Fix cursor drawing in hscrolled R2L screen lines.

 src/xdisp.c (get_glyph_string_clip_rects): Don't let the width of a
 clipping rectangle become negative (i.e. large positive, since
 it's an unsigned data type).  This can happen in R2L hscrolled
 glyph rows, and caused us to draw the cursor glyph on the fringe.
 For the details, see
 http://lists.gnu.org/archive/html/emacs-devel/2014-08/msg00543.html.

2 files changed, 13 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 8f2e01f8cf9..26ee524acda 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2014-08-31  Eli Zaretskii  <eliz@gnu.org>
+
+	* xdisp.c (get_glyph_string_clip_rects): Don't let the width of a
+	clipping rectangle become negative (i.e. large positive, since
+	it's an unsigned data type).  This can happen in R2L hscrolled
+	glyph rows, and caused us to draw the cursor glyph on the fringe.
+	For the details, see
+	http://lists.gnu.org/archive/html/emacs-devel/2014-08/msg00543.html.
+
 2014-08-31  Ken Brown  <kbrown@cornell.edu>
 
 	* gmalloc.c: Don't include <stdlib.h>.  Declare system malloc and
diff --git a/src/xdisp.c b/src/xdisp.c
index 2b12dd8f557..4383c497d7a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2174,7 +2174,10 @@ get_glyph_string_clip_rects (struct glyph_string *s, NativeRectangle *rects, int
 
       if (s->x > r.x)
 	{
-	  r.width -= s->x - r.x;
+	  if (r.width >= s->x - r.x)
+	    r.width -= s->x - r.x;
+	  else	/* R2L hscrolled row with cursor outside text area */
+	    r.width = 0;
 	  r.x = s->x;
 	}
       r.width = min (r.width, glyph->pixel_width);