Question

I have a simple UIView which I’m filling with a patterned background, like this

    self.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"backgroundPattern"]];

I want to be able to manipulate the origin of the view by modifying its bounds property and have the background move with the change in origin (as if the background is fixed to the content, not floating behind it). Is this possible? Currently the background seems fixed to the view’s frame instead of its bounds and the pattern doesn’t scroll when the content scrolls.

To change the origin I’m using a block animation like this

self.bounds = CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height);
[UIView animateWithDuration:1. delay:0. options:UIViewAnimationOptionRepeat animations:^{
    self.bounds = CGRectMake(0, 100, self.bounds.size.width, self.bounds.size.height);
} completion:nil];

With that code, my child views repeatedly scroll and reset, but the background stays fixed in place. Is it possible to specify a background which scrolls with the view instead?

Answer 1

I haven’t been able to find anything on making a background pattern “stick” to the view’s origin system. My solution for my app has been to make a child view and set the background pattern on that. Then the child view will move with the origin change and the background pattern will follow it. The problem with that solution is that the child view has to be large enough to cover the range of potential origins, which can be difficult to handle if the content area might be arbitrarily large.