[gimp/gimp-2-10] app: zero-out transparent pixels when converting to indexed

[Ell <ell src gnome org>]

commit 5771393379f7108ac604040f68faabf3654478ab
Author: Ell <ell_se yahoo com>
Date:   Wed May 20 21:14:56 2020 +0300

    app: zero-out transparent pixels when converting to indexed
    
    When converting an image to indexed mode, zero-out transparent
    pixels instead of leaving junk in their indices, which might well
    be out of range of the palette.
    
    (cherry picked from commit 09870d4b153bc390f61a713961e9c1d12e8ef316)

 app/core/gimpimage-convert-indexed.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/app/core/gimpimage-convert-indexed.c b/app/core/gimpimage-convert-indexed.c
index ab1457ae14..4d1b1144d8 100644
--- a/app/core/gimpimage-convert-indexed.c
+++ b/app/core/gimpimage-convert-indexed.c
@@ -714,6 +714,8 @@ remap_indexed_layer (GimpLayer    *layer,
             {
               if (data[ALPHA_I])
                 data[INDEXED] = remap_table[data[INDEXED]];
+              else
+                data[INDEXED] = 0;
 
               data += bpp;
             }