[gimp/gimp-2-10] app: in GimpDrawableFilter, use the drawable format as the cache format

[Ell <ell src gnome org>]

commit 37b0832c2dabf8241221b00c6fd40cdffc8b5243
Author: Ell <ell_se yahoo com>
Date:   Fri Dec 28 02:13:07 2018 -0500

    app: in GimpDrawableFilter, use the drawable format as the cache format
    
    In GimpDrawableFilter, set the applicator's output format to the
    drawable format, so that the cache uses the drawable format, and so
    copying the cached result to the drawble's buffer when comitting
    the filter becomes much cheaper, and, in particular, doesn't
    require reading tiles out of the swap.  This notably improves
    commit speed in large images, at the expense of requiring a few
    extra conversions during preview.
    
    (cherry picked from commit 8e57ee22657726aa2b6b381d7f61cab825e81dda)

 app/core/gimpdrawablefilter.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)
---
diff --git a/app/core/gimpdrawablefilter.c b/app/core/gimpdrawablefilter.c
index bd0f7e7435..c392768331 100644
--- a/app/core/gimpdrawablefilter.c
+++ b/app/core/gimpdrawablefilter.c
@@ -100,6 +100,7 @@ static void       gimp_drawable_filter_sync_preview     (GimpDrawableFilter  *fi
 static void       gimp_drawable_filter_sync_opacity     (GimpDrawableFilter  *filter);
 static void       gimp_drawable_filter_sync_mode        (GimpDrawableFilter  *filter);
 static void       gimp_drawable_filter_sync_affect      (GimpDrawableFilter  *filter);
+static void       gimp_drawable_filter_sync_format      (GimpDrawableFilter  *filter);
 static void       gimp_drawable_filter_sync_mask        (GimpDrawableFilter  *filter);
 static void       gimp_drawable_filter_sync_transform   (GimpDrawableFilter  *filter);
 static void       gimp_drawable_filter_sync_gamma_hack  (GimpDrawableFilter  *filter);
@@ -118,6 +119,8 @@ static void       gimp_drawable_filter_mask_changed     (GimpImage           *im
                                                          GimpDrawableFilter  *filter);
 static void       gimp_drawable_filter_profile_changed  (GimpColorManaged    *managed,
                                                          GimpDrawableFilter  *filter);
+static void       gimp_drawable_filter_format_changed   (GimpDrawable        *drawable,
+                                                         GimpDrawableFilter  *filter);
 static void       gimp_drawable_filter_drawable_removed (GimpDrawable        *drawable,
                                                          GimpDrawableFilter  *filter);
 
@@ -651,6 +654,14 @@ gimp_drawable_filter_sync_affect (GimpDrawableFilter *filter)
   gimp_applicator_set_affect (filter->applicator, active_mask);
 }
 
+static void
+gimp_drawable_filter_sync_format (GimpDrawableFilter *filter)
+{
+  gimp_applicator_set_output_format (
+    filter->applicator,
+    gimp_drawable_get_format (filter->drawable));
+}
+
 static void
 gimp_drawable_filter_sync_mask (GimpDrawableFilter *filter)
 {
@@ -854,6 +865,7 @@ gimp_drawable_filter_add_filter (GimpDrawableFilter *filter)
       gimp_drawable_filter_sync_opacity (filter);
       gimp_drawable_filter_sync_mode (filter);
       gimp_drawable_filter_sync_affect (filter);
+      gimp_drawable_filter_sync_format (filter);
       gimp_drawable_filter_sync_transform (filter);
       gimp_drawable_filter_sync_gamma_hack (filter);
 
@@ -869,6 +881,9 @@ gimp_drawable_filter_add_filter (GimpDrawableFilter *filter)
       g_signal_connect (image, "profile-changed",
                         G_CALLBACK (gimp_drawable_filter_profile_changed),
                         filter);
+      g_signal_connect (filter->drawable, "format-changed",
+                        G_CALLBACK (gimp_drawable_filter_format_changed),
+                        filter);
       g_signal_connect (filter->drawable, "removed",
                         G_CALLBACK (gimp_drawable_filter_drawable_removed),
                         filter);
@@ -889,6 +904,9 @@ gimp_drawable_filter_remove_filter (GimpDrawableFilter *filter)
       g_signal_handlers_disconnect_by_func (filter->drawable,
                                             gimp_drawable_filter_drawable_removed,
                                             filter);
+      g_signal_handlers_disconnect_by_func (filter->drawable,
+                                            gimp_drawable_filter_format_changed,
+                                            filter);
       g_signal_handlers_disconnect_by_func (image,
                                             gimp_drawable_filter_profile_changed,
                                             filter);
@@ -981,6 +999,14 @@ gimp_drawable_filter_profile_changed (GimpColorManaged   *managed,
   gimp_drawable_filter_update_drawable (filter, NULL);
 }
 
+static void
+gimp_drawable_filter_format_changed (GimpDrawable       *drawable,
+                                     GimpDrawableFilter *filter)
+{
+  gimp_drawable_filter_sync_format (filter);
+  gimp_drawable_filter_update_drawable (filter, NULL);
+}
+
 static void
 gimp_drawable_filter_drawable_removed (GimpDrawable       *drawable,
                                        GimpDrawableFilter *filter)