How to fill space between two UIBezierPaths

Question

I'm working on drawing application which provides drawing lines with variable line width which depends on drawing speed. This behavior inspired by Paper app.

Algorithm which I'm trying to implement -- draw two bezier path with variable distance between them. The solution which described in sosborn's answer. Then smooth paths and fill the distance between them.

Actually I don't figured out how to fill space between paths.

Answer 1

You create a single path from the 2 bezier curves and fill it, like this:

NSBezierPath* path = [NSBezierPath bezierPath];

// Move to the start point
[path moveToPoint:startPt];

// Make the lower part of the curve
[path curveToPoint:endPt controlPoint1:cp1 controlPoint2:cp2];

// Make the upper part of the curve as part of the same path:
[path curveToPoint:startPt contorPoint1:cp3 controlPoint2:cp4];

// Now fill it
[path fill];