First, here's an example of the result that I'm after: http://www.mathopenref.com/trianglecircumcenter.html with one addition: I want to also be able to drag the center dot.
I'm just getting started with both drawing in WPF and adorners, and want to make sure I don't head off into the woods. I found a good example of using adorners to resize rectangular controls, but this is really very different. I'm currently am thinking I want to compose a DrawingGroup and create some geometry-busy handlers that reshape the elements based on dragging the four points. Is that reasonable?
I'd like to have an elegant solution and would welcome some expert design guidance.
--Douglas