[Pixman] [PATCH] Improve handling of tangent circles

Siarhei Siamashka siarhei.siamashka at gmail.com
Tue Jan 4 01:59:48 PST 2011

On Monday 03 January 2011 10:15:09 Andrea Canciani wrote:
> When b is 0, avoid the division by zero and just return transparent
> black.
> When the solution t would have an invalid radius (negative or outside
> [0,1] for none-extended gradients), return transparent black.

Thanks for keeping improving radial gradients code.

I just wonder if it would be difficult to add a test to pixman for this
particular division by zero case? Or is it somehow triggered by cairo

One of the problems with the pixman radial code is that it is slow.
And this path further slows it down a bit by adding a new branch in the
inner loop. This is perfectly fine for a reference implementation, but if
somebody decides to add some performance optimizations, then we need to have
at least some basic tests which can catch possible errors and regressions.

Best regards,
Siarhei Siamashka

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