Re: CALL for DISCUSSION: eXIf 20170115

Glenn Randers-Pehrson <[email protected]>
Newsgroups gmane.comp.graphics.png.general
Message-ID <CA+PdXcsHSdf9MrhOcNNJoc_fg-DX_uXPvOs_-hFvXqq8vtUvzg@mail.gmail.com>
On Tue, Jan 24, 2017 at 6:39 PM, John Bowler <
[email protected]> wrote:

> On Tue, Jan 24, 2017 at 2:23 PM, Glenn Randers-Pehrson
> <[email protected]> wrote:
> .  As I said, in the long run I'll
> > probably
> > use the code that's already existing in libpng for iCCP decoding.
>
> That would be impossible.  ICC profiles start with a "profile length"
> field.  The code uses that to head off all the security issues at the
> pass.
>
> You seem totally set on compressing it regardless of any advice to the
> contrary.  Are you going to enhance libpng 1.2?
>

I'm not changing any version of libpng.  I meant that I would copy
existing libpng code into the user chunk reading function.  Cannot
use it directly because libpng does not export png_inflate, etc.
libpng-1.2 doesn't even support iTXt by default, right?

I am "totally set" on responding to your challenge, "show me the
code", and presenting proof-of-concept for the vote.

Pass or fail, I'll probably go ahead with replacing the current
hex-encoded-zTXt with zxIf as a private chunk, in ImageMagick
and GraphicsMagick, just to avoid hearing people complain
about their files getting bigger for no apparent reason if
I switch from hex to uncompressed eXIF.

Glenn

------------------------------------------------------------------------------
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
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.