You never call drawView or any method prefixed by drawView directly. When you call draw , it redraws a bounding rectangle that you specify, or the entire view, if you do not specify a bounding rectangle. If the redrawn rectangle intersects the bounds of a subview, the draw method also calls the drawView method of the subview. When you create a custom view, you override its drawView method to specify drawing behavior, but you still draw to the screen by calling draw . To customize specific aspects of a component's drawing, override methods prefixed by drawView.
Coordinates are integers and fall between physical screen pixels.
The pixel corresponding to a coordinate occupies the space down and to the right of the coordinate. IFC drawing coordinates The bounding rectangle of a view and all drawing operations are specified in terms of this coordinate system. Each view has its own coordinate system. You perform drawing operations by sending messages to a graphics object . The graphics object encapsulates a drawing environment, maintaining important state information such as the current color and font.