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1 Basic Commands

Initializes the library’s graphics routines. It must be called before any other graphics operations.

Closes all of the windows. Until open-graphics is called again, no graphics routines will work.

Determines if the graphics have been opened (or not).

(open-viewport name horiz vert)  viewport?
  name : string?
  horiz : exact-nonnegative-integer?
  vert : exact-nonnegative-integer?
(open-viewport name dimensions)  viewport?
  name : string?
  dimensions : posn?
Creates a new window called name. The window is horiz pixels wide and vert pixels high. For backward compatibility, a single posn value can be submitted in the place of horiz and vert. The result is a viewport descriptor.

(open-pixmap name horiz vert)  viewport?
  name : string?
  horiz : exact-nonnegative-integer?
  vert : exact-nonnegative-integer?
(open-pixmap name dimensions)  viewport?
  name : string?
  dimensions : posn?
Like open-viewport, but the resulting viewport is not displayed on the screen. Offscreen pixmaps are useful for executing a sequence of drawing commands and displaying them all at once with copy-viewport.

Offscreen pixmaps are also useful in conjunction with viewport->snip (see below). This allows functions to compute with graphical objects and view the graphics when results are returned to the interactions window.

(close-viewport viewport)  void?
  viewport : viewport?
Removes the viewport from the screen and makes subsequent operations dealing with the viewport illegal.

(viewport? v)  boolean?
  v : any/c
Returns #t if v is a viewport (i.e., a destination for drawing), #f otherwise.