106
PRINTING A DESIGN OR LOGO
Since you control the firing of every pin, you can print nearly
anything with your printer that can draw (and probably better, if
you’re like most computer users!). You can be used for creating
“computer art” or drawing maps. Or, as we’ll show you here,
you can use dot graphics to print your logo at the top of each let-
ter you print.
Designing an image to print with dot graphics is much like
designing download characters. The best way to start is to lay
out your image on graph paper. Since you can print eight rows
(seven with a 7-bit interface) of dots with each pass of the print
head, draw a heavy horizontal line every eight rows on your
graph paper. And it may be helpful to write the dot values
(128,64,32, etc.) down the left side of each row. Then after
you’ve filled in the “dots” that you want to print, it’s time to get
out the old calculator again! Just as you did with download
characters, add up the values of each column of dots; this makes
up one byte.
! ! s&s -- ~--~~~~~ ~~~~~~ _J
Figure 7-2. By laying out the logo on graph paper, you can
calculate all of the graphics data.