OCCT

// Created on: 1992-08-19
// Created by: Modelistation
// Copyright (c) 1992-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#ifndef _Hatch_Hatcher_HeaderFile
#define _Hatch_Hatcher_HeaderFile

#include <Standard.hxx>
#include <Standard_DefineAlloc.hxx>

#include <Hatch_Line.hxx>
#include <NCollection_Sequence.hxx>
#include <Hatch_LineForm.hxx>
#include <Standard_Integer.hxx>
class gp_Lin2d;
class gp_Dir2d;
class gp_Pnt2d;

//! The Hatcher is an algorithm to compute cross
//! hatchings in a 2d plane. It is mainly dedicated to
//! display purpose.
//!
//! Computing cross hatchings is a 3 steps process :
//!
//! 1. The users stores in the Hatcher a set of 2d
//! lines to be trimmed. Methods in the "Lines"
//! category.
//!
//! 2. The user trims the lines with a boundary. The
//! inside of a boundary is on the left side. Methods
//! in the "Trimming" category.
//!
//! 3. The user reads back the trimmed lines. Methods
//! in the "Results" category.
//!
//! The result is a set of parameter intervals on the
//! line. The first parameter of an Interval may be
//! RealFirst() and the last may be RealLast().
//!
//! A line can be a line parallel to the axis (X or Y
//! line or a 2D line.
//!
//! The Hatcher has two modes :
//!
//! * The "Oriented" mode, where the orientation of
//! the trimming curves is considered. The hatch are
//! kept on the left of the trimming curve. In this
//! mode infinite hatch can be computed.
//!
//! * The "UnOriented" mode, where the hatch are
//! always finite.
class Hatch_Hatcher
{
public:
  DEFINE_STANDARD_ALLOC

  //! Returns an empty hatcher. <Tol> is the tolerance
  //! for intersections.
  Standard_EXPORT Hatch_Hatcher(const double Tol, const bool Oriented = true);

  void Tolerance(const double Tol);

  double Tolerance() const;

  //! Add a line <L> to be trimmed. <T> the type is
  //! only kept from information. It is not used in the
  //! computation.
  Standard_EXPORT void AddLine(const gp_Lin2d& L, const Hatch_LineForm T = Hatch_ANYLINE);

  //! Add an infinite line on direction <D> at distance
  //! <Dist> from the origin to be trimmed. <Dist> may
  //! be negative.
  //!
  //! If O is the origin of the 2D plane, and V the
  //! vector perpendicular to D (in the direct direction).
  //!
  //! A point P is on the line if :
  //! OP dot V = Dist
  //! The parameter of P on the line is
  //! OP dot D
  Standard_EXPORT void AddLine(const gp_Dir2d& D, const double Dist);

  //! Add an infinite line parallel to the Y-axis at
  //! abciss <X>.
  Standard_EXPORT void AddXLine(const double X);

  //! Add an infinite line parallel to the X-axis at
  //! ordinate <Y>.
  Standard_EXPORT void AddYLine(const double Y);

  //! Trims the lines at intersections with <L>.
  Standard_EXPORT void Trim(const gp_Lin2d& L, const int Index = 0);

  //! Trims the lines at intersections with <L> in the
  //! parameter range <Start>, <End>
  Standard_EXPORT void Trim(const gp_Lin2d& L,
                            const double    Start,
                            const double    End,
                            const int       Index = 0);

  //! Trims the line at intersection with the oriented
  //! segment P1,P2.
  Standard_EXPORT void Trim(const gp_Pnt2d& P1, const gp_Pnt2d& P2, const int Index = 0);

  //! Returns the total number of intervals on all the
  //! lines.
  Standard_EXPORT int NbIntervals() const;

  //! Returns the number of lines.
  Standard_EXPORT int NbLines() const;

  //! Returns the line of index <I>.
  Standard_EXPORT const gp_Lin2d& Line(const int I) const;

  //! Returns the type of the line of index <I>.
  Standard_EXPORT Hatch_LineForm LineForm(const int I) const;

  //! Returns True if the line of index <I> has a
  //! constant X value.
  bool IsXLine(const int I) const;

  //! Returns True if the line of index <I> has a
  //! constant Y value.
  bool IsYLine(const int I) const;

  //! Returns the X or Y coordinate of the line of index
  //! <I> if it is a X or a Y line.
  Standard_EXPORT double Coordinate(const int I) const;

  //! Returns the number of intervals on line of index <I>.
  Standard_EXPORT int NbIntervals(const int I) const;

  //! Returns the first parameter of interval <J> on
  //! line <I>.
  Standard_EXPORT double Start(const int I, const int J) const;

  //! Returns the first Index and Par2 of interval <J> on
  //! line <I>.
  Standard_EXPORT void StartIndex(const int I, const int J, int& Index, double& Par2) const;

  //! Returns the last parameter of interval <J> on
  //! line <I>.
  Standard_EXPORT double End(const int I, const int J) const;

  //! Returns the last Index and Par2 of interval <J> on
  //! line <I>.
  Standard_EXPORT void EndIndex(const int I, const int J, int& Index, double& Par2) const;

private:
  double                           myToler;
  NCollection_Sequence<Hatch_Line> myLines;
  bool                             myOrient;
};

#include <Hatch_Hatcher.lxx>

#endif // _Hatch_Hatcher_HeaderFile