IOS图片翻转相关

CIImage翻转90度

ciImage = ciImage.oriented(CGImagePropertyOrientation.right)

UIImage翻转90度

UI层面的翻转，数据结构没变。

let flipImageOrientation = (detectionImage.imageOrientation.rawValue + 2) % 8
 
let flipImage =  UIImage(cgImage:detectionImage.cgImage!,
                           scale:detectionImage.scale,
                     orientation:UIImage.Orientation(rawValue: flipImageOrientation)!)

UIImage旋转任意角度

extension UIImage
{
    func rotate(by degrees: CGFloat, flip: Bool? = nil) -> UIImage
    {
        let radians = CGFloat(degrees * (CGFloat.pi / 180.0))
        
        let bufferView = UIView(frame: CGRect(origin: CGPoint.zero, size: self.size))
        let t: CGAffineTransform = CGAffineTransform(rotationAngle: radians)
        bufferView.transform = t
        let bufferSize = bufferView.frame.size
        
        UIGraphicsBeginImageContextWithOptions(bufferSize, false, self.scale)
        let bitmap = UIGraphicsGetCurrentContext()
        bitmap?.translateBy(x: bufferSize.width / 2, y: bufferSize.height / 2)
        bitmap?.rotate(by: radians)
        if let isFlipped = flip {
            if !isFlipped {
                bitmap?.scaleBy(x: 1.0, y: -1.0)
            } else {
                bitmap?.scaleBy(x: -1.0, y: -1.0)
            }
        } else {
            bitmap?.scaleBy(x: -1.0, y: -1.0)
        }
        bitmap?.draw(self.cgImage!, in: CGRect(origin: CGPoint(x: -self.size.width / 2, y: -self.size.height / 2), size: self.size))
        
        let finalBuffer = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return finalBuffer!
    }
}

UIImage矫正翻转

- (UIImage *)fixOrientation:(UIImage *)aImage {
    
    // No-op if the orientation is already correct
    if (aImage.imageOrientation == UIImageOrientationUp)
    return aImage;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        default:
            break;
    }
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        default:
            break;
    }
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
                                             CGImageGetBitsPerComponent(aImage.CGImage), 0,
                                             CGImageGetColorSpace(aImage.CGImage),
                                             CGImageGetBitmapInfo(aImage.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (aImage.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

NSImage旋转（90、180、270）

func orienteImage(degrees:CGFloat) -> NSImage{
        if degrees != 90 && degrees != 180 && degrees != 270 {
            return self
        }
        var imageBounds = NSZeroRect ; imageBounds.size = self.size
        let pathBounds = NSBezierPath(rect: imageBounds)
        var transform = NSAffineTransform()
        transform.rotate(byDegrees: degrees)
        pathBounds.transform(using: transform as AffineTransform)
        
        var rotatedSize = self.size
        if degrees == 90 || degrees == 270{
            rotatedSize = CGSize(width: self.size.height,height: self.size.width)
        }
        
        let rotated = NSImage.init(size: rotatedSize)
        
        transform = NSAffineTransform()
        transform.translateX(by: rotatedSize.width/2, yBy: rotatedSize.height/2)
        transform.rotate(byDegrees: degrees)
        transform.translateX(by: -rotatedSize.width/2, yBy: -rotatedSize.height/2)
        
        rotated.lockFocus()
        transform.concat()
        self.draw(in: imageBounds, from: NSZeroRect, operation: NSCompositingOperation.copy, fraction: 1.0)
        rotated.unlockFocus()
        
        return rotated
    }