Filter
Top Products
the same time, add up the numbers of the pins and send the sum to the
printer. Therefore, with these labels for the pins, you fire the top pin by
sending 128. To fire the bottom pin, you send 1. If you want to fire only
the top and bottom pins, you simply add
128
and 1, and send
129.
By adding the appropriate label numbers together, you can fire any
combination of pins. The figure below shows three examples of how to
calculate the number that fires a particular pattern of pins.
With this numbering system, any combination of the eight pins adds up
to a decimal number between 0 and
255,
and no numbers are duplicated.
Before you can put these numbers in a graphics program, however, you
need to know the format for graphics commands.
Graphics commands
Graphics commands are quite different from most other commands. For
most of the other modes, such as emphasized and double-wide, one
command turns the mode on and another turns it off. For graphics, the
command is more complicated because the command that turns on a
graphics mode also specifies how many columns of graphics will be
printed. After the printer receives this command, it interprets the next
numbers as pin patterns and prints them on the paper.
The graphics command format
There are several different graphics commands giving different horizontal
dot densities and printing speeds. Because the format is almost the same
for all the commands, however, the example here keeps things simple by
using only the single-density graphics command,
ESC
K. In single-
density graphics, there are
60
dots per inch horizontally.
Using Software and Graphics
4-11