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by bschwindHN 370 days ago
> Just browsing the source I see Porter Duff blend modes. Really, in 2025? Have fun dealing with alpha compositing issues on this one.

What should we be using in 2025? I thought pre-multiplied alpha is essentially what you go for if you want a chance of alpha compositing ending up correct, but my knowledge is probably outdated.
1 comments
kookamamie 370 days ago
You absolutely want premult alpha when dealing with multiple transparent layers in graphics.
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bschwindHN 370 days ago
Right - maybe I'm mistaken but doesn't Porter-Duff compositing encompass premultiplied alpha?
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kookamamie 369 days ago
Yes, they introduced the concept in their paper. See this article for an in-depth guide to the topic: https://ciechanow.ski/alpha-compositing/
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bschwindHN 369 days ago
Great article! I'm going to have to take my time on that one.

But I guess I'm confused why @morio said "Just browsing the source I see Porter Duff blend modes. Really, in 2025?" because I'm not sure what they were expecting to be used in 2025.

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