Take account of periodic fringe bitmap's dependency on y-position in redrawing.

* dispextern.h (struct glyph_row): New member fringe_bitmap_periodic_p.

* dispnew.c (shift_glyph_matrix, scrolling_window): Mark scrolled row
for fringe update if it has periodic bitmap.
(row_equal_p): Also compare left_fringe_offset,	right_fringe_offset,
and fringe_bitmap_periodic_p.

* fringe.c (get_fringe_bitmap_data): New function.
(draw_fringe_bitmap_1, update_window_fringes): Use it.
(update_window_fringes): Record periodicity of fringe bitmap in glyph
row.  Mark glyph row for fringe update if periodicity changed.

* xdisp.c (try_window_reusing_current_matrix): Don't mark scrolled row
for fringe update unless it has periodic bitmap.

1 files changed, 25 insertions, 14 deletions

diff --git a/src/fringe.c b/src/fringe.c
index 880fe2c6e42..e160353914e 100644
--- a/src/fringe.c
+++ b/src/fringe.c
@@ -541,6 +541,20 @@ get_fringe_bitmap_name (bn)
   return num;
 }
 
+/* Get fringe bitmap data for bitmap number BN.  */
+
+static struct fringe_bitmap *
+get_fringe_bitmap_data (int bn)
+{
+  struct fringe_bitmap *fb;
+
+  fb = fringe_bitmaps[bn];
+  if (fb == NULL)
+    fb = &standard_bitmaps[bn < MAX_STANDARD_FRINGE_BITMAPS
+                           ? bn : UNDEF_FRINGE_BITMAP];
+
+  return fb;
+}
 
 /* Draw the bitmap WHICH in one of the left or right fringes of
    window W.  ROW is the glyph row for which to display the bitmap; it
@@ -593,10 +607,7 @@ draw_fringe_bitmap_1 (w, row, left_p, overlay, which)
         face_id = FRINGE_FACE_ID;
     }
 
-  fb = fringe_bitmaps[which];
-  if (fb == NULL)
-    fb = &standard_bitmaps[which < MAX_STANDARD_FRINGE_BITMAPS
-                           ? which : UNDEF_FRINGE_BITMAP];
+  fb = get_fringe_bitmap_data (which);
 
   period = fb->period;
 
@@ -1075,12 +1086,8 @@ update_window_fringes (w, keep_current_p)
 
       if (bn != NO_FRINGE_BITMAP)
         {
-          struct fringe_bitmap *fb;
+          struct fringe_bitmap *fb = get_fringe_bitmap_data (bn);
 
-          fb = fringe_bitmaps[bn];
-          if (fb == NULL)
-            fb = &standard_bitmaps[bn < MAX_STANDARD_FRINGE_BITMAPS
-                                   ? bn : UNDEF_FRINGE_BITMAP];
           if (fb->align == ALIGN_BITMAP_TOP && fb->period == 0)
             {
               struct glyph_row *row1;
@@ -1134,12 +1141,8 @@ update_window_fringes (w, keep_current_p)
 
       if (bn != NO_FRINGE_BITMAP)
         {
-          struct fringe_bitmap *fb;
+          struct fringe_bitmap *fb = get_fringe_bitmap_data (bn);
 
-          fb = fringe_bitmaps[bn];
-          if (fb == NULL)
-            fb = &standard_bitmaps[bn < MAX_STANDARD_FRINGE_BITMAPS
-                                   ? bn : UNDEF_FRINGE_BITMAP];
           if (fb->align == ALIGN_BITMAP_BOTTOM && fb->period == 0)
             {
               struct glyph_row *row1;
@@ -1175,6 +1178,7 @@ update_window_fringes (w, keep_current_p)
       int left, right;
       unsigned left_face_id, right_face_id;
       int left_offset, right_offset;
+      int periodic_p;
 
       row = w->desired_matrix->rows + rn;
       cur = w->current_matrix->rows + rn;
@@ -1183,6 +1187,7 @@ update_window_fringes (w, keep_current_p)
 
       left_face_id = right_face_id = DEFAULT_FACE_ID;
       left_offset = right_offset = 0;
+      periodic_p = 0;
 
       /* Decide which bitmap to draw in the left fringe.  */
       if (WINDOW_LEFT_FRINGE_WIDTH (w) == 0)
@@ -1270,6 +1275,9 @@ update_window_fringes (w, keep_current_p)
       else
         right = NO_FRINGE_BITMAP;
 
+      periodic_p = (get_fringe_bitmap_data (left)->period != 0
+                    || get_fringe_bitmap_data (right)->period != 0);
+
       if (row->y != cur->y
           || row->visible_height != cur->visible_height
           || row->ends_at_zv_p != cur->ends_at_zv_p
@@ -1279,6 +1287,7 @@ update_window_fringes (w, keep_current_p)
           || right_face_id != cur->right_fringe_face_id
           || left_offset != cur->left_fringe_offset
           || right_offset != cur->right_fringe_offset
+          || periodic_p != cur->fringe_bitmap_periodic_p
           || cur->redraw_fringe_bitmaps_p)
         {
           redraw_p = row->redraw_fringe_bitmaps_p = 1;
@@ -1291,6 +1300,7 @@ update_window_fringes (w, keep_current_p)
               cur->right_fringe_face_id = right_face_id;
               cur->left_fringe_offset = left_offset;
               cur->right_fringe_offset = right_offset;
+              cur->fringe_bitmap_periodic_p = periodic_p;
             }
         }
 
@@ -1309,6 +1319,7 @@ update_window_fringes (w, keep_current_p)
       row->right_fringe_face_id = right_face_id;
       row->left_fringe_offset = left_offset;
       row->right_fringe_offset = right_offset;
+      row->fringe_bitmap_periodic_p = periodic_p;
     }
 
   return redraw_p && !keep_current_p;