On 5 April 2016 at 00:51, Andrei Chis <chisvasileandrei@gmail.com> wrote:

btw, Andrei , if you looking how you can test if point contains shape or not, take a look at��AthensCurveFlattener.

It converts curved path, that containing Bezier curves (or not) into simple polygonal shape that consists only from a simple lines.

Then there��AthensPolygonTester, that has the piece you missing:

- a small algorithm that can test if given point inside or outside that polygon.

Please note that it is simpler even-odd rule algorithm. It not works correctly for all possible cases.

There's another algorithm- winding number algorithm, that is much better,

but i had to switch to other stuff before were able to get my hands to it.

It is more reliable, since it can work for self-intersecting shapes.

https://en.wikipedia.org/wiki/Point_in_polygon

��

So, what you need is to wire these things down to Bloc.Then whenever you need to test whether point within shape or not, you can convert any path into polygon and perform the test. And of course, you can cache the results of conversion in order to avoid expensive computations every time you need to perform such tests. Once path is converted, the test is relatively cheap and costs something like O(n), where n is number of line segments.

Or maybe, to simplify things, you could extend the shape protocol and introduce #containsPoint:��

or as variant #containsPoint:ifNotAvailable:��

so that if shape implements such feature - it can answer true or false, and if not - evaluating a block. So, you don't have to implement all tests for all kinds of shapes that invented or not yet invented in universe.

Best regards,
Igor Stasenko.