AT&T 6300 Programmer's Manual page 512

WINDOW
Statement
Examples
7-356
WINDOW also features a "zoom in"/" zoom
out" facility. Choosing window coordinates
larger than an image will display the entire
image, but the image will be small. Choosing
window coordinates smaller than an image
will cause clipping, allowing only a portion of
the image to be displayed and magnified. By
specifying small and large window sizes, you
can zoom in until an object occupies the entire
screen, or you can zoom out until the image is
nothing but a spot on the screen.
RUN, SCREEN, and WINDOW with no
attributes will disable any WINDOW
coordinates and return the screen to physical
coordinates.
The following example demonstrates image
clipping.
10 SCREEN 100
20 CLS
30 WINDOW [-6,-6)-(6,6)
40 CIRCLE [4,4),5,1
50 'the
circle is
large - only part is visible
60 WINDOW [-100,-100)-[100,100)
70 CIRCLE [4,4),5,1 'the circle is small
80 END