[cairo] Render to image buffer artifacts

[Chris]

On Thu, 2005-01-13 at 19:33 -0500, Carl Worth wrote:
> This was really an old bug that we knew about, but didn't work around
> completely. The current algorithm for rasterizing trapezoids has a
> weird edge effect that can cause it to compute an alpha value of 1 in
> pixels outside of the trapezoids.
> 
> I've now committed the below fix to libpixman to fixes the bug. I've
> also committed a test case to the regression suite called
> leaky_polygon.

Thanks for taking time to look into this.  Your patch appears to create
some rendering artifacts.  Take a look here:

http://imago.functionalfuture.com/images/scratchy.png

Some of the edges look "scratchy."  I'm not sure if the width of the
line has anything to do with it.  Reverting the patch makes the
artifacts go away.

-- 
// Chris