From: Eli Zaretskii <eliz@gnu.org>
Date: Wed, 12 Sep 2012 17:12:10 +0000 (+0300)
Subject: Fix bug #12403 with garbled display under non-zero scroll-margin.
X-Git-Url: http://git.hcoop.net/bpt/emacs.git/commitdiff_plain/aa36e4d28b7a405fa542d9fa1dbbfd9758980f22

Fix bug #12403 with garbled display under non-zero scroll-margin.

 src/xdisp.c (try_window_reusing_current_matrix): Under bidi
 reordering, locate the cursor by calling set_cursor_from_row; if
 that fails, clear the desired glyph matrix before returning a
 failure indication to the caller.  Fixes leaving garbled display
 when fast scrolling with a down-key when scroll-margin is non-zero.
---

diff --git a/src/ChangeLog b/src/ChangeLog
index 49c1fa345b..39bdd19118 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,11 @@
+2012-09-12  Eli Zaretskii  <eliz@gnu.org>
+
+	* xdisp.c (try_window_reusing_current_matrix): Under bidi
+	reordering, locate the cursor by calling set_cursor_from_row; if
+	that fails, clear the desired glyph matrix before returning a
+	failure indication to the caller.  Fixes leaving garbled display
+	when fast scrolling with a down-key.  (Bug#12403)
+
 2012-09-12  Jan Djärv  <jan.h.d@swipnet.se>
 
 	* gtkutil.c (x_wm_set_size_hint): Use 1 col for base_width so it
diff --git a/src/xdisp.c b/src/xdisp.c
index 6762bf85eb..3fab4b54cf 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -16593,28 +16593,33 @@ try_window_reusing_current_matrix (struct window *w)
 	    }
 	  if (row < bottom_row)
 	    {
-	      struct glyph *glyph = row->glyphs[TEXT_AREA] + w->cursor.hpos;
-	      struct glyph *end = row->glyphs[TEXT_AREA] + row->used[TEXT_AREA];
-
-	      /* Can't use this optimization with bidi-reordered glyph
-		 rows, unless cursor is already at point. */
+	      /* Can't simply scan the row for point with
+		 bidi-reordered glyph rows.  Let set_cursor_from_row
+		 figure out where to put the cursor, and if it fails,
+		 give up.  */
 	      if (!NILP (BVAR (XBUFFER (w->buffer), bidi_display_reordering)))
 		{
-		  if (!(w->cursor.hpos >= 0
-			&& w->cursor.hpos < row->used[TEXT_AREA]
-			&& BUFFERP (glyph->object)
-			&& glyph->charpos == PT))
-		    return 0;
+		  if (!set_cursor_from_row (w, row, w->current_matrix,
+					    0, 0, 0, 0))
+		    {
+		      clear_glyph_matrix (w->desired_matrix);
+		      return 0;
+		    }
 		}
 	      else
-		for (; glyph < end
-		       && (!BUFFERP (glyph->object)
-			   || glyph->charpos < PT);
-		     glyph++)
-		  {
-		    w->cursor.hpos++;
-		    w->cursor.x += glyph->pixel_width;
-		  }
+		{
+		  struct glyph *glyph = row->glyphs[TEXT_AREA] + w->cursor.hpos;
+		  struct glyph *end = row->glyphs[TEXT_AREA] + row->used[TEXT_AREA];
+
+		  for (; glyph < end
+			 && (!BUFFERP (glyph->object)
+			     || glyph->charpos < PT);
+		       glyph++)
+		    {
+		      w->cursor.hpos++;
+		      w->cursor.x += glyph->pixel_width;
+		    }
+		}
 	    }
 	}