Re: cOMp chunk [was: EXIF support in PNG]
Glenn Randers-Pehrson <[email protected]>
| Newsgroups | gmane.comp.graphics.png.general |
|---|---|
| Message-ID | <CA+PdXcvvyH8T39ijvboa55WUNj3fNp1Df9n+HhhObnX0jLYyRw@mail.gmail.com> |
Not COMp -- according to the PNG spec, "the safe-to-copy bit will always be 0 for critical chunks". Glenn On Sun, Jan 1, 2017 at 2:07 PM, John Bowler < [email protected]> wrote: > On Sun, Jan 1, 2017 at 11:00 AM, Soni L. <[email protected]> wrote: > >> >> Why not make it COMP and require everything to verify the inner chunk? >> That way COMP could be added to chunks like PLTE and stuff. >> > > I'm suggesting a set of four chunks; cOMp, cOMP, COMp and COMP, but I've > just realized that PLTE cannot be compressed without violating the > specification because that would result in a file that cannot be read by a > fully conformant ISO-PNG decoder, so it wouldn't be a PNG. > > PLTE on color type != 3 (not palette) cannot even be compressed using cOMP > because the potential result is a PNG that contains multiple PLTE chunks. > > Hum, this requires a little thought; I'm not sure unknown chunks can be > compressed this way. > > John Bowler > > ------------------------------------------------------------ > ------------------ > 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 > > ------------------------------------------------------------------------------ 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