C H A P T E R 9

User Input

Like other graphical user interfaces, Mac OS X is optimized for use with a pointing device, such as a mouse. Many users, however, prefer or need to interact with the computer using the keyboard instead of the mouse. In Mac OS X (version 10.1 and later), users have the option of enabling keyboard access for all functions available using a point-and-click device.

The Mouse and Other Pointing Devices

In the Macintosh interface the standard pointing device is the mouse. Users can substitute other devices—such as trackballs and stylus pens—that maintain the behavior of direct manipulation of objects on screen.

Moving the mouse without pressing the mouse button moves the pointer. The onscreen pointer can assume different shapes according to the context of the application and the pointer’s position. For example, in a word processor, the pointer takes the I-beam shape while it’s over the text and changes to an arrow when it’s over a tools palette. Change the pointer’s shape only to provide information to the user about changes in the pointer’s function.

Each pointer has a hot spot—the portion of the pointer that must be positioned over a screen object before mouse clicks have an effect on the object. The hot spot should be intuitive, such as the tip of an arrow pointer or the center point of a crosshair.

Screen objects have a hot zone—the area that the pointer’s hot spot must be within in order for mouse clicks to have an effect.