Fix highlight of trailing whitespace is right-to-left lines.

 xdisp.c (highlight_trailing_whitespace): Support highlight of
 trailing whitespace in right-to-left rows.

2 files changed, 46 insertions, 11 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9d70a3327b6..3c43c80764a 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2010-03-31  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (highlight_trailing_whitespace): Support highlight of
+        trailing whitespace in right-to-left rows.
+
 2010-03-31  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         Get rid of the direct_output optimizations.
diff --git a/src/xdisp.c b/src/xdisp.c
index b3aaa52e2e5..709ff5f6d68 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -16868,19 +16868,37 @@ highlight_trailing_whitespace (f, row)
       struct glyph *start = row->glyphs[TEXT_AREA];
       struct glyph *glyph = start + used - 1;
 
+      if (row->reversed_p)
+        {
+          /* Right-to-left rows need to be processed in the opposite
+             direction, so swap the edge pointers. */
+          glyph = start;
+          start = row->glyphs[TEXT_AREA] + used - 1;
+        }
+
       /* Skip over glyphs inserted to display the cursor at the
          end of a line, for extending the face of the last glyph
          to the end of the line on terminals, and for truncation
          and continuation glyphs.  */
-      while (glyph >= start
-             && glyph->type == CHAR_GLYPH
-             && INTEGERP (glyph->object))
-        --glyph;
+      if (!row->reversed_p)
+        {
+          while (glyph >= start
+                 && glyph->type == CHAR_GLYPH
+                 && INTEGERP (glyph->object))
+            --glyph;
+        }
+      else
+        {
+          while (glyph <= start
+                 && glyph->type == CHAR_GLYPH
+                 && INTEGERP (glyph->object))
+            ++glyph;
+        }
 
       /* If last glyph is a space or stretch, and it's trailing
          whitespace, set the face of all trailing whitespace glyphs in
          IT->glyph_row to `trailing-whitespace'.  */
-      if (glyph >= start
+      if ((row->reversed_p ? glyph <= start : glyph >= start)
           && BUFFERP (glyph->object)
           && (glyph->type == STRETCH_GLYPH
               || (glyph->type == CHAR_GLYPH
@@ -16891,12 +16909,24 @@ highlight_trailing_whitespace (f, row)
           if (face_id < 0)
             return;
 
-          while (glyph >= start
-                 && BUFFERP (glyph->object)
-                 && (glyph->type == STRETCH_GLYPH
-                     || (glyph->type == CHAR_GLYPH
-                         && glyph->u.ch == ' ')))
-            (glyph--)->face_id = face_id;
+          if (!row->reversed_p)
+            {
+              while (glyph >= start
+                     && BUFFERP (glyph->object)
+                     && (glyph->type == STRETCH_GLYPH
+                         || (glyph->type == CHAR_GLYPH
+                             && glyph->u.ch == ' ')))
+                (glyph--)->face_id = face_id;
+            }
+          else
+            {
+              while (glyph <= start
+                     && BUFFERP (glyph->object)
+                     && (glyph->type == STRETCH_GLYPH
+                         || (glyph->type == CHAR_GLYPH
+                             && glyph->u.ch == ' ')))
+                (glyph++)->face_id = face_id;
+            }
         }
     }
 }