[gimp/gimp-2-10] Issue #1283 - Artifacts in filters when aux input depends on filter result

[Ell <ell src gnome org>]

commit a997027da4add9fa310efa025f75aaf75882f921
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.
    
    (cherry picked from commit 9f85efd825b694daa30e3557c61773d8c7b95d07)

 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 f13b84462e..bb19ef250f 100644
--- a/app/widgets/gimpbuffersourcebox.c
+++ b/app/widgets/gimpbuffersourcebox.c
@@ -29,6 +29,8 @@
 
 #include "widgets-types.h"
 
+#include "gegl/gimp-gegl-utils.h"
+
 #include "core/gimpcontext.h"
 #include "core/gimppickable.h"
 
@@ -278,7 +280,13 @@ 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),
@@ -294,6 +302,8 @@ gimp_buffer_source_box_update_node (GimpBufferSourceBox *box)
   gegl_node_set (box->priv->source_node,
                  "buffer", buffer,
                  NULL);
+
+  g_clear_object (&buffer);
 }
 
 static void