Render the gradients into a resizable UIImage via CG. That differs from approach #2 in the article, which does the same thing, but generates a non-resizable UIImage.

To make a resizable image at runtime, draw into an image as described in approach #2, but make the image have width of left cap + 1 point + right cap, then use -[UIImage resizableImageWithCapInsets:] to generate a wrapper with the correct resizing behavior.

Then: make sure that if you have 100 buttons on-screen which all use the same gradients, you end up reusing the same generated UIImage. You don't want to redraw the same thing for each of them.