[Cyan]<CedarChest6.0>CubicSplinePackage>CubicSplines.mesa!1

m.stone February 19, 1980 5:20 PM

Last Edited by: Stone, March 15, 1983 3:26 pm

CubicSplines: CEDAR DEFINITIONS = BEGIN

X: NAT = 1;

Y: NAT = 2;

NDIM: NAT = Y;

points in object space

FPCoords: TYPE = ARRAY [X..NDIM] OF REAL;

points in screen space

ScrPt: TYPE = ARRAY [X..NDIM] OF REAL;

Coeffs: TYPE = RECORD

[t3: FPCoords,

t2: FPCoords,

t1: FPCoords,

t0: FPCoords];

CoeffsSequence: TYPE = REF CoeffsSequenceRec;

CoeffsSequenceRec: TYPE = RECORD[element: SEQUENCE length:NAT OF Coeffs];

KnotSequence: TYPE = REF KnotSequenceRec;

KnotSequenceRec: TYPE = RECORD[element: SEQUENCE length:NAT OF FPCoords];

SplineType: TYPE =

global splines

{naturalUM,cyclicUM,naturalAL,cyclicAL,

special case cubic curves

bezier,bsplineInterp,

local splines

bspline,crspline};

TooFewKnots: SIGNAL[numknots: INTEGER] ;

UnknownSpline: SIGNAL[splineType: SplineType] ;

UnmatchedEnds: SIGNAL ;

NoInitSplines: SIGNAL ;

MakeSpline: PROCEDURE

[knots: KnotSequence, splineType: SplineType] RETURNS [CoeffsSequence];

DisplayCubic: PROCEDURE

[coeffs: Coeffs,

MoveTo: PROCEDURE[ScrPt],

DrawTo: PROCEDURE[ScrPt],

tol: REAL ← 0.5];

END.