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How the program works
This program begins by assigning a number of printer commands to BASIC
string variables (lines 1000to 1060).You can find most of these commands
near the beginning of chapter 8.
s
p i
feeds in graphics data.
p begins in line 1090. Using the preassigned commands, the
program prints samplesofitsdifferentfonts,followedbysamplesof theprint
pitches, then some expanded printing.
comes the central attraction of the program: a line of text printed
fourteen times inexpanding and contracting loopsto give abarrel 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 ofthe
printer’s word-processing abilities: italic printing, bold printing, underlin-
ing, 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 finalpartoftheprogram usesdotgraphicsto printan“M &W“ logo.The
dot pattern of the logo was originally laidouton 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 1940sets the linespacing 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.