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> PNG is basically zip with some extra tricks. Sure, if with "some extra tricks" you mean "four relatively simple scanline filters[0] that nevertheless Paretro
by vanderZwan 8y ago
> PNG is basically zip with some extra tricks.
Sure, if with "some extra tricks" you mean "four relatively simple scanline filters[0] that nevertheless Paretro Principle[1] the heck out of more complex forms of lossless compression".
Especially Paeth is amazing in how it makes gradients so much cheaper than naive approaches with such a simple formula.
Similarly relying on DEFLATE is smart too, as that means any improvement to that format can be safely applied to PNG as well, like with zopflipng[1].
[0] https://www.w3.org/TR/PNG-Filters.html https://www.w3.org/TR/PNG-Filters.html
[1] https://github.com/google/zopfli/blob/master/README.zopflipng https://github.com/google/zopfli/blob/master/README.zopflipn...
- tinus_hn 8y agoSure it’s smart and well thought-out. It’s not worth the Nobel prize though. The achievement in PNG is in beating the de facto standard when it was created, GIF. That’s pretty difficult because GIF is almost good enough, except for features that are hard to explain to non technical people. They don’t care that GIF was covered by software patents and they don’t know about 1 bit transparency and color palettes. They know that GIF is supported in all software they care about, and that GIF has animation to boot.