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| author | Robin Watts <robin.watts@artifex.com> | 2016-10-06 19:51:29 +0100 |
|---|---|---|
| committer | Robin Watts <robin.watts@artifex.com> | 2016-10-07 16:56:46 +0100 |
| commit | c5f8d745e4dc42404409a2c166181d85bc87934b (patch) | |
| tree | 1ff341b87b3891a998aba07fb3699b1dd4148ce4 /docs | |
| parent | 7836643e0d6e9cc8e9d0d5c71cbfac5ee772ae21 (diff) | |
| download | mupdf-c5f8d745e4dc42404409a2c166181d85bc87934b.tar.xz | |
Correct maths error in painters.
As part of the blending calculations, we do:
dst = src * mask_alpha + dst * (1-mask_alpha.src_alpha)
We calculate mask_alpha as ma, and 1-mask_alpha.src_alpha as masa.
In full accuracy, we should never have ma + masa >= 1.
Unfortunately, with the formulation used in the painters at the
moment, we can. We therefore rejig the calculations slightly.
Diffstat (limited to 'docs')
0 files changed, 0 insertions, 0 deletions