Chapter 7: Advanced Graphics - Epson MX-80 User Manual

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Chapter 7

Advanced Graphics

In the earlier Chapter on Graphics, we concentrated on the graphics character set

itself, how its ASCII numbers are offset to allow use of more reliable control

codes, and how to dump displays from screen to printer. In this Chapter we will

practice using the Printer's unique capabilities to create graphics, some of which

cannot even be duplicated on the screen.

We have several special things going for us:

1. The Printer's vertical spacing can be adjusted to increment as small as 1/72

of an inch.

2. We can switch between 80 and 132 characters per line.

3. We can switch between single and double width.

We have learned how to utilize all 3 of the features above, but let's experiment a

bit more with the first one. Type in this program:

1 0

L P R I N T C H R $ ( 2 7 ) " A "

C H R $ ( 1 )

C H R $ ( 2 7 ) " 2 "

2 0 FOR N = 1 TO

2 0

3 0

L P R I N T

T A B ( 4 0 )

4 0 NEXT N

5 0 L P R I N T C H R $ ( 2 7 ) " A " C H R $ ( 1 2 )

C H R $ ( 2 7 ) " 2 "

and RUN.

Figure 7-1

Here's what happened:

Line 10 set the vertical spacing to 1/72 of an inch.

Lines 20-40 printed 20 periods in a vertical stack.

Line 50 reset the vertical spacing back to 1/6 of an inch.

We created our own new character. It may not be award winning, but the possi-

bilities this sort of thing opens u p for the creative graphics designer are nearly

endless.