Epson Apex-80 User Manual

Page 66

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WIDTH statements

Some software (including most versions of BASIC) automatically

inserts carriage return and line feed codes after every 80 or 130

characters. This is usually no problem with text, but it can spoil your

graphics. Two extra columns of graphics are printed in the middle of

the ones you send, and are left over and printed as text.

In some versions of BASIC you can prevent unwanted control codes

in graphics by putting a WIDTH statement at the beginning of all

graphics programs. The format in many forms of BASIC is either

WIDTH “LPT1:“, 255 or WIDTH LPRINT 255. Check your software

manual for the proper format.

Printing taller patterns

The next example shows how several lines of graphics can be formed

into a figure taller than eight dots. It uses programming techniques for

producing textured or repetitive patterns.

The program is listed below. The lines inside each pair of FOR and

NEXT statements have been indented so that you can see how the

program works; the spaces are not needed for the program to run.

100 WIDTH "LPT1:", 255
110 LPRINT CHR$(27);"A";CHR$(8);
120 FOR R = 1 TO

6

130

LPRINT

CHR$(27);"K";CHR$(100);CHR$(0);

1 4 0

FOR X = 1

to

50

1 5 0

LPRINT CHR$(170);CHR$(85);

160

NEXT X: LPRINT

170

NEXT R

180 LPRINT CHR$(27);"@"

If you run the program, you will see how it combines six print lines

into a pattern.

There are five basic steps that the program goes through to produce

this kind of pattern.

Introduction to Dot Graphics

6.7

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