Re: PNG file gamma not handled

On Sunday 06 of November 2005 17:38, Christopher Martin wrote:
> On October 27, 2005 12:46, Lubos Lunak wrote:
> > On Thursday 27 of October 2005 17:32, Christopher Martin wrote:
> > > Hello,
> > >
> > > It seems that neither Qt nor Gwenview handle gamma values associated
> > > with PNG files correctly. For instance, the images at
> > > http://www.christian-seiler.de/temp/gamma.html look different in
> > > Mozilla/Firefox, as they should, but unless your Qt is patched, they
> > > will look identical in Konqueror (the patch to fix this is in qt-copy,
> > > but looks a little dodgy).
> > >
> > > Gwenview seems to borrow code from Qt, and it inherits this problem.
> > > The attached patch seems to fix the issue, so that the images at the
> > > above link (and those at http://www.w3.org/Graphics/PNG/all_seven.html,
> > > another handy site) all look correct when viewed in Gwenview.
> >
> >  The PNG decoder in Gwenview is more or less a copy of the one in Qt,
> > with some modifications (I don't remember exactly why right now), so the
> > qt-copy patch should apply to it as well.
> >
> >  I've sent a patch to the person who created the patch asking about the
> > status.
>
> It looks like the qt-copy patch has been dropped, in favour of a fix in
> kdelibs itself.
>
> Since this new fix doesn't solve Gwenview's issue, then my patch is still
> needed.

 I've pointed Brah Hards, the author of the qt-copy patch, to the kfm-devel 
posts, because he said ... well, see below. Besides that, I don't really 
understand this stuff, the png loader is just a copy from Qt fix some fixes, 
so I'm no authority on this. If the patch's made it into khtml, feel free to 
commit it to gweview too.

----------  Forwarded Message  ----------

Subject: Re: qt-copy patch #0053 / KDE bug #61829
Date: Friday 04 of November 2005 06:19
From: Brad Hards <bradh@...>
To: Lubos Lunak <l.lunak@...>

On Saturday 29 October 2005 21:20 pm, Lubos Lunak wrote:
> Dne čt 27. října 2005 22:52 jste napsal(a):
> > On Friday 28 October 2005 02:39 am, Lubos Lunak wrote:
> > >  Hello,
> > >
> > >  I'd like to ask what the status of %subj% is. Have TT already accepted
> > > the patch? I can't see anything like that in Qt4 or recent Qt3.
> >
> > I haven't heard anything. AFAICT it is still a problem.
>
>  I see. Note that on the Gwenview mailing list the Debian asked us to fix
> the problem too, but his patch is different and he says your patch has
> problems too.
> (http://sourceforge.net/mailarchive/forum.php?thread_id=8823928&forum_id=12
>10)

I had a look, but there appears to be confusion between screen gamma, and
 file gamma. There is a (bad) description in the libpng docs about this.

Brad

-------------------------------------------------------

--

-- 
Lubos Lunak
KDE developer
---------------------------------------------------------------------
SuSE CR, s.r.o.  e-mail: l.lunak@... , l.lunak@...
Drahobejlova 27  tel: +420 2 9654 2373
190 00 Praha 9   fax: +420 2 9654 2374
Czech Republic   http://www.suse.cz/

-------------------------------------------------------
SF.Net email is sponsored by:
Tame your development challenges with Apache's Geronimo App Server. Download
it for free - -and be entered to win a 42" plasma tv or your very own
Sony(tm)PSP.  Click here to play: http://sourceforge.net/geronimo.php