[gimp/gimp-2-8] Bug 645345: 'Color Management' display filter causes performance problems

[Massimo Valentini <mvalentini src gnome org>]

commit 41ce828243cd751618ac8ea90916f8aa880faeb4
Author: Massimo Valentini <mvalentini src gnome org>
Date:   Sat Jun 9 15:36:34 2012 +0200

    Bug 645345: 'Color Management' display filter causes performance problems

 app/display/gimpcanvasarc.c           |   27 +++++++++++++++++++++++----
 app/display/gimpdisplayshell-render.c |   20 ++++++++++++++++----
 2 files changed, 39 insertions(+), 8 deletions(-)
---
diff --git a/app/display/gimpcanvasarc.c b/app/display/gimpcanvasarc.c
index bdf4d80..93433b4 100644
--- a/app/display/gimpcanvasarc.c
+++ b/app/display/gimpcanvasarc.c
@@ -292,9 +292,11 @@ static cairo_region_t *
 gimp_canvas_arc_get_extents (GimpCanvasItem   *item,
                              GimpDisplayShell *shell)
 {
-  cairo_rectangle_int_t rectangle;
-  gdouble               center_x, center_y;
-  gdouble               radius_x, radius_y;
+  GimpCanvasArcPrivate  *private = GET_PRIVATE (item);
+  cairo_region_t        *region;
+  cairo_rectangle_int_t  rectangle;
+  gdouble                center_x, center_y;
+  gdouble                radius_x, radius_y;
 
   gimp_canvas_arc_transform (item, shell,
                              &center_x, &center_y,
@@ -305,7 +307,24 @@ gimp_canvas_arc_get_extents (GimpCanvasItem   *item,
   rectangle.width  = ceil (center_x + radius_x + 1.5) - rectangle.x;
   rectangle.height = ceil (center_y + radius_y + 1.5) - rectangle.y;
 
-  return cairo_region_create_rectangle (&rectangle);
+  region = cairo_region_create_rectangle (&rectangle);
+
+  if (! private->filled &&
+      rectangle.width > 64 * 1.43 &&
+      rectangle.height > 64 * 1.43)
+    {
+      radius_x *= 0.7;
+      radius_y *= 0.7;
+
+      rectangle.x      = ceil (center_x - radius_x + 1.5);
+      rectangle.y      = ceil (center_y - radius_y + 1.5);
+      rectangle.width  = floor (center_x + radius_x - 1.5) - rectangle.x;
+      rectangle.height = floor (center_y + radius_y - 1.5) - rectangle.y;
+
+      cairo_region_subtract_rectangle (region, &rectangle);
+    }
+
+  return region;
 }
 
 GimpCanvasItem *
diff --git a/app/display/gimpdisplayshell-render.c b/app/display/gimpdisplayshell-render.c
index 1f41541..a8811ec 100644
--- a/app/display/gimpdisplayshell-render.c
+++ b/app/display/gimpdisplayshell-render.c
@@ -172,12 +172,24 @@ gimp_display_shell_render (GimpDisplayShell *shell,
       g_assert_not_reached ();
     }
 
-  cairo_surface_mark_dirty (shell->render_surface);
-
   /*  apply filters to the rendered projection  */
   if (shell->filter_stack)
-    gimp_color_display_stack_convert_surface (shell->filter_stack,
-                                              shell->render_surface);
+    {
+      cairo_surface_t *sub = shell->render_surface;
+
+      if (w != GIMP_DISPLAY_RENDER_BUF_WIDTH ||
+          h != GIMP_DISPLAY_RENDER_BUF_HEIGHT)
+        sub = cairo_image_surface_create_for_data (cairo_image_surface_get_data (sub),
+                                                   CAIRO_FORMAT_ARGB32, w, h,
+                                                   GIMP_DISPLAY_RENDER_BUF_WIDTH * 4);
+
+      gimp_color_display_stack_convert_surface (shell->filter_stack, sub);
+
+      if (sub != shell->render_surface)
+        cairo_surface_destroy (sub);
+    }
+
+  cairo_surface_mark_dirty_rectangle (shell->render_surface, 0, 0, w, h);
 
   if (shell->mask)
     {