放大后旋转并平移，在UIView中计算rect

Question

我需要构建一个裁剪图像，让用户捏住\ out并旋转图像。

我有父UIView，它持有UIImageView。

• 父UIView是clipsToBounds = YES
• 内部UIImageView是contentMode = UIViewContentModeScaleAspectFill;

我不明白如何计算庄稼。

这是选择图像之前的父视图：

这是在UIImageView添加到带框架（0,0，parent.width，parent.height）和UIViewContentModeScaleAspectFill的parentView之后。

这是在捏之后：

这是我的裁剪代码。

 -(UIImage*)createImageToPost:(UIImageView*)imageView withParentView:(UIView*)paretView
{

CGRect rectToCrop = CGRectMake(paretView.frame.origin.x - imageView.frame.origin.x , paretView.frame.origin.y - imageView.frame.origin.y, fabs(paretView.frame.size.width - imageView.image.size.width), fabs(paretView.frame.size.height - imageView.image.size.height));

UIImage * newCropImage =  [self cropWithImageView:imageView withCropRect:rectToCrop];

return newCropImage;
}

-(UIImage*)cropWithImageView:(UIImageView*)imageView withCropRect:(CGRect)cropRect
{

CGRect rect = CGRectMake(0, 0, imageView.image.size.width, imageView.image.size.height);
// Begin the drawing
UIGraphicsBeginImageContext(imageView.image.size);
CGContextRef ctx = UIGraphicsGetCurrentContext();

// Clear whole thing
CGContextClearRect(ctx, rect);

// Transform the image (as the image view has been transformed)
CGContextTranslateCTM(ctx, rect.size.width*0.5, rect.size.height*0.5);
CGContextConcatCTM(ctx, imageView.transform);
CGContextTranslateCTM(ctx, -rect.size.width*0.5, -rect.size.height*0.5);

// Tanslate and scale upside-down to compensate for Quartz's inverted coordinate system
CGContextTranslateCTM(ctx, 0.0, rect.size.height);
CGContextScaleCTM(ctx, 1.0, -1.0);

// Draw view into context
CGContextDrawImage(ctx, rect, imageView.image.CGImage);

// Create the new UIImage from the context
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

// End the drawing
UIGraphicsEndImageContext();

// Begin the drawing (again)
UIGraphicsBeginImageContext(cropRect.size);
ctx = UIGraphicsGetCurrentContext();

// Clear whole thing
CGContextClearRect(ctx, CGRectMake(0, 0, cropRect.size.width, cropRect.size.height));

// Translate to compensate for the different positions of the image
CGContextTranslateCTM(ctx, -((newImage.size.width*0.5)-(cropRect.size.width*0.5)),
                      (newImage.size.height*0.5)-(cropRect.size.height*0.5));

// Tanslate and scale upside-down to compensate for Quartz's inverted coordinate system
CGContextTranslateCTM(ctx, 0.0, cropRect.size.height);
CGContextScaleCTM(ctx, 1.0, -1.0);

// Draw view into context
CGContextDrawImage(ctx, CGRectMake(0,0,newImage.size.width,newImage.size.height), newImage.CGImage);

// Create the new UIImage from the context
newImage = UIGraphicsGetImageFromCurrentImageContext();

// End the drawing
UIGraphicsEndImageContext();

return newImage;
 }



    UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchGestureDetected:)];
[pinchGestureRecognizer setDelegate:self];
[imageView addGestureRecognizer:pinchGestureRecognizer];

// create and configure the rotation gesture
UIRotationGestureRecognizer *rotationGestureRecognizer = [[UIRotationGestureRecognizer alloc] initWithTarget:self action:@selector(rotationGestureDetected:)];
[rotationGestureRecognizer setDelegate:self];
[imageView addGestureRecognizer:rotationGestureRecognizer];

// creat and configure the pan gesture
UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureDetected:)];
[panGestureRecognizer setDelegate:self];
    [imageView addGestureRecognizer:panGestureRecognizer];

- (void)pinchGestureDetected:(UIPinchGestureRecognizer *)recognizer
{
UIGestureRecognizerState state = [recognizer state];

if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
{
    CGFloat scale = [recognizer scale];
    [recognizer.view setTransform:CGAffineTransformScale(recognizer.view.transform, scale, scale)];
    [recognizer setScale:1.0];
}
}


- (void)rotationGestureDetected:(UIRotationGestureRecognizer *)recognizer
{
UIGestureRecognizerState state = [recognizer state];

if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
{
    CGFloat rotation = [recognizer rotation];
    [recognizer.view setTransform:CGAffineTransformRotate(recognizer.view.transform, rotation)];
    [recognizer setRotation:0];
}
}

- (void)panGestureDetected:(UIPanGestureRecognizer *)recognizer
{
UIGestureRecognizerState state = [recognizer state];

if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged)
{
    CGPoint translation = [recognizer translationInView:recognizer.view];
    [recognizer.view setTransform:CGAffineTransformTranslate(recognizer.view.transform, translation.x, translation.y)];
    [recognizer setTranslation:CGPointZero inView:recognizer.view];
}
}

这是我在作物后得到的图像：