diff options
Diffstat (limited to 'lib/jxl/alpha.cc')
| -rw-r--r-- | lib/jxl/alpha.cc | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/jxl/alpha.cc b/lib/jxl/alpha.cc index 77ac902..f0ab39a 100644 --- a/lib/jxl/alpha.cc +++ b/lib/jxl/alpha.cc @@ -108,4 +108,13 @@ void UnpremultiplyAlpha(float* JXL_RESTRICT r, float* JXL_RESTRICT g, } } +void UnpremultiplyAlpha(float* JXL_RESTRICT rgba, size_t num_pixels) { + for (size_t x = 0, ix = 0; x < num_pixels; ++x, ix += 4) { + const float multiplier = 1.f / std::max(kSmallAlpha, rgba[ix + 3]); + rgba[ix] *= multiplier; + rgba[ix + 1] *= multiplier; + rgba[ix + 2] *= multiplier; + } +} + } // namespace jxl |