Understanding path/segment/item data structure

[Colin Kingsbury]

I am working on a prototype which involves interactive drawing and editing of paths. I'm slowly getting things to work and having some real fun, but I am still having some difficulty understanding how to navigate some of the basic data structures.

Here is a sketch of a path consisting of three straight lines:

http://imgur.com/XbMGIQH

If I do a Project.HitTest for a point along B, I get a HitResult with type=stroke, item=my path, segment=null. How do I determine which segment in my path I clicked (i.e. "B") and get the two points at either end (2 and 3)?

More generally, I am trying to understand how paths, segments, and curves actually fit together in terms of the data model. From reading the docs I see that a path has multiple segments which makes sense, but that a segment only has one point (its anchor point?). If I inspect a simple line (straight line between two points) in a debugger I see that its path actually consists of two segments where each segment contains one endpoint.

Is there anything anywhere I could read which explains the principle behind this a little more clearly? Or can anyone shed a little light?

Thanks in advance!