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How the program works
This program begins b y assigning anumberofprinter commands toBASIC
string variables
(lines 1000to1100). Y ou canfind mostofthese c ommands
near thebeginning o fchapter 4 .
TheWIDTH"LPT1:"255 statementin line 1120meansinfiniteline width.
It preventsthe IBM-PCfrom insertingunwantedcarriagereturnsand line
feedsin graphicsdata.
Actualprintingbeginsin line 1130.Usingthe preassignedcommands,the
programprints samplesof its differentfonts, followedby samplesof the
print pitches,then somedoubleand quadruple-sized printing.
Next
comes thecentral attraction
of theprogram: a line of text printed
fourteen times inexpanding a ndcontracting
loops togive abarrel effect.
The
workis doneby four printer
commands:acommand setting
the right margin
(line 1 450); a centering command (line 1 470); a command tovarytheline
spacing ( lines 1490and 1540); a nd a command tomicro-adjust
thespace
between charactem ( lines 1500and 1550).
Nextthe
program returns tonormal spacing a ndgives ademonstration
ofthe
printer's
word-processing
abilities:
italic
printing,
boldprinting,
underlin-
ing, subscripts,
etc.
The row of telephonesymbolsin the next printedline is createdby down-
loading two new character patterns, which are printed in place of the
character"<" (character60). Detailscan be foundin Chapter5.
Thefinalpartoftheprogramusesdotgraphicstoprintan"M&W"logo.The
dotpatternofthelogowasoriginallylaidouton graphpaper,thenconverted
to the datain lines 3180to 4640 withthe help of a calculator.Eachnumber
representseightverticaldots. (See "Graphicscommands"in Chapter4 for
details.)
The patternis printedin three rows,each row is twenty-fourdotshigh and
240 dots wide.Line 2040setsthe line spacingto 8/60inch so thatthe rows
will connectvertically.The loop in lines 2050to 2130 doesthe printingin
three passesof the print head.
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