Laser Printer User Manual

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5.6 GRAPHICS
If youareusinga commercialgraphicsprogram,suchas Lotus1-2-3, you
won’tneed to use the commandsin this section.Usuallyyou’lljust draw
yourimageon yourscreenandthensendit to theprinter.
ShouldyouwanttosendyourowngraphicscommandsinFX-850emulation
mode, though,it’s best to start off knowinga little binary arithmetic.If
you’rerusty on binaryyou can reviewcomputerarithmeticin Chapter1.
We’llassumeyoualreadyknowelementaryprogramminginthefollowing
discussion.
5.6.1 Printingdots
FX-850 emulationprints graphicsas lines eight pin-dotshigh. Youjust
specifywhichof theeightdotsto printforeachdot-widecolumn.
Thatsoundseasy,butit canbe a lotof work.It meansspecifyingan eight-
bitbinary number60 to 240 timesper inch,rightac~ossthe page.That’s
maybe 2000 calculationsfor every line! As you can imagine, graphics
softwareusesplentyof programloops.
Thefigurebelowshowsthevalueofeachdotontheleft.The exampleson
therightshowhowyouwouldaddup dots,to tellyourprinterwhatdotsto
printfor a coupleof columns:
128●
840
32
●
16 .
80
40
20
10
128
●
o
32
●
:
40
0
10
165
0
640
0
0
80
0
20
0
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5.6.2 Whatdographicscommandslook like?
To printFX-850graphicsyouhaveto makefour decisions:
● Whatline spacingdo youwantto use?
● Howmanydotsdoyouwantperhonzontal inch?Thatis,whatdensity
do
YOUWtU’lt?
● Howwideisthepageareaonwhichyouwantto’’paint”yourgraphics?
● Whatdot patternwill yourdatahave?
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