# Geom2dGcc_Circ2dTanCen Class Reference

This class implements the algorithms used to create 2d circles tangent to a curve and centered on a point. The arguments of all construction methods are : More...

`#include <Geom2dGcc_Circ2dTanCen.hxx>`

## Public Member Functions

Geom2dGcc_Circ2dTanCen (const Geom2dGcc_QualifiedCurve &Qualified1, const Handle< Geom2d_Point > &Pcenter, const Standard_Real Tolerance)
Constructs one or more 2D circles tangential to the curve Qualified1 and centered on the point Pcenter. Tolerance is a tolerance criterion used by the algorithm to find a solution when, mathematically, the problem posed does not have a solution, but where there is numeric uncertainty attached to the arguments. Tolerance is only used in these algorithms in very specific cases where the center of the solution is very close to the circle to which it is tangential, and where the solution is thus a very small circle. Exceptions GccEnt_BadQualifier if a qualifier is inconsistent with the argument it qualifies (for example, enclosing for a line). More...

Standard_Boolean IsDone () const
Returns true if the construction algorithm does not fail (even if it finds no solution). Note: IsDone protects against a failure arising from a more internal intersection algorithm, which has reached its numeric limits. More...

Standard_Integer NbSolutions () const
Returns the number of circles, representing solutions computed by this algorithm. Exceptions StdFail_NotDone if the construction fails. More...

gp_Circ2d ThisSolution (const Standard_Integer Index) const
Returns a circle, representing the solution of index Index computed by this algorithm. Warning This indexing simply provides a means of consulting the solutions. The index values are not associated with these solutions outside the context of the algorithm object. Exceptions Standard_OutOfRange if Index is less than zero or greater than the number of solutions computed by this algorithm. StdFail_NotDone if the construction fails. More...

void WhichQualifier (const Standard_Integer Index, GccEnt_Position &Qualif1) const
Returns the qualifier Qualif1 of the tangency argument for the solution of index Index computed by this algorithm. The returned qualifier is: More...

void Tangency1 (const Standard_Integer Index, Standard_Real &ParSol, Standard_Real &ParArg, gp_Pnt2d &PntSol) const
Returns informations about the tangency point between the result number Index and the first argument. ParSol is the intrinsic parameter of the point PntSol on the solution curv. ParArg is the intrinsic parameter of the point PntSol on the argument curv. Exceptions Standard_OutOfRange if Index is less than zero or greater than the number of solutions computed by this algorithm. StdFail_NotDone if the construction fails. More...

Standard_Boolean IsTheSame1 (const Standard_Integer Index) const
Returns true if the solution of index Index and the first argument of this algorithm are the same (i.e. there are 2 identical circles). If Rarg is the radius of the first argument, Rsol is the radius of the solution and dist is the distance between the two centers, we consider the two circles to be identical if |Rarg - Rsol| and dist are less than or equal to the tolerance criterion given at the time of construction of this algorithm. NotDone is raised if the construction algorithm didn't succeed. OutOfRange is raised if Index is greater than the number of solutions. More...

## Detailed Description

This class implements the algorithms used to create 2d circles tangent to a curve and centered on a point. The arguments of all construction methods are :

• The qualified element for the tangency constrains (QualifiedCurv). -The center point Pcenter.
• A real Tolerance. Tolerance is only used in the limits cases. For example : We want to create a circle tangent to an EnclosedCurv C1 with a tolerance Tolerance. If we did not used Tolerance it is impossible to find a solution in the the following case : Pcenter is outside C1. With Tolerance we will give a solution if the distance between C1 and Pcenter is lower than or equal Tolerance/2.

## Constructor & Destructor Documentation

 Geom2dGcc_Circ2dTanCen::Geom2dGcc_Circ2dTanCen ( const Geom2dGcc_QualifiedCurve & Qualified1, const Handle< Geom2d_Point > & Pcenter, const Standard_Real Tolerance )

Constructs one or more 2D circles tangential to the curve Qualified1 and centered on the point Pcenter. Tolerance is a tolerance criterion used by the algorithm to find a solution when, mathematically, the problem posed does not have a solution, but where there is numeric uncertainty attached to the arguments. Tolerance is only used in these algorithms in very specific cases where the center of the solution is very close to the circle to which it is tangential, and where the solution is thus a very small circle. Exceptions GccEnt_BadQualifier if a qualifier is inconsistent with the argument it qualifies (for example, enclosing for a line).

## Member Function Documentation

 Standard_Boolean Geom2dGcc_Circ2dTanCen::IsDone ( ) const

Returns true if the construction algorithm does not fail (even if it finds no solution). Note: IsDone protects against a failure arising from a more internal intersection algorithm, which has reached its numeric limits.

 Standard_Boolean Geom2dGcc_Circ2dTanCen::IsTheSame1 ( const Standard_Integer Index ) const

Returns true if the solution of index Index and the first argument of this algorithm are the same (i.e. there are 2 identical circles). If Rarg is the radius of the first argument, Rsol is the radius of the solution and dist is the distance between the two centers, we consider the two circles to be identical if |Rarg - Rsol| and dist are less than or equal to the tolerance criterion given at the time of construction of this algorithm. NotDone is raised if the construction algorithm didn't succeed. OutOfRange is raised if Index is greater than the number of solutions.

 Standard_Integer Geom2dGcc_Circ2dTanCen::NbSolutions ( ) const

Returns the number of circles, representing solutions computed by this algorithm. Exceptions StdFail_NotDone if the construction fails.

 void Geom2dGcc_Circ2dTanCen::Tangency1 ( const Standard_Integer Index, Standard_Real & ParSol, Standard_Real & ParArg, gp_Pnt2d & PntSol ) const

Returns informations about the tangency point between the result number Index and the first argument. ParSol is the intrinsic parameter of the point PntSol on the solution curv. ParArg is the intrinsic parameter of the point PntSol on the argument curv. Exceptions Standard_OutOfRange if Index is less than zero or greater than the number of solutions computed by this algorithm. StdFail_NotDone if the construction fails.

 gp_Circ2d Geom2dGcc_Circ2dTanCen::ThisSolution ( const Standard_Integer Index ) const

Returns a circle, representing the solution of index Index computed by this algorithm. Warning This indexing simply provides a means of consulting the solutions. The index values are not associated with these solutions outside the context of the algorithm object. Exceptions Standard_OutOfRange if Index is less than zero or greater than the number of solutions computed by this algorithm. StdFail_NotDone if the construction fails.

 void Geom2dGcc_Circ2dTanCen::WhichQualifier ( const Standard_Integer Index, GccEnt_Position & Qualif1 ) const

Returns the qualifier Qualif1 of the tangency argument for the solution of index Index computed by this algorithm. The returned qualifier is:

• that specified at the start of construction when the solutions are defined as enclosed, enclosing or outside with respect to the argument, or
• that computed during construction (i.e. enclosed, enclosing or outside) when the solutions are defined as unqualified with respect to the argument. Exceptions Standard_OutOfRange if Index is less than zero or greater than the number of solutions computed by this algorithm. StdFail_NotDone if the construction fails.

The documentation for this class was generated from the following file: