(expose_overlaps): New function.

(expose_window): Use it to fix the display of overlapping rows.

1 files changed, 49 insertions, 1 deletions

diff --git a/src/xterm.c b/src/xterm.c
index 151fe744193..3fbdd725c43 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -485,6 +485,8 @@ static int x_intersect_rectangles P_ ((XRectangle *, XRectangle *,
                                        XRectangle *));
 static void expose_frame P_ ((struct frame *, int, int, int, int));
 static int expose_window_tree P_ ((struct window *, XRectangle *));
+static void expose_overlaps P_ ((struct window *, struct glyph_row *,
+                                 struct glyph_row *));
 static int expose_window P_ ((struct window *, XRectangle *));
 static void expose_area P_ ((struct window *, struct glyph_row *,
                              XRectangle *, enum glyph_row_area));
@@ -6070,6 +6072,39 @@ x_phys_cursor_in_rect_p (w, r)
 }
 
 
+/* Redraw those parts of glyphs rows during expose event handling that
+   overlap other rows.  Redrawing of an exposed line writes over parts
+   of lines overlapping that exposed line; this function fixes that.
+
+   W is the window being exposed.  FIRST_OVERLAPPING_ROW is the first
+   row in W's current matrix that is exposed and overlaps other rows.
+   LAST_OVERLAPPING_ROW is the last such row.  */
+
+static void
+expose_overlaps (w, first_overlapping_row, last_overlapping_row)
+     struct window *w;
+     struct glyph_row *first_overlapping_row;
+     struct glyph_row *last_overlapping_row;
+{
+  struct glyph_row *row;
+  
+  for (row = first_overlapping_row; row <= last_overlapping_row; ++row)
+    if (row->overlapping_p)
+      {
+        xassert (row->enabled_p && !row->mode_line_p);
+          
+        if (row->used[LEFT_MARGIN_AREA])
+          x_fix_overlapping_area (w, row, LEFT_MARGIN_AREA);
+  
+        if (row->used[TEXT_AREA])
+          x_fix_overlapping_area (w, row, TEXT_AREA);
+  
+        if (row->used[RIGHT_MARGIN_AREA])
+          x_fix_overlapping_area (w, row, RIGHT_MARGIN_AREA);
+      }
+}
+
+
 /* Redraw the part of window W intersection rectangle FR.  Pixel
    coordinates in FR are frame-relative.  Call this function with
    input blocked.  Value is non-zero if the exposure overwrites
@@ -6111,6 +6146,7 @@ expose_window (w, fr)
       int yb = window_text_bottom_y (w);
       struct glyph_row *row;
       int cursor_cleared_p;
+      struct glyph_row *first_overlapping_row, *last_overlapping_row;
   
       TRACE ((stderr, "expose_window (%d, %d, %d, %d)\n",
               r.x, r.y, r.width, r.height));
@@ -6129,7 +6165,8 @@ expose_window (w, fr)
       else
         cursor_cleared_p = 0;
 
-      /* Find the first row intersecting the rectangle R.  */
+      /* Update lines intersecting rectangle R.  */
+      first_overlapping_row = last_overlapping_row = NULL;
       for (row = w->current_matrix->rows;
            row->enabled_p;
            ++row)
@@ -6142,6 +6179,13 @@ expose_window (w, fr)
               || (r.y >= y0 && r.y < y1)
               || (r.y + r.height > y0 && r.y + r.height < y1))
             {
+              if (row->overlapping_p)
+                {
+                  if (first_overlapping_row == NULL)
+                    first_overlapping_row = row;
+                  last_overlapping_row = row;
+                }
+              
               if (expose_line (w, row, &r))
                 mouse_face_overwritten_p = 1;
             }
@@ -6162,6 +6206,10 @@ expose_window (w, fr)
 
       if (!w->pseudo_window_p)
         {
+          /* Fix the display of overlapping rows.  */
+          if (first_overlapping_row)
+            expose_overlaps (w, first_overlapping_row, last_overlapping_row);
+          
           /* Draw border between windows.  */
           x_draw_vertical_border (w);