Star Micronics LC24-15 user manual How the program works

How the program works

This program begins by assigning a number of printer commands to BASIC string variables (lines 1000 to 1090). You can find most of these commands near the beginning of chapter 4.

The WIDTH “LPTl :” 255 statement in line 1110 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 1120. Using the preassigned commands, the program prints samples of its different font styles, including a line showing all styles in italics, followed by samples of the print pitches, then some double and quadruple-sized 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 four printer commands: a command setting the right margin (line 1460); a centering command (line 1480); a command to vary the line spacing (lines 1500 and 1550); and a command to micro-adjust the space between characters (lines 1510 and 1560).

Next the program returns to normal spacing and gives a demonstration of the printer’s word-processing abilities: bold printing, underlining, subscripts, etc.

The row of telephone symbols in the next printed line is created by down- loading two new character patterns, which are printed in place of the character “<“ (character 60). Details can be found in Chapter 5.

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 2570 to 4030 with the help of a calculator. Each number represents eight vertical dots. (See “Graphics commands” in Chapter 4 for details.)

The pattern is printed in three rows, each twenty-four dots high and 240 dots wide. Line 1990 sets the line spacing to 8/60 inch so that the rows will connect vertically. The loop in lines 2000 to 2080 does the printing in three passes of the print head.

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