[gimp] app: in GimpDrawableFilter, don't mask-out alpha comonent for alpha-less drawables

[Ell <ell src gnome org>]

commit af2c7d1b33a61ca3928620d0ce9834f1f34193e1
Author: Ell <ell_se yahoo com>
Date:   Sat Feb 16 13:01:18 2019 -0500

    app: in GimpDrawableFilter, don't mask-out alpha comonent for alpha-less drawables
    
    In gimp_drawable_filter_sync_affect(), don't mask-out the filter's
    alpha component when the drawable doesn't have an alpha channel,
    since this is no longer necessary -- we now explicitly convert the
    output to the drawable format as part of the graph -- and it
    prevents the gimp:mask-components node from becoming a NOP.

 app/core/gimpdrawablefilter.c | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)
---
diff --git a/app/core/gimpdrawablefilter.c b/app/core/gimpdrawablefilter.c
index 395e761424..ecc157ccc8 100644
--- a/app/core/gimpdrawablefilter.c
+++ b/app/core/gimpdrawablefilter.c
@@ -668,18 +668,9 @@ gimp_drawable_filter_sync_mode (GimpDrawableFilter *filter)
 static void
 gimp_drawable_filter_sync_affect (GimpDrawableFilter *filter)
 {
-  GimpComponentMask active_mask;
-
-  active_mask = gimp_drawable_get_active_mask (filter->drawable);
-
-  /*  don't let the filter affect the drawable projection's alpha,
-   *  because it can't affect the drawable buffer's alpha either when
-   *  finally merged (see bug #699279)
-   */
-  if (! gimp_drawable_has_alpha (filter->drawable))
-    active_mask &= ~GIMP_COMPONENT_MASK_ALPHA;
-
-  gimp_applicator_set_affect (filter->applicator, active_mask);
+  gimp_applicator_set_affect (
+    filter->applicator,
+    gimp_drawable_get_active_mask (filter->drawable));
 }
 
 static void