CODEWITHSUNDEEP
iphoneobjective-ciosrotation
user1511244
user1511244

Reputation: 725

How to rotate an image 90 degrees on iOS?

What I want to do is take a snapshot from my camera , send it to a server and then the server sends me back the image on a viewController. If the image is in portrait mode the image appears well on screen , however if the image was taken in landscape mode the image appears streched on the screen(as it tries to appear on portrait mode!). I dont know how to fix this but i guess one solution is first to check if the image is in portrait/landscape mode and then if it is on landscape mode rotate it by 90degrees before showing it on screen. So how could i do that?

Upvotes: 50

Views: 95224

Answers (15)

fanton
fanton

Reputation: 71

If you just want an image rotated to 90 degree in any direction, this would may be help:

let yourImage = ...
let rotatedImage = UIImage(cgImage: yourImage.cgImage!, scale: 1.0, orientation: .left)

Instead of .left use .right for opposite 90 degree direction.

Upvotes: 0

Matthew Usdin
Matthew Usdin

Reputation: 1284

I got an error trying this in XCode 6.3 Swift 1.2

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2);

You should try this to force type cast fix:

self.imageview.transform = CGAffineTransformMakeRotation(CGFloat(M_PI_2));

Swift 4 Edit

imageview.transform = CGAffineTransform(rotationAngle: .pi/2)

Upvotes: 6

dengApro
dengApro

Reputation: 4008

Doing it in the Image Level, in Swift 5:

extension UIImage{
    
    
    func imageRotated(by radian: CGFloat) -> UIImage{
        
        let rotatedSize = CGRect(origin: .zero, size: size)
            .applying(CGAffineTransform(rotationAngle: radian))
            .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: radian)
            draw(in: CGRect(x: -origin.y, y: -origin.x,
                            width: size.width, height: size.height))
            let rotatedImage = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()

            return rotatedImage ?? self
        }

        return self

    }
}

Upvotes: 1

COzkurt
COzkurt

Reputation: 427

If you are looking to save image then you need to rotate picture context not the view. I have used provided examples above but they did not work well when centering the image. So I have enhanced and fixed as follows :

func imageRotatedByDegrees(deg degrees: CGFloat) -> UIImage {

    UIGraphicsBeginImageContext(CGSize(width: self.size.height, height: self.size.width))

    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: self.size.width / 2, y: self.size.height / 2)

    // Rotate the image context
    bitmap.rotate(by: (degrees * CGFloat(Double.pi / 180)))

    // Now, draw the rotated/scaled image into the context
    bitmap.scaleBy(x: 1.0, y: -1.0)

    let origin = CGPoint(x: -self.size.height / 2, y: -self.size.width / 2)

    bitmap.draw(self.cgImage!, in: CGRect(origin: origin, size: CGSize(width: self.size.width, height: self.size.height)))

    let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!

    UIGraphicsEndImageContext()

    return newImage
}

Upvotes: 0

mandeep-dhiman
mandeep-dhiman

Reputation: 2535

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2);

Swift 4+:

self.imageview.transform = CGAffineTransform(rotationAngle: CGFloat(Double.pi/2))

Upvotes: 131

urvashi bhagat
urvashi bhagat

Reputation: 1163

 func imageRotatedByDegrees(oldImage: UIImage, deg degrees: CGFloat) -> UIImage {

    let size = oldImage.size
    UIGraphicsBeginImageContext(size)

    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: size.width / 2, y: size.height / 2)
    //Rotate the image context
    bitmap.rotate(by: (degrees * CGFloat(Double.pi / 180)))
    //Now, draw the rotated/scaled image into the context
    bitmap.scaleBy(x: 1.0, y: -1.0)

    let origin = CGPoint(x: -size.width / 2, y: -size.width / 2)

    bitmap.draw(oldImage.cgImage!, in: CGRect(origin: origin, size: size))

    let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()
    return newImage

}

Use of function 

imageRotatedByDegrees(oldImage: yourImage, deg: degree)

Upvotes: 2

Luis Ortiz
Luis Ortiz

Reputation: 1

It´s best only use the bitmap. In my case use a UIImage that is in reference.image and I converted image at base64String. Without CGAffineTransformMakeRotation and without rotatedViewBox.transform

var rotatedSize = reference.image.size;
                //Create bitmap context
                UIGraphicsBeginImageContext(rotatedSize);
                var bitmap = UIGraphicsGetCurrentContext();
                //move origin to the middle of the image for rotation
                CGContextTranslateCTM(bitmap, rotatedSize.width / 2, rotatedSize.height / 2);
                //rotate image context
                CGContextRotateCTM(bitmap, 1.5708);
                CGContextDrawImage(bitmap, CGRectMake(-reference.image.size.width / 2, -reference.image.size.height / 2, reference.image.size.width, reference.image.size.height), reference.image.CGImage);
                var rotatedImage = UIGraphicsGetImageFromCurrentImageContext();
                var base64Image = UIImageJPEGRepresentation(rotatedImage, compression).base64EncodedStringWithOptions(0);
                UIGraphicsEndImageContext();
                return base64Image;

Upvotes: 0

Jesus Rodriguez
Jesus Rodriguez

Reputation: 2611

Swift 3 and Swift 4 use .pi instead

eg:

//rotate 90 degrees
myImageView.transform = CGAffineTransform(rotationAngle: .pi / 2)

//rotate 180 degrees
myImageView.transform = CGAffineTransform(rotationAngle: .pi)

//rotate 270 degrees
myImageView.transform = CGAffineTransform(rotationAngle: .pi * 1.5)

Upvotes: 23

Jack
Jack

Reputation: 14329

Swift 4+.

arrowImageView.transform = CGAffineTransform(rotationAngle: .pi/2)

Note: angle is in radian

.pi = 180 degree

.pi/2 = 90 degree

If you want to add with animation

  @IBAction func applyTransForm(sender: UIButton) {
        sender.isSelected = !sender.isSelected
        UIView.animate(withDuration: 1, animations: {
        if sender.isSelected {
            self.arrowImageView.transform = CGAffineTransform(rotationAngle: .pi)
        } else {
            self.arrowImageView.transform = CGAffineTransform(rotationAngle: 0)

        }
        })
    }

Output:

enter image description here

Upvotes: 3

Frank Eno
Frank Eno

Reputation: 2649

Swift 4 | Xcode 9 syntax (please note that this code rotates a UIImageView 90 degrees clockwise, not a UIImage):

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

Upvotes: 2

Dhruv Khatri
Dhruv Khatri

Reputation: 813

Swift 3 version:

imageView.transform = CGAffineTransform(rotationAngle: CGFloat(M_PI_2))

Upvotes: 3

Beninho85
Beninho85

Reputation: 3311

Here is the Swift 2.2 version of The iOSDev answer (in UIImage extension):

func degreesToRadians(degrees: CGFloat) -> CGFloat {
    return degrees * CGFloat(M_PI) / 180
}

func imageRotatedByDegrees(degrees: CGFloat) -> UIImage {
    // calculate the size of the rotated view's containing box for our drawing space
    let rotatedViewBox = UIView(frame: CGRectMake(0,0,self.size.width, self.size.height))
    let t = CGAffineTransformMakeRotation(self.degreesToRadians(degrees))
    rotatedViewBox.transform = t
    let rotatedSize = rotatedViewBox.frame.size

    // Create the bitmap context
    UIGraphicsBeginImageContext(rotatedSize)
    let bitmap = 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);

    // Now, draw the rotated/scaled image into the context
    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), self.CGImage);

    let newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;

}

Upvotes: 0

The iOSDev
The iOSDev

Reputation: 5267

This is the complete code for rotation of image to any degree just add it to appropriate file ie in .m as below where you want to use the image processing

for .m

@interface UIImage (RotationMethods)
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees;
@end

@implementation UIImage (RotationMethods)

static CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;};

- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees 
{   
    // calculate the size of the rotated view's containing box for our drawing space
    UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.size.width, self.size.height)];
    CGAffineTransform t = CGAffineTransformMakeRotation(DegreesToRadians(degrees));
    rotatedViewBox.transform = t;
    CGSize rotatedSize = rotatedViewBox.frame.size;

    // Create the bitmap context
    UIGraphicsBeginImageContext(rotatedSize);
    CGContextRef bitmap = 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, DegreesToRadians(degrees));

    // Now, draw the rotated/scaled image into the context
    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;

}

@end

This is the code snippet form apple's SquareCam example.

To call the above method just use the below code

UIImage *rotatedSquareImage = [square imageRotatedByDegrees:rotationDegrees];

Here the square is one UIImage and rotationDegrees is one flote ivar to rotate the image that degrees

Upvotes: 30

janusfidel
janusfidel

Reputation: 8106

- (UIImage *)rotateImage:(UIImage*)image byDegree:(CGFloat)degrees 
{   
    UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,image.size.width, image.size.height)];
    CGAffineTransform t = CGAffineTransformMakeRotation(DegreesToRadians(degrees));
    rotatedViewBox.transform = t;
    CGSize rotatedSize = rotatedViewBox.frame.size;
    [rotatedViewBox release];

    UIGraphicsBeginImageContext(rotatedSize);
    CGContextRef bitmap = UIGraphicsGetCurrentContext();


    CGContextTranslateCTM(bitmap, rotatedSize.width, rotatedSize.height);

    CGContextRotateCTM(bitmap, DegreesToRadians(degrees));


    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-image.size.width, -image.size.height, image.size.width, image.size.height), [image CGImage]);

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;

}

Upvotes: 14

IronManGill
IronManGill

Reputation: 7226

Simply add this code to the image.

Image.transform=CGAffineTransformMakeRotation(M_PI / 2);

Upvotes: 8

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