Tandy 1000 Basic Reference Manual page 347

Chapter 10
I
BASIC Ke.ywords
WINDOW Statement
Lets you change the physical coordinates of the screen (or cur-
rent viewport) by defining "world coordinates." World coordinates
can be any single-precision floating point numbers, including
numbers outside the physical range of the screen as defined by
the VIEW statement.
Note: The viewport is set to the entire screen by de-
fault. For more information on viewports, see the
VIEW command.
(x1,yl) specifies the world coordinates for the upper-left corner of
the screen. x
is the horizontal coordinate, and y is the vertical
coordinate.
( ~ 2 ~ 2 ) specifies the world coordinates for the lower-left corner of
the display.
x
is the horizontal coordinate, and y is the vertical
coordinate.
The SCREEN option tells BASIC to set the coordinates like the
screen display where the lesser y-coordinate is in the upper-left
corner of the screen. If you omit screen, BASIC inverts the
y-coordinates to show a true Cartesian coordinate system. That
is, the lesser y-coordinate is i n t h e lower-left corner of the
screen.
WINDOW lets you plot points outside the normal screen coordi-
nate limits by setting new world coordinates to the screen. WIN-
DOW transforms the new world coordinates onto the screen,
usually altering the aspect ratio.
Note: CIRCLE, GET, and PUT do not use world
coordinates.
You can easily plot graphs by specifying coordinates that are di-
rectly proportional t o the limits of the graph. For example, t o plot
the increase of sales from 1984 to 1987 with sales averaging
100,000 to 300,000, you can use the following command:
W I N D O W
< 1 9 8 4 , 1 0 0 0 0 0 ) - < 1 9 8 7 , 3 0 0 0 0 0 )
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