Star Micronics 4 manual

Thecommandto startgraphicsmustbe transmittednext.Thiscommandis:

<ESC>*r n A

wheren can takea valueof eitherOor 1.Whenn=O,themarginfor printing 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 margin for graphicsis set to the current print position,and any graphicsimage will appearonly to the rightof that margin.

Threegraphicdatacompressionformatsare availablefor datatransfer.The data compressionformat to be used is selectedusing the followingcom- mand:

<ESC>*b n M

wheren can take the valueO,1 or 2. Any otherwilueis interpretedas O.A fill discussionof data compressiontechniquesis outsidethe scopeof this manual,but a brief explanationof this commandshouldbe useful.

. Wheren=O,no encodingtakesplace,and a simplebinarytransfertakes place.Bit7 of thefirstbytecorrespondsto thefirstdotin a rasterrow,bit 6 to the second,and so on.

. Where n=l, run-lengthencoding takes place. This is a compression techniquewherethe data is dividedintopaics;the first byteof each pair servingas the repetitioncountfor the datain the secondpair. If the first byteof thepairis equalto zero,thedatainthesecondbyteis notrepeated.

●Where n=2,the data to followis in TaggedImage File Format (TIFF) confofrningto RV.4.Ostandards.The demandsof spacedo not allow a detailed discussion of TIFF standards here, but briefly, TIFF files combinefeaturesof non-encodedandnon-encoded.fdes. Manyproprie- tary graphicspackagesuseTIFFencodingwhenstoringandtransmitting graphicdata.

When transferring raster graphic data, each line of raster data must be prefixedby the command:

<ESC>*b n W

wherengivesthenumberofdatabytesto follow(themaximumis255before anothersuchcommandis sent).Thisdatamustfollowthecompressionrules setin thepreviouscommand.For instance,a TIFF imageinterpretedin any