[gegl] mix: propagate BablSpace

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 9ac97fcbb3d6bb76c57c6de0ec4bdd4d268edf92
Author: Øyvind Kolås <pippin gimp org>
Date:   Thu Jul 5 21:54:51 2018 +0200

    mix: propagate BablSpace

 operations/common/mix.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/operations/common/mix.c b/operations/common/mix.c
index 94b82487b..14945a10e 100644
--- a/operations/common/mix.c
+++ b/operations/common/mix.c
@@ -35,8 +35,8 @@ property_double (ratio, _("Ratio"), 0.5)
 
 static void prepare (GeglOperation *operation)
 {
-  const Babl *format;
-  format = babl_format ("RGBA float");
+  const Babl *space = gegl_operation_get_source_space (operation, "input");
+  const Babl *format = babl_format_with_space ("RGBA float", space);
   gegl_operation_set_format (operation, "input", format);
   gegl_operation_set_format (operation, "aux", format);
   gegl_operation_set_format (operation, "output", format);