On Wed, Jul 30, 2003 at 05:19:49PM +0200, Andreas Robinson wrote:
> Hi all,
> 
> I'm trying to implement support for the blitting flags in the cle266 driver.
> (Within the limitations of the hardware anyway.)

It looks like DirectFB will have another full featured driver soon :)

> 1. DSBLIT_BLEND_ALPHACHANNEL and DSBLIT_BLEND_COLORALPHA are mutually exclusive.

Incorrect. If both are set then the source alpha should be modulated by
color alpha.

> 2. DSBLIT_COLORIZE, DSBLIT_SRC_PREMULTIPLY, DSBLIT_DST_PREMULTIPLY and 
> DSBLIT_DEMULTIPLY can be combined freely.

Correct.

> 3. DSBLIT_BLEND_ALPHACHANNEL =
> 
>    Pass on source pixel alpha channel to the blending function
>    If the source image does not have an alpha channel, assume
>    a fixed alpha of 1.0.
>    Can not be combined with DSBLIT_BLEND_COLORALPHA.
> 
> 4. DSBLIT_BLEND_COLORALPHA =
> 
>    Use a fixed alpha, set by the current drawing color instead
>    of the source pixel alpha, in the blending function.
>    Can not be combined with DSBLIT_BLEND_ALPHACHANNEL.

Correct except for the combined part.

> 5. DSBLIT_COLORIZE =
> 
>    Multiply color and alpha of a source pixel with the current
>    corresponding elements in the current drawing color, before
>    passing the pixel on to the blending function.

Doesn't modulate alpha. Otherwise correct.

Your other observations seem to be correct.

-- 
Ville Syrj�l�
[EMAIL PROTECTED]
http://www.sci.fi/~syrjala/


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