Laser Printer User Manual

Thecommandto startgraphicsmustbetransmittednext.Thiscommandis:

<ESC>*r n A

wherencantakeavalueofeitherOor 1.Whenn=O,themarginforprinting

graphics will be the left-most printable edge of the page (this is not

necessarilythe same as the left text margin).If n=l, the left marginfor

graphicsis set to the currentprintposition,and anygraphicsimagewill

appearonlyto therightof thatmargin.

Threegraphicdatacompressionformatsareavailablefordatatransfer.The

data compressionformatto be usedis selectedusing the followingcom-

mand:

<ESC>*b n M

wheren cantakethevalueO,1or 2. Anyotherwilueis interpretedasO.A

fill discussionof datacompressiontechniquesis outsidethe scopeof this

manual,buta briefexplanationof thiscommandshouldbe useful.

●

Wheren=O,no encodingtakesplace,anda simplebinarytransfertakes

place.Bit7 ofthefirstbytecorrespondstothefirstdotin arasterrow,bit

6 to thesecond,andso on.

Where n=l, run-lengthencodingtakes place. This is a compression

techniquewherethedatais dividedintopaics;thefirstbyteof eachpair

servingastherepetitioncountforthedatain thesecondpair.If thefirst

byteofthepairis equaltozero,thedatainthesecondbyteisnotrepeated.

Wheren=2,the data to followis in TaggedImageFile Format(TIFF)

confofrningto RV.4.Ostandards.The demandsof spacedo not allowa

detailed discussion of TIFF standards here, but briefly, TIFF files

combinefeaturesofnon-encodedandnon-encoded.fdes.Manyproprie-

tarygraphicspackagesuseTIFFencodingwhenstoringandtransmitting

graphicdata.

When transferringraster graphicdata, each line of raster data must be

prefixedby thecommand:

<ESC>*b n W

wherengivesthenumberofdatabytestofollow(themaximumis255before

anothersuchcommandissent).Thisdatamustfollowthecompressionrules

setin thepreviouscommand.Forinstance,aTIFFimageinterpretedinany