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--
-- File : ConicArc.cdl
-- Created : Sat 9 Jan 1993
-- Author : CKY / Contract Toubro-Larsen (Kiran)
--
---Copyright : MATRA-DATAVISION 1993
--
class ConicArc from IGESGeom inherits IGESEntity
---Purpose: defines IGESConicArc, Type <104> Form <0-3> in package IGESGeom
-- A conic arc is a bounded connected portion of a parent
-- conic curve which consists of more than one point. The
-- parent conic curve is either an ellipse, a parabola, or
-- a hyperbola. The definition space coordinate system is
-- always chosen so that the conic arc lies in a plane either
-- coincident with or parallel to XT, YT plane. Within such
-- a plane a conic is defined by the six coefficients in the
-- following equation.
-- A*XT^2 + B*XT*YT + C*YT^2 + D*XT + E*YT + F = 0
uses
Pnt from gp,
Pnt2d from gp,
Dir from gp,
XY from gp
is
Create returns mutable ConicArc;
-- Specific Methods pertaining to the class
Init (me : mutable;
A, B, C, D, E, F, ZT : Real;
aStart, anEnd : XY);
---Purpose : This method is used to set the fields of the class
-- ConicalArc
-- - A, B, C, D, E, F : Coefficients of the equation
-- defining conic arc
-- - ZT : Parallel ZT displacement of the arc
-- from XT, YT plane.
-- - aStart : Starting point of the conic arc
-- - anEnd : End point of the conic arc
OwnCorrect (me : mutable) returns Boolean;
---Purpose : sets the Form Number equal to ComputedFormNumber,
-- returns True if changed
ComputedFormNumber (me) returns Integer;
---Purpose : Computes the Form Number according to the equation
-- 1 for Ellipse, 2 for Hyperbola, 3 for Parabola
Equation (me; A, B, C, D, E, F : out Real);
-- returns the basic equation defining the arc
-- A, B, C, D, E, F are the coefficients of the equation
ZPlane (me) returns Real;
---Purpose : returns the Z displacement of the arc from XT, YT plane
StartPoint (me) returns Pnt2d;
---Purpose : returns the starting point of the arc
TransformedStartPoint (me) returns Pnt;
---Purpose : returns the starting point of the arc after applying
-- Transf. Matrix
EndPoint (me) returns Pnt2d;
---Purpose : returns the end point of the arc
TransformedEndPoint (me) returns Pnt;
---Purpose : returns the end point of the arc after applying
-- Transf. Matrix
IsFromEllipse (me) returns Boolean;
---Purpose : returns True if parent conic curve is an ellipse
IsFromParabola (me) returns Boolean;
---Purpose : returns True if parent conic curve is a parabola
IsFromHyperbola (me) returns Boolean;
---Purpose : returns True if parent conic curve is a hyperbola
IsClosed (me) returns Boolean;
---Purpose : returns True if StartPoint = EndPoint
Axis(me) returns Dir;
---Purpose : Z-Axis of conic (i.e. [0,0,1])
TransformedAxis (me) returns Dir;
---Purpose : Z-Axis after applying Trans. Matrix
Definition (me; Center : out Pnt; MainAxis : out Dir;
rmin, rmax : out Real);
---Purpose : Returns a Definition computed from equation, easier to use
-- <Center> : the center of the the conic (meaningless for
-- a parabola) (defined with Z displacement)
-- <MainAxis> : the Main Axis of the conic (for a Circle,
-- arbitrary the X Axis)
-- <Rmin,Rmax> : Minor and Major Radii of the conic
-- For a Circle, Rmin = Rmax,
-- For a Parabola, Rmin = Rmax = the Focal
-- Warning : the basic definition (by equation) is not very stable,
-- limit cases may be approximative
TransformedDefinition (me; Center : out Pnt; MainAxis : out Dir;
rmin, rmax : out Real);
---Purpose : Same as Definition, but the Location is applied on the
-- Center and the MainAxis
ComputedDefinition (me; Xcen,Ycen, Xax, Yax, Rmin,Rmax : out Real);
---Purpose : Computes and returns the coordinates of the definition of
-- a comic from its equation. Used by Definition &
-- TransformedDefinition, or may be called directly if needed
fields
--
-- Class : IGESGeom_ConicArc
--
-- Purpose : Declaration of variables specific to the definition
-- of the Class ConicArc.
--
-- Reminder : A ConicArc instance is defined by :
-- The six coefficients in the following equation.
-- A*XT^2 + B*XT*YT + C*YT^2 + D*XT + E*YT + F = 0
-- The parent curve could be a parabola or a hyperbola
-- or an ellipse. The arc has one start and one end point.
theA : Real;
theB : Real;
theC : Real;
theD : Real;
theE : Real;
theF : Real;
-- Conic coefficients
theZT : Real;
theStart : XY;
theEnd : XY;
end ConicArc;
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