如何在iOS上將圖像旋轉90度？

Question

我想要做的是從我的相機拍攝一張快照，發送給服務器，然後服務器發送給我一個viewController上的圖像。如果圖像處於肖像模式，則圖像在屏幕上顯示效果良好，但如果圖像是在橫向模式下拍攝的，則圖像在屏幕上顯示爲拉伸（因爲它會嘗試以縱向模式顯示！）。我不知道如何解決這個問題，但我想一個解決方案是首先檢查圖像是在縱向/橫向模式，然後如果是在橫向模式下旋轉90度，然後再在屏幕上顯示。 那我該怎麼做？

Answer 1

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2); 

Answer 2

- (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; 

} 

Answer 3

只需將此代碼添加到圖像。

Image.transform=CGAffineTransformMakeRotation(M_PI/2); 

Answer 4

這是任何程度的圖像旋轉的完整代碼只是把它添加到即.M適當的文件，如下您要使用的圖像處理

爲.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 

這是蘋果的SquareCam示例代碼片段。

要調用上述方法只需要使用下面的代碼

UIImage *rotatedSquareImage = [square imageRotatedByDegrees:rotationDegrees]; 

這裏平方是一個UIImage和rotationDegrees是一個flote的ivar轉動該度

Answer 5

我得到的圖像在XCode 6.3中嘗試這個錯誤Swift 1.2

self.imageview.transform = CGAffineTransformMakeRotation(M_PI_2); 

你應該試試這個強制類型轉換解決：

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

Answer 6

這裏是雨燕2.2版本的iOSDev答案（在UIImage的擴展名）：

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; 

} 

Answer 7

斯威夫特3版本：

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

Answer 8

Swift 3和Swift 4使用.pi而不是

例如：

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

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

Answer 9

Swift 4 | Xcode的9語法（請注意，此代碼順時針旋轉一個UIImageView 90度，而不是一個UIImage）：

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

Answer 10

斯威夫特4+。

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

Note: angle is in radian

。PI = 180度

.pi/2 = 90度

如果要與動畫添加

@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) 

     } 
     }) 
    } 

輸出：的