Commodore MPS 1200 - DESIGNING GRAPHICS

In nine-pin graphics, the first data code determines the pattcrII or
the top eight pins in the usual way. The second code determines
whether the bottom pin is printed: a code 128 or greater prints the
bottom pin; a code less than 128 does not print the bottom pin.
Because
of this, nine-pin graphics is not used for routine applica-
tions.
But for very intense graphics applications such as scrccn
dumps and plotter graphics, the increase in speed may make thc
additional
programming effort worthwhile.
The nine-pin graphics command is ESC i. To use it send the MPS
1200 ESC i, followed by chr$(O) for single density or chr$(l) for
double density, followed
by the usual chr$(n1) and chr$(n2) to sct
the line length.
DESIGNING GRAPHICS
Graphics can be designed in two ways. In the first method YOll
define the shapes by sketching them on paper and then tell the MPS
1200 the exact pin
numbers to print in each column. In the second
method, sometimes called plotting, the shapes and pin numbers are
calculated
by the computer according to a formula you supply in a
program.
Defining Shapes
Any graphic pattern can be defined using graph paper as shown in
Figure 6-3. Each horizontal row on the graph paper corresponds to
a pin
number and each vertical column corresponds to a column or
dots. You simply sketch the shape you want on the paper and note
the blocks
where dots are to be printed. Then add the required pin
numbers in each column to determine the pin number codes.
6-11