2 files changed, 44 insertions, 31 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 7444c76d91c..ee13b6a4b35 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -3,6 +3,7 @@
         * xdisp.c (mouse_face_from_buffer_pos): Fix code using bug#1220 as
         test case.  Implement  highlight for R2L rows.  Fix the case of
         continued L2R lines.
+        (show_mouse_face): Support drawing highlighted R2L lines.
 
 2010-08-21  Eli Zaretskii  <eliz@gnu.org>
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 92d3dbea319..3a99435123a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -23711,8 +23711,30 @@ show_mouse_face (Display_Info *dpyinfo, enum draw_glyphs_face draw)
           /* For all but the first row, the highlight starts at column 0.  */
           if (row == first)
             {
-              start_hpos = dpyinfo->mouse_face_beg_col;
-              start_x = dpyinfo->mouse_face_beg_x;
+              /* R2L rows have BEG and END in reversed order, but the
+                 screen drawing geometry is always left to right.  So
+                 we need to mirror the beginning and end of the
+                 highlighted area in R2L rows.  */
+              if (!row->reversed_p)
+                {
+                  start_hpos = dpyinfo->mouse_face_beg_col;
+                  start_x = dpyinfo->mouse_face_beg_x;
+                }
+              else if (row == last)
+                {
+                  start_hpos = dpyinfo->mouse_face_end_col;
+                  start_x = dpyinfo->mouse_face_end_x;
+                }
+              else
+                {
+                  start_hpos = 0;
+                  start_x = 0;
+                }
+            }
+          else if (row->reversed_p && row == last)
+            {
+              start_hpos = dpyinfo->mouse_face_end_col;
+              start_x = dpyinfo->mouse_face_end_x;
             }
           else
             {
@@ -23721,7 +23743,20 @@ show_mouse_face (Display_Info *dpyinfo, enum draw_glyphs_face draw)
             }
 
           if (row == last)
-            end_hpos = dpyinfo->mouse_face_end_col;
+            {
+              if (!row->reversed_p)
+                end_hpos = dpyinfo->mouse_face_end_col;
+              else if (row == first)
+                end_hpos = dpyinfo->mouse_face_beg_col;
+              else
+                {
+                  end_hpos = row->used[TEXT_AREA];
+                  if (draw == DRAW_NORMAL_TEXT)
+                    row->fill_line_p = 1; /* Clear to end of line */
+                }
+            }
+          else if (row->reversed_p && row == first)
+            end_hpos = dpyinfo->mouse_face_beg_col;
           else
             {
               end_hpos = row->used[TEXT_AREA];
@@ -24002,16 +24037,11 @@ mouse_face_from_buffer_pos (Lisp_Object window,
                 }
             }
 
-          /* Mouse highlight uses the screen geometry, which is left
-             to right even in R2L paragraphs.  Therefore, for R2L
-             paragraphs, the "first" highlighted glyph actually
-             determines the _end_ column and x of the highlighted
-             area.  */
-          glyph++;      /* first glyph beyond the highlighted area */
+          glyph++; /* first glyph to the right of the highlighted area */
           for (g = row->glyphs[TEXT_AREA], x = row->x; g < glyph; g++)
             x += g->pixel_width;
-          dpyinfo->mouse_face_end_x = x;
-          dpyinfo->mouse_face_end_col = glyph - row->glyphs[TEXT_AREA];
+          dpyinfo->mouse_face_beg_x = x;
+          dpyinfo->mouse_face_beg_col = glyph - row->glyphs[TEXT_AREA];
         }
     }
 
@@ -24041,13 +24071,6 @@ mouse_face_from_buffer_pos (Lisp_Object window,
      for the end row.  */
   if (r != row)
     {
-      /* If the beginning row was an R2L row, we actually computed
-         above the beginning of the highlighted area, not its end.  */
-      if (row->reversed_p)
-        {
-          dpyinfo->mouse_face_beg_x = dpyinfo->mouse_face_end_x;
-          dpyinfo->mouse_face_beg_col = dpyinfo->mouse_face_end_col;
-        }
       if (!r->reversed_p)
         {
           glyph = r->glyphs[TEXT_AREA];
@@ -24154,19 +24177,8 @@ mouse_face_from_buffer_pos (Lisp_Object window,
             }
           x += end->pixel_width;
         }
-      /* In the left-to-right screen geometry, END is actually the
-         _beginning_ of the highlighted area for R2L paragraphs, if
-         the highlight begins and ends in the same row.  */
-      if (dpyinfo->mouse_face_end_row == dpyinfo->mouse_face_beg_row)
-        {
-          dpyinfo->mouse_face_beg_x = x;
-          dpyinfo->mouse_face_beg_col = end - row->glyphs[TEXT_AREA];
-        }
-      else
-        {
-          dpyinfo->mouse_face_end_x = x;
-          dpyinfo->mouse_face_end_col = end - row->glyphs[TEXT_AREA];
-        }
+      dpyinfo->mouse_face_end_x = x;
+      dpyinfo->mouse_face_end_col = end - row->glyphs[TEXT_AREA];
     }
 
   dpyinfo->mouse_face_window = window;