How can I change the inner image position of an UIImageView?

Question

I have defined an UIImageView in my nib. After the app launches, I display an image in that UIImageView. Maybe I am on the wrong way, but what I want to do is the following:

The image which I load into the view is bigger than the view itself. I want that it is displayed in original size with hidden overlay. Then I want to slowly move that image inside that view in random directions.

Maybe you know html div containers with background images. there, you can set a position of that background image and change that position with JavaScript. I need something similar on iPhone.

Maybe an UIImageView is not the right thing for that? Or must I set the UIImageView to the full size of that image and then move the UIImageView around slowly? Could it be bigger than the iPhone's screen?

Answer 1

You need to crop the image. See Lounges' answer to this question.

Answer 2

This is the gist of my answer to pretty much the same question:

There isn't a simple class method to do this, but there is a function that you can use to get the desired results: CGImageCreateWithImageInRect(CGImageRef, CGRect) will help you out.

Here's a short example using it:

CGImageRef imageRef = CGImageCreateWithImageInRect([largeImage CGImage], cropRect);
[UIImageView setImage:[UIImage imageWithCGImage:imageRef]];
CGImageRelease(imageRef);