Copyright (c) Digital Equipment Corporation 1990. All rights reserved


COMPONENT: Terminal OP/SYS: VMS, Version 4.n
VMS, Version 5.n

SOURCE: Digital Customer Support Center


OVERVIEW:

This article describes how to draw lines and boxes on VT1xx, VT2xx,
and VT3xx terminals. It also provides the Line Drawing Character Set
for drawing other figures.


DISCUSSION:

The following escape sequences assign and load the character sets into the terminal buffers:

< ESC>)0 (Escape = Decimal 27) Assigns DEC Special Character Set to G1.
^N (Decimal 14 - "Shift Out") Maps the G1 character set into GL.
^O (Decimal 15 - "Shift In") Maps the G0 character set into GL.

The following is a listing of the DEC Character Set ASCII symbols that will be replaced with the actual DEC Special Character Set when mapped to GL:

DEC Special Character Set

ASCII
SYMBOL DESCRIPTION

_ Blank
` Solid Diamond
a Checkerboard
b "HT"
c "FF"
d "CR"
e "LF"
f Degree Sign
g Plus/Minus Sign
h "NL"
i "VT"
j Lower-Right Corner
k Upper-Right Corner
l Upper-Left Corner
m Lower-Left Corner
n Crossing Lines
o Horizontal Line, scan 1
p Horizontal Line, scan 3
q Horizontal Line, scan 5
r Horizontal Line, scan 7
s Horizontal Line, scan 9
t Left "T"
u Right "T"
v Bottom "T"
w Top "T"
x Vertical Bar
y Less Than or Equal Sign
z Greater Than or Equal Sign
{ Greek Letter pi
| Not Equal Sign
} Pound Sign
~ Middle Dot


SIMPLE EXAMPLES:

1) Simple box:

< ESC)0
^Nlqqqqqqqqqqqqk
x              x
x              x
x              x
x              x
x              x
x              x
mqqqqqqqqqqqqj^O


2) Box with text inserted:

Note that this example contains an escape sequence for cursor
positioning. It is "<ESC>[NC", where N is the number of
characters to move. The first line of this example will clear
the screen.

< ESC>[H<ESC>[J
< ESC>)0^Nlqqqqqqqqqqqqqwqqqqqqqqqqqqqqqqqqwqqqqqqqqqqqqqk
x<ESC>[13Cx^O<ESC>[2CTest Box With<ESC>[3C^Nx^O<ESC>[4C^N<ESC>[9Cx
x<ESC>[13Cx^O<ESC>[2CText Inserted<ESC>[3C^Nx^O<ESC>[13C^Nx
mqqqqqqqqqqqqqvqqqqqqqqqqqqqqqqqqvqqqqqqqqqqqqqj^O

NOTE: In both examples the characters <ESC>, ^O, and ^N must be
changed to the actual escape sequences.