Fix support for R2L lines. Tested with reordered text.

 xdisp.c (mouse_face_from_string_pos): Fix support for R2L lines.

2 files changed, 59 insertions, 34 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index d6e93b28299..a86b33fa3af 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -5,6 +5,7 @@
         our early if no row in the window belongs to the highlighted
         string.  Always back up after exiting the second loop.
         Fix off-by-one error when testing against ENDPOS.
+        Fix support for R2L lines.
 
 2010-10-16  Eli Zaretskii  <eliz@gnu.org>
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 2db6ab8dbd1..fe3eeec982b 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -24425,35 +24425,48 @@ mouse_face_from_string_pos (struct window *w, Display_Info *dpyinfo,
   int found = 0;
 
   /* Find the glyph row with at least one position in the range
-     [STARTPOS..ENDPOS], and the leftmost glyph in that row whose
+     [STARTPOS..ENDPOS], and the first glyph in that row whose
      position belongs to that range.  */
   for (r = MATRIX_FIRST_TEXT_ROW (w->current_matrix);
        r->enabled_p && r->y < yb;
        ++r)
     {
-      g = r->glyphs[TEXT_AREA];
-      e = g + r->used[TEXT_AREA];
-      for (gx = r->x; g < e; gx += g->pixel_width, ++g)
-        if (EQ (g->object, object)
-            && startpos <= g->charpos && g->charpos <= endpos)
-          {
-            dpyinfo->mouse_face_beg_row = r - w->current_matrix->rows;
-            dpyinfo->mouse_face_beg_y = r->y;
-            if (!r->reversed_p)
+      if (!r->reversed_p)
+        {
+          g = r->glyphs[TEXT_AREA];
+          e = g + r->used[TEXT_AREA];
+          for (gx = r->x; g < e; gx += g->pixel_width, ++g)
+            if (EQ (g->object, object)
+                && startpos <= g->charpos && g->charpos <= endpos)
               {
+                dpyinfo->mouse_face_beg_row = r - w->current_matrix->rows;
+                dpyinfo->mouse_face_beg_y = r->y;
                 dpyinfo->mouse_face_beg_col = g - r->glyphs[TEXT_AREA];
                 dpyinfo->mouse_face_beg_x = gx;
+                found = 1;
+                break;
               }
-            else
+        }
+      else
+        {
+          struct glyph *g1;
+
+          e = r->glyphs[TEXT_AREA];
+          g = e + r->used[TEXT_AREA];
+          for ( ; g > e; --g)
+            if (EQ ((g-1)->object, object)
+                && startpos <= (g-1)->charpos && (g-1)->charpos <= endpos)
               {
-                /* R2L rows want BEG and END swapped, see
-                   show_mouse_face.  */
-                dpyinfo->mouse_face_end_col = g - r->glyphs[TEXT_AREA];
-                dpyinfo->mouse_face_end_x = gx;
+                dpyinfo->mouse_face_beg_row = r - w->current_matrix->rows;
+                dpyinfo->mouse_face_beg_y = r->y;
+                dpyinfo->mouse_face_beg_col = g - r->glyphs[TEXT_AREA];
+                for (gx = r->x, g1 = r->glyphs[TEXT_AREA]; g1 < g; ++g1)
+                  gx += g1->pixel_width;
+                dpyinfo->mouse_face_beg_x = gx;
+                found = 1;
+                break;
               }
-            found = 1;
-            break;
-          }
+        }
       if (found)
         break;
     }
@@ -24486,25 +24499,36 @@ mouse_face_from_string_pos (struct window *w, Display_Info *dpyinfo,
   dpyinfo->mouse_face_end_row = r - w->current_matrix->rows;
   dpyinfo->mouse_face_end_y = r->y;
 
-  /* Compute and set the end column.  */
-  g = r->glyphs[TEXT_AREA];
-  e = g + r->used[TEXT_AREA];
-  for ( ; e > g; --e)
-    if (EQ ((e-1)->object, object)
-        && startpos <= (e-1)->charpos && (e-1)->charpos <= endpos)
-      break;
+  /* Compute and set the end column and the end column's horizontal
+     pixel coordinate.  */
   if (!r->reversed_p)
-    dpyinfo->mouse_face_end_col = e - g;
-  else
-    dpyinfo->mouse_face_beg_col = e - g;
+    {
+      g = r->glyphs[TEXT_AREA];
+      e = g + r->used[TEXT_AREA];
+      for ( ; e > g; --e)
+        if (EQ ((e-1)->object, object)
+            && startpos <= (e-1)->charpos && (e-1)->charpos <= endpos)
+          break;
+      dpyinfo->mouse_face_end_col = e - g;
 
-  /* Compute and set the end column's horizontal pixel coordinate.  */
-  for (gx = r->x; g < e; ++g)
-    gx += g->pixel_width;
-  if (!r->reversed_p)
-    dpyinfo->mouse_face_end_x = gx;
+      for (gx = r->x; g < e; ++g)
+        gx += g->pixel_width;
+      dpyinfo->mouse_face_end_x = gx;
+    }
   else
-    dpyinfo->mouse_face_beg_x = gx;
+    {
+      e = r->glyphs[TEXT_AREA];
+      g = e + r->used[TEXT_AREA];
+      for (gx = r->x ; e < g; ++e)
+        {
+          if (EQ (e->object, object)
+              && startpos <= e->charpos && e->charpos <= endpos)
+            break;
+          gx += e->pixel_width;
+        }
+      dpyinfo->mouse_face_end_col = e - r->glyphs[TEXT_AREA];
+      dpyinfo->mouse_face_end_x = gx;
+    }
 }
 
 /* See if position X, Y is within a hot-spot of an image.  */