Re: [AD] Is there a licensing reason why PNG isn't built-in to Allegro?

["Peter Hull" <peterhull90@xxxxxxxxxx>]

I can't check at the moment, but I might have mean libpng, not loadpng

http://www.allegro.cc/resource/resource-view.php?id=21

I'll check for you later.

Pete

On 4/4/06, Peter Wang <tjaden@xxxxxxxxxx> wrote:
> On 2006-04-04, Siarhei Siamashka <siarhei.siamashka@xxxxxxxxxx> wrote:
> > Peter Hull wrote:
> >
> > >I know that OpenLayer works on OSX, and that  loads  pngs. But I think
> > >it uses ldpng rather than loadpng,  and I have a feeling these are two
> > >separate things.
> > >
> > >In fact, OSX's NSImage class can load BMP, GIF, JPG, TIFF and PNG so on
> > >that platform, a BITMAP <-> NSImage bridge would work well. Likewise
> > >GdiPlus::Bitmap for windows folk.
> >
> > We are using 1.4pre1 version of loadpng taken from here:
> > http://tjaden.strangesoft.net/loadpng/index.html
> >
> > I searched for 'ldpng' but did not find anything. If it is really some
> > other png loader for allegro, a link would be welcome.
>
> 'ldpng' is the name used when 'loadpng' won't fit into 8.3 filename
> restrictions so I am guessing they are one and the same.
>
> > If the same
> > loadpng is used in OpenLayer, I wonder how it is possible that they were
> > not struck by this bug in OSX.
>
> I guess few people use Allegro with OSX, and even fewer use Allegro,
> OpenLayer, OSX, and PNG images with alpha channels.
>
> > >    This is somewhat related. Did anybody successfully use loadpng addon on
> > >    MacOS X? Looks like we are having some strange problems. Alpha channel
> > >    and some other colors appear to be swapped, see screenshot:
> > >    http://www.xcomufo.com/forums/index.php?showtopic=8571&st=47
> > >    <http://www.xcomufo.com/forums/index.php?showtopic=8571&st=47>
> > >
> > >    I don't have Mac myself, so it is hard to investigate this problem for
> > >    me. But if it is loadpng problem, having loadpng as a part of allegro
> > >    library would certainly help to improve its portability.
>
> We can put loadpng into the Allegro SVN tree so other people can commit
> patches to it, or start a new SF project.  I have been wanting another
> maintainer anyway.
>
> > Index: loadpng.c
> > ===================================================================
> > --- loadpng.c (revision 1000)
> > +++ loadpng.c (revision 1011)
> > @@ -191,6 +191,9 @@
> >       unsigned char *pc = (unsigned char *)&c;
> >       if (pc[0] == 255)
> >           png_set_bgr(png_ptr);
> > +#ifdef ALLEGRO_BIG_ENDIAN
> > +     png_set_swap_alpha(png_ptr);
> > +#endif
> >      }
> >
> >      /* Read the image, one line at a line (easier to debug!) */
>
> I have been testing 'recent' loadpng releases against the PngSuite and
> as far as I remember all the BGR problems were sorted out on i386.
> If someone could test this patch on OSX against the PngSuite then
> that would be great.  I will probably commit it and make a release
> in a couple of weeks anyway, unless I forget, which I will (remind me).
>
> http://www.schaik.com/pngsuite/
>
> Peter
>
>
>
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