Custom Drawing in drawRect:
So far, you have subclassed UIView, created instances of the subclass, inserted them into the view hierarchy, and specified their frames and backgroundColors. In this section, you will write the custom drawing code for BNRHypnosisView in its drawRect: method.
The drawRect: method is the rendering step where a view draws itself onto its layer. UIView subclasses override drawRect: to perform custom drawing. For example, the drawRect: method of UIButton draws light-blue text centered in a rectangle.
The first thing that you typically do when overriding drawRect: is get the bounds rectangle of the view. The bounds property, inherited from UIView, is the rectangle that defines the area where the view will ...