The solution to do UIImage flipping is with the Objective-C code:
[UIImage imageWithCGImage:img.CGImage scale:1.0 orientation: UIImageOrientationDownMirrored]
However, imageWithCGImage is not available in Swift! Is there a solution for flipping image horizontally with Swift? Thanks!
In Swift.... (6.3.1)
YourUIImage.transform = CGAffineTransformMakeScale(-1, 1)
This also works with a UIView
Most factory methods are converted to initializers in swift. Whenever available, even if the class method is still available, they are preferred. You can use:
init(CGImage cgImage: CGImage!, scale: CGFloat, orientation: UIImageOrientation)
The usage would look like this:
var image = UIImage(CGImage: img.CGImage, scale: 1.0, orientation: .DownMirrored)
Swift 5
var image = UIImage(cgImage: img.cgImage!, scale: 1.0, orientation: .downMirrored)
For me the simplest way was to use the .withHorizontallyFlippedOrientation()
instance method of UIImage
as follows:
let flippedImage = straightImage.withHorizontallyFlippedOrientation()
Simple one-liners always make me happy :)
Changing image orientation parameter is not actually flipping the image in all cases. Image must be redrawn somehow... For example like this:
Swift 3
func flipImageLeftRight(_ image: UIImage) -> UIImage? {
UIGraphicsBeginImageContextWithOptions(image.size, false, image.scale)
let context = UIGraphicsGetCurrentContext()!
context.translateBy(x: image.size.width, y: image.size.height)
context.scaleBy(x: -image.scale, y: -image.scale)
context.draw(image.cgImage!, in: CGRect(origin:CGPoint.zero, size: image.size))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
斯威夫特 4
YOURIMAGEVIEW.transform = CGAffineTransform(scaleX: -1, y: 1)
Here is the simplest solution for actually flipping the image
extension UIImage {
func flipHorizontally() -> UIImage? {
UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)
let context = UIGraphicsGetCurrentContext()!
context.translateBy(x: self.size.width/2, y: self.size.height/2)
context.scaleBy(x: -1.0, y: 1.0)
context.translateBy(x: -self.size.width/2, y: -self.size.height/2)
self.draw(in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
}
and to use this solution you can do the following
let image = UIImage(named: "image.png")!
let newImage = image.flipHorizontally()
To flip image in swift 4
class ViewController: UIViewController {
var first = 1
var second = 1
@IBOutlet weak var img: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
@IBAction func flip1(_ sender: Any) {
if first == 1 {
img.transform = CGAffineTransform(scaleX: -1, y: 1)
first = 2
}
else if first == 2
{
img.transform = CGAffineTransform(scaleX: +1, y: 1)
first = 1
}
}
}
There is couple of similar questions on SO. And I believe it's worth to post solution using CoreImage
here too.
Please note: when getting final UIImage
, it's necessary to convert to CGImage
first to respect extent of CIImage
extension UIImage {
func imageRotated(by degrees: CGFloat) -> UIImage {
let orientation = CGImagePropertyOrientation(imageOrientation)
// Create CIImage respecting image's orientation
guard let inputImage = CIImage(image: self)?.oriented(orientation)
else { return self }
// Flip the image itself
let flip = CGAffineTransform(scaleX: 1, y: -1)
let outputImage = inputImage.transformed(by: flip)
// Create CGImage first
guard let cgImage = CIContext().createCGImage(outputImage, from: outputImage.extent)
else { return self }
// Create output UIImage from CGImage
return UIImage(cgImage: cgImage)
}
}
Swift 5
If your use case requires saving the UIImage
after transforming, it will need to be drawn into a new CGContext
.
extension UIImage {
enum Axis {
case horizontal, vertical
}
func flipped(_ axis: Axis) -> UIImage {
let renderer = UIGraphicsImageRenderer(size: size)
return renderer.image {
let context = $0.cgContext
context.translateBy(x: size.width / 2, y: size.height / 2)
switch axis {
case .horizontal:
context.scaleBy(x: -1, y: 1)
case .vertical:
context.scaleBy(x: 1, y: -1)
}
context.translateBy(x: -size.width / 2, y: -size.height / 2)
draw(at: .zero)
}
}
}
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