Open CASCADE Technology
6.5.4
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#include <Standard.hxx>
#include <Standard_DefineHandle.hxx>
#include <Handle_Geom2d_OffsetCurve.hxx>
#include <Handle_Geom2d_Curve.hxx>
#include <Standard_Real.hxx>
#include <Geom2d_Curve.hxx>
#include <GeomAbs_Shape.hxx>
#include <Standard_Integer.hxx>
#include <Standard_Boolean.hxx>
#include <Handle_Geom2d_Geometry.hxx>
Data Structures | |
class | Geom2d_OffsetCurve |
This class implements the basis services for the creation, edition, modification and evaluation of planar offset curve. The offset curve is obtained by offsetting by distance along the normal to a basis curve defined in 2D space. The offset curve in this package can be a self intersecting curve even if the basis curve does not self-intersect. The self intersecting portions are not deleted at the construction time. An offset curve is a curve at constant distance (Offset) from a basis curve and the offset curve takes its parametrization from the basis curve. The Offset curve is in the direction of the normal to the basis curve N. The distance offset may be positive or negative to indicate the preferred side of the curve : . distance offset >0 => the curve is in the direction of N . distance offset >0 => the curve is in the direction of - N On the Offset curve : Value(u) = BasisCurve.Value(U) + (Offset * (T ^ Z)) / ||T ^ Z|| where T is the tangent vector to the basis curve and Z the direction of the normal vector to the plane of the curve, N = T ^ Z defines the offset direction and should not have null length. Warnings : In this package we suppose that the continuity of the offset curve is one degree less than the continuity of the basis curve and we don't check that at any point ||T^Z|| != 0.0 So to evaluate the curve it is better to check that the offset curve is well defined at any point because an exception could be raised. The check is not done in this package at the creation of the offset curve because the control needs the use of an algorithm which cannot be implemented in this package. The OffsetCurve is closed if the first point and the last point are the same (The distance between these two points is lower or equal to the Resolution sea package gp) . The OffsetCurve can be closed even if the basis curve is not closed. More... |