Adjust tobytes premul formula #2966
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itzpr3d4t0r
reviewed
Jul 3, 2024
MyreMylar
approved these changes
Jul 25, 2024
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While I'm working on my
tobytesimprovement branch, I ported the code to useSurface.premul_alphato handleRGBA_PREMULTandARGB_PREMULT.The problem is,
Surface.premul_alphauses a slightly different formula:((pixel + 1) * alpha) >> 8(which is equivalent to((pixel + 1) * alpha) / 256) instead of the classic(pixel * alpha) / 255formula, probably for performance reasons. I believe these two formulas are close enough to result in very similar looking outputs.Hence this PR: I figured I should separate out the slight behaviour change into it's own PR and keep the refactor PR for later.