[gimp] app: cache the GeglBuffer used for display filters in GimpDisplayShell

[Michael Natterer <mitch src gnome org>]

commit 57d291e130674c59a27fe772de72bc7700483a96
Author: Michael Natterer <mitch gimp org>
Date:   Sat Nov 2 20:56:25 2013 +0100

    app: cache the GeglBuffer used for display filters in GimpDisplayShell
    
    so it is not created and destroyed all the time.

 app/display/gimpdisplayshell-render.c |   42 ++++++++++++++++++---------------
 app/display/gimpdisplayshell.c        |    8 ++++++
 app/display/gimpdisplayshell.h        |    6 ++++-
 3 files changed, 36 insertions(+), 20 deletions(-)
---
diff --git a/app/display/gimpdisplayshell-render.c b/app/display/gimpdisplayshell-render.c
index a50c7e9..7f10009 100644
--- a/app/display/gimpdisplayshell-render.c
+++ b/app/display/gimpdisplayshell-render.c
@@ -114,13 +114,26 @@ gimp_display_shell_render (GimpDisplayShell *shell,
   /*  apply filters to the rendered projection  */
   if (shell->filter_stack)
     {
-      const Babl *tmp_format = babl_format ("R'G'B'A float");
-      GeglBuffer *tmp_buffer;
-      guchar     *tmp_data;
+      const Babl *filter_format = babl_format ("R'G'B'A float");
 
-      tmp_data = gegl_malloc (w * window_scale *
-                              h * window_scale *
-                              babl_format_get_bytes_per_pixel (tmp_format));
+      if (! shell->filter_buffer)
+        {
+          gint w = GIMP_DISPLAY_RENDER_BUF_WIDTH  * GIMP_DISPLAY_RENDER_MAX_SCALE;
+          gint h = GIMP_DISPLAY_RENDER_BUF_HEIGHT * GIMP_DISPLAY_RENDER_MAX_SCALE;
+
+          shell->filter_data =
+            gegl_malloc (w * h * babl_format_get_bytes_per_pixel (filter_format));
+
+          shell->filter_stride = w * babl_format_get_bytes_per_pixel (filter_format);
+
+          shell->filter_buffer =
+            gegl_buffer_linear_new_from_data (shell->filter_data,
+                                              filter_format,
+                                              GEGL_RECTANGLE (0, 0, w, h),
+                                              GEGL_AUTO_ROWSTRIDE,
+                                              (GDestroyNotify) gegl_free,
+                                              shell->filter_data);
+        }
 
       gegl_buffer_get (buffer,
                        GEGL_RECTANGLE ((x + viewport_offset_x) * window_scale,
@@ -128,24 +141,17 @@ gimp_display_shell_render (GimpDisplayShell *shell,
                                        w * window_scale,
                                        h * window_scale),
                        shell->scale_x * window_scale,
-                       tmp_format, tmp_data,
-                       GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
+                       filter_format, shell->filter_data,
+                       shell->filter_stride, GEGL_ABYSS_NONE);
 
-      tmp_buffer =
-        gegl_buffer_linear_new_from_data (tmp_data, tmp_format,
-                                          GEGL_RECTANGLE (0, 0,
-                                                          w * window_scale,
-                                                          h * window_scale),
-                                          GEGL_AUTO_ROWSTRIDE,
-                                          (GDestroyNotify) gegl_free, tmp_data);
 
       gimp_color_display_stack_convert_buffer (shell->filter_stack,
-                                               tmp_buffer,
+                                               shell->filter_buffer,
                                                GEGL_RECTANGLE (0, 0,
                                                                w * window_scale,
                                                                h * window_scale));
 
-      gegl_buffer_get (tmp_buffer,
+      gegl_buffer_get (shell->filter_buffer,
                        GEGL_RECTANGLE (0, 0,
                                        w * window_scale,
                                        h * window_scale),
@@ -153,8 +159,6 @@ gimp_display_shell_render (GimpDisplayShell *shell,
                        babl_format ("cairo-ARGB32"),
                        data, stride,
                        GEGL_ABYSS_NONE);
-
-      g_object_unref (tmp_buffer);
     }
   else
     {
diff --git a/app/display/gimpdisplayshell.c b/app/display/gimpdisplayshell.c
index 4b94b30..108339a 100644
--- a/app/display/gimpdisplayshell.c
+++ b/app/display/gimpdisplayshell.c
@@ -797,6 +797,14 @@ gimp_display_shell_dispose (GObject *object)
       shell->checkerboard = NULL;
     }
 
+  if (shell->filter_buffer)
+    {
+      g_object_unref (shell->filter_buffer);
+      shell->filter_buffer = NULL;
+      shell->filter_data   = NULL;
+      shell->filter_stride = 0;
+    }
+
   if (shell->mask)
     {
       g_object_unref (shell->mask);
diff --git a/app/display/gimpdisplayshell.h b/app/display/gimpdisplayshell.h
index ffe04bf..c9b1058 100644
--- a/app/display/gimpdisplayshell.h
+++ b/app/display/gimpdisplayshell.h
@@ -108,10 +108,14 @@ struct _GimpDisplayShell
 
   GtkWidget         *statusbar;        /*  statusbar                          */
 
-  GimpDisplayXfer   *xfer;             /*  managers image buffer transfers    */
+  GimpDisplayXfer   *xfer;             /*  manages image buffer transfers     */
   cairo_surface_t   *mask_surface;     /*  buffer for rendering the mask      */
   cairo_pattern_t   *checkerboard;     /*  checkerboard pattern               */
 
+  GeglBuffer        *filter_buffer;    /*  buffer for display filters         */
+  guchar            *filter_data;      /*  filter_buffer's pixels             */
+  gint               filter_stride;    /*  filter_buffer's stride             */
+
   GimpCanvasItem    *canvas_item;      /*  items drawn on the canvas          */
   GimpCanvasItem    *unrotated_item;   /*  unrotated items for e.g. cursor    */
   GimpCanvasItem    *passe_partout;    /*  item for the highlight             */