How to make special gray overlay in objective c

Question

If you should do something like this overlay in Objective C how would you approach it? http://screencast.com/t/Hgif0AtCFl

It must follow the current time of the day so I don't think an image will work - any ideas?

Answer 1

I solved it using background image tiles:

self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"lines_texture.png"]];