Genicom GEK 00031B - Manual (Page 69)

GEK-00029B 5000 Series Programmer’s Manual 69
PRINTRONIX GRAPHICS
The Printronix emulation graphics mode provides a horizontal dot
placement plotting method. This method enables the printing of
ASCH characters in their binary code form. Since each character has
a unique pattern of 1s and 0s (dots and voids) that make up its
binary code, the correct placement of these binary forms enables you
to form larger images on the paper.
For clarity in the text, a binary 1 (a printed dot) Will be shown as an
X and a binary 0 (empty dot position) will be shown as a 0.
In the graphics mode, only the low order six bits of a seven- or eight-
bit character are used (bits 1-6). Looking at an ASCH code chart, the
question mark character (?) is represented by the binary number
1111110 (bit 1 - bit 7). Since only the first 6 bits are used, a ? would
print six dots on the paper. An asterisk (*) is represented by 010101
which would print 0X0X0X0 across the page horizontally.
Using the question mark that prints all dots, a series of these
characters produces a one dot high solid line across the paper. By
repeating, omitting, and mixing characters across a page, images
such as graphs, charts, and pictures can be produced.
Dot Patterns and Densities
The chart on the next page shows the dot patterns for each of the
ASCII characters. Each character represents six dots (or dot
positions)* and their spacing is dependent on the density selected.
Graphics data printed in horizontal format is comprised of a stream
of bytes from left to right across each dot row.
This chart shows that byte 1 (or character 1) in row 1 will print its six
bits from left to right in a single dot row. The next byte (byte 2) prints
its six bits, representing a character, in the same dot row across the
page.
Byte! ! ! !
Row " " " "
Byte 1 Byte 2 Byte n
1 1 2 3 4 5 6 1 2 3 4 5 6 …1 2 3 4 5 6
2 1 2 3 4 5 6 1 2 3 4 5 6 …1 2 3 4 5 6
3 1 2 3 4 5 6 1 2 3 4 5 6 …1 2 3 4 5 6
. . . . . . . . . . . . . …. . . . . .
. . . . . . . . . . . . . …. . . . . .
6 1 2 3 4 5 6 1 2 3 4 5 6 …1 2 3 4 5 6