Re: CALL for DISCUSSION: eXIf 20170115
Pavel Zlatovratskii <[email protected]>
| Newsgroups | gmane.comp.graphics.png.general |
|---|---|
| Message-ID | <[email protected]> |
When you're using pam/pnm you don't use metadata. pngexif is tool for metadata, not for image itself. And it use worst source of metadata: image could be processed several time with zXIf/eXIf unaware tools. These tools will write their own (correct) data in pHYs and gAMA, leaving zXIf/eXIf intact. And pngexif will use obsolete EXIF data, which may be inapplicable for current image - gAMA and iCCP are unsafe-to-copy for reasons. Using pam/pnm you know that there is no metadata. Worst case - you miss metadata. Using (incl. recoding) image without metadata could be worse, but still be useful. Using pngexif you using metadata with some obsolete part. Using image with inappropriate metadata could result in broken images or even bugs with software(e.g. if it meet 'Transfer function' inapplicable for current image data). You write software for smart users... well, most users that are able to use *nix CLI not totally stupid. I write software for stupid users(they ask me 'how to export', sending screenshot of form with 'Export' button). That's why I prefer make specification as fool-proof as possible. And 'link zlib' is good test for this. At least better than nothing. 01.02.2017 18:34, Willem van Schaik пишет: > I wrote pamtopng, pnmtopng, pngtopnm and couple others. So don't lecture > me on "real image processing". :) > > Willem > > > On 2017-02-01 08:19, Pavel Zlatovratskii wrote: >> Well, I think such kind of tool is good as example, but very VERY BAD as >> part of real image processing. >> >> Using pngexif in real image processing encourage users to ignore iCCP, >> gAMA, pHYs and may be even size from IHDR in favour of EXIF data (e.g. >> if user have some tool to parse EXIF). >> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ png-mng-misc mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/png-mng-misc