Disable scrolling optimizations when a stipple is present

* src/dispextern.h (struct glyph_row): New field `stippled_p'.
We cannot just use the contents of the glyph row, since it has
to be set in `gui_clear_end_of_line' and is more convenient to
set inside the various draw_glyph_string functions.

* src/dispnew.c (scrolling_window): Disable if a row in the
current matrix has the stipple_p flag set.

* src/xdisp.c (gui_clear_end_of_line):
* src/xterm.c (x_draw_image_glyph_string)
(x_draw_stretch_glyph_string, x_draw_glyph_string): Set
`stipple_p' if a stipple pattern was drawn.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/dispextern.h b/src/dispextern.h
index e9b19a7f135..a7f478acdf8 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -1075,6 +1075,9 @@ struct glyph_row
      right-to-left paragraph.  */
   bool_bf reversed_p : 1;
 
+  /* Whether or not a stipple was drawn in this row at some point.  */
+  bool_bf stipple_p : 1;
+
   /* Continuation lines width at the start of the row.  */
   int continuation_lines_width;