Hello all, I need to add a vertex, with handles, to an existing vector shape. I'm using a modified version of Michael Geary's Vector Editor program.
I have a unfilled circle. The user clicks anywhere on the circumference, and I add a vertex there. I know how to add the vertex, and the syntax for adding the handles. I'm not sure how to figure out where the handles go, though. Existing vertex points already have handles, each one 20 pixels out from the point, and tangent to the circle. For example, the point at (92, 20) (upper right quadrant) has handles going to (20, -20) and (-20, 20). Is it enough to know which quadrant I'm in, and just go out 20 pixels in either direction? If so, does somebody have a formula to figure out which quadrant the point is in? I'm afraid it's been 25 years since I finished my third semester of calculus, and I've successfully forgotten most everything back through Trig. Here's the vertexList: [[#vertex: point(0, 0)], [#vertex: point(0, 0)], [#newCurve], [#vertex: point(20, 20), #handle1: point(20, -20), #handle2: point(-20, 20)], [#vertex: point(92, 20), #handle1: point(20, 20), #handle2: point(-20, -20)], [#vertex: point(92, 92), #handle1: point(-20, 20), #handle2: point(20, -20)], [#vertex: point(20, 92), #handle1: point(-20, -20), #handle2: point(20, 20)]] It appears visually that those points all lie on lines with a slope of 1 and -1, going through the origin. Cordially, Kerry Thompson [To remove yourself from this list, or to change to digest mode, go to http://www.penworks.com/lingo-l.cgi To post messages to the list, email [email protected] (Problems, email [EMAIL PROTECTED]). Lingo-L is for learning and helping with programming Lingo. Thanks!]
