如何显示一个UIImageView来填充屏幕的宽度，并设置高度以保持纵横比？

Question

I have an image view I initialize like this:

self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, 200)];
[self.imageView setContentMode:UIViewContentModeScaleAspectFill];
self.imageView.clipsToBounds = YES;

I then fetch the image on the web and place it in the view. My problem is that I actually want to show the full image, and not crop it so it fits 200 px.

How I can I do this? Thanks!

Answer 1

So you inspect the image and calculate the width based on the image's dimensions:

UIImage *downloadedImage; // assuming this is not nil
CGFloat imageRatio = downloadedImage.size.height / downloadedImage.size.width;
self.imageView.frame = CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_WIDTH * imageRatio);

There is a better way to get the screen width than using a macro by the way ( CGRectGetWidth(self.view.bounds) ), but that's not relevant to your question.

Answer 2

Using the content mode UIViewContentModeScaleAspectFit scales the image to fit the image view, keeping the aspect ratio of the image.

Your question title doesn't match your question body, so I'm going with the body:

My problem is that I actually want to show the full image, and not crop it so it fits 200 px.