Defines logical dimensions for the current graphics viewport. Use the WINDOW
statement to define your own viewport coordinate system.
 
WINDOW [[SCREEN] (x1!,y1!)-(x2!,y2!)]
 
    - SCREEN       Inverts the normal Cartesian direction of the y screen
                   coordinates so that y values increase from the top of the
                   screen to the bottom.
    - (x1!,y1!)    Logical coordinates that map to the upper-left screen
                   coordinates of the viewport.
    - (x2!,y2!)    Logical coordinates that map to the lower-right screen
                   coordinates of the viewport.
 
    - WINDOW with no arguments disables the logical coordinate system.
    - Use the VIEW statement to change the size of the viewport.
 
Example:
    'This example requires a color graphics adapter.
    SCREEN 1
    FOR i% = 1 TO 10 STEP 2
        WINDOW (-160 / i%, -100 / i%)-(160 / i%, 100 / i%)
        CIRCLE (0, 0), 10
    NEXT i%
 
See Also    <CLS>    <PMAP>    <POINT>    <SCREEN>    <VIEW>    <WIDTH>