[gimp] app: speed up gimp_image_contiguous_region_by_seed using a temporary GeglBuffer

[Michael Henning <mhenning src gnome org>]

commit e839ae09559890c0d11bea4033303a0f3b850de1
Author: Michael Henning <drawoc darkrefraction com>
Date:   Mon Apr 8 15:02:23 2013 -0400

    app: speed up gimp_image_contiguous_region_by_seed using a temporary GeglBuffer
    
    This is identical to c204b0ac413539ee763483970a64eb437a43de3f, except
    it avoids setting the buffer type of the drawable using a buffer copy.
    (that issue is explained in d53deda61bf60535a8505b7f6e6e37d28f405925)

 app/core/gimpimage-contiguous-region.c |   17 +++++++++++++----
 1 files changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/app/core/gimpimage-contiguous-region.c b/app/core/gimpimage-contiguous-region.c
index 9b94dff..b00b0fe 100644
--- a/app/core/gimpimage-contiguous-region.c
+++ b/app/core/gimpimage-contiguous-region.c
@@ -135,11 +135,10 @@ gimp_image_contiguous_region_by_seed (GimpImage           *image,
       select_transparent = FALSE;
     }
 
-  mask = gimp_channel_new_mask (image,
-                                gegl_buffer_get_width  (src_buffer),
-                                gegl_buffer_get_height (src_buffer));
+  mask_buffer = gegl_buffer_new (gegl_buffer_get_extent (src_buffer),
+                                 babl_format ("Y float"));
 
-  mask_buffer = gimp_drawable_get_buffer (GIMP_DRAWABLE (mask));
+  gegl_buffer_clear (mask_buffer, NULL);
 
   find_contiguous_region_helper (src_buffer, mask_buffer,
                                  format, n_components, has_alpha,
@@ -147,6 +146,16 @@ gimp_image_contiguous_region_by_seed (GimpImage           *image,
                                  antialias, threshold,
                                  x, y, start_col);
 
+  /* wrap mask_buffer in a drawable and return it */
+  mask = gimp_channel_new_mask (image,
+                                gegl_buffer_get_width  (mask_buffer),
+                                gegl_buffer_get_height (mask_buffer));
+
+  gegl_buffer_copy (mask_buffer, NULL,
+                    gimp_drawable_get_buffer (GIMP_DRAWABLE (mask)), NULL);
+
+  g_object_unref (mask_buffer);
+
   return mask;
 }