
|
|
start_color();
|
|
cbreak();
|
|
noecho();
|
|
keypad(stdscr, TRUE);
|
|
|
|
/* Initialize few color pairs */
|
|
init_pair(1, COLOR_RED, COLOR_BLACK);
|
|
|
|
/* Initialize the fields */
|
|
field[0] = new_field(1, 10, 6, 1, 0, 0);
|
|
field[1] = new_field(1, 10, 8, 1, 0, 0);
|
|
field[2] = NULL;
|
|
|
|
/* Set field options */
|
|
set_field_back(field[0], A_UNDERLINE);
|
|
field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
|
|
/* Field is filled up */
|
|
set_field_back(field[1], A_UNDERLINE);
|
|
field_opts_off(field[1], O_AUTOSKIP);
|
|
|
|
/* Create the form and post it */
|
|
my_form = new_form(field);
|
|
|
|
/* Calculate the area required for the form */
|
|
scale_form(my_form, &rows, &cols);
|
|
|
|
/* Create the window to be associated with the form */
|
|
my_form_win = newwin(rows + 4, cols + 4, 4, 4);
|
|
keypad(my_form_win, TRUE);
|
|
|
|
/* Set main window and sub window */
|
|
set_form_win(my_form, my_form_win);
|
|
set_form_sub(my_form, derwin(my_form_win, rows, cols, 2, 2));
|
|
|
|
/* Print a border around the main window and print a title */
|
|
box(my_form_win, 0, 0);
|
|
print_in_middle(my_form_win, 1, 0, cols + 4, "My Form", COLOR_PAIR(1));
|
|
|
|
post_form(my_form);
|
|
wrefresh(my_form_win);
|
|
|
|
mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
|
|
refresh();
|
|
|
|
/* Loop through to get user requests */
|
|
while((ch = wgetch(my_form_win)) != KEY_F(1))
|
|
{ switch(ch)
|
|
{ case KEY_DOWN:
|
|
/* Go to next field */
|
|
form_driver(my_form, REQ_NEXT_FIELD);
|
|
/* Go to the end of the present buffer */
|
|
/* Leaves nicely at the last character */
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
case KEY_UP:
|
|
/* Go to previous field */
|
|
form_driver(my_form, REQ_PREV_FIELD);
|
|
form_driver(my_form, REQ_END_LINE);
|
|
break;
|
|
default:
|
|
/* If this is a normal character, it gets */
|
|
/* Printed */
|
|
form_driver(my_form, ch);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Un post form and free the memory */
|
|
unpost_form(my_form);
|
|
free_form(my_form);
|
|
free_field(field[0]);
|
|
free_field(field[1]);
|
|
|
|
endwin();
|
|
return 0;
|
|
}
|
|
|
|
void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
|
|
{ int length, x, y;
|
|
float temp;
|
|
|
|
if(win == NULL)
|
|
win = stdscr;
|
|
getyx(win, y, x);
|
|
if(startx != 0)
|
|
x = startx;
|
|
if(starty != 0)
|
|
y = starty;
|
|
if(width == 0)
|
|
width = 80;
|
|
|
|
length = strlen(string);
|
|
temp = (width - length)/ 2;
|
|
x = startx + (int)temp;
|
|
wattron(win, color);
|
|
mvwprintw(win, y, x, "%s", string);
|
|
wattroff(win, color);
|
|
refresh();
|
|
}</SPAN
|
|
></PRE
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="FILEDVALIDATE"
|
|
>18.5. Field Validation</A
|
|
></H3
|
|
><P
|
|
>By default, a field will accept any data input by the user. It is possible to
|
|
attach validation to the field. Then any attempt by the user to leave the field,
|
|
while it contains data that doesn't match the validation type will fail. Some
|
|
validation types also have a character-validity check for each time a character
|
|
is entered in the field.</P
|
|
><P
|
|
>Validation can be attached to a field with the following function.
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_type(FIELD *field, /* field to alter */
|
|
FIELDTYPE *ftype, /* type to associate */
|
|
...); /* additional arguments*/</PRE
|
|
>
|
|
Once set, the validation type for a field can be queried with
|
|
<PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>FIELDTYPE *field_type(FIELD *field); /* field to query */</PRE
|
|
></P
|
|
><P
|
|
>The form driver validates the data in a field only when data is entered by the
|
|
end-user. Validation does not occur when </P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
>the application program changes the field value by calling set_field_buffer. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>linked field values are changed indirectly -- by changing the field to which
|
|
they are linked</P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>The following are the pre-defined validation types. You can also specify custom
|
|
validation, though it's a bit tricky and cumbersome.</P
|
|
><H1
|
|
CLASS="BRIDGEHEAD"
|
|
><A
|
|
NAME="AEN1069"
|
|
></A
|
|
>TYPE_ALPHA</H1
|
|
><P
|
|
>This field type accepts alphabetic data; no blanks, no digits, no special
|
|
characters (this is checked at character-entry time). It is set up with: </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_type(FIELD *field, /* field to alter */
|
|
TYPE_ALPHA, /* type to associate */
|
|
int width); /* maximum width of field */</PRE
|
|
><P
|
|
>The width argument sets a minimum width of data. The user has to enter at-least
|
|
width number of characters before he can leave the field. Typically
|
|
you'll want to set this to the field width; if it's greater than the
|
|
field width, the validation check will always fail. A minimum width
|
|
of zero makes field completion optional. </P
|
|
><H1
|
|
CLASS="BRIDGEHEAD"
|
|
><A
|
|
NAME="AEN1073"
|
|
></A
|
|
>TYPE_ALNUM</H1
|
|
><P
|
|
>This field type accepts alphabetic data and digits; no blanks, no special
|
|
characters (this is checked at character-entry time). It is set up with: </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_type(FIELD *field, /* field to alter */
|
|
TYPE_ALNUM, /* type to associate */
|
|
int width); /* maximum width of field */</PRE
|
|
><P
|
|
>The width argument sets a minimum width of data. As with
|
|
TYPE_ALPHA, typically you'll want to set this to the field width; if it's
|
|
greater than the field width, the validation check will always fail. A
|
|
minimum width of zero makes field completion optional. </P
|
|
><H1
|
|
CLASS="BRIDGEHEAD"
|
|
><A
|
|
NAME="AEN1077"
|
|
></A
|
|
>TYPE_ENUM</H1
|
|
><P
|
|
>This type allows you to restrict a field's values to be among a specified
|
|
set of string values (for example, the two-letter postal codes for U.S.
|
|
states). It is set up with: </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_type(FIELD *field, /* field to alter */
|
|
TYPE_ENUM, /* type to associate */
|
|
char **valuelist; /* list of possible values */
|
|
int checkcase; /* case-sensitive? */
|
|
int checkunique); /* must specify uniquely? */</PRE
|
|
><P
|
|
>The valuelist parameter must point at a NULL-terminated list of
|
|
valid strings. The checkcase argument, if true, makes comparison
|
|
with the string case-sensitive. </P
|
|
><P
|
|
>When the user exits a TYPE_ENUM field, the validation procedure tries to
|
|
complete the data in the buffer to a valid entry. If a complete choice string
|
|
has been entered, it is of course valid. But it is also possible to enter a
|
|
prefix of a valid string and have it completed for you. </P
|
|
><P
|
|
>By default, if you enter such a prefix and it matches more than one value
|
|
in the string list, the prefix will be completed to the first matching
|
|
value. But the checkunique argument, if true, requires prefix
|
|
matches to be unique in order to be valid. </P
|
|
><P
|
|
>The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be particularly
|
|
useful with these fields. </P
|
|
><H1
|
|
CLASS="BRIDGEHEAD"
|
|
><A
|
|
NAME="AEN1084"
|
|
></A
|
|
>TYPE_INTEGER</H1
|
|
><P
|
|
>This field type accepts an integer. It is set up as follows: </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_type(FIELD *field, /* field to alter */
|
|
TYPE_INTEGER, /* type to associate */
|
|
int padding, /* # places to zero-pad to */
|
|
int vmin, int vmax); /* valid range */</PRE
|
|
><P
|
|
>Valid characters consist of an optional leading minus and digits.
|
|
The range check is performed on exit. If the range maximum is less
|
|
than or equal to the minimum, the range is ignored. </P
|
|
><P
|
|
>If the value passes its range check, it is padded with as many leading
|
|
zero digits as necessary to meet the padding argument. </P
|
|
><P
|
|
>A TYPE_INTEGER value buffer can conveniently be interpreted with the C library
|
|
function atoi(3).</P
|
|
><H1
|
|
CLASS="BRIDGEHEAD"
|
|
><A
|
|
NAME="AEN1090"
|
|
></A
|
|
>TYPE_NUMERIC</H1
|
|
><P
|
|
>This field type accepts a decimal number. It is set up as follows: </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_type(FIELD *field, /* field to alter */
|
|
TYPE_NUMERIC, /* type to associate */
|
|
int padding, /* # places of precision */
|
|
int vmin, int vmax); /* valid range */</PRE
|
|
><P
|
|
>Valid characters consist of an optional leading minus and digits. possibly
|
|
including a decimal point. The range check is performed on exit. If the
|
|
range maximum is less than or equal to the minimum, the range is
|
|
ignored. </P
|
|
><P
|
|
>If the value passes its range check, it is padded with as many trailing
|
|
zero digits as necessary to meet the padding argument. </P
|
|
><P
|
|
>A TYPE_NUMERIC value buffer can conveniently be interpreted with the C library
|
|
function atof(3).</P
|
|
><H1
|
|
CLASS="BRIDGEHEAD"
|
|
><A
|
|
NAME="AEN1096"
|
|
></A
|
|
>TYPE_REGEXP</H1
|
|
><P
|
|
>This field type accepts data matching a regular expression. It is set up
|
|
as follows: </P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_field_type(FIELD *field, /* field to alter */
|
|
TYPE_REGEXP, /* type to associate */
|
|
char *regexp); /* expression to match */</PRE
|
|
><P
|
|
>The syntax for regular expressions is that of regcomp(3).
|
|
The check for regular-expression match is performed on exit.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="FORMDRIVER"
|
|
>18.6. Form Driver: The work horse of the forms system</A
|
|
></H3
|
|
><P
|
|
>As in the menu system, form_driver() plays a very important role in forms
|
|
system. All types of requests to forms system should be funneled through
|
|
form_driver().</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int form_driver(FORM *form, /* form on which to operate */
|
|
int request) /* form request code */</PRE
|
|
><P
|
|
>As you have seen some of the examples above, you have to be in a loop looking
|
|
for user input and then decide whether it's a field data or a form request. The
|
|
form requests are then passed to form_driver() to do the work.</P
|
|
><P
|
|
>The requests roughly can be divided into following categories. Different
|
|
requests and their usage is explained below:</P
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="PAGENAVREQ"
|
|
>18.6.1. Page Navigation Requests</A
|
|
></H4
|
|
><P
|
|
>These requests cause page-level moves through the form, triggering display of a
|
|
new form screen. A form can be made of multiple pages. If you have a big form
|
|
with lot of fields and logical sections, then you can divide the form into
|
|
pages. The function set_new_page() to set a new page at the field specified.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>int set_new_page(FIELD *field,/* Field at which page break to be set or unset */
|
|
bool new_page_flag); /* should be TRUE to put a break */</PRE
|
|
><P
|
|
>The following requests allow you to move to different pages</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_NEXT_PAGE</I
|
|
></SPAN
|
|
> Move to the next form page.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_PREV_PAGE</I
|
|
></SPAN
|
|
> Move to the previous
|
|
form page.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_FIRST_PAGE</I
|
|
></SPAN
|
|
> Move to the first form page.</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_LAST_PAGE</I
|
|
></SPAN
|
|
> Move to the last form page. </P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>These requests treat the list as cyclic; that is, REQ_NEXT_PAGE from the
|
|
last page goes to the first, and REQ_PREV_PAGE from the first page goes to
|
|
the last.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="INTERFIELDNAVREQ"
|
|
>18.6.2. Inter-Field Navigation Requests</A
|
|
></H4
|
|
><P
|
|
>These requests handle navigation between fields on the same page.</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_NEXT_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to next field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_PREV_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to previous field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_FIRST_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to the first field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_LAST_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to the last field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SNEXT_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to sorted next field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SPREV_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to sorted previous field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SFIRST_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to the sorted first field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SLAST_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to the sorted last field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_LEFT_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move left to field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_RIGHT_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move right to field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_UP_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move up to field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_DOWN_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move down to field. </P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>These requests treat the list of fields on a page as cyclic; that is,
|
|
REQ_NEXT_FIELD from the last field goes to the first, and REQ_PREV_FIELD
|
|
from the first field goes to the last. The order of the fields for these
|
|
(and the REQ_FIRST_FIELD and REQ_LAST_FIELD requests) is simply the order of
|
|
the field pointers in the form array (as set up by new_form() or
|
|
set_form_fields()</P
|
|
><P
|
|
>It is also possible to traverse the fields as if they had been sorted in
|
|
screen-position order, so the sequence goes left-to-right and top-to-bottom.
|
|
To do this, use the second group of four sorted-movement requests.</P
|
|
><P
|
|
>Finally, it is possible to move between fields using visual directions up,
|
|
down, right, and left. To accomplish this, use the third group of four
|
|
requests. Note, however, that the position of a form for purposes of these
|
|
requests is its upper-left corner.</P
|
|
><P
|
|
>For example, suppose you have a multi-line field B, and two single-line
|
|
fields A and C on the same line with B, with A to the left of B and C to the
|
|
right of B. A REQ_MOVE_RIGHT from A will go to B only if A, B, and C all
|
|
share the same first line; otherwise it will skip over B to C.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="INTRAFIELDNAVREQ"
|
|
>18.6.3. Intra-Field Navigation Requests</A
|
|
></H4
|
|
><P
|
|
>These requests drive movement of the edit cursor within the currently
|
|
selected field.</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_NEXT_CHAR</I
|
|
></SPAN
|
|
>
|
|
Move to next character. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_PREV_CHAR</I
|
|
></SPAN
|
|
>
|
|
Move to previous character. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_NEXT_LINE</I
|
|
></SPAN
|
|
>
|
|
Move to next line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_PREV_LINE</I
|
|
></SPAN
|
|
>
|
|
Move to previous line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_NEXT_WORD</I
|
|
></SPAN
|
|
>
|
|
Move to next word. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_PREV_WORD</I
|
|
></SPAN
|
|
>
|
|
Move to previous word. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_BEG_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to beginning of field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_END_FIELD</I
|
|
></SPAN
|
|
>
|
|
Move to end of field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_BEG_LINE</I
|
|
></SPAN
|
|
>
|
|
Move to beginning of line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_END_LINE</I
|
|
></SPAN
|
|
>
|
|
Move to end of line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_LEFT_CHAR</I
|
|
></SPAN
|
|
>
|
|
Move left in field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_RIGHT_CHAR</I
|
|
></SPAN
|
|
>
|
|
Move right in field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_UP_CHAR</I
|
|
></SPAN
|
|
>
|
|
Move up in field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_DOWN_CHAR</I
|
|
></SPAN
|
|
>
|
|
Move down in field. </P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>Each word is separated from the previous and next characters by whitespace.
|
|
The commands to move to beginning and end of line or field look for the
|
|
first or last non-pad character in their ranges.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="SCROLLREQ"
|
|
>18.6.4. Scrolling Requests</A
|
|
></H4
|
|
><P
|
|
>Fields that are dynamic and have grown and fields explicitly created with
|
|
offscreen rows are scrollable. One-line fields scroll horizontally;
|
|
multi-line fields scroll vertically. Most scrolling is triggered by editing
|
|
and intra-field movement (the library scrolls the field to keep the cursor
|
|
visible). It is possible to explicitly request scrolling with the following
|
|
requests:</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_FLINE</I
|
|
></SPAN
|
|
>
|
|
Scroll vertically forward a line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_BLINE</I
|
|
></SPAN
|
|
>
|
|
Scroll vertically backward a line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_FPAGE</I
|
|
></SPAN
|
|
>
|
|
Scroll vertically forward a page. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_BPAGE</I
|
|
></SPAN
|
|
>
|
|
Scroll vertically backward a page. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_FHPAGE</I
|
|
></SPAN
|
|
>
|
|
Scroll vertically forward half a page. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_BHPAGE</I
|
|
></SPAN
|
|
>
|
|
Scroll vertically backward half a page. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_FCHAR</I
|
|
></SPAN
|
|
>
|
|
Scroll horizontally forward a character. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_BCHAR</I
|
|
></SPAN
|
|
>
|
|
Scroll horizontally backward a character. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_HFLINE</I
|
|
></SPAN
|
|
>
|
|
Scroll horizontally one field width forward. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_HBLINE</I
|
|
></SPAN
|
|
>
|
|
Scroll horizontally one field width backward. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_HFHALF</I
|
|
></SPAN
|
|
>
|
|
Scroll horizontally one half field width forward. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_SCR_HBHALF</I
|
|
></SPAN
|
|
>
|
|
Scroll horizontally one half field width backward. </P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>For scrolling purposes, a page of a field is the height of its visible part.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="EDITREQ"
|
|
>18.6.5. Editing Requests</A
|
|
></H4
|
|
><P
|
|
>When you pass the forms driver an ASCII character, it is treated as a
|
|
request to add the character to the field's data buffer. Whether this is an
|
|
insertion or a replacement depends on the field's edit mode (insertion is
|
|
the default.</P
|
|
><P
|
|
>The following requests support editing the field and changing the edit mode:</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_INS_MODE</I
|
|
></SPAN
|
|
>
|
|
Set insertion mode. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_OVL_MODE</I
|
|
></SPAN
|
|
>
|
|
Set overlay mode. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_NEW_LINE</I
|
|
></SPAN
|
|
>
|
|
New line request (see below for explanation). </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_INS_CHAR</I
|
|
></SPAN
|
|
>
|
|
Insert space at character location. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_INS_LINE</I
|
|
></SPAN
|
|
>
|
|
Insert blank line at character location. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_DEL_CHAR</I
|
|
></SPAN
|
|
>
|
|
Delete character at cursor. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_DEL_PREV</I
|
|
></SPAN
|
|
>
|
|
Delete previous word at cursor. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_DEL_LINE</I
|
|
></SPAN
|
|
>
|
|
Delete line at cursor. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_DEL_WORD</I
|
|
></SPAN
|
|
>
|
|
Delete word at cursor. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_CLR_EOL</I
|
|
></SPAN
|
|
>
|
|
Clear to end of line. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_CLR_EOF</I
|
|
></SPAN
|
|
>
|
|
Clear to end of field. </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_CLR_FIELD</I
|
|
></SPAN
|
|
>
|
|
Clear entire field. </P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>The behavior of the REQ_NEW_LINE and REQ_DEL_PREV requests is complicated
|
|
and partly controlled by a pair of forms options. The special cases are
|
|
triggered when the cursor is at the beginning of a field, or on the last
|
|
line of the field.</P
|
|
><P
|
|
>First, we consider REQ_NEW_LINE:</P
|
|
><P
|
|
>The normal behavior of REQ_NEW_LINE in insert mode is to break the current
|
|
line at the position of the edit cursor, inserting the portion of the
|
|
current line after the cursor as a new line following the current and moving
|
|
the cursor to the beginning of that new line (you may think of this as
|
|
inserting a newline in the field buffer).</P
|
|
><P
|
|
>The normal behavior of REQ_NEW_LINE in overlay mode is to clear the current
|
|
line from the position of the edit cursor to end of line. The cursor is then
|
|
moved to the beginning of the next line.</P
|
|
><P
|
|
>However, REQ_NEW_LINE at the beginning of a field, or on the last line of a
|
|
field, instead does a REQ_NEXT_FIELD. O_NL_OVERLOAD option is off, this
|
|
special action is disabled.</P
|
|
><P
|
|
>Now, let us consider REQ_DEL_PREV:</P
|
|
><P
|
|
>The normal behavior of REQ_DEL_PREV is to delete the previous character. If
|
|
insert mode is on, and the cursor is at the start of a line, and the text on
|
|
that line will fit on the previous one, it instead appends the contents of
|
|
the current line to the previous one and deletes the current line (you may
|
|
think of this as deleting a newline from the field buffer).</P
|
|
><P
|
|
>However, REQ_DEL_PREV at the beginning of a field is instead treated as a
|
|
REQ_PREV_FIELD.</P
|
|
><P
|
|
>If the O_BS_OVERLOAD option is off, this special action is disabled and the
|
|
forms driver just returns E_REQUEST_DENIED.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="ORDERREQ"
|
|
>18.6.6. Order Requests</A
|
|
></H4
|
|
><P
|
|
>If the type of your field is ordered, and has associated functions for
|
|
getting the next and previous values of the type from a given value, there
|
|
are requests that can fetch that value into the field buffer:</P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_NEXT_CHOICE</I
|
|
></SPAN
|
|
>
|
|
Place the successor value of the current value in the buffer.
|
|
</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>REQ_PREV_CHOICE</I
|
|
></SPAN
|
|
>
|
|
Place the predecessor value of the current value in the buffer.
|
|
</P
|
|
></LI
|
|
></UL
|
|
><P
|
|
>Of the built-in field types, only TYPE_ENUM has built-in successor and
|
|
predecessor functions. When you define a field type of your own (see Custom
|
|
Validation Types), you can associate our own ordering functions.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="APPLICCOMMANDS"
|
|
>18.6.7. Application Commands</A
|
|
></H4
|
|
><P
|
|
>Form requests are represented as integers above the curses value greater than
|
|
KEY_MAX and less than or equal to the constant MAX_COMMAND. A value within this
|
|
range gets ignored by form_driver(). So this can be used for any purpose by the
|
|
application. It can be treated as an application specific action and take
|
|
corresponding action.</P
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="TOOLS"
|
|
>19. Tools and Widget Libraries</A
|
|
></H2
|
|
><P
|
|
>
|
|
Now that you have seen the capabilities of ncurses and its sister libraries, you
|
|
are rolling your sleeves up and gearing for a project that heavily manipulates
|
|
screen. But wait.. It can be pretty difficult to write and maintain complex GUI
|
|
widgets in plain ncurses or even with the additional libraries. There are some
|
|
ready-to-use tools and widget libraries that can be used instead of writing your
|
|
own widgets. You can use some of them, get ideas from the code, or even extend
|
|
them.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="CDK"
|
|
>19.1. CDK (Curses Development Kit)</A
|
|
></H3
|
|
><P
|
|
>In the author's words </P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>
|
|
CDK stands for 'Curses Development Kit' and it currently contains 21 ready
|
|
to use widgets which facilitate the speedy development of full screen
|
|
curses programs. </I
|
|
></SPAN
|
|
></P
|
|
><P
|
|
>The kit provides some useful widgets, which can be used in your programs
|
|
directly. It's pretty well written and the documentation is very good. The
|
|
examples in the examples directory can be a good place to start for beginners.
|
|
The CDK can be downloaded from <A
|
|
HREF="http://invisible-island.net/cdk/"
|
|
TARGET="_top"
|
|
>http://invisible-island.net/cdk/</A
|
|
>
|
|
. Follow the instructions in
|
|
README file to install it.</P
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="WIDGETLIST"
|
|
>19.1.1. Widget List</A
|
|
></H4
|
|
><P
|
|
>The following is the list of widgets provided with cdk and their description.</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>Widget Type Quick Description
|
|
===========================================================================
|
|
Alphalist Allows a user to select from a list of words, with
|
|
the ability to narrow the search list by typing in a
|
|
few characters of the desired word.
|
|
Buttonbox This creates a multiple button widget.
|
|
Calendar Creates a little simple calendar widget.
|
|
Dialog Prompts the user with a message, and the user
|
|
can pick an answer from the buttons provided.
|
|
Entry Allows the user to enter various types of information.
|
|
File Selector A file selector built from Cdk base widgets. This
|
|
example shows how to create more complicated widgets
|
|
using the Cdk widget library.
|
|
Graph Draws a graph.
|
|
Histogram Draws a histogram.
|
|
Item List Creates a pop up field which allows the user to select
|
|
one of several choices in a small field. Very useful
|
|
for things like days of the week or month names.
|
|
Label Displays messages in a pop up box, or the label can be
|
|
considered part of the screen.
|
|
Marquee Displays a message in a scrolling marquee.
|
|
Matrix Creates a complex matrix with lots of options.
|
|
Menu Creates a pull-down menu interface.
|
|
Multiple Line Entry A multiple line entry field. Very useful
|
|
for long fields. (like a description
|
|
field)
|
|
Radio List Creates a radio button list.
|
|
Scale Creates a numeric scale. Used for allowing a user to
|
|
pick a numeric value and restrict them to a range of
|
|
values.
|
|
Scrolling List Creates a scrolling list/menu list.
|
|
Scrolling Window Creates a scrolling log file viewer. Can add
|
|
information into the window while its running.
|
|
A good widget for displaying the progress of
|
|
something. (akin to a console window)
|
|
Selection List Creates a multiple option selection list.
|
|
Slider Akin to the scale widget, this widget provides a
|
|
visual slide bar to represent the numeric value.
|
|
Template Creates a entry field with character sensitive
|
|
positions. Used for pre-formatted fields like
|
|
dates and phone numbers.
|
|
Viewer This is a file/information viewer. Very useful
|
|
when you need to display loads of information.
|
|
===========================================================================</PRE
|
|
><P
|
|
>A few of the widgets are modified by Thomas Dickey in recent versions.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="CDKATTRACT"
|
|
>19.1.2. Some Attractive Features</A
|
|
></H4
|
|
><P
|
|
>Apart from making our life easier with readily usable widgets, cdk solves one
|
|
frustrating problem with printing multi colored strings, justified strings
|
|
elegantly. Special formatting tags can be embedded in the strings which are
|
|
passed to CDK functions. For Example</P
|
|
><P
|
|
>If the string</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
>"</B/1>This line should have a yellow foreground and a blue
|
|
background.<!1>"</PRE
|
|
><P
|
|
>given as a parameter to newCDKLabel(), it prints the line with yellow foreground
|
|
and blue background. There are other tags available for justifying string,
|
|
embedding special drawing characters etc.. Please refer to the man page
|
|
cdk_display(3X) for details. The man page explains the usage with nice examples.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT3"
|
|
><HR><H4
|
|
CLASS="SECT3"
|
|
><A
|
|
NAME="CDKCONCLUSION"
|
|
>19.1.3. Conclusion</A
|
|
></H4
|
|
><P
|
|
>All in all, CDK is a well-written package of widgets, which if used properly can
|
|
form a strong frame work for developing complex GUI.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="DIALOG"
|
|
>19.2. The dialog</A
|
|
></H3
|
|
><P
|
|
>Long long ago, in September 1994, when few people knew linux, Jeff Tranter wrote
|
|
an <A
|
|
HREF="http://www2.linuxjournal.com/lj-issues/issue5/2807.html"
|
|
TARGET="_top"
|
|
>article</A
|
|
> on dialog in Linux Journal. He starts the article with these words..</P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>Linux is based on the Unix operating system, but also features a number of
|
|
unique and useful kernel features and application programs that often go beyond
|
|
what is available under Unix. One little-known gem is "dialog", a utility for
|
|
creating professional-looking dialog boxes from within shell scripts. This
|
|
article presents a tutorial introduction to the dialog utility, and shows
|
|
examples of how and where it can be used</I
|
|
></SPAN
|
|
></P
|
|
><P
|
|
>
|
|
As he explains, dialog is a real gem in making professional-looking dialog boxes
|
|
with ease. It creates a variety of dialog boxes, menus, check lists etc.. It is
|
|
usually installed by default. If not, you can download it from <A
|
|
HREF="http://invisible-island.net/dialog/"
|
|
TARGET="_top"
|
|
>Thomas Dickey</A
|
|
>'s site. </P
|
|
><P
|
|
>The above-mentioned article gives a very good overview of its uses and
|
|
capabilites. The man page has more details. It can be used in variety of
|
|
situations. One good example is building of linux kernel in text mode. Linux
|
|
kernel uses a modified version of dialog tailored for its needs. </P
|
|
><P
|
|
>dialog was initially designed to be used with shell scripts. If you want to use
|
|
its functionality in a c program, then you can use libdialog. The documentation
|
|
regarding this is sparse. Definitive reference is the dialog.h header file which
|
|
comes with the library. You may need to hack here and there to get the required
|
|
output. The source is easily customizable. I have used it on a number of
|
|
occasions by modifying the code.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="PERLCURSES"
|
|
>19.3. Perl Curses Modules CURSES::FORM and CURSES::WIDGETS</A
|
|
></H3
|
|
><P
|
|
>The perl module Curses, Curses::Form and Curses::Widgets give access to curses
|
|
from perl. If you have curses and basic perl is installed, you can get these
|
|
modules from <A
|
|
HREF="http://www.cpan.org/modules/01modules.index.html"
|
|
TARGET="_top"
|
|
> CPAN
|
|
All Modules page</A
|
|
>. Get the three zipped modules in the Curses category.
|
|
Once installed you can use these modules from perl scripts like any other
|
|
module. For more information on perl modules see perlmod man page. The above
|
|
modules come with good documentation and they have some demo scripts to test the
|
|
functionality. Though the widgets provided are very rudimentary, these modules
|
|
provide good access to curses library from perl.</P
|
|
><P
|
|
>Some of my code examples are converted to perl by Anuradha Ratnaweera and they
|
|
are available in the <TT
|
|
CLASS="LITERAL"
|
|
>perl</TT
|
|
> directory.</P
|
|
><P
|
|
>
|
|
For more information see man pages Curses(3) , Curses::Form(3) and
|
|
Curses::Widgets(3). These pages are installed only when the above modules are
|
|
acquired and installed.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="JUSTFORFUN"
|
|
>20. Just For Fun !!!</A
|
|
></H2
|
|
><P
|
|
>This section contains few programs written by me just for fun. They don't
|
|
signify a better programming practice or the best way of using ncurses. They are
|
|
provided here so as to allow beginners to get ideas and add more programs to
|
|
this section. If you have written a couple of nice, simple programs in curses
|
|
and want them to included here, contact <A
|
|
HREF="mailto:ppadala@gmail.com"
|
|
TARGET="_top"
|
|
>me</A
|
|
>.</P
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="GAMEOFLIFE"
|
|
>20.1. The Game of Life</A
|
|
></H3
|
|
><P
|
|
>Game of life is a wonder of math. In
|
|
<A
|
|
HREF="http://www.math.com/students/wonders/life/life.html"
|
|
TARGET="_top"
|
|
>Paul Callahan</A
|
|
>'s words</P
|
|
><PRE
|
|
CLASS="PROGRAMLISTING"
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>The Game of Life (or simply Life) is not a game in the conventional sense. There
|
|
are no players, and no winning or losing. Once the "pieces" are placed in the
|
|
starting position, the rules determine everything that happens later.
|
|
Nevertheless, Life is full of surprises! In most cases, it is impossible to look
|
|
at a starting position (or pattern) and see what will happen in the future. The
|
|
only way to find out is to follow the rules of the game.</I
|
|
></SPAN
|
|
></PRE
|
|
><P
|
|
>This program starts with a simple inverted U pattern and shows how wonderful
|
|
life works. There is a lot of room for improvement in the program. You can let
|
|
the user enter pattern of his choice or even take input from a file. You can
|
|
also change rules and play with a lot of variations. Search on <A
|
|
HREF="http://www.google.com"
|
|
TARGET="_top"
|
|
>google</A
|
|
> for interesting information on game
|
|
of life.</P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>File Path: JustForFun/life.c</I
|
|
></SPAN
|
|
></P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="MAGIC"
|
|
>20.2. Magic Square</A
|
|
></H3
|
|
><P
|
|
>Magic Square, another wonder of math, is very simple to understand but very
|
|
difficult to make. In a magic square sum of the numbers in each row, each column
|
|
is equal. Even diagnol sum can be equal. There are many variations which have
|
|
special properties.</P
|
|
><P
|
|
>This program creates a simple magic square of odd order.</P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>File Path: JustForFun/magic.c</I
|
|
></SPAN
|
|
></P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="HANOI"
|
|
>20.3. Towers of Hanoi</A
|
|
></H3
|
|
><P
|
|
>The famous towers of hanoi solver. The aim of the game is to move the disks on
|
|
the first peg to last peg, using middle peg as a temporary stay. The catch is
|
|
not to place a larger disk over a small disk at any time.</P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>File Path: JustForFun/hanoi.c</I
|
|
></SPAN
|
|
></P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="QUEENS"
|
|
>20.4. Queens Puzzle</A
|
|
></H3
|
|
><P
|
|
>The objective of the famous N-Queen puzzle is to put N queens on a N X N chess
|
|
board without attacking each other. </P
|
|
><P
|
|
>This program solves it with a simple backtracking technique.</P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>File Path: JustForFun/queens.c</I
|
|
></SPAN
|
|
></P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="SHUFFLE"
|
|
>20.5. Shuffle</A
|
|
></H3
|
|
><P
|
|
>A fun game, if you have time to kill. </P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>File Path: JustForFun/shuffle.c</I
|
|
></SPAN
|
|
></P
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT2"
|
|
><HR><H3
|
|
CLASS="SECT2"
|
|
><A
|
|
NAME="TT"
|
|
>20.6. Typing Tutor</A
|
|
></H3
|
|
><P
|
|
>A simple typing tutor, I created more out of need than for ease of use. If you
|
|
know how to put your fingers correctly on the keyboard, but lack practice, this
|
|
can be helpful. </P
|
|
><P
|
|
><SPAN
|
|
CLASS="emphasis"
|
|
><I
|
|
CLASS="EMPHASIS"
|
|
>File Path: JustForFun/tt.c</I
|
|
></SPAN
|
|
></P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="SECT1"
|
|
><HR><H2
|
|
CLASS="SECT1"
|
|
><A
|
|
NAME="REF"
|
|
>21. References</A
|
|
></H2
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
>NCURSES man pages </P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>NCURSES FAQ at <A
|
|
HREF="http://invisible-island.net/ncurses/ncurses.faq.html"
|
|
TARGET="_top"
|
|
>http://invisible-island.net/ncurses/ncurses.faq.html</A
|
|
>
|
|
</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Writing programs with NCURSES by Eric Raymond and Zeyd M.
|
|
Ben-Halim at
|
|
<A
|
|
HREF="http://invisible-island.net/ncurses/ncurses-intro.html"
|
|
TARGET="_top"
|
|
>http://invisible-island.net/ncurses/ncurses-intro.html</A
|
|
> - somewhat
|
|
obsolete. I was inspired by this document and the structure of this HOWTO
|
|
follows from the original document</P
|
|
></LI
|
|
></UL
|
|
></DIV
|
|
></DIV
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></BODY
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></HTML
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> |