[gimp] Issue #1283 - Artifacts in filters when aux input depends on filter result

[Ell <ell src gnome org>]

commit 9f85efd825b694daa30e3557c61773d8c7b95d07
Author: Massimo Valentini <mvalentini335 gmail com>
Date:   Tue Sep 17 18:12:08 2019 +0200

    Issue #1283 - Artifacts in filters when aux input depends on filter result
    
    In GimpBufferSourceBox, dup the selected buffer (and flush the
    pickable to make sure it's fully rendered) instead of using it
    directly in the source node.  This avoids chunking artifacts when
    the buffer's content depends on the filter output, such as when
    using the affected layer, or a dependent projection, as input.

 app/widgets/gimpbuffersourcebox.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
---
diff --git a/app/widgets/gimpbuffersourcebox.c b/app/widgets/gimpbuffersourcebox.c
index eedd20625d..afb9fad060 100644
--- a/app/widgets/gimpbuffersourcebox.c
+++ b/app/widgets/gimpbuffersourcebox.c
@@ -30,6 +30,8 @@
 
 #include "widgets-types.h"
 
+#include "gegl/gimp-gegl-utils.h"
+
 #include "core/gimpcontext.h"
 #include "core/gimppickable.h"
 
@@ -275,7 +277,13 @@ gimp_buffer_source_box_update_node (GimpBufferSourceBox *box)
 
       if (box->priv->enabled)
         {
-          buffer = gimp_pickable_get_buffer (box->priv->pickable);
+          gimp_pickable_flush (box->priv->pickable);
+
+          /* dup the buffer, since the original may be modified while applying
+           * the operation.  see issue #1283.
+           */
+          buffer = gimp_gegl_buffer_dup (
+            gimp_pickable_get_buffer (box->priv->pickable));
         }
 
       desc = gimp_viewable_get_description (GIMP_VIEWABLE (box->priv->pickable),
@@ -291,6 +299,8 @@ gimp_buffer_source_box_update_node (GimpBufferSourceBox *box)
   gegl_node_set (box->priv->source_node,
                  "buffer", buffer,
                  NULL);
+
+  g_clear_object (&buffer);
 }
 
 static void