![]() ![]() Some folks might incorrectly try to take a 24-bit source image and save as PNG, then take the same source and save as GIF, and will note that the GIF is way smaller - as it should be, since GIF doesn't support 24 bpp images, whereas PNG does. In my defense, though, I should say that many people did manage to compress existing GIF files using my PNG library (which shipped as part of the Mastersoft File Utilities by Adobe, a product that unfortunately didn't last long) one magazine reviewer specifically used this software suite to convert a bunch of GIFs to PNGs, and concluded that in most cases, the PNGs were indeed smaller.Īs soon as you start dealing with non-indexed color images, though, PNG is no better than TIFF. If they used my code, then it's quite possible that I'm to blame for Photoshop saving out crappy PNG files that are too big. I don't know if Adobe is using my PNG writing code in Photoshop, but since Adobe purchased the IP of Mastersoft in the Frame acquisition, it's not inconceivable that they used my code rather than writing their own. Lastly, the version of zlib that I used was current as of the drafting of the original PNG specification subsequent versions of zlib were released which were slightly more efficient, and a few nasty bugs were stomped out. I also used a relatively small PNG chunk size since each chunk has some overhead, more chunks means larger PNG files. My choice had the virtue of saving time in writing a PNG file to disk, but doesn't necessarily produce the smallest PNG files. Specifically, I avoided using any scanline filter type other than Paeth for my PNG writing library most modern PNG writers will try all 5 filter types on each scanline, and see which compresses the best. However, due to time constraints and some performance requirements, the compression done by my PNG writer libraries wasn't the best. I was very proud of the fact that my libraries were the first commercial implementation of PNG, as far as I can tell. The libraries I wrote used Jean-Loup Gailly's (sp?) zlib (since I didn't want to reinvent the wheel and debug a compression library), but did not rely on the pnglib reference implementation in any way. While at Mastersoft, I developed an implementation of a PNG reading and writing library for use in various file format conversion products these reading and writing libraries were also licensed to OEMs for inclusion in other commercial products, so they're in a lot of places. I used to work for a company named Mastersoft, which was acquired by Frame, the makers of Frame Maker (the now-discontinued DTP app) Frame was subsequently acquired by Adobe.
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