|
24
|
1 |
|
|
|
2 |
** Premultiplication:
|
|
|
3 |
|
|
|
4 |
- Any kind of BLENDING -> all components TO premultiplied. We MUST have the
|
|
|
5 |
components in internal precision also.
|
|
|
6 |
|
|
|
7 |
- This includes all the IMAGE BLENDING operations
|
|
|
8 |
|
|
|
9 |
- Corner case: rendering SRC_OVER with all/some alpha == 1.0
|
|
|
10 |
|
|
|
11 |
- Any FILTERING
|
|
|
12 |
|
|
|
13 |
- AFTER Color tranformation
|
|
|
14 |
|
|
|
15 |
- Unless no absolutely no blending after that, and destination NOT in
|
|
|
16 |
premultiplied format (-> color interpolation in np format)
|
|
|
17 |
|
|
|
18 |
** Unpremultiplication:
|
|
|
19 |
|
|
|
20 |
- BEFORE Color transformation
|
|
|
21 |
|
|
|
22 |
- Color conversion to dst
|
|
|
23 |
|
|
|
24 |
- After blending if dst NOT premultiplied
|
|
|
25 |
|
|
|
26 |
- If input PATTERN or IMAGE and NOT premultiplied -> This happens only when
|
|
|
27 |
the image data is not premultiplied and no filtering is done.
|
|
|
28 |
|
|
|
29 |
** In internal format if:
|
|
|
30 |
|
|
|
31 |
- Any BLEND operation
|
|
|
32 |
|
|
|
33 |
- FILTERING applied to image source
|
|
|
34 |
|
|
|
35 |
** Description of actions to take:
|
|
|
36 |
|
|
|
37 |
- Premultiply IMMEDIATELY after any color transforms, if it hasn't been done
|
|
|
38 |
before that. All the following operations can then assume that the input has
|
|
|
39 |
been premultiplied.
|
|
|
40 |
|
|
|
41 |
- Premultiplication can be only skipped if load is skipped for the pixel. This
|
|
|
42 |
can only occur when opacity and alpha are both 1.0.
|
|
|
43 |
|
|
|
44 |
** Color-space conversion
|
|
|
45 |
|
|
|
46 |
- Before blending, convert generated color into destination color-space.
|
|
|
47 |
|
|
|
48 |
- gamma srgb -> gamma slum is ungamma, tolum, gamma
|
|
|
49 |
|