Graphics Mode - Epson FX-80 User Manual

with 66 rows-that makes a total of 792 dots extending down the
page. Calculators ready? That gives a grand total potential for
380,160 dots on a single sheet of paper. Whew! And that doesn't take
into account the printer's ability to compress the print, both horizon-
tally and vertically. Let's face it, we'll need a lot of dots and data to fill
the entire page with graphics!
Graphics Mode
Printing hrgh-resolution graphics on the FX-80 requires an entirely
new kind of mode. In any of the several versions of Graphics Mode,
none of the
predefined
characters or symbols in the printer's memory
are used. Instead, you create the patterns of dots that are printed. Yes,
you control where and when each and every dot is printed. That's
power!
And how do these modes operate? Essentially, a single pattern of
dots is printed on each pass of the print head. Even though there are 9
pins on the print head, the printer is designed to print only 8 at a
time-the top 8. (There is an optional9-dot mode which we will get to
in due time.) The limiting factor is that printer / computer communica-
tions are based on 8 data lines, and each pin of the print head corre-
sponds to 10f these 8. So each sweep of the head prints up to 8 dots.
Seven-bit computers are further limited since they control only 7 of
the 9 pins (more on this in a moment).
To print figures taller than 7 or 8 dots, just adjust the line spacing to
8 dots (7 dots for 7-bit computers), and print several lines until the
figure is complete. See Figure 11-1, below .
•••••• : .............. 1' ............................... - ••••••..............................................................
.••.••••••••• - •••••••
~
......................................................
.I'~.-
•••••••••••• - ......................... .
a. 7·dot line spacing. b. 12·dot line spacing.
Figure 11·1. Comparison of 7· and 12·dot line spacing.
Each pass of the print head contains one piece of the total pattern,
which can be as tall as you desire. You don't have to use the whole
128