Epson NX Wartungshandbuch PDF herunterladen (Seite 112)

104

How the program works

This program begins by assigning a number of printer commands to BASIC

string variables (lines 1000 to 1060). You can find most of these commands

near the beginning of chapter 7.

The WIDTH “LPT1:” 255 statement in line 1080 means infinite line width.

It prevents the IBM-PC from inserting unwanted carriage returns and line

feeds in graphics data.

Actual printing begins in line 1090. Using the preassigned commands, the

program prints samples of its different fonts, followed by samples of the

print pitches, then some expanded printing.

Next comes the central attraction of the program: a line of text printed fourteen

times in expanding and contracting loops to give a barrel effect. The work is

done by two printer commands: a command to vary the line spacing (lines

1400 and 1450); and a command to micro-adjust the space between characters

(lines 1410 and 1460).

Next the program returns to normal spacing and gives a demonstration of the

printer’s word-processing abilities: italic printig, bold printing, underlining,

subscripts, etc.

The row of telephone symbols in the next printed line is created by

downloading two new character patterns, which are printed in place of the

character “<“ (character 60). Details can be found in Chapter 9.

The final part of the program uses dot graphics to print an “M & W” logo.

The dot pattern of the logo was originally laid out on graph paper, then

converted to the data in lines 3180 to 4640 with the help of a calculator.

Each number represents eight vertical dots. (See “Graphics commands” in

Chapter 8 for details.)

The pattern is printed in three rows, each row is twenty-four dots high and

240 dots wide. Line 1940 sets the line spacing to 8/60 inch so that the rows

will connect vertically. The loop in lines 1950 to 2030 does the printing in

three passes of the print head.

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Epson NX Wartungshandbuch Seite 112