从自定义相机捕获的图像在裁剪 iOS 后被旋转

Question

我在裁剪图像后面临图像旋转问题。我已经将我目前使用的逐步方法放在下面。

这是我得到结果的过程：

步骤：1 通过自定义相机拍照

- (void)captureImageWithCompletionHander:(void (^)(id))completionHandler{
    [_cameraOverlayView hideHightLightOverlay];
    if (_isCapturing) return;

    __weak typeof(self) weakSelf = self;
    [weakSelf hideGLKView:YES completion:^{
        [weakSelf hideGLKView:NO completion:^{
            [weakSelf hideGLKView:YES completion:nil];
        }];
    }];
    _isCapturing = YES;

    AVCaptureConnection *videoConnection = nil;
    for (AVCaptureConnection *connection in self.stillImageOutput.connections){
        for (AVCaptureInputPort *port in [connection inputPorts]){
            if ([[port mediaType] isEqual:AVMediaTypeVideo] ){
                videoConnection = connection;
                break;
            }
        }
        if (videoConnection) break;
    }

    [self.stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error){
        if(!CMSampleBufferIsValid(imageSampleBuffer)){
            return;
        }
        NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];

        UIImage * capturedImage = [[UIImage alloc]initWithData:imageData scale:1];
        NSLog(@"%lu",(unsigned long)UIImageJPEGRepresentation(capturedImage, 1.0).length);
        if (_myDevice == [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo][0]) {
            capturedImage = capturedImage;
        }else if (_myDevice == [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo][1]) {
        }

        [weakSelf hideGLKView:NO completion:nil];
        completionHandler(capturedImage);
         _isCapturing = NO;
     }];
}

步骤：2固定方向

-(id)initWithImage:(UIImage*) image{
    self =  [super init];
    if (self){
        self.originalImage = [image fixOrientation];
    }

    return self;
}

//Method for fix orientation
@implementation UIImage (fixOrientation)

- (UIImage *)fixOrientation {

    // No-op if the orientation is already correct
    if (self.imageOrientation == UIImageOrientationUp) return self;

    // 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 (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;

        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;

        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationUpMirrored:
            break;
    }

    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;

        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationDown:
        case UIImageOrientationLeft:
        case UIImageOrientationRight:
            break;
    }

    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;

        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.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;
}
@end

步骤：3裁剪图像

-(UIImage *)cropImage:(UIImage *)image{
    CGFloat overlayHeight = self.frame.size.height;
    UIImageOrientation originalOrientation = image.imageOrientation;
    CGFloat originalScale = image.scale;
    CIImage *rawImage = [CIImage imageWithCGImage:image.CGImage];

    NSMutableDictionary *rectangleCoordinates = [NSMutableDictionary new];
    rectangleCoordinates[@"inputTopLeft"] = [CIVector vectorWithCGPoint:CGPointMake(topLeftPath.x * _absoluteWidth, (overlayHeight - topLeftPath.y) * _absoluteHeight)];
    rectangleCoordinates[@"inputTopRight"] = [CIVector vectorWithCGPoint:CGPointMake(topRightPath.x * _absoluteWidth, (overlayHeight - topRightPath.y) * _absoluteHeight)];
    rectangleCoordinates[@"inputBottomLeft"] = [CIVector vectorWithCGPoint:CGPointMake(bottomLeftPath.x * _absoluteWidth, (overlayHeight - bottomLeftPath.y) * _absoluteHeight)];
    rectangleCoordinates[@"inputBottomRight"] = [CIVector vectorWithCGPoint:CGPointMake(bottomRightPath.x * _absoluteWidth, (overlayHeight - bottomRightPath.y) * _absoluteHeight)];
    rawImage = [rawImage imageByApplyingFilter:@"CIPerspectiveCorrection" withInputParameters:rectangleCoordinates];

    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef cgImage = [context createCGImage:rawImage fromRect:[rawImage extent]];
    UIImage *RImage = [UIImage imageWithCGImage:cgImage scale:originalScale orientation:originalOrientation];
    return RImage;
}

结果：

• 捕获图像后，我正在显示原始图像并且看起来很直。没有问题。

查看图片：

• 但裁剪后会旋转

查看图片：

一些我已经尝试过但没有奏效的参考资料：

Using CoreImage to filter an image results in image rotation

iOS UIImagePickerController result image orientation after upload

iOS - UIImageView - how to handle UIImage image orientation

How to get the Correct orientation of the image selected from the Default Image gallery

Convert a UIImage to a CIImage to crop to a CGRect. AVFoundation

如果有人指导解决这个问题，那就太好了。

提前致谢。

Answer 1

只需在“cropImage”方法的下一行中将方向替换为 UIImageOrientationUp。

UIImage *RImage = [UIImage imageWithCGImage:cgImage scale:originalScale orientation:UIImageOrientationUp];

Answer 2

经过这么多实验和尝试这么多解决方案，最后我通过转移到UIBeizerPath解决了这个问题。

我注意到方向问题的出现只是因为CIImage，它永远不会得到解决。即使是原始图像也能正确显示，因为CIImage 在裁剪后会旋转。

所以尝试使用UIBeizerPath & 这是我所做的：

UIBezierPath *path = [_overlayView getPath];
CGRect rect = CGRectZero;
rect.size = _detectedImage.frame.size;

CAShapeLayer *shapeLayer = [CAShapeLayer layer];
shapeLayer.frame = CGRectMake(0, 0, _detectedImage.frame.size.width, _detectedImage.frame.size.height);
shapeLayer.path = path.CGPath;
shapeLayer.fillColor = [[UIColor whiteColor] CGColor];
shapeLayer.backgroundColor = [[UIColor clearColor] CGColor];
[_detectedImage.layer setMask:shapeLayer];

UIGraphicsBeginImageContextWithOptions(_detectedImage.layer.frame.size, NO, 0);
[_detectedImage.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();
UIImage *cpImage = [outputImage imageByTrimmingTransparentPixelsRequiringFullOpacity:YES];
UIGraphicsEndImageContext();

希望对某人有所帮助。