Overview

Synopsis

include "draw.m";
include "prefab.m";
prefab:= load Prefab Prefab->PATH;

Description

Using the Draw module's operations for simple text and images (see Chapter 11), the Prefab module can group individual items, treat those groups as units, and then activate the items on command. The other user interface module (Tk) provides facilities for keyboard- and mouse-driven applications (see Chapter 13).

The objects on the screen are of type Compound, each of which occupies a unique window on the display and contains objects of type Element. An Element may be a single object or a list of further Elements that can be used to build hierarchically structured components.

Prefab defines Environ and Style types that specify the appearance of objects: their colors, fonts, backgrounds, and so on. A Style gives font and color information, while an Environ identifies the Screen upon which the items will be displayed and the Style in which they will be drawn.

Applications should allocate an Element or Compound only through the appropriate member functions as described in the corresponding sections of the manual. Moreover, except where indicated, applications should not modify the data members directly. Although the type definitions make data members visible, the members should be treated as read-only data.

See Also

Draw Module in Chapter 11

ir - infrared remote control in Chapter 15