根据其子视图设置主视图的大小

Question

I have a Main View with frame

0, 60, 768, 1024,

It has many views as subView. First subview is an UIImageView . The property associated with ImageView is AspectFit. Now I want to take screenshot of the only part of screen which bounds that of UIImageView (There are at least 4-5 Subviews which CAN or can not be above This UIImageView) The standard coding given by iPhone has been used here. The image i get is of Main View. Now to get only screenshot of UIImageView and whatever above is, I need to set the dimension of my main view to envelop only UIImageView.

Suppose The image size is 100,100. When I press button, How should I set the Bounds/fRAME OF my mainView? Or In other terms how can I get the frame of UIImageView relative to self.view

Answer 1

Instead of changing the frame of main view, try to calculate coordinates of the UIImageView .

Assume that frames of your main view and image view are (0, 60, 768, 1024) and (20, 20, 100, 100), respectively.

So frame of your image view with respect to global coordinate system is (20, 80, 100, 100). Just add x, y coordinates of main view to its subviews to achieve this. Then, you may get the screenshot of desired frame.

Answer 2

One way would be to grab the entire view's image, then crop it. No reframing needed. Combining best answers from here and here , it might look like this:

- (UIImage *)imageWithView:(UIView *)view croppedBy:(CGRect)rect {

    UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], rect);
    UIImage *result = [UIImage imageWithCGImage:imageRef]; 
    CGImageRelease(imageRef);
    return result;
}

For your app, call it like this (assuming we're in a view controller):

UIImage *justMyImageView = [self imageWithView:self.view croppedBy:self.myImageView.frame];