Defining Yourownnlqcharacters - Star Micronics LC-20 User Manual

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DEFINING YOUR OWN NLQ CHARACTERS
As you probablynoticed,NLQ charactersare printedby two passesof the
printhead.Halfofthecharacters printedonthefirstpass,andtheremainder
onthesecondpass.Thepaperisrolledup halfa dotheightinbetweenpasses
to let the printhead print dotson the secondpass that overlapthe previous
dots,b onler to fill in the spacesand producedenserchamctem.Addition-
ally,the print head speed is halved,and the dots are printed at doublethe
densityof draft characters.For this reason,NLQ charactemcan containup
to 23 dots in the horizontaldirection.
Fundamentally, t he processto defineandprintdownloadedNLQcharacter
is the same as for draft characters,exceptthat you must supplyaboutfour
timesasmuchcharacterdata,andyoumustdesignthecharacterwiththetwo
passes of the print head in mind. There are small differenceswith the
standardmode in the way the attributeinformationis processedalso.
In the draft qualitymode the attributebyte carriesthe descenderdata, and
specifiesthe left spaceandthe characterwidth.In the NLQ mode,the first
bit also carries the descenderdata, and the next three bits describe the
character'sleft space as with the draft charactem,but the last four bits
describethe right space.Appropriateallocationof data in these sevenbits
lets you place the character where you like within the grid, with the
restrictionthat the charactermust be at least 9 dots wide.
Usethe gridin Figure5-4 to helpplotthedata.Dueto thetwo-passprocess,
NLQcharacterscan containup to 16dotsvertically.ml to m23arethedata
for the f~st pass, and m24 to m46are the data for the secondpass.
To makethe characterdataeasierto calculate,put the firstpass dotsinside
theboxesonthegridwhenyouaredesigningyourcharacters,andthesecond
pass dotson the lines.Rememberthat adjacentdotsmay not overlapon the
samepass;in otherwords,if onedotis in a box,its adjacentdoton the same
passmaynotbeon aline.Therefore,tomakesmoothcharactm, putthedots
neededto overlapany spacesin a characterin the appropriateplacesin the
secondpass grid.
If weplotourcar-shapedsymbolforNLQ,thegriddatawilllooklikeFigure
5-5.
Thedefiningprocessis thesameas fordraftcharacters, e xceptthatyoumust
selectNLQ mode, and you must define46 data. If you wish to print your
NLQ characterswith the regularcharacterset, the remarks regardingthe
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