[evince] libview: Don't queue a redraw when damaged region hasn't changed

[Carlos Garcia Campos <carlosgc src gnome org>]

commit 4093541cef545ac30cfe64eb0f4fb7bd7a11fb34
Author: Carlos Garcia Campos <carlosgc gnome org>
Date:   Thu Jun 27 14:34:14 2013 +0200

    libview: Don't queue a redraw when damaged region hasn't changed
    
    When the region covered by old and new selection is the same, don't
    schedule a new redraw for the union.

 libview/ev-view.c |   50 ++++++++++++++++++++++++++------------------------
 1 files changed, 26 insertions(+), 24 deletions(-)
---
diff --git a/libview/ev-view.c b/libview/ev-view.c
index 4bc12e7..042a621 100644
--- a/libview/ev-view.c
+++ b/libview/ev-view.c
@@ -7285,30 +7285,32 @@ merge_selection_region (EvView *view,
                /* Now we figure out what needs redrawing */
                if (old_sel && new_sel) {
                        if (old_sel->covered_region && new_sel->covered_region) {
-                               /* Anything that was previously or currently selected may
-                                * have changed */
-                               region = cairo_region_copy (old_sel->covered_region);
-                               cairo_region_union (region, new_sel->covered_region);
-
-                               if (cairo_region_is_empty (region)) {
-                                       cairo_region_destroy (region);
-                                       region = NULL;
-                               } else {
-                                       gint num_rectangles = cairo_region_num_rectangles (region);
-                                       GdkRectangle r;
-
-                                       /* We need to make the damage region a little bigger
-                                        * because the edges of the old selection might change
-                                        */
-                                       cairo_region_get_rectangle (region, 0, &r);
-                                       r.x -= 5;
-                                       r.width = 5;
-                                       cairo_region_union_rectangle (region, &r);
-
-                                       cairo_region_get_rectangle (region, num_rectangles - 1, &r);
-                                       r.x += r.width;
-                                       r.width = 5;
-                                       cairo_region_union_rectangle (region, &r);
+                               if (!cairo_region_equal (old_sel->covered_region, new_sel->covered_region)) {
+                                       /* Anything that was previously or currently selected may
+                                        * have changed */
+                                       region = cairo_region_copy (old_sel->covered_region);
+                                       cairo_region_union (region, new_sel->covered_region);
+
+                                       if (cairo_region_is_empty (region)) {
+                                               cairo_region_destroy (region);
+                                               region = NULL;
+                                       } else {
+                                               gint num_rectangles = cairo_region_num_rectangles (region);
+                                               GdkRectangle r;
+
+                                               /* We need to make the damage region a little bigger
+                                                * because the edges of the old selection might change
+                                                */
+                                               cairo_region_get_rectangle (region, 0, &r);
+                                               r.x -= 5;
+                                               r.width = 5;
+                                               cairo_region_union_rectangle (region, &r);
+
+                                               cairo_region_get_rectangle (region, num_rectangles - 1, &r);
+                                               r.x += r.width;
+                                               r.width = 5;
+                                               cairo_region_union_rectangle (region, &r);
+                                       }
                                }
                        } else if (old_sel->covered_region) {
                                region = cairo_region_copy (old_sel->covered_region);