[cairo] Extending XRender to support non-blurry edges for transformations(?)

[Clemens Eisserer]

Hi Owen,

>  - You'll get fuzzing out towards the edges of the pixels that are
>   present in the mask... the same way if you drew a transformed
>   rectangle and used EXTEND_NONE rather than EXTEND_PAD for the
>   repeat mode.
>
>  - No antialiasing, so it might look OK (except for the fuzzing out
>   problem mentioned above) for scaling, but isn't going to look
>   OK for rotation.

I tried it with rotation, using a 100x scaled 2x2 image as source
(that why it looks like a gradient) and for me it looks quite good.
I tried it one time with a nearest filtered mask (no AA) and one time
with billinear filtering (AA):
http://picasaweb.google.com/linuxhippy/Transformations/photo#5229203425413416738

For the demo the scaled source picture is much larger than the drawn
rectangle, but shouldn't this work once REPEAT_PAD is implemented in
X?

Thanks, Clemens