Open CASCADE Technology  6.5.4
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Public Member Functions
GCPnts_QuasiUniformDeflection Class Reference

This class computes a distribution of points on a
curve. The points may respect the deflection. The algorithm
is not based on the classical prediction (with second
derivative of curve), but either on the evaluation of
the distance between the mid point and the point of
mid parameter of the two points, or the distance
between the mid point and the point at parameter 0.5
on the cubic interpolation of the two points and their
tangents.
Note: this algorithm is faster than a
GCPnts_UniformDeflection algorithm, and is
able to work with non-"C2" continuous curves.
However, it generates more points in the distribution.

#include <GCPnts_QuasiUniformDeflection.hxx>

Public Member Functions

DEFINE_STANDARD_ALLOC GCPnts_QuasiUniformDeflection ()
 Constructs an empty algorithm. To define the problem
to be solved, use the function Initialize.

 GCPnts_QuasiUniformDeflection (Adaptor3d_Curve &C, const Standard_Real Deflection, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Computes a QuasiUniform Deflection distribution
of points on the Curve .

 GCPnts_QuasiUniformDeflection (Adaptor2d_Curve2d &C, const Standard_Real Deflection, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Computes a QuasiUniform Deflection distribution
of points on the Curve .

 GCPnts_QuasiUniformDeflection (Adaptor3d_Curve &C, const Standard_Real Deflection, const Standard_Real U1, const Standard_Real U2, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Computes a QuasiUniform Deflection distribution
of points on a part of the Curve .

 GCPnts_QuasiUniformDeflection (Adaptor2d_Curve2d &C, const Standard_Real Deflection, const Standard_Real U1, const Standard_Real U2, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Computes a QuasiUniform Deflection distribution
of points on a part of the Curve .
This and the above algorithms compute a distribution of points:

void Initialize (Adaptor3d_Curve &C, const Standard_Real Deflection, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Initialize the algoritms with , <Deflection>

void Initialize (Adaptor2d_Curve2d &C, const Standard_Real Deflection, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Initialize the algoritms with , <Deflection>

void Initialize (Adaptor3d_Curve &C, const Standard_Real Deflection, const Standard_Real U1, const Standard_Real U2, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Initialize the algoritms with , <Deflection>,
<U1>,<U2>

void Initialize (Adaptor2d_Curve2d &C, const Standard_Real Deflection, const Standard_Real U1, const Standard_Real U2, const GeomAbs_Shape Continuity=GeomAbs_C1)
 Initialize the algoritms with , <Deflection>,
-- <U1>,<U2>
This and the above algorithms initialize (or reinitialize)
this algorithm and compute a distribution of points:

Standard_Boolean IsDone () const
 Returns true if the computation was successful.
IsDone is a protection against:

Standard_Integer NbPoints () const
 Returns the number of points of the distribution
computed by this algorithm.
Exceptions
StdFail_NotDone if this algorithm has not been
initialized, or if the computation was not successful.

Standard_Real Parameter (const Standard_Integer Index) const
 Returns the parameter of the point of index Index in
the distribution computed by this algorithm.
Warning
Index must be greater than or equal to 1, and less
than or equal to the number of points of the
distribution. However, pay particular attention as this
condition is not checked by this function.
Exceptions
StdFail_NotDone if this algorithm has not been
initialized, or if the computation was not successful.

gp_Pnt Value (const Standard_Integer Index) const
 Returns the point of index Index in the distribution
computed by this algorithm.
Warning
Index must be greater than or equal to 1, and less
than or equal to the number of points of the
distribution. However, pay particular attention as this
condition is not checked by this function.
Exceptions
StdFail_NotDone if this algorithm has not been
initialized, or if the computation was not successful.

Standard_Real Deflection () const
 Returns the deflection between the curve and the
polygon resulting from the points of the distribution
computed by this algorithm.
This is the value given to the algorithm at the time
of construction (or initialization).
Exceptions
StdFail_NotDone if this algorithm has not been
initialized, or if the computation was not successful.


Constructor & Destructor Documentation

  • on the curve C, or
  • on the part of curve C limited by the two
    parameter values U1 and U2,
    where the deflection resulting from the distributed
    points is not greater than Deflection.
    The first point of the distribution is either the origin of
    curve C or the point of parameter U1. The last point
    of the distribution is either the end point of curve C or
    the point of parameter U2.
    Intermediate points of the distribution are built such
    that the deflection is not greater than Deflection.
    Using the following evaluation of the deflection:
    if Pi and Pj are two consecutive points of the
    distribution, respectively of parameter ui and uj on
    the curve, the deflection is the distance between:
  • the mid-point of Pi and Pj (the center of the
    chord joining these two points)
  • and the point of mid-parameter of these two
    points (the point of parameter [(ui+uj) / 2 ] on curve C).
    Continuity, defaulted to GeomAbs_C1, gives the
    degree of continuity of the curve C. (Note that C is an
    Adaptor3d_Curve or an Adaptor2d_Curve2d
    object, and does not know the degree of continuity of
    the underlying curve).
    Use the function IsDone to verify that the
    computation was successful, the function NbPoints
    to obtain the number of points of the computed
    distribution, and the function Parameter to read the
    parameter of each point.
    Warning
  • The roles of U1 and U2 are inverted if U1 > U2.
  • Derivative functions on the curve are called
    according to Continuity. An error may occur if
    Continuity is greater than the real degree of
    continuity of the curve.
    Warning
    C is an adapted curve, i.e. an object which is an
    interface between:
  • the services provided by either a 2D curve from
    the package Geom2d (in the case of an
    Adaptor2d_Curve2d curve) or a 3D curve from
    the package Geom (in the case of an
    Adaptor3d_Curve curve),
  • and those required on the curve by the
    computation algorithm.

Member Function Documentation

  • on the curve C, or
  • on the part of curve C limited by the two
    parameter values U1 and U2,
    where the deflection resulting from the distributed
    points is not greater than Deflection.
    The first point of the distribution is either the origin
    of curve C or the point of parameter U1. The last
    point of the distribution is either the end point of
    curve C or the point of parameter U2.
    Intermediate points of the distribution are built in
    such a way that the deflection is not greater than
    Deflection. Using the following evaluation of the deflection:
    if Pi and Pj are two consecutive points of the
    distribution, respectively of parameter ui and uj
    on the curve, the deflection is the distance between:
  • the mid-point of Pi and Pj (the center of the
    chord joining these two points)
  • and the point of mid-parameter of these two
    points (the point of parameter [(ui+uj) / 2 ] on curve C).
    Continuity, defaulted to GeomAbs_C1, gives the
    degree of continuity of the curve C. (Note that C is
    an Adaptor3d_Curve or an
    Adaptor2d_Curve2d object, and does not know
    the degree of continuity of the underlying curve).
    Use the function IsDone to verify that the
    computation was successful, the function NbPoints
    to obtain the number of points of the computed
    distribution, and the function Parameter to read
    the parameter of each point.
    Warning
  • The roles of U1 and U2 are inverted if U1 > U2.
  • Derivative functions on the curve are called
    according to Continuity. An error may occur if
    Continuity is greater than the real degree of
    continuity of the curve.
    Warning
    C is an adapted curve, i.e. an object which is an
    interface between:
  • the services provided by either a 2D curve from
    the package Geom2d (in the case of an
    Adaptor2d_Curve2d curve) or a 3D curve from
    the package Geom (in the case of an Adaptor3d_Curve curve),
    and those required on the curve by the computation algorithm.
  • non-convergence of the algorithm
  • querying the results before computation.

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