如何在iOS上将图像旋转90度？-Java 学习之路

我想要做的是从我的相机拍摄快照，将其发送到服务器，然后服务器将我的图像发送回viewController . 如果图像处于纵向模式，则图像在屏幕上显示良好，但是如果图像是以横向模式拍摄的，则图像在屏幕上显示为拉伸（因为它试图以纵向模式显示！） . 我不知道如何解决这个问题，但我猜一个解决方案是首先检查图像是否处于纵向/横向模式，然后如果处于横向模式，则在将其显示在屏幕上之前将其旋转90度 . 那我该怎么办呢？

11 回答

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2);

Swift 4:

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

回复于 2024-05-06T06:04:03+08:00

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，即在.m中，如下所示，您要使用图像处理

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

这是苹果公司的代码片段SquareCam示例 .

要调用上述方法，只需使用以下代码即可

UIImage *rotatedSquareImage = [square imageRotatedByDegrees:rotationDegrees];

这里 square 是一个 UIImage 和 rotationDegrees 是一个 flote ivar旋转图像度

回复于 2024-05-06T06:04:03+08:00

Swift 3和Swift 4使用.pi代替

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)

回复于 2024-05-06T06:04:03+08:00

108

- (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;

}

回复于 2024-05-06T06:04:03+08:00

13
只需将此代码添加到图像中即可 .
```
Image.transform=CGAffineTransformMakeRotation(M_PI / 2);
```
回复于 2024-05-06T06:04:03+08:00

我在XCode 6.3 Swift 1.2中尝试了这个错误

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2);

你应该尝试这个强制类型转换修复：

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

回复于 2024-05-06T06:04:03+08:00

Swift 3版本：

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

回复于 2024-05-06T06:04:03+08:00

3
Swift 4 | Xcode 9 syntax （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))
```
回复于 2024-05-06T06:04:03+08:00

Swift 4+.

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

Note: angle is in radian

.pi = 180度.pi / 2 = 90度

如果你想添加动画

@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)

        }
        })
    }

Output:

enter image description here

回复于 2024-05-06T06:04:03+08:00

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;

}

回复于 2024-05-06T06:04:03+08:00

最好只使用位图 . 在我的情况下使用在reference.image中的UIImage，我在base64String转换了图像 . 没有CGAffineTransformMakeRotation而没有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;

回复于 2024-05-06T06:04:03+08:00

如何在iOS上将图像旋转90度？

11 回答

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