This is an demonstration of rendering a circular arrow in Objective-C, including animation of the arrow with a display link.
Note, I also used IB_DESIGNABLE view so that you can render (and customize the appearance) in Interface Builder storyboard. You don't have to do this, but it makes designing of user interfaces a little easier.
See https://stackoverflow.com/a/28202828/1271826. Unlike that example, here I'm using the path to update a shape layer, enjoying the efficiencies of CAShapeLayer as opposed to overriding drawRect, but also opening up the possibility of using the CAShapeLayer to update a mask instead of simply displaying the shape layer.
This was developed in Objective-C on Xcode 9.1 for iOS 11.1. But, the basic ideas are equally applicable for different versions of Objective-C and iOS versions.
Copyright © 2017 Robert Ryan. All rights reserved.
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
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13 November 2017