How to scale, stretch, move, and rotate UIViews using CGAffineTransform

Swift version: 5.10

Paul Hudson @twostraws June 1st 2019

Every UIView subclass has a transform property that lets you manipulate its size, position and rotation using something called an affine transform. This property is animatable, which means you can make a view smoothly double in size, or make it spin around, just by changing one value.

Here are some examples to get you started:

imageView.transform = CGAffineTransform(scaleX: 2, y: 2)
imageView.transform = CGAffineTransform(translationX: -256, y: -256)
imageView.transform = CGAffineTransform(rotationAngle: CGFloat.pi)
imageView.transform = CGAffineTransform.identity

The first one makes an image view double in size, the second one makes it move up and left 256 points, the third one makes it spin around 180 degrees (the values are expressed in radians), and the fourth one sets the image view's transform back to "identity" – this means "reset."