From: Marcus Sundberg <e94_msu@elixir.e.kth.se>
  To  : ggi-develop@eskimo.com
  Date: Sun, 09 Aug 1998 16:12:18 +0200

Re: LibGGI & 24/32 bit modes

> 1) 32 bit modes -- the set of masks describe the layout perfectly,
>    without any funniness like you get with reverse-endian 16 bit modes,
>    so shouldn't we avoid using the GGI_PF_REVERSE_ENDIAN flag here ?

Sure, every mode should be described in the most simple way that still
is correct.

> 2) 24 bit modes have to be read / written 1 byte at a time, but in
>    what order ?  There are two possibilities:
> 
>       buf[0] = (ggi_pixel & 0xff0000) >> 16;
>       buf[1] = (ggi_pixel & 0xff00) >> 8;
>       buf[2] = (ggi_pixel & 0xff)
> 
>       versus
> 
>       buf[0] = (ggi_pixel & 0xff)
>       buf[1] = (ggi_pixel & 0xff00) >> 8;
>       buf[2] = (ggi_pixel & 0xff0000) >> 16;
>
>    We should pick one and stick to it.  I think the second version looks
>    easier to optimize (e.g. *buf++ = (uint8) pix; pix >>= 8).

Well, that will depend on the endianness.
When reading/writing multiple pixels at a time we should put 4 bytes
at a time (8 an 64-bit machines), and the order we put the bytes in
when writing a single pixel must be the same as it is when putting
multiple ones.

//Marcus