REALBasic: TDG, 2nd Edition

Chapter 28. Animation

Earlier chapters have mentioned various ways to achieve animated effects in REALbasic: you can redraw parts of a Canvas, for example (Chapter 11), or use a MoviePlayer (Chapter 27). But REALbasic also provides a control class whose primary purpose is animation—the SpriteSurface control. Figure 28-1 shows an example of a SpriteSurface; it’s being used to play a little game, PacMan On Mars, which we’ll develop later in the chapter. But first, let’s start with the basics.

Figure 28-1. PacMan On Mars

A SpriteSurface is a RectControl, and therefore receives all the events and has all the methods listed in Chapter 10: Open and Close events; Visible, Enabled, and AutoDeactivate properties; Top, Left, Height, and Width properties; LockLeft, LockRight, LockTop, and LockBottom properties; MouseEnter, MouseMove, and MouseExit events; and Refresh and RefreshRect methods. For drag-and-drop, see Chapter 24.

A SpriteSurface is a rectangular area of a window that functions as a “stage” within which animation can take place. A SpriteSurface can contain two sorts of thing:

The background

An image that fills the SpriteSurface. It can be animated by assigning a different image, or by scrolling.

One or more sprites

A sprite is an instance of the Sprite class. It has an image, which is drawn transparently in front of the background. It can be animated by changing its ...