Rotate UIImage in swift - ios

Question

I want to rotate UIImage in clockwise direction. But my current code do not perform function accurate some time it rotate and some time its skip rotation. I want my UIImage will continuously rotate clockwise on my action button.
Here is my current code:
imageView.image = imageView.image!.imageRotatedByDegrees(angle, flip: false)
angle = angle + 90
if angle > 360{
angle = 0
}

Answer 1

This works for me:
works Fine :)
func imageRotatedByDegrees(oldImage: UIImage, deg degrees: CGFloat) -> UIImage {
//Calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox: UIView = UIView(frame: CGRectMake(0, 0, oldImage.size.width, oldImage.size.height))
let t: CGAffineTransform = CGAffineTransformMakeRotation(degrees * CGFloat(M_PI / 180))
rotatedViewBox.transform = t
let rotatedSize: CGSize = rotatedViewBox.frame.size
//Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap: CGContextRef = UIGraphicsGetCurrentContext()!
//Move the origin to the middle of the image so we will rotate and scale around the center.
CGContextTranslateCTM(bitmap, rotatedSize.width / 2, rotatedSize.height / 2)
//Rotate the image context
CGContextRotateCTM(bitmap, (degrees * CGFloat(M_PI / 180)))
//Now, draw the rotated/scaled image into the context
CGContextScaleCTM(bitmap, 1.0, -1.0)
CGContextDrawImage(bitmap, CGRectMake(-oldImage.size.width / 2, -oldImage.size.height / 2, oldImage.size.width, oldImage.size.height), oldImage.CGImage)
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
Swift 3:
func imageRotatedByDegrees(oldImage: UIImage, deg degrees: CGFloat) -> UIImage {
//Calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox: UIView = UIView(frame: CGRect(x: 0, y: 0, width: oldImage.size.width, height: oldImage.size.height))
let t: CGAffineTransform = CGAffineTransform(rotationAngle: degrees * CGFloat.pi / 180)
rotatedViewBox.transform = t
let rotatedSize: CGSize = rotatedViewBox.frame.size
//Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap: CGContext = UIGraphicsGetCurrentContext()!
//Move the origin to the middle of the image so we will rotate and scale around the center.
bitmap.translateBy(x: rotatedSize.width / 2, y: rotatedSize.height / 2)
//Rotate the image context
bitmap.rotate(by: (degrees * CGFloat.pi / 180))
//Now, draw the rotated/scaled image into the context
bitmap.scaleBy(x: 1.0, y: -1.0)
bitmap.draw(oldImage.cgImage!, in: CGRect(x: -oldImage.size.width / 2, y: -oldImage.size.height / 2, width: oldImage.size.width, height: oldImage.size.height))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}

Answer 2

extension UIImage {
public func imageRotatedByDegrees(degrees: CGFloat) -> UIImage {
//Calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox: UIView = UIView(frame: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
let t: CGAffineTransform = CGAffineTransform(rotationAngle: degrees * CGFloat.pi / 180)
rotatedViewBox.transform = t
let rotatedSize: CGSize = rotatedViewBox.frame.size
//Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap: CGContext = UIGraphicsGetCurrentContext()!
//Move the origin to the middle of the image so we will rotate and scale around the center.
bitmap.translateBy(x: rotatedSize.width / 2, y: rotatedSize.height / 2)
//Rotate the image context
bitmap.rotate(by: (degrees * CGFloat.pi / 180))
//Now, draw the rotated/scaled image into the context
bitmap.scaleBy(x: 1.0, y: -1.0)
bitmap.draw(self.cgImage!, in: CGRect(x: -self.size.width / 2, y: -self.size.height / 2, width: self.size.width, height: self.size.height))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}
public func fixedOrientation() -> UIImage {
if imageOrientation == UIImageOrientation.up {
return self
}
var transform: CGAffineTransform = CGAffineTransform.identity
switch imageOrientation {
case UIImageOrientation.down, UIImageOrientation.downMirrored:
transform = transform.translatedBy(x: size.width, y: size.height)
transform = transform.rotated(by: CGFloat.pi)
break
case UIImageOrientation.left, UIImageOrientation.leftMirrored:
transform = transform.translatedBy(x: size.width, y: 0)
transform = transform.rotated(by: CGFloat.pi/2)
break
case UIImageOrientation.right, UIImageOrientation.rightMirrored:
transform = transform.translatedBy(x: 0, y: size.height)
transform = transform.rotated(by: -CGFloat.pi/2)
break
case UIImageOrientation.up, UIImageOrientation.upMirrored:
break
}
switch imageOrientation {
case UIImageOrientation.upMirrored, UIImageOrientation.downMirrored:
transform.translatedBy(x: size.width, y: 0)
transform.scaledBy(x: -1, y: 1)
break
case UIImageOrientation.leftMirrored, UIImageOrientation.rightMirrored:
transform.translatedBy(x: size.height, y: 0)
transform.scaledBy(x: -1, y: 1)
case UIImageOrientation.up, UIImageOrientation.down, UIImageOrientation.left, UIImageOrientation.right:
break
}
let ctx: CGContext = CGContext(data: nil,
width: Int(size.width),
height: Int(size.height),
bitsPerComponent: self.cgImage!.bitsPerComponent,
bytesPerRow: 0,
space: self.cgImage!.colorSpace!,
bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue)!
ctx.concatenate(transform)
switch imageOrientation {
case UIImageOrientation.left, UIImageOrientation.leftMirrored, UIImageOrientation.right, UIImageOrientation.rightMirrored:
ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
default:
ctx.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
break
}
let cgImage: CGImage = ctx.makeImage()!
return UIImage(cgImage: cgImage)
}
}
#Jason, You should fix orientation of image before rotation.
let image = oldimage.fixedOrientation().imageRotatedByDegrees(90.0)

Answer 3

#Jason Chitla, I cant comment yet, so Im posting it as a new answer. The above solution from #Albert works, but only for square images. The problem is, that
bitmap.draw(oldImage.cgImage!, in: CGRect(x: -oldImage.size.width / 2, y: -oldImage.size.height / 2, width: oldImage.size.width, height: oldImage.size.height))
is still using the original size, so if you rotate it 90 degrees, aspect is wrong.
What works for me is to use the new rotatedSize, like this:
func imageRotatedByDegrees(oldImage: UIImage, deg degrees: CGFloat) -> UIImage {
//Calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox: UIView = UIView(frame: CGRect(x: 0, y: 0, width: oldImage.size.width, height: oldImage.size.height))
let t: CGAffineTransform = CGAffineTransform(rotationAngle: degrees * CGFloat(M_PI / 180))
rotatedViewBox.transform = t
let rotatedSize: CGSize = rotatedViewBox.frame.size
//Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap: CGContext = UIGraphicsGetCurrentContext()!
//Move the origin to the middle of the image so we will rotate and scale around the center.
bitmap.translateBy(x: rotatedSize.width / 2, y: rotatedSize.height / 2)
//Rotate the image context
bitmap.rotate(by: (degrees * CGFloat(M_PI / 180)))
//Now, draw the rotated/scaled image into the context
bitmap.scaleBy(x: 1.0, y: -1.0)
bitmap.draw(self.cgImage!, in: CGRect(x: -rotatedSize.width / 2, y: -rotatedSize.height / 2, width: rotatedSize.width, height: rotatedSize.height))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}

Answer 4

You can create a function like this to make your image rotate in clockwise forever:
override func viewDidLoad() {
super.viewDidLoad()
let kRotationAnimationKey = "com.myapplication.rotationanimationkey"
func rotateView(view: UIView, duration: Double = 1) {
if view.layer.animationForKey(kRotationAnimationKey) == nil {
let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation")
rotationAnimation.fromValue = 0.0
rotationAnimation.toValue = Float(M_PI * 2.0)
rotationAnimation.duration = duration
rotationAnimation.repeatCount = Float.infinity
view.layer.addAnimation(rotationAnimation, forKey: kRotationAnimationKey)
}
}
rotateView(self.imageView)
}
Result is:

Answer 5

For those who need the code from #Mughees in Swift 3:
func imageRotatedByDegrees(oldImage: UIImage, deg degrees: CGFloat) -> UIImage {
//Calculate the size of the rotated view's containing box for our drawing space
let rotatedViewBox: UIView = UIView(frame: CGRect(x: 0, y: 0, width: oldImage.size.width, height: oldImage.size.height))
let t: CGAffineTransform = CGAffineTransform(rotationAngle: degrees * CGFloat(M_PI / 180))
rotatedViewBox.transform = t
let rotatedSize: CGSize = rotatedViewBox.frame.size
//Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap: CGContext = UIGraphicsGetCurrentContext()!
//Move the origin to the middle of the image so we will rotate and scale around the center.
bitmap.translateBy(x: rotatedSize.width / 2, y: rotatedSize.height / 2)
//Rotate the image context
bitmap.rotate(by: (degrees * CGFloat(M_PI / 180)))
//Now, draw the rotated/scaled image into the context
bitmap.scaleBy(x: 1.0, y: -1.0)
bitmap.draw(oldImage.cgImage!, in: CGRect(x: -oldImage.size.width / 2, y: -oldImage.size.height / 2, width: oldImage.size.width, height: oldImage.size.height))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}

Answer 6

I fixed first function of #gleb's answer little bit. Size calculation is not necessary there. We simply should do it with reverse.
Because if you do it size of 1149 x 356 with #gleb's function then you will get image sized 357 x 1149.
extension UIImage {
public func imageRotatedByDegrees(degrees: CGFloat) -> UIImage {
let rotatedSize: CGSize = CGRect(x: 0, y: 0, width: self.size.height, height: self.size.width).size
//Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize)
let bitmap: CGContext = UIGraphicsGetCurrentContext()!
//Move the origin to the middle of the image so we will rotate and scale around the center.
bitmap.translateBy(x: rotatedSize.width / 2, y: rotatedSize.height / 2)
//Rotate the image context
bitmap.rotate(by: (degrees * CGFloat.pi / 180))
//Now, draw the rotated/scaled image into the context
bitmap.scaleBy(x: 1.0, y: -1.0)
bitmap.draw(self.cgImage!, in: CGRect(x: -self.size.width / 2, y: -self.size.height / 2, width: self.size.width, height: self.size.height))
let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
return newImage
}
}

Answer 7

This s probably easier and it is Swift 5 syntax:
// MARK: Rotate
extension UIImage {
func rotate(radians: Float) -> UIImage? {
var newSize = CGRect(origin: CGPoint.zero, size: self.size).applying(CGAffineTransform(rotationAngle: CGFloat(radians))).size
// Trim off the extremely small float value to prevent core graphics from rounding it up
newSize.width = floor(newSize.width)
newSize.height = floor(newSize.height)
UIGraphicsBeginImageContextWithOptions(newSize, false, self.scale)
let context = UIGraphicsGetCurrentContext()!
// Move origin to middle
context.translateBy(x: newSize.width/2, y: newSize.height/2)
// Rotate around middle
context.rotate(by: CGFloat(radians))
// Draw the image at its center
self.draw(in: CGRect(x: -self.size.width/2, y: -self.size.height/2, width: self.size.width, height: self.size.height))
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
}

Answer 8

I believe it's worth to post solution using CoreImage. It's just couple of lines and it works great for me.
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 }
// Rotate the image itself
let rotation = CGAffineTransform(rotationAngle: (degrees * CGFloat.pi / 180))
let outputImage = inputImage.transformed(by: rotation)
// Create CGImage first
guard let cgImage = CIContext().createCGImage(outputImage, from: outputImage.extent)
else { return self }
// Create output UIImage from CGImage
return UIImage(cgImage: cgImage)
}
}