A presentation space is a data structure, maintained by the operating system, that describes the drawing environment for an application. An application can create and hold several presentation spaces, each describing a different drawing environment. All drawing in a PM application must be directed to a presentation space.
Normally each presentation space is associated with a device context that describes the physical device where graphics commands are displayed. The device context translates graphics commands made to the presentation space into commands that enable the physical device to display information. Typical device contexts are the screen, printers and plotters, and off-screen memory bit maps. By creating presentation spaces and associating them with particular device contexts, an application can control where its graphics output appears. Typically, a presentation space and device context isolate the application from the physical details of displaying graphics, so the same graphics commands can be used for many types of displays. This virtualization of output can reduce the amount of display code an application must include to support multiple output devices.
This chapter describes how an application sets up its presentation spaces and device contexts before drawing, and how to use window-drawing functions. Refer to the Graphics Programming Interface Programming Guide for the graphics functions available to PM applications.