Graphics
The graphics commands
The graphics mode commands are quite different from other
commands used by the printer. For most of the other printer
modes, such as emphasized and double-wide, one ESC code turns
the mode on and another turns it off. The graphics commands are
more complicated because the code that turns on the graphics
mode also specifies how many columns of graphics will be printed.
After the printer receives this command, it interprets all
subsequent numbers sent to the printer as column patterns, until
the specified number of columns has been printed.
While there are alternate commands for four of the most
commonly used options (see Chapter
9),
your printer has one
special command that allows you to use any of the seven graphics
options. The format of the command is:
ESC * m n1 n2 data
In this command, m selects the graphics option and n1 and n2
specify the number of columns to reserve for graphics. The
available graphics options are listed below.
Option
m
Horiz. density (dots/in.)
Single-density
Double-density
High-speed double-density*
Quadruple-density*
CRT I
Plotter
(1:l)
CRT II
60
120
120
240
80
72
90
* Adjacent dots cannot be printed in this mode.
4-12
Software and Graphics
