I want to draw a path gradually, i.e. I want the path to appear as if it is drawn by hand. I have managed to create the path I need. I have also managed to create a CAKeyFrameAnimation that uses this path. But so far I can only move an object along this path. I would like to both move an object (say a pencil) along the path, and have the path appear as if it is drawn.
Any pointers?
Create a CAShapeLayer with your path and animate the layer's strokeEnd from 0.0 to 1.0. (This is new in iOS SDK 4.2, won't work with previous versions.)
来源：https://stackoverflow.com/questions/4390911/drawing-a-path-with-cakeyframeanimation-on-iphone