SB-10 USER'S MANUAL

• PRINTING 8-61-r GRAPHICS
In 8-bit, normal-density graphics, the graphic image is divided into
“dot columns”, each directly corresponding to the pin configuration
in the print head. Each “dot column” can be controlled by 1 byte
of data. As a result, every bit in the byte corresponds to a particular
pin in the print head (Figure F-l). This mode, which yields 180 dots
per inch horizontally and up to 120 dots per inch vertically, uses the
following setup format:
Table F-l. Setup codes for the printer’s four graphics modes.
GRAPHICS MODE
ESCAPE CODE SEQUENCE
8-bit
Y “nl” “n2” “ml” “m2”.. .
16-bit
I “nl” “172” “ml” “m.‘.. .
24-bit
< ESC> V “nl *I “n2” “ml” “m2”.. .
8x3-bit
K “n” “n2” “ml” “n-L..
Using this code sequence, the “r-t” and “n2” tell the printer how
many bytes of graphics data (measured in dot columns) you are
going to send per line. (The “ml”, “m2”, etc., tell the printer exactly
which pins to fire on each column. We’ll demonstrate this shortly.)
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H SPECIFYING THE NUMBER OF DOT COLUMNS.
To determine the values of nl and n2, you will need to calculate
the width (in dot columns) of your graphics image and send this
information to the printer. To do this, you’ll have to convert the
number of dot columns into two separate values, using the formula
given in Table F-2. This conversion is necessary because the maximum
number you can send in one byte is 255, while normal-density
graphics mode can print as many as 1,440 columns across the page.
The formula shown in Table F-2 allows you to tell the printer exactly
what your printing parameters will be, specifying the exact number -
of bytes to represent dot columns. (In the formula, x = the number
of dot columns in your graphic image; thus, if you have a total of
500 columns, divide 500 by 256. Since 256 “goes into” 500 only once,
n2 = 1. nl is the remainder of this division, so nl = 244.
Specifying the graphics data
When you have entered < ESC > Y nl and n2, you’ve set up the
8-bit graphics mode, telling the printer how much data to expect per
line. Now you are free to specify the exact picture itself (the “ml,
m2, etc.“of the sequence). Figure F-5 shows that each pin on the
print head is labeled with a value; the topmost pin has the highest
value, and each pin corresponds to a particular value in descending
order.
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