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 “LPTl:“, 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

"LPTl:", 255

110

LPRINT

CHR$(27);"A";CHR$(8);

120

FOR R

= 1 TO 6

130LPRINT CHR$(27);"K";CHR$(100);CHR$(0);

140FOR X = 1 to 50

150LPRINT CHR$(170);CHR$(85);

160NEXT X: LPRINT

170NEXT R

180LPRINT 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.

Graphics and User-defined Characters

5-7