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-- File: CLProps.cdl
-- Created: Mon Mar 25 16:30:42 1991
-- Author: Michel CHAUVAT
-- <mca@topsn3>
---Copyright: Matra Datavision 1991, 1992
generic class CLProps from LProp
(Curve as any;
Vec as any; -- as Vec or Vec2d
Pnt as any; -- as Pnt or Pnt2d
Dir as any; -- as Dir or Dir2d
Tool as any) -- as ToolCurve(Curve, Pnt, Vec)
---Purpose: Computation of Curve Local Properties:
-- - point,
-- - derivatives,
-- - tangent,
-- - normal plane,
-- - curvature,
-- - normal,
-- - centre of curvature,
uses Status from LProp
raises BadContinuity from LProp,
DomainError from Standard,
OutOfRange from Standard,
NotDefined from LProp
is
Create(C: Curve; N: Integer; Resolution: Real)
---Purpose: Initializes the local properties of the curve <C>
-- The current point and the derivatives are
-- computed at the same time, which allows an
-- optimization of the computation time.
-- <N> indicates the maximum number of derivations to
-- be done (0, 1, 2 or 3). For example, to compute
-- only the tangent, N should be equal to 1.
-- <Resolution> is the linear tolerance (it is used to test
-- if a vector is null).
returns CLProps
raises OutOfRange;
-- if N < 0 or N > 3.
Create(C: Curve; U : Real; N: Integer; Resolution: Real)
--- Purpose : Same as previous constructor but here the parameter is
-- set to the value <U>.
-- All the computations done will be related to <C> and <U>.
returns CLProps
raises OutOfRange;
-- if N < 0 or N > 3.
Create(N : Integer;Resolution:Real)
--- Purpose : Same as previous constructor but here the parameter is
-- set to the value <U> and the curve is set
-- with SetCurve.
-- the curve can have a empty constructor
-- All the computations done will be related to <C> and <U>
-- when the functions "set" will be done.
returns CLProps
raises OutOfRange;
SetParameter(me: in out; U : Real)
---Purpose: Initializes the local properties of the curve
-- for the parameter value <U>.
is static;
SetCurve(me: in out; C : Curve)
---Purpose: Initializes the local properties of the curve
-- for the new curve.
is static;
Value(me) returns Pnt is static;
---Purpose: Returns the Point.
---C++: return const &
D1(me: in out) returns Vec is static;
---Purpose: Returns the first derivative.
-- The derivative is computed if it has not been yet.
---C++: return const &
D2(me: in out) returns Vec is static;
---Purpose: Returns the second derivative.
-- The derivative is computed if it has not been yet.
---C++: return const &
D3(me: in out) returns Vec is static;
---Purpose: Returns the third derivative.
-- The derivative is computed if it has not been yet.
---C++: return const &
IsTangentDefined(me: in out) returns Boolean is static;
---Purpose: Returns True if the tangent is defined.
-- For example, the tangent is not defined if the
-- three first derivatives are all null.
Tangent(me: in out; D : out Dir)
---Purpose: output the tangent direction <D>
raises NotDefined
-- if IsTangentDefined(me)=False.
is static;
Curvature(me: in out)
---Purpose: Returns the curvature.
returns Real
raises NotDefined
-- if IsTangentDefined(me) == False.
is static;
Normal(me: in out; N : out Dir)
---Purpose: Returns the normal direction <N>.
raises NotDefined
-- if Curvature(me) < Resolution
is static;
CentreOfCurvature(me: in out; P : out Pnt)
---Purpose: Returns the centre of curvature <P>.
raises NotDefined
-- if Curvature(me) < Resolution
is static;
fields
myCurve : Curve; -- the Curve on which thw calculus are done
u : Real; -- the current value of the parameter
level : Integer; -- the order of derivation
cn : Real; -- the order of continuity of the Curve
linTol : Real; -- the tolerance for null Vector
pnt : Pnt; -- the current point value
d : Vec[3]; -- the current first, second and third derivative
-- value
tangent : Dir; -- the tangent value
curvature : Real; -- the curvature value
tangentStatus : Status from LProp;
-- the status of the tangent direction
significantFirstDerivativeOrder : Integer;
-- the order of the first non null derivative
--
end CLProps;
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