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5.6 GRAPHICS
If youareusingacommercialgraphicsprogram,suchasLotus1-2-3, you
won’tneed to use thecommandsin this section.Usuallyyou’lljust draw
yourimageon yourscreenandthen senditto the printer.
ShouldyouwanttosendyourowngraphicscommandsinFX-850emulation
mode, though,it’s best to start off knowinga little binary arithmetic.If
you’rerustyon binaryyou can reviewcomputerarithmeticin Chapter1.
We’llassumeyoualreadyknowelementaryprogrammingin thefollowing
discussion.
5.6.1 Printingdots
FX-850 emulationprints graphicsas lines eight pin-dotshigh. Youjust
specifywhichof theeightdotsto printforeachdot-widecolumn.
Thatsoundseasy,butitcanbe a lotof work.Itmeansspecifyingan eight-
bitbinary number60 to 240 timesper inch,rightac~ossthe page.That’s
maybe 2000 calculationsfor every line! As you can imagine, graphics
softwareuses plentyof programloops.
Thefigurebelowshowsthevalueof eachdotontheleft.The exampleson
therightshowhowyouwouldaddup dots,totellyourprinterwhatdotsto
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 Whatdographicscommandslooklike?
To printFX-850graphicsyouhaveto makefourdecisions:
● Whatlinespacingdo youwantto use?
● Howmanydotsdoyouwantperhonzontal inch?Thatis,whatdensity
do
YOUWtU’lt?
● Howwideisthepageareaonwhichyouwantto’’paint”yourgraphics?
● Whatdot patternwill yourdatahave?
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