将ImageView调整为UIViewContentModeScaleAspectFit内容的大小

Question

Sorry if it might sound as a stupid question. I want to get the rect size of an image after i scaled it to fit. One way i thought of doing it is if i could resize the imageView itself and use ".frame", can i do so? is there any other way to get rid from the blank space around?

Answer 1

Based on the contentMode of the imageView being UIViewContentModeScaleAspectFit , once you set the image property of the imageView, you could use the following to determine the size (in points) of the image on the screen:

-(CGSize)onScreenPointSizeOfImageInImageView:(UIImageView *)imageView{
    CGFloat scale;
    if (imageView.frame.size.width > imageView.frame.size.height) {
        if (imageView.image.size.width > imageView.image.size.height) {
            scale = imageView.image.size.height / imageView.frame.size.height;
        } else {
            scale = imageView.image.size.width / imageView.frame.size.width;
        }
    } else {
        if (imageView.image.size.width > imageView.image.size.height) {
            scale = imageView.image.size.width / imageView.frame.size.width;
        } else {
            scale = imageView.image.size.height / imageView.frame.size.height;
        }
    }
    return CGSizeMake(imageView.image.size.width / scale, imageView.image.size.height / scale);
}

Then set the frame of the image view based on the on-screen size of the image to eliminate the 'blank space' around the image, eg;

myImageView.image = myImage;
CGSize imageSize = [self onScreenPointSizeOfImageInImageView:myImageView];
CGRect imageViewRect = myImageView.frame;
imageViewRect.size = imageSize;
myImageView.frame = imageViewRect;