Cocoa Programming for OS X: The Big Nerd Ranch Guide

17 NSView and Drawing

All visible objects in an application are either windows or views. Windows are instances of the class NSWindow and views are instances of the class NSView. A window has a collection of views, and each of these views is responsible for a rectangle of the window. The view draws inside that rectangle and handles mouse events that occur there. A view may also handle keyboard events.

You have worked with several subclasses of NSView including NSButton, NSTextField, NSTableView, and NSColorWell. From time to time, you may need to draw something or respond to a mouse event in a way that a standard view class cannot help you with. In these cases, the answer is to write your own NSView subclass.

In this chapter, ...