ClassPackage: cgToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 8.1
Unrevised from 8.0 to 8.1.
8.0 version

bitmap-stream

A class of object similar to windows in that you can draw onto it but it is never visible on the screen. Its contents, however, can be copied onto a visible window using copy-stream-area. A bitmap-window (or bitmap-pane) has the functionality of a bitmap-stream hardwired into it, implementing the backing-store for automatically refreshing and redisplaying the window. Bitmap-stream is provided in case you want to manage the drawings stored in memory independently. For an example using bitmap-streams, choose the Help menu | CG Examples and look for Bitmap-streams: custom backing store.

One creates a bitmap-stream by calling open-stream, passing the desired size as the value of page-width and page-height keyword arguments. Below is an example expression that creates a bitmap-stream; the two nil arguments are required due to the two deprecated optional parameters of open-stream.

(open-stream 'bitmap-stream nil nil
  :page-width 600 :page-height 400
  :background-color yellow)

A diagram of window and widget classes is shown in Widget and window classes in cgide.htm.


Copyright (c) 1998-2009, Franz Inc. Oakland, CA., USA. All rights reserved.
Documentation for Allegro CL version 8.1. This page was not revised from the 8.0 page.
Created 2009.7.29.

ToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 8.1
Unrevised from 8.0 to 8.1.
8.0 version