How to draw a rounded rectangle in Core Graphics / Quartz 2D?

Instead of making your own path out of lines and arcs, you can use

[UIBezierPath bezierPathWithRoundedRect:cornerRadius:]

or

[UIBezierPath bezierPathWithRoundedRect:byRoundingCorners:cornerRadii:]

(the second one lets you specify which corners are rounded)

Available in iOS 3.2 or later.