Stefan Seefeld writes:
> I understand that the mapping between pixels and colors depends
> on the visual type being used. Supposing that we deal with TrueColor
> visuals exclusively in the following.
>
> If I querry the pixel format, it appears I can write any RGBA
> value into a pixel buffer I want. The ggiMapColor and family
> seem only convenience (again, when using TrueColor). Is this right ?
Right, if you query the pixel format and understand it.
Good LibGGI programs OTOH work even if they don't understand the pixel
format (by using fallback methods, e.g. ggiMapColor).
> Further, the GGI color model doesn't deal with alpha channels (from
> the docs). What if I specify the alpha value in the pixels directly ?
> Is this simply ignored when I issue a ggiPutBox call ? Or can I use the
> alpha value to put a shaped (masked) region ?
Anything in bits not specified in the pixel format's bitmasks will be
ignored by LibGGI and probably the hardware too. There is an alpha
mask in the ggi_pixelformat but AFAIK it never does anything (in
LibGGI or in hardware).
Cheers,
__
\/ Andrew Apted <[EMAIL PROTECTED]>
