[patch] on the performance of KisCircleMaskGenerator::valueAt

[Geoffry Song]

> I ran KisStrokeBenchmark 20 times each for the old and new code. Only
> the first two tests (pixelbrush300px and bixpelbrush300pxRL) call
> KisCircleMaskGenerator::valueAt a significant number of times, so
> unsurprisingly they are the only benchmarks that show a significant
> change: 489.9 msec (stdev 14.62) to 456.8 msec (stdev 14.20) for
> pixelbrush300px, and 2788 msec (stdev 73.25) to 2619 msec (stdev
> 88.89) for pixelbrush300pxRL. It's not a big difference, but it's
> there.

FWIW, I redid these two benchmarks one hundred times each, without X
running, and got 476.08 ms (stdev 12.24) -> 438.91 ms (stdev 13.40),
and 2709.2 ms (stdev 64.00) -> 2515.1 ms (stdev 74.13).


-- 
Segmentation fault