> No. As Andreas pointed out, it is only used to determine if the pixel
> below your mouse pinter is transparent or not. This is one call per
> frame per SketchMorph, which is okay.

It is one call per frame per SketchMorph where the bounding box test
succeeds which is even less. In almost all situations it's *at most* 1 test
per frame.

Cheers,
  - Andreas