[SDL] Faster blitting?

[Glenn Maynard]

On Wed, Mar 31, 2004 at 08:00:04PM +0200, David Olofson wrote:
> > I know very few formats, if any (some TGA format?) support a 8bpp
> > indexed image and 8 bit alpha. AFAIK GIF and PNG support paletted
> > images only with 1 bit alpha.
> 
> GIF doesn't support alpha at all AFAIK; only colorkey transparency. 
> Dunno about PNG... It seems like GIMP won't even let you create a 
> palettized image with an alpha channel in it's internal format, so I 
> can't try it either.

PNG supports alpha channel for RGB images (eg. plain RGBA).  I believe
it supports alpha channel for paletted images, but I'm not entirely sure
how that works right now (the documentation for the tRNS chunk is poor),
but I know that it and SDL_image will at least handle simple color keying
properly.

The last time I tried Gimp (a year or two ago?), loading then saving a PNG
with alpha information threw it away, which was horribly broken, so I went
back (having been rather disgusted in Gimp :) to Photoshop and havn't tried
it since.

-- 
Glenn Maynard