[Pixman] Performance of radial gradients

Luca Barbato lu_zero at gentoo.org
Fri Feb 19 04:04:58 PST 2010

On 02/19/2010 12:57 PM, Siarhei Siamashka wrote:
> Adding small increments to the values at the end of loop iteration could be
> the biggest source of precision loss. Replacing this with explicit calculation
> like 'pdx = pdx0 + cx * n' should improve precision and maybe allow to use
> floats freely. And floats work better with SIMD on any platforms.

And all the SIMD we are covering have a multiply-accumulate instruction
that would be in use, I'm a bit more concerned about the sqrt usage

> In any case, seems like radial gradients are not covered by any
> correctness/precision tests at the moment. This looks like the first
> thing which needs to be implemented :)

Indeed =)



Luca Barbato

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