

Hit testing for arbitrary paths on the iPhone - baroova
http://www.dragozov.com/2009/10/hit-testing-for-arbitrary-paths-on.html

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ajg1977
This approach seems really dumb to me.

1) Testing rectangles against paths is an easy thing to solve on the CPU.

2) On the first iPhone models if you're doing anything graphics related the
bottleneck is likely to be the GPU, so why give it more work?

3) Having the GPU rasterize into a user surface (which by definition must be
available immediately) is going to cause an ugly stall as you wait for the
drawing pipeline to be flushed. (no lock semantics in core graphics).

4) Having the CPU block on results from the GPU mid-frame is one of the worst
things you can do in architectures that feature graphics acceleration.

