[Pixman] [cairo] pixman: New ARM NEON optimizations
Bill Spitzak
spitzak at gmail.com
Fri Feb 11 12:13:17 PST 2011
Soeren Sandmann wrote:
> (1) The equation would be
>
> (src OP dst) LERP_mask dst
>
> and not
>
> (src IN mask) OP dst
>
> (2) The RGB channels of Alpha-only images would be considered to be
> the same as the alpha channel, and not 0 as they are now. For
> example, a 0xb9 pixel in an a8 image would be considered
> equivalent to 0xb9b9b9b9 and not to 0xb9000000. That is, they
> would be considered a translucent white rather than a translucent
> black.
Why not just try making these changes directly to Render? This is pretty
much what Cairo did and nobody complained. Panicking about
back-compatibility when it is likely that nobody relies on the current
behavior is silly.
The only software I know of using Render for anything other than OVER is
Cairo, and it must be avoiding all the cases where changing this would
make a difference because it does not match it's rules anyway.
Of course if there are real examples of existing and in-use clients (ie
something actually distributed on Linux systems) that rely on the
current behavior then you can't change it.
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