iphone - 如何在 iOS 上将图像旋转 90 度？

Question

我想要做的是从我的相机拍摄快照，将其发送到服务器，然后服务器将我发送回 viewController 上的图像。如果图像处于纵向模式，则图像在屏幕上显示良好，但是如果图像是在横向模式下拍摄的，则图像在屏幕上会出现拉伸（因为它试图以纵向模式出现！）。我不知道如何解决这个问题，但我想一个解决方案是首先检查图像是否处于纵向/横向模式，然后如果它处于横向模式，则将其旋转 90 度，然后再将其显示在屏幕上。那么我该怎么做呢？

score 128 · Accepted Answer

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2);

斯威夫特 4+：

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

score 30 · Accepted Answer

这是将图像旋转到任何程度的完整代码，只需将其添加到适当的文件中，即 .m 中，如下所示，您要在其中使用图像处理

形式

@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

这是苹果SquareCam示例的代码片段。

要调用上述方法，只需使用以下代码

UIImage *rotatedSquareImage = [square imageRotatedByDegrees:rotationDegrees];

这里的正方形是 1 UIImage，rotationDegrees是 1flote以将图像旋转角度

score 21 · Accepted Answer

Swift 3 和 Swift 4 改用 .pi

例如：

//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)

score 14 · Accepted Answer

- (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;

}

score 8 · Accepted Answer

8

只需将此代码添加到图像中。

Image.transform=CGAffineTransformMakeRotation(M_PI / 2);

于 2012-07-26T10:46:35.147 回答

score 6 · Accepted Answer

我在 XCode 6.3 Swift 1.2 中尝试此操作时出错

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2);

你应该试试这个来强制类型转换修复：

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

斯威夫特 4 编辑

imageview.transform = CGAffineTransform(rotationAngle: .pi)

score 3 · Accepted Answer

3

斯威夫特 3 版本：

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

于 2017-02-03T08:11:54.800 回答

score 3 · Accepted Answer

斯威夫特 4+。

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

注：角度以弧度为单位

.pi = 180 度

.pi/2 = 90 度

如果要添加动画

  @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)

        }
        })
    }

输出：

score 2 · Accepted Answer

斯威夫特 4 | Xcode 9 语法（请注意，此代码将 UIImageView 顺时针旋转 90 度，而不是 UIImage）：

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

score 2 · Accepted Answer

 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

}

函数的使用

imageRotatedByDegrees(oldImage: yourImage, deg: degree)

score 1 · Accepted Answer

在Swift 5Image的关卡中执行此操作：

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

    }
}

score 0 · Accepted Answer

这是 iOSDev 答案的 Swift 2.2 版本（在 UIImage 扩展中）：

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;

}

score 0 · Accepted Answer

最好只使用位图。在我的情况下，使用 reference.image 中的 UIImage，我在 base64String 处转换了图像。没有 CGAffineTransformMakeRotation 和没有 rotateViewBox.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;

score 0 · Accepted Answer

如果您要保存图像，则需要旋转图片上下文而不是视图。我已经使用了上面提供的示例，但是在将图像居中时它们效果不佳。所以我已经增强和修复如下：

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
}

iphone - 如何在 iOS 上将图像旋转 90 度？

14 回答 14

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