Epson LX-90 User Manual - IBM PC Jr. 8690 PIC for LX-90 - Page 55

WIDTH Statements, Multiple-Line Exercise, LPRINT CHR$27KCHR$100CHR$0

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WIDTH Statements Some software (including IBM Personal Computer BASIC) automatically inserts the control codes for a carriage return and a line feed after every 80 - 130 characters. This insertion is usually no problem with text, but it can spoil your graphics. In the graphics mode it may insert the control codes in the middle of a line. You can usually prevent these unwanted control codes with a WIDTH statement. The format in BASIC is shown below: WIDTH "LPT1:",255 Put a WIDTH statement in one of the first lines of all your graphics programs. It is easier to put a WIDTH statement in all of your programs than to examine each one to see whether or not such a statement is necessary. Multiple-Line Exercise Now that you've entered and run a simple graphics program, you can go on to an exercise that shows you how the LX-90 combines several lines of graphics for a figure taller than eight dots. Start with a line for 100 columns of single-density graphics and lines to print two pin patterns. Notice that since there are two pin patterns in the loop, it is only executed 50 times. NEW 10 WIDTH "LPT1:",255 40 LPRINT CHR$(27)"K"CHR$(100)CHR$(0); 50 FOR X=1 TO 50: LPRINT CHR$(85)CHR$(42); 60 NEXT X: LPRINT 100 LPRINT CHR$(27)"@" If you run the program now, you'll see how one line of the pattern looks: To see how more than one line combines to form a figure, enter and run the following program, which uses the lines you have already typed and adds several more. 50

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WIDTH Statements
Some software (including IBM Personal Computer BASIC) auto-
matically inserts the control codes for a carriage return and a line feed
after every 80 - 130 characters. This insertion is usually no problem
with text, but it can spoil your graphics. In the graphics mode it may
insert the control codes in the middle of a line.
You can usually prevent these unwanted control codes with a
WIDTH statement. The format in BASIC is shown below:
WIDTH "LPT1:",255
Put a WIDTH statement in one of the first lines of all your graphics
programs. It is easier to put a WIDTH statement in all of your pro-
grams than to examine each one to see whether or not such a state-
ment is necessary.
Multiple-Line Exercise
Now that you’ve entered and run a simple graphics program, you
can go on to an exercise that shows you how the LX-90 combines
several lines of graphics for a figure taller than eight dots.
Start with a line for 100 columns of single-density graphics and lines
to print two pin patterns. Notice that since there are two pin patterns
in the loop, it is only executed 50 times.
NEW
10 WIDTH "LPT1:",255
40
LPRINT CHR$(27)"K"CHR$(100)CHR$(0);
50 FOR X=1 TO 50: LPRINT CHR$(85)CHR$(42);
60 NEXT X: LPRINT
100 LPRINT CHR$(27)"@"
If you run the program now, you’ll see how one line of the pattern
looks:
To see how more than one line combines to form a figure, enter and
run the following program, which uses the lines you have already
typed and adds several more.
50