One of the new effects in iOS7 is blurred content. At WWDC this year they were showing off how to do this with snapshots and image filtering. The downside to that is that it’s a static image and wont change with the content behind the view.
The CGContext provides a great way to draw to the screen on iOS, I use it often to draw custom images. Something that didn’t occur to me initially when I used the UIGraphicsGetCurrentContext() method to obtain a CGContextRef was that it was not thread safe. It was only a few weeks back I drew to a context in a thread, which worked fine sometimes and other times failed. It was obviously a threading problem, and here is the solution.