How to rotate image in Swift?

set ImageView image

ImageView.transform = ImageView.transform.rotated(by: CGFloat(M_PI_2))

Swift 5

ImageView.transform = ImageView.transform.rotated(by: .pi)        // 180˚ImageView.transform = ImageView.transform.rotated(by: .pi / 2)    // 90˚ImageView.transform = ImageView.transform.rotated(by: .pi * 1.5)  // 270˚

In one line:

rotatedViewBox.transform = CGAffineTransform(rotationAngle: CGFloat.pi/2)

This is an extension of UIImage that targets Swift 4.0 and can rotate just the image without the need for a UIImageView. Tested successfully that the image was rotated, and not just had its exif data changed.

import UIKitextension UIImage {    func rotate(radians: CGFloat) -> UIImage {        let rotatedSize = CGRect(origin: .zero, size: size)            .applying(CGAffineTransform(rotationAngle: CGFloat(radians)))            .integral.size        UIGraphicsBeginImageContext(rotatedSize)        if let context = UIGraphicsGetCurrentContext() {            let origin = CGPoint(x: rotatedSize.width / 2.0,                                 y: rotatedSize.height / 2.0)            context.translateBy(x: origin.x, y: origin.y)            context.rotate(by: radians)            draw(in: CGRect(x: -origin.y, y: -origin.x,                            width: size.width, height: size.height))            let rotatedImage = UIGraphicsGetImageFromCurrentImageContext()            UIGraphicsEndImageContext()            return rotatedImage ?? self        }        return self    }}

To perform a 180 degree rotation, you can call it like this:

let rotatedImage = image.rotate(radians: .pi)

If for whatever reason it fails to rotate, the original image will then be returned.