Re: Compositing and alpha

[BALATON Zoltan]

On Wed, 7 Aug 2002, Alexander Malmberg wrote:
> I have a whole bunch of tests like this collected in DPSTest app,
> similar to GSTest for gui:
>
> http://w1.423.telia.com/~u42308495/alex/DPSTest-0.5.tar.gz
>
> Basically, some tests set up state (the ones that activate), and some
> actually draw (the draw buttons, or draw menu entry), and some do both.
> Bundle contributions are welcome! :) (The image test isn't complete
> yet.)

I know and use it already. I haven't found the compositing tests in there
though. I'll have a closer look. Unfortunately without font handling it is
a bit tricky to use it with the gslib backend currently :-)

> So we're caught between two alpha models :/. It would be nice to have
> some sort of official word about what the ultimate goal for GNUstep is
> (Adam Fedor?).
>
> Implementing both at once would be tricky, but a OS 4.2 compatibility
> flag would be an option (ie. you'd set some default key for apps that
> expect the old behavior).

With the gslib backend supporting both is no problem as gs is supposed to
implement both ps and pdf imaging models. (The tricky part has already
been done by the ghostsript developers. In fact some blending code from
libart is also integrated in ghostscript to implement PDF 1.4
compositing.) The problem is mostly to find and fix ghostscript bugs, and
to implement parts that are implemented in postscript for gs (such as font
loading in case of font handling).

Regards,
BALATON Zoltan