wumpus-basic

Copperbox revision 1582.

I've added arrow drawing for straight line connectors - i.e. objects of the AGraphic2 type. The code also manages retracting a point back along a line - this is needed for open stroked arrow heads.

Somewhere in the original Wumpus or in Wumpus-Extra I have code for working out the end angle of Bezier curve - its different to the angle to the control point if memory serves. I also have the code for retracting a point back along a curve - which is a variation of the de Casteljau algorithm.