CPNG, a backwards compatible fork of PNG

Post by sspiff » Sun, Dec 10, 2023, 1:25 PM UTC

Too wrote: post #96

sspiff wrote: post #57

Earlier quoted context omitted.

I would say at least in the context of extra data to extend the bit depth for HDR, that data could be considered ancillary? We've been rendering images in SDR forever, and most people don't have HDR capable hardware or software yet, so I don't know how you could consider it as broken to render the image without the HDR data?

This assumes the image is presented in isolation. I’ve seen countless of issues where you place a PNG logo on top of a css background:#123456 and expect the colors to match, so the logo blends in seamlessly to the whole page. On your machine it does and everything looks beautiful. On the customer machine with Internet explorer they don’t, so the logo has an ugly square around it.

Post by ttfkam » Sun, Dec 10, 2023, 2:55 PM UTC

Nullabillity wrote: post #86

solardev wrote: post #72

Earlier quoted context omitted.

Minor nitpick, just for clarity: Vectors aren't really the "ultimate" format, they're just a different format for storing a different kind of information. Vectors are good for things that can be mathematically described/simplified without significant loss of information (such as curves, shapes, some gradients, etc., and compositions of those) Many logos and fonts fall into this category, for example, and some clip-ar…

> Real pixels do hold data, and vectorizing them will typically cause some data loss. Chickens and eggs. If you have vector data already, it's better to distribute the raw vectors than to rasterize them. If you only have raster data, distribute the rasters (where viable) instead of trying to trace them. Lossy operations are lossy. Vectors are largely preferable to rasters, but that doesn't mean you can reproduce them…

Post by skybrian » Sun, Dec 10, 2023, 3:43 PM UTC

pwdisswordfishc wrote: post #98

skybrian wrote: post #67

Earlier quoted context omitted.

It seems like it’s not going to look broken? Unlike, say, the difference between black & white and color TV, or an animated image that doesn’t animate, it will be a subtle difference that most users won’t notice or care about. Some designers may be annoyed, but it doesn’t seem like that big a deal.

Though doesn't that mean the feature is less likely to be implemented in the first place? Nobody gave a shit about Unicode grapheme clusters until EEMAWDJI came about. Sadly.

Post by Nullabillity » Sun, Dec 10, 2023, 5:25 PM UTC

ttfkam wrote: post #103

Nullabillity wrote: post #86

Earlier quoted context omitted.

> Real pixels do hold data, and vectorizing them will typically cause some data loss. Chickens and eggs. If you have vector data already, it's better to distribute the raw vectors than to rasterize them. If you only have raster data, distribute the rasters (where viable) instead of trying to trace them. Lossy operations are lossy. Vectors are largely preferable to rasters, but that doesn't mean you can reproduce them…

> Vectors are largely preferable to rasters Not for continuous tone images like photographs, they're not. They are excellent however for line art.

Post by Retr0id » Sun, Dec 10, 2023, 8:08 PM UTC

ack_complete wrote: post #108

Retr0id wrote: post #33

I've also been pondering a backwards-compatible fork of PNG - but rather than a fork, mine would be a subset. Specifically, it would be an as-simple-as-possible uncompressed* bitmap format, suitable for use in low-complexity embedded systems etc. (e.g. bootloaders, wink wink). By being backwards compatible, you get the added benefit of retaining compatibility with existing image viewers, but without having to impleme…

I would think that something like a bootloader would have fixed input and be able to rely on that, with signing if necessary, rather than the robustness of the decoder. Otherwise, someone who could replace the image would probably be able to replace the code as well. Without Deflate compression, PNG would have no compression at all, as the predictor mechanism gives no savings on its own. TARGA with RLE would be a bet…