ios - How to flip UIImage horizontally?

Question

How to flip the UIImage horizontally, I found UIImageOrientationUpMirrored enumeration value in the UIImage class reference, how to make use of this property to flip UIImage.

score 247 · Accepted Answer

Objective-C

UIImage* sourceImage = [UIImage imageNamed:@"whatever.png"];

UIImage* flippedImage = [UIImage imageWithCGImage:sourceImage.CGImage 
                                            scale:sourceImage.scale
                                      orientation:UIImageOrientationUpMirrored];

Swift

let flippedImage = myImage.withHorizontallyFlippedOrientation()

score 75 · Accepted Answer

实现此目的的一个非常简单的方法是创建一个 UIImageView 而不是 UIImage 并在 UIImageView 上进行转换。

yourImageView.image =[UIImage imageNamed:@"whatever.png"];
yourImageView.transform = CGAffineTransform(scaleX: -1, y: 1); //Flipped

希望这可以帮助。

score 36 · Accepted Answer

垂直翻转通常需要使用glTexImage2d(...). 上面提出的技巧实际上并没有修改图像数据，并且在这种情况下不起作用。这是受https://stackoverflow.com/a/17909372启发的执行实际数据翻转的代码

- (UIImage *)flipImage:(UIImage *)image
{
    UIGraphicsBeginImageContext(image.size);
    CGContextDrawImage(UIGraphicsGetCurrentContext(),CGRectMake(0.,0., image.size.width, image.size.height),image.CGImage);
    UIImage *i = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return i;
}

score 16 · Accepted Answer

我已经尝试使用 imageFlippedForRightToLeftLayoutDirection，并创建了一个具有不同方向的新 UIImage，但至少这是我找到的翻转图像的唯一解决方案

let ciimage: CIImage = CIImage(CGImage: imagenInicial.CGImage!)
let rotada3 = ciimage.imageByApplyingTransform(CGAffineTransformMakeScale(-1, 1))

正如你在我的操场上看到的那样，它奏效了！！:)

当然，让 finalImage = UIImage(CIImage: rotada3)

score 12 · Accepted Answer

因为它的图像方向定义：

typedef NS_ENUM(NSInteger, UIImageOrientation) {
UIImageOrientationUp,            // default orientation
UIImageOrientationDown,          // 180 deg rotation
UIImageOrientationLeft,          // 90 deg CCW
UIImageOrientationRight,         // 90 deg CW
UIImageOrientationUpMirrored,    // as above but image mirrored along other axis. horizontal flip
UIImageOrientationDownMirrored,  // horizontal flip
UIImageOrientationLeftMirrored,  // vertical flip
UIImageOrientationRightMirrored, // vertical flip
};

我对更多情况进行了一些改进，例如从 AVCaptureSession 处理 UIImage。

UIImage* sourceImage = [UIImage imageNamed:@"whatever.png"];
UIImageOrientation flipingOrientation;
if(sourceImage.imageOrientation>=4){
    flippedOrientation = sourceImage.imageOrientation - 4;
}else{
    flippedOrientation = sourceImage.imageOrientation + 4;
}
UIImage* flippedImage = [UIImage imageWithCGImage:sourceImage.CGImage 
                     scale: sourceImage.scale orientation: flipingOrientation];

score 9 · Accepted Answer

这是快速版本：（我在评论中看到了这个问题）

let srcImage = UIImage(named: "imageName")
let flippedImage = UIImage(CGImage: srcImage.CGImage, scale: srcImage.scale, orientation: UIImageOrientation.UpMirrored)

score 9 · Accepted Answer

这是水平镜像/翻转 UIImage 的可靠实现，并且可以来回应用于图像。由于它改变了底层图像数据，绘图（如屏幕截图）也会改变。经测试工作，无质量损失。

func flipImage() -> UIImage? {
        UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)
        let bitmap = UIGraphicsGetCurrentContext()!

        bitmap.translateBy(x: size.width / 2, y: size.height / 2)
        bitmap.scaleBy(x: -1.0, y: -1.0)

        bitmap.translateBy(x: -size.width / 2, y: -size.height / 2)
        bitmap.draw(self.cgImage!, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return image?
}

score 9 · Accepted Answer

iOS 10+

[myImage imageWithHorizontallyFlippedOrientation];

斯威夫特 4：

let flippedImage = myImage.withHorizontallyFlippedOrientation()

score 5 · Accepted Answer

可能这对某些人有用：

    UIImageOrientation imageOrientation;

    switch (sourceImage.imageOrientation) {
        case UIImageOrientationDown:
            imageOrientation = UIImageOrientationDownMirrored;
            break;

        case UIImageOrientationDownMirrored:
            imageOrientation = UIImageOrientationDown;
            break;

        case UIImageOrientationLeft:
            imageOrientation = UIImageOrientationLeftMirrored;
            break;

        case UIImageOrientationLeftMirrored:
            imageOrientation = UIImageOrientationLeft;

            break;

        case UIImageOrientationRight:
            imageOrientation = UIImageOrientationRightMirrored;

            break;

        case UIImageOrientationRightMirrored:
            imageOrientation = UIImageOrientationRight;

            break;

        case UIImageOrientationUp:
            imageOrientation = UIImageOrientationUpMirrored;
            break;

        case UIImageOrientationUpMirrored:
            imageOrientation = UIImageOrientationUp;
            break;
        default:
            break;
    }

    resultImage = [UIImage imageWithCGImage:sourceImage.CGImage scale:sourceImage.scale orientation:imageOrientation];

score 5 · Accepted Answer

5

对于斯威夫特 3/4：

imageView.transform = CGAffineTransform(scaleX: -1, y: 1)

于 2016-12-15T13:45:59.360 回答

score 2 · Accepted Answer

一个简单的扩展。

extension UIImage {

    var flipped: UIImage {
        guard let cgImage = cgImage else {
            return self
        }

        return UIImage(cgImage: cgImage, scale: scale, orientation: .upMirrored)
    }
}

用法：

let image = #imageLiteral(resourceName: "imageName")
let imageView = UIImageView(image: image.flipped)

score 1 · Accepted Answer

这是一个有效的 iOS8/9 兼容版本：

UIImage *image = [UIImage imageNamed:name];

if ([[UIApplication sharedApplication] userInterfaceLayoutDirection] == UIUserInterfaceLayoutDirectionRightToLeft) {

    if ([image respondsToSelector:@selector(imageFlippedForRightToLeftLayoutDirection)]) {
        //iOS9
        image = image.imageFlippedForRightToLeftLayoutDirection;
    }
    else {
        //iOS8
        CIImage *coreImage = [CIImage imageWithCGImage:image.CGImage];
        coreImage = [coreImage imageByApplyingTransform:CGAffineTransformMakeScale(-1, 1)];
        image = [UIImage imageWithCIImage:coreImage scale:image.scale orientation:UIImageOrientationUp];
    }
}

return image;

score 1 · Accepted Answer

在 Swift 3 及更高版本中测试

这是通过扩展解决此问题的简单解决方案。我对其进行了测试，它奏效了。您可以向任何方向镜像。

extension UIImage {

    func imageUpMirror() -> UIImage {
        guard let cgImage = cgImage else { return self }
        return UIImage(cgImage: cgImage, scale: scale, orientation: .upMirrored)
    }

    func imageDownMirror() -> UIImage {
        guard let cgImage = cgImage else { return self }
        return UIImage(cgImage: cgImage, scale: scale, orientation: .downMirrored)
    }

    func imageLeftMirror() -> UIImage {
        guard let cgImage = cgImage else { return self }
        return UIImage(cgImage: cgImage, scale: scale, orientation: .leftMirrored)
    }

    func imageRightMirror() -> UIImage {
        guard let cgImage = cgImage else { return self }
        return UIImage(cgImage: cgImage, scale: scale, orientation: .rightMirrored)
    }
}

此代码的用法

let image = #imageLiteral(resourceName: "imageName")
flipHorizontally = image.imageUpMirror()

以此类推，您可以使用其他功能。

score 0 · Accepted Answer

这是上面修改的答案之一，在Swift 3中，当您有一个需要不断来回翻转图像的按钮时，我发现它特别有用。

func flipImage(sourceImage: UIImage,orientation: UIImageOrientation) -> UIImage {


        var imageOrientation = orientation

        switch sourceImage.imageOrientation {

        case UIImageOrientation.down:
            imageOrientation = UIImageOrientation.downMirrored;
            break;

        case UIImageOrientation.downMirrored:
            imageOrientation = UIImageOrientation.down;
            break;

        case UIImageOrientation.left:
            imageOrientation = UIImageOrientation.leftMirrored;
            break;

        case UIImageOrientation.leftMirrored:
            imageOrientation = UIImageOrientation.left;

            break;

        case UIImageOrientation.right:
            imageOrientation = UIImageOrientation.rightMirrored;

            break;

        case UIImageOrientation.rightMirrored:
            imageOrientation = UIImageOrientation.right;

            break;

        case UIImageOrientation.up:
            imageOrientation = UIImageOrientation.upMirrored;
            break;

        case UIImageOrientation.upMirrored:
            imageOrientation = UIImageOrientation.up;
            break;


        }


        return UIImage(cgImage: sourceImage.cgImage!, scale: sourceImage.scale, orientation: imageOrientation)

    }

利用：

imageToFlip: UIImage = flipImage(sourceImage: imageToFlip, orientation: imageToFlip.imageOrientation)

score 0 · Accepted Answer

aroth 在SWIFT 3 中的回答：

let sourceImage = UIImage(named: "whatever.png")!
let flippedImage = UIImage(cgImage: sourceImage.cgImage!, scale: sourceImage.scale, orientation: .upMirrored)

score 0 · Accepted Answer

0

斯威夫特 4

yourImage.transform = CGAffineTransform(scaleX: -1, y: 1)

于 2017-12-13T20:58:05.327 回答

score 0 · Accepted Answer

您可以使用它随意旋转图像

斯威夫特 4

extension UIImage {
public func imageRotatedByDegrees(degrees: CGFloat, flip: Bool) -> UIImage {
    let radiansToDegrees: (CGFloat) -> CGFloat = {
        return $0 * (180.0 / CGFloat(M_PI))
    }
    let degreesToRadians: (CGFloat) -> CGFloat = {
        return $0 / 180.0 * CGFloat(M_PI)
    }

    // calculate the size of the rotated view's containing box for our drawing space
    let rotatedViewBox = UIView(frame: CGRect(origin: CGPoint.zero, size: size))
    let t = CGAffineTransform(rotationAngle: degreesToRadians(degrees));
    rotatedViewBox.transform = t
    let rotatedSize = rotatedViewBox.frame.size

    // Create the bitmap context
    UIGraphicsBeginImageContext(rotatedSize)
    let bitmap = UIGraphicsGetCurrentContext()!

    bitmap.translateBy(x: rotatedSize.width / 2.0, y: rotatedSize.height / 2.0)
    // Move the origin to the middle of the image so we will rotate and scale around the center.
    //CGContextTranslateCTM(bitmap, rotatedSize.width / 2.0, rotatedSize.height / 2.0);

    //   // Rotate the image context
    bitmap.rotate(by: degreesToRadians(degrees))
   // CGContextRotateCTM(bitmap, degreesToRadians(degrees));

    // Now, draw the rotated/scaled image into the context
    var yFlip: CGFloat

    if(flip){
        yFlip = CGFloat(-1.0)
    } else {
        yFlip = CGFloat(1.0)
    }
    bitmap.scaleBy(x: yFlip, y: -1.0)
    //CGContextScaleCTM(bitmap, yFlip, -1.0)
    bitmap.draw(self.cgImage!, in: CGRect.init(x: -size.width / 2, y: -size.height / 2, width: size.width, height: size.height))
   // CGContextDrawImage(bitmap, CGRectMake(-size.width / 2, -size.height / 2, size.width, size.height), CGImage)

    let newImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()

    return newImage
}

}

score 0 · Accepted Answer

由于展开，请执行以下操作：

let srcImage = UIImage(named: "myimage")!
let flippedImage = UIImage(cgImage: srcImage.cgImage!, 
                   scale: srcImage.scale, orientation: UIImage.Orientation.upMirrored)

score -2 · Accepted Answer

斯威夫特 5 - Xcode 11.5

水平旋转的最佳解决方案：观看此视频：

https://m.youtube.com/watch?v=4kSLbuB-MlU

或使用以下代码：

    
import UIKit
class FirstViewControl: UIViewController {
    @IBOutlet weak var buttonAnim: UIButton!

    @IBAction func ClickOnButtonAnim(_ sender: UIButton) {    
        UIView.transition(with: buttonAnim, duration: 0.4, options: .transitionFlipFromLeft, animation: nil , completion: nil)
    }

}

您可以在此动画中使用任何 ui（按钮或标签或 uiview 或图像）。

ios - How to flip UIImage horizontally?

19 回答 19

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