smr / polygonviewdemo Goto Github PK

Swift Polygon View using CAShapeLayer

This is an demonstration of using CAShapeLayer/UIBezierPath to create a view that contains a polygon in Swift.

The basic idea is to create a CAShapeLayer and add it to the CALayer hierarchy once, but then update the path for that shape layer whenever the view changes size (either in layoutSubviews in UIView class or viewDidLayoutSubviews in UIViewController). Personally, I like to do this stuff as an @IBDesignable view subclass, like I have here, because that way I can use it in a storyboard (just drag a a simple "View" object onto the scene and then set its base class to be PolygonView (or whatever you call it here). The only trick with using designables is that Apple advises putting them in a separate framework target, like I have here.

But none of this IBDesignable stuff is critical to the question at hand, namely just use CAShapeLayer and update its path when the view changes size.

This is not intended as an end-user library, but this is for illustrative purposes only.

See http://stackoverflow.com/a/41476105/1271826.

Developed in Swift 3 on Xcode 8.2.1 for iOS 10. But, the basic ideas are equally applicable for different versions of Swift and/or Objective-C.

License

Copyright © 2017 Robert Ryan. All rights reserved.

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

--

16 January 2017