title: How to tint a UIButton?
body: <p>I'm in the process of adding custom buttons to my iPhone UI and want to make them have the glassy look from Apple's apps. I have a good default glass image, but I'd hate to have to have a separate image for each tint I want (red, green, blue, etc.). </p>
  
  <p>Is there a way to load a grayscale PNG and adjust it to the color I want? Better yet, is there a way to get Apple's glassy look without having to load custom images at all?</p>