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A new PNG spec

(www.programmax.net)
612 points bluedel | 1 comments | 24 Jun 25 13:01 UTC | HN request time: 0.275s | source
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ProgramMax ◴[25 Jun 25 19:00 UTC] No.44380761[source]▶
Author here. Hello everyone! Feel free to ask me anything. I'll go ahead and dispel some doubts I already see here:

- It isn't really a "new format". It's an update to the existing format. - It is very backwards compatible. -- Old programs will load new PNGs to the best of their capability. A user will still know "that is a picture of a red apple".

There also seems to be some confusion about how PNGs work internally. Short and sweet: - There are chunks of data. -- Chunks have a name, which says what data it contains. A program can skip a chunk it doesn't recognize. - There is only one image stream.

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1. account42 ◴[26 Jun 25 08:30 UTC] No.44385382[source]▶
> It isn't really a "new format". It's an update to the existing format. - It is very backwards compatible. -- Old programs will load new PNGs to the best of their capability. A user will still know "that is a picture of a red apple".

This is great but also has the issue that users might not notice that their setup is giving them a less than optimal result. Of course that is probably still better than not having backwards compatibility.

Edit: Seems the backwards compatibility isn't as great as it could be. Old programs show a washed out image instead which sucks. This should have been avoidable in the same way JPG gain maps work so that you only need updated programs to take advantage of the increased gamut on more-than-sRGB screens and not to correctly show colors that fit into sRGB.