I was wanting a lightweight function to resize, rotate, and skew DisplayObjects based on a dynamic registration point so I made a function to apply my desired matrix settings.

One thing that bothers me is that I could not figure out how to skew along the X and Y axis at the same time. When I do set "c" and "b" Matrix properties, one of the skewed axis does not skew parallel like it should. And if I concatenate separate skew Matrices, the last concatenated skew Matrix transforms correctly but not the one before it. I'm trying to avoid using nested DisplayObjects to perform the separate X and Y skews, but that looks like an option I will have to use.

Here is an ActionScript 3 function that will return intersection information between a segment and circle.
It's useful to me to know if a segment is partially intersecting with a circle or going completely through.

The intersection Point of two lines is useful to know. This is a function to find it in AS3.