How to smooth the edge of a zig-zag line?

Currently I draw a zig-zap line by CGContextMoveToPoint, CGContextAddLineToPoint, and CGContextStrokePath, following touchesMoved events. How can I smoo开发者_开发问答th the edges of the line? Such that when the user draw a circle-like shape, the circle can be more round'ed. The GLPaint example use OpenGL, is that the only way to do it?

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You can simply set the line join to round, to make the edges less visible:

CGContextSetLineJoin(ctx, kCGLineJoinRound);

Other than that you option would be to use some kind of spline interpolation.