iOS如何调整图像和蒙版（图像或蒙版任何人都放大无法同时调整两者）

Question

我正在做一个应用程序，我将从相机或相机胶卷中拍摄照片并使用蒙版图像进行蒙版，但我如何调整图像或蒙版？我尝试使用滚动视图进行放大和缩小以及捏合手势？

- (void)viewDidLoad
{
    [super viewDidLoad];

    // for zoomin
    [self.imageview setImage:imageView.image];
    [self.scrollView setMaximumZoomScale:5.0f];
    [self.scrollView setClipsToBounds:YES];


    // for drag
    UIPinchGestureRecognizer *pinch=[[UIPinchGestureRecognizer alloc]initWithTarget:self     action:@selector(pinched:)];
    [self.imageview addGestureRecognizer:pinch];

}


- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
    return self.imageview;
}

- (void)pinched:(UIPinchGestureRecognizer *)sender {
    if (sender.scale >1.0f && sender.scale < 2.5f) {
        CGAffineTransform transform = CGAffineTransformMakeScale(sender.scale, sender.scale);
        imageView.transform = transform;
     }
 }

-(IBAction)camera:(id)sender {
    picker = [[UIImagePickerController alloc]init];
    picker.delegate = self;

    [picker setSourceType:(UIImagePickerControllerSourceTypeCamera)];
    [self presentViewController:picker1 animated:YES completion:NULL];
}

- (void)imagePickerController:(UIImagePickerController *)photoPicker     didFinishPickingMediaWithInfo:(NSDictionary *)info {

    img = [info valueForKey:UIImagePickerControllerOriginalImage];
    [self.imageview setImage:img];
    [self dismissViewControllerAnimated:YES completion:NULL];
}

-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
    [picker dismissViewControllerAnimated:YES completion:NULL];
}
  - (UIImage*) maskImage:(UIImage *) image withMask:(UIImage *) mask
{
CGImageRef imageReference = image.CGImage;
CGImageRef maskReference = mask.CGImage;

CGImageRef imageMask = CGImageMaskCreate(CGImageGetWidth(maskReference),
                                         CGImageGetHeight(maskReference),
                                         CGImageGetBitsPerComponent(maskReference),
                                         CGImageGetBitsPerPixel(maskReference),
                                         CGImageGetBytesPerRow(maskReference),
                                         CGImageGetDataProvider(maskReference),
                                         NULL, // Decode is null
                                         YES // Should interpolate
                                         );

CGImageRef maskedReference = CGImageCreateWithMask(imageReference, imageMask);
CGImageRelease(imageMask);

UIImage *maskedImage = [UIImage imageWithCGImage:maskedReference];
CGImageRelease(maskedReference);

return maskedImage;

}

- (IBAction)mask:(id)sender {

    self.imageview.image = [self maskImage:img withMask:[UIImage imageNamed:@"18.jpg"]];
    [sender addTarget:self
               action:@selector(maskButtonClicked:)
     forControlEvents:UIControlEventTouchUpInside];
}

Answer 1

在与CGImageRef 相互转换时，您会丢失方向数据。

用这个代替imageWithCGImage:：

[UIImage imageWithCGImage:maskedReference scale:image.scale orientation:image.imageOrientation];

编辑

蒙版也忽略了图像方向，因此最简单的方法可能只是在对图像方向进行任何操作之前对其进行规范化。 See this answer for more details.

在你得到图像之后，在你开始屏蔽它之前，用这个来固定它的方向：

- (UIImage *)normalizedImage:(UIImage *)inputImage 
{
    if (inputImage.imageOrientation == UIImageOrientationUp) return inputImage; 

    UIGraphicsBeginImageContextWithOptions(inputImage.size, NO, inputImage.scale);
    [inputImage drawInRect:(CGRect){0, 0, inputImage.size}];
    UIImage *normalizedImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return normalizedImage;
}