iOS Programming: The Big Nerd Ranch Guide

Gold Challenge: Shadows and Gradients

At this time, adding drop shadows and drawing with gradients can only be done using Core Graphics.

To create a drop shadow, you install a shadow on the graphics context. After that, anything opaque that you draw will have a drop shadow. The shadow has an offset (which is expressed with an CGSize), and a blur in points. Here is the declaration of the method used to install the shadow on the graphics context:

void CGContextSetShadow (
   CGContextRef context,
   CGSize offset,
   CGFloat blur);

(There is a version that takes a color, but you almost always want a dark shadow.)

There is no unset shadow function. Thus, you will need to save the graphics state before setting the shadow and then restore it after ...