Color management: add "Color Unpremultiply" option for images and render settings.

For premultiplied alpha images, this makes any color space conversion for the image
or render output work on color without alpha multiplied in.

This is typically useful to avoid fringing when the image was or will be composited
over a light background. If the image will be composited over a black background on
the other hand, leaving this option off will give correct results.

In an ideal world, there should never be any color space conversion on images with
alpha, since it's undefined what to do then, but in practice it's useful to have
this option.

Patch by Troy Sobotka, with changes by me.

1 files changed, 8 insertions, 8 deletions

diff --git a/source/blender/makesdna/DNA_image_types.h b/source/blender/makesdna/DNA_image_types.h
index fc8807d0f7c..a1b0ab06ecd 100644
--- a/source/blender/makesdna/DNA_image_types.h
+++ b/source/blender/makesdna/DNA_image_types.h
@@ -112,14 +112,14 @@ typedef struct Image {
 /* **************** IMAGE ********************* */
 
 /* Image.flag */
-#define IMA_FIELDS		1
-#define IMA_STD_FIELD	2
-#define IMA_DO_PREMUL	4
-
-#define	IMA_REFLECT		16
-#define IMA_NOCOLLECT   32
-#define IMA_DEPRECATED	64
-#define IMA_OLD_PREMUL	128
+#define IMA_FIELDS			1
+#define IMA_STD_FIELD		2
+#define IMA_DO_PREMUL		4
+#define IMA_REFLECT			16
+#define IMA_NOCOLLECT   	32
+#define IMA_DEPRECATED		64
+#define IMA_OLD_PREMUL		128
+#define IMA_CM_PREDIVIDE	256
 
 /* Image.tpageflag */
 #define IMA_TILES			1