diff --git a/lib/libvgl/bitmap.c b/lib/libvgl/bitmap.c
index eafced3cc7e0..0a7f049d9fa0 100644
--- a/lib/libvgl/bitmap.c
+++ b/lib/libvgl/bitmap.c
@@ -207,7 +207,7 @@ __VGLBitmapCopy(VGLBitmap *src, int srcx, int srcy,
   yextra = 0;
   ystep = 1;
   if (src->Bitmap == dst->Bitmap && srcy < dsty) {
-    yend = srcy;
+    yend = srcy - 1;
     yextra = hight - 1;
     ystep = -1;
   }