From d708f23ebb06cfc9cf8f96f17a43eb63653b818a Mon Sep 17 00:00:00 2001
From: Toomas Soome <tsoome@FreeBSD.org>
Date: Sat, 6 Mar 2021 12:19:43 +0200
Subject: [PATCH] loader: cursor off should restore display content

When drawing cursor, we should store original display
content because there may be image data we would like to restore
when the cursor is removed.

PR:		254054
Reported by:	Jose Luis Duran
MFC after:	3 days
---
 stand/common/gfx_fb.c | 38 ++++++++++++++++++++++++++++++++++++++
 stand/common/gfx_fb.h |  2 ++
 2 files changed, 40 insertions(+)

diff --git a/stand/common/gfx_fb.c b/stand/common/gfx_fb.c
index 77cf1d39854f..3eae0a3a859e 100644
--- a/stand/common/gfx_fb.c
+++ b/stand/common/gfx_fb.c
@@ -978,6 +978,7 @@ gfx_fb_fill(void *arg, const teken_rect_t *r, teken_char_t c,
 static void
 gfx_fb_cursor_draw(teken_gfx_t *state, const teken_pos_t *p, bool on)
 {
+	unsigned x, y, width, height;
 	const uint8_t *glyph;
 	int idx;
 
@@ -985,10 +986,47 @@ gfx_fb_cursor_draw(teken_gfx_t *state, const teken_pos_t *p, bool on)
 	if (idx >= state->tg_tp.tp_col * state->tg_tp.tp_row)
 		return;
 
+	width = state->tg_font.vf_width;
+	height = state->tg_font.vf_height;
+	x = state->tg_origin.tp_col + p->tp_col * width;
+	y = state->tg_origin.tp_row + p->tp_row * height;
+
+	/*
+	 * Save original display content to preserve image data.
+	 */
+	if (on) {
+		if (state->tg_cursor_image == NULL ||
+		    state->tg_cursor_size != width * height * 4) {
+			free(state->tg_cursor_image);
+			state->tg_cursor_size = width * height * 4;
+			state->tg_cursor_image = malloc(state->tg_cursor_size);
+		}
+		if (state->tg_cursor_image != NULL) {
+			if (gfxfb_blt(state->tg_cursor_image,
+			    GfxFbBltVideoToBltBuffer, x, y, 0, 0,
+			    width, height, 0) != 0) {
+				free(state->tg_cursor_image);
+				state->tg_cursor_image = NULL;
+			}
+		}
+	} else {
+		/*
+		 * Restore display from tg_cursor_image.
+		 * If there is no image, restore char from screen_buffer.
+		 */
+		if (state->tg_cursor_image != NULL &&
+		    gfxfb_blt(state->tg_cursor_image, GfxFbBltBufferToVideo,
+		    0, 0, x, y, width, height, 0) == 0) {
+			state->tg_cursor = *p;
+			return;
+		}
+	}
+
 	glyph = font_lookup(&state->tg_font, screen_buffer[idx].c,
 	    &screen_buffer[idx].a);
 	gfx_bitblt_bitmap(state, glyph, &screen_buffer[idx].a, 0xff, on);
 	gfx_fb_printchar(state, p);
+
 	state->tg_cursor = *p;
 }
 
diff --git a/stand/common/gfx_fb.h b/stand/common/gfx_fb.h
index ac63d7939cef..89b060a02cf9 100644
--- a/stand/common/gfx_fb.h
+++ b/stand/common/gfx_fb.h
@@ -210,6 +210,8 @@ typedef struct teken_gfx {
 	teken_t		tg_teken;		/* Teken core */
 	teken_pos_t	tg_cursor;		/* Where cursor was drawn */
 	bool		tg_cursor_visible;
+	uint8_t		*tg_cursor_image;	/* Memory for cursor */
+	size_t		tg_cursor_size;
 	teken_pos_t	tg_tp;			/* Terminal dimensions */
 	teken_pos_t	tg_origin;		/* Point of origin in pixels */
 	uint8_t		*tg_glyph;		/* Memory for glyph */