
p w
Thisprogrambeginsbyassigninganumberofprintercommandsto BASIC
stringvariables(lines1000to 1090).Youcanfindmostofthesecommands
nearthe beginningof chapter4.
TheWIDTH“LPT1:“255statementin line 1110meansintlnitelinewidth.
It preventsthe IBM-PCfrominsertingunwantedcarriagereturnsand line
feedsin graphicsdata.
Actualprintingbeginsin line 1120.Usingthe preassignedcommands,the
programprints samplesof its differentfonts,includinga line showingall
stylesin italics,followedby samplesoftheprintpitches,thensomedouble
and quadruple-sizedprinting.
Next comes the central attractionof the program:a line of text printed
fourteentimesinexpandingandcontractingloopstogiveabarreleffect.The
workisdoneby fourprintercommands:acommandsettingtherightmargin
(line 14@);a centeringcommand(line 1420);a commandto varythe line
spacing(lines 1440and 1490);and a commandto micro-adjustthe space
betweencharactm (lines 1450and 15W).
Nexttheprogramreturnstonormalspacingandgivesademonstrationofthe
printer’swc)rd-processingabilities:bold printing,underlining,subscripts,
etc.
The row of automobilesin thenextprintedlineis createdby dGwrdoading
twonewcharacterpatterns,whichareprintedinplaceof thecharacter“<”
(character60).Detailscanbe fwnd in Chapter5.
The finalpart of theprogramuses dot graphicsto printsome“SW”IGgm
withvariousdensities.Thedotpatternofthelogowasoriginallylaidouton
graphpaper,thenconvertedto thedatain lines2400to 2630withthehelp
of a calculator.Eachnumber~presentseightverticaIdots.(See“Graphics
cGmmands”in Chapter4 for details.)
Thepatternis printedin fourrows,eachrowis eightdotshighand65dots
wide.Lines1800to 1850readthedotdataintoastringarrayvariablenamed
LOGO$.Line 1860setstheline spacingtG8/72inchso that the rowswill
connectvertically.Theloopin lines 1870tG1960dGestheprintingin four
passesof theprinthead.
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