Tandy 1000 Basic Reference Manual page 339

ChuDter 10 I BASIC Keywords
VIE WIGraphics
Statement
Creates a viewport that redefines the screen parameters. This
defined area, a window, becomes the only place you can draw
graphic displays.
(XI ,yI) specifies the upper-left coordinates for the rectangular
viewport.
( ~ 2 3 2 ) specifies the lower-right coordinates for the rectangular
viewport.
All coordinates must be within the limitations of the screen.
Color lets you fill in the specified viewport with the specified
color. See Chapter 8, "Displaying Color and Graphics," for infor-
mation on color.
Border
is a n integer in the range 0 to 15. See Chapter 8, "Dis-
playing Color and Graphics," for information on the 16 color set
used for borders.
SCREEN specifies that all coordinates used in drawing are ab-
solute to Point 0,0 on the screen. If you omit SCREEN, all coor-
dinates specified are relative to the viewport coordinates.
If you omit all options, BASIC sets the viewport to define the en-
tire screen.
Examples
V I E W (10,10)-(100,1 00)
sets up a viewport with the upper-left corner at 10,10 and the
lower-right corner a t 100,100. Since SCREEN is omitted, all
subsequent coordinates are relative to the viewport.
For
example,
PSET (5,5),3 actually sets point 15,15.
V I E W S C R E E N
< 2 0 , 2 5 ) - < 1 0 0 , 1 5 0 )
sets up
a viewport. Because SCREEN is specified, all subse-
quent coordinates are absolute. For example, PSET (5,5),3 does
not appear because it is outside the viewport. PSET (30,30),3 is
within the viewport.
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