Tally Genicom 6600 - Manual (Page 16)

16
Chapter 1 Graphics Processing Language
Graphics Processing Language
The Graphics Processing Language (GPL) consists of a set of commands
that are used to print graphics images such as block characters, barcodes,
lines, and boxes, as well as provide formatting control for the correct
placement of these images. Relatively complex images may be created
through the use of a few simple commands.
The original version of QMS Code V (version 1) differs slightly from the
current version (version 2). The primary difference between the two is in the
way vertical justification commands are implemented. Specifically, version 1
used an approximation for 0.1 inch that has been made more precise in
version 2. If you are running an application designed for version 1, the printer
can be switched to a mode that can emulate it.
Graphics Mode
For the printer to recognize GPL commands, it must first be placed in
Graphics Mode. When the printer is in Graphics Mode, the printer scans the
data received from the host for GPL commands, passing non-Graphics data
to the current emulation. When the printer is not in Graphics Mode, Code V is
disabled and will not search the incoming data for GPL commands.
Graphics Mode may be entered while the printer is in any emulation. Graphics
Mode should not be entered while the printer is in Plot Mode. The printed
output of Code V adheres to all the applicable Control Panel settings (such as
LPI, CPI, Form Length, etc.).
NOTE: All escape sequences in this manual are in ASCII notation.
Turning Graphics Mode On
Graphics Mode is turned on with command ^PY, which must begin in the first
column of a line, followed by one of the following six terminators.
1. ^- (caret hyphen)
2. ^* (caret asterisk)
3. ^, (caret comma)
4. Carriage Return
5. Line Feed
6. Form Feed
Once the printer is in Graphics Mode, the data it receives is read into a Pass
buffer. The printer will stop looking for characters from the host and process
the data held in this buffer when one of the terminators is received. If the
buffer fills up before receiving a Pass Terminator, data in the buffer will be
processed and printed before the printer accepts any more characters.