[gegl] value-invert: propaget BablSpace

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

commit 1a97251b764e8edfed48579b4fea150ee8da38bc
Author: Øyvind Kolås <pippin gimp org>
Date:   Thu Jul 5 22:00:40 2018 +0200

    value-invert: propaget BablSpace

 operations/common/value-invert.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/operations/common/value-invert.c b/operations/common/value-invert.c
index c203cb1e2..108f06a96 100644
--- a/operations/common/value-invert.c
+++ b/operations/common/value-invert.c
@@ -55,8 +55,9 @@
 static void
 prepare (GeglOperation *operation)
 {
-  gegl_operation_set_format (operation, "input", babl_format ("R'G'B'A float"));
-  gegl_operation_set_format (operation, "output", babl_format ("R'G'B'A float"));
+  const Babl *space = gegl_operation_get_source_space (operation, "input");
+  gegl_operation_set_format (operation, "input", babl_format_with_space ("R'G'B'A float", space));
+  gegl_operation_set_format (operation, "output", babl_format_with_space ("R'G'B'A float", space));
 }
 
 static gboolean