* dispextern.h (struct glyph_string): New members clip_head and

	clip_tail.
* xdisp.c (get_glyph_string_clip_rect): Restrict horizontal clip
	region to the area between clip_head and clip_tail.
	(draw_glyphs): Record the area that need to be actually redrawn to
	the new variables clip_head and clip_tail when there are
	overhangs.  Set values of these variables to the corresponding
	members in struct glyph_string.  Refine x coordinates for
* macgui.h (STORE_XCHARSETSTRUCT): New macro.
* macterm.c (mac_compute_glyph_string_overhangs): Implement with
	QDTextBounds.
	(x_draw_glyph_string): Don't fill the background of the successor
	of a glyph with a right overhang if the successor will draw a
	cursor.
	(XLoadQueryFont): Obtain font metrics using QDTextBounds.
	(x_redisplay_interface): Add entry for
	compute_glyph_string_overhangs.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/dispextern.h b/src/dispextern.h
index 53ae50f3c2a..89a8fe39aeb 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -1193,6 +1193,11 @@ struct glyph_string
   /* Slice */
   struct glyph_slice slice;
 
+  /* Non-null means the horizontal clipping region starts from the
+     left edge of *clip_head, and ends with the right edge of
+     *clip_tail, not including their overhangs.  */
+  struct glyph_string *clip_head, *clip_tail;
+
   struct glyph_string *next, *prev;
 };