[gimp/gimp-2-8] Bug 675994 - Opening image with a saved selection breaks histogram updating

[Michael Natterer <mitch src gnome org>]

commit 1e402a46f03d773d8e292033b18f15f7d4ab6fbd
Author: Michael Natterer <mitch gimp org>
Date:   Mon May 14 01:44:41 2012 +0200

    Bug 675994 - Opening image with a saved selection breaks histogram updating
    
    In fact, it broke much more than that because the way XCF loading
    replaced the image's mask prevented the image's "mask-changed" signal
    from ever being emitted. Add private API gimp_image_take_mask() which
    properly sets the mask and use it for image construction and the XCF
    selection loading hack.
    (cherry picked from commit ab4c613a700daed56afbf06331f5c96a862b66b1)

 app/core/gimpimage-private.h      |    3 +++
 app/core/gimpimage.c              |   35 ++++++++++++++++++++++++++---------
 app/widgets/gimphistogrameditor.c |    3 +++
 app/xcf/xcf-load.c                |    9 +++------
 4 files changed, 35 insertions(+), 15 deletions(-)
---
diff --git a/app/core/gimpimage-private.h b/app/core/gimpimage-private.h
index b966ba0..ea9f54d 100644
--- a/app/core/gimpimage-private.h
+++ b/app/core/gimpimage-private.h
@@ -109,5 +109,8 @@ struct _GimpImagePrivate
                                      GIMP_TYPE_IMAGE, \
                                      GimpImagePrivate)
 
+void   gimp_image_take_mask (GimpImage   *image,
+                             GimpChannel *mask);
+
 
 #endif  /* __GIMP_IMAGE_PRIVATE_H__ */
diff --git a/app/core/gimpimage.c b/app/core/gimpimage.c
index 47f31c3..e940cca 100644
--- a/app/core/gimpimage.c
+++ b/app/core/gimpimage.c
@@ -740,6 +740,7 @@ gimp_image_constructed (GObject *object)
 {
   GimpImage        *image   = GIMP_IMAGE (object);
   GimpImagePrivate *private = GIMP_IMAGE_GET_PRIVATE (image);
+  GimpChannel      *selection;
   GimpCoreConfig   *config;
   GimpTemplate     *template;
 
@@ -765,15 +766,10 @@ gimp_image_constructed (GObject *object)
   if (private->base_type == GIMP_INDEXED)
     gimp_image_colormap_init (image);
 
-  /* create the selection mask */
-  private->selection_mask = gimp_selection_new (image,
-                                                gimp_image_get_width  (image),
-                                                gimp_image_get_height (image));
-  g_object_ref_sink (private->selection_mask);
-
-  g_signal_connect (private->selection_mask, "update",
-                    G_CALLBACK (gimp_image_mask_update),
-                    image);
+  selection = gimp_selection_new (image,
+                                  gimp_image_get_width  (image),
+                                  gimp_image_get_height (image));
+  gimp_image_take_mask (image, selection);
 
   g_signal_connect_object (config, "notify::transparency-type",
                            G_CALLBACK (gimp_item_stack_invalidate_previews),
@@ -1971,6 +1967,27 @@ gimp_image_mask_changed (GimpImage *image)
   g_signal_emit (image, gimp_image_signals[MASK_CHANGED], 0);
 }
 
+void
+gimp_image_take_mask (GimpImage   *image,
+                      GimpChannel *mask)
+{
+  GimpImagePrivate *private;
+
+  g_return_if_fail (GIMP_IS_IMAGE (image));
+  g_return_if_fail (GIMP_IS_SELECTION (mask));
+
+  private = GIMP_IMAGE_GET_PRIVATE (image);
+
+  if (private->selection_mask)
+    g_object_unref (private->selection_mask);
+
+  private->selection_mask = g_object_ref_sink (mask);
+
+  g_signal_connect (private->selection_mask, "update",
+                    G_CALLBACK (gimp_image_mask_update),
+                    image);
+}
+
 
 /*  image components  */
 
diff --git a/app/widgets/gimphistogrameditor.c b/app/widgets/gimphistogrameditor.c
index 4edd65b..44a1e0b 100644
--- a/app/widgets/gimphistogrameditor.c
+++ b/app/widgets/gimphistogrameditor.c
@@ -251,6 +251,9 @@ gimp_histogram_editor_set_image (GimpImageEditor *image_editor,
         }
 
       g_signal_handlers_disconnect_by_func (image_editor->image,
+                                            gimp_histogram_editor_update,
+                                            editor);
+      g_signal_handlers_disconnect_by_func (image_editor->image,
                                             gimp_histogram_editor_layer_changed,
                                             editor);
       g_signal_handlers_disconnect_by_func (image_editor->image,
diff --git a/app/xcf/xcf-load.c b/app/xcf/xcf-load.c
index 23593c6..f703922 100644
--- a/app/xcf/xcf-load.c
+++ b/app/xcf/xcf-load.c
@@ -916,16 +916,13 @@ xcf_load_channel_props (XcfInfo      *info,
 
         case PROP_SELECTION:
           {
-            GimpImagePrivate *private = GIMP_IMAGE_GET_PRIVATE (image);
-            GimpChannel      *mask;
-
-            g_object_unref (gimp_image_get_mask (image));
+            GimpChannel *mask;
 
-            mask = private->selection_mask =
+            mask =
               gimp_selection_new (image,
                                   gimp_item_get_width  (GIMP_ITEM (*channel)),
                                   gimp_item_get_height (GIMP_ITEM (*channel)));
-            g_object_ref_sink (mask);
+            gimp_image_take_mask (image, mask);
 
             tile_manager_unref (GIMP_DRAWABLE (mask)->private->tiles);
             GIMP_DRAWABLE (mask)->private->tiles =