Filter
Top Products
I
DEFINING YOUR OWN NLQ CHARACTERS
As you probablynoticed,NLQ charactersareprintedby two passesof the
printhead.Halfofthecharacterisprintedonthefirstpass,andtheremainder
onthesecondpass.Thepaperisrolleduphalfadotheightinbetweenpasses
to let the printhead printdotson the secondpassthatoverlapthe previous
dots,in otier to fillin thespacesandproducedensercharacters.Addition-
ally,tie printhead speedis halved,andthe dots are printedat doublethe
densityof draft characters.For thisreason,NLQcharacterscan containup
to 23 dotsin the horizontaldirection.
Fundamentally,theprocessto defineandprintdownloadedNLQcharacter
is the sameas for draft charactem,exceptthat youmustsupplyaboutfour
timesasmuchcharacterdata,andyoumustdesignthecharacterwiththe?SVO
passes of the print head in mind. There are small diffextmceswith the
standardmodein the way the attributeinformationis processedalso.
In the draft qualitymodethe attributebytecarriesthe descenderdata,and
specifiesthe leftspaceandthecharacterwidth.In theNLQmode,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 rightspace.Appropriateallocationof data in thesesevenbits
lets you place the character whe~ you like within the grid, with the
nxtrictionthatthe charactermustbe at least9 dotswide.
Usethe gridinFigure5-4to helpplotthedata.Dueto thetwo-passprocess,
NLQcharacterscancontainup to 16dotsvertically.ml to m23arethedata
for the firstpass, andm24to m46 arethe datafor the secondpass.
To makethecharacterdataeasierto calculate,putthefirstpassdotsinside
theboxesonthegridwhenyouaredesigningyourcharacters,andthesecond
passdotsonthelines.Rememberthatadjacentdotsmaynotoverlapon the
samepass;in otherwords,if onedotisin abox,its adjacentdotonthesame
passmaynotbeonaline.l%erefom,tomakesmoothcharactm, putthedots
neededto overlapanyspacesin a characterin the appropriateplacesin the
secondpass grid.
Ifweplotourcar-shapedsymbolforNLQ,thegriddatawilllooklikeFigure
5-5.
Thedefiningprocessisthesameasfordraftcharacters,exceptthatyoumust
selectNLQ mode,and youmust define46 data.If you wish to print your
NLQ characterswith the regularcharacterset, the remarksregardingthe
74