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Chapter6:CreatingDrawingswithDraw
Thecurves,thathavebeendrawnusingtheabovesteps,areBéziercurves.Thepointsona
Béziercurvearecalleddatapoints.
•
EachdatapointontheBéziercurvecanbe“symmetric”.Thecurvethenhasthesame
curvatureeithersideofthepoint.
•
Orthedatapointis“smooth”.Thecurvethenhasdifferentcurvatureseithersideofthe
point.
•
Ifthecurveisnotsteadilycontinuedatthedatapoint,butinsteadformsacornerortip,it
isacornerpoint.Anytypeofdatapointcanbeconvertedintoanyother,thusgivinggood
controlovertheshapeofthecurve.
Note:Whenpreciselylinkingtwoexistingpointsinadrawingusinglines,clickthe
Line
icononthemaintoolbar
andalsoactivatethe
option
barviaView>Toolbars>OptionBar.SelecttheSnaptoObjectPointsicononthis
toolbar.
EditingCurves
Datapointscanbeeditediftheyaredisplayedassmallrectangles.Toworkonacurvelater,
whenitisnolongerselected,clicktheEditPointsiconontheobjectbarandselectthe
curve.Iftheobjectbarisnotvisible,clickbrieflyonSelectonthemaintoolbar:
1. NowclickEditPointsonthefarleftoftheobjectbarorontheoptionbar.
2. Clickonceonthepointforediting.Itwillappearasafilledsquare,andthereshouldbe
twoBézierlineswithcontrolpointsattheends.(Pleasenotethatsometimesoneofthe
controlpointsisdirectlyontopoftheBézierpointandthushardtosee.)Inthecaseof
cornerpoints,whichdefinerightangles,thecontrolpointsliedirectlyontheBézierpoint.
NowmovetheBézierpointandthecontrolpointsasneeded.Notehowthecurvechanges
accordingly.Thechangeinformofthecursorindicatesineachcasethefunctionthatcan
beexecuted.
Theobjectbarcontainsseveraliconswithwhichcan,amongotheroptions,changethe
typeoftheselectedpoint.Adetailedexplanationofthevariousoptionscanbefoundin
Help.
3. Toconvertthetypeofdatapoint,selectthepoint.Theobjectbarshowsthetypeofpoint:
cornerpoint,smoothtransitionorsymmetrictransition.
4. Clickoneoftheiconstochangethetypeofpoint.
Ofcourse,curvescanalsobeeditedinthe“conventional”manner,i.e.,changingwidth,
colour,and(inthecaseofafilledcurve)theobjectfill.Theoptionsforchangingthese
attributesarefoundintheObjectbar.IftheEditpointsiconisnotpressed,usethecontext
menuortheFormatandModifymenus.
AlsotryouttheothericonsontheCurvesfloatingtoolbar.Whenafilledcurveisfinishedby
doubleclicking,itisautomaticallyclosedandall“internalareas”arefilled.
OpenOffice.orgUserGuidefor2.x
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