/* $NoKeywords: $ */
/*
//
// Copyright (c) 1993-2011 Robert McNeel & Associates. All rights reserved.
// OpenNURBS, Rhinoceros, and Rhino3D are registered trademarks of Robert
// McNeel & Associates.
//
// THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY.
// ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE AND OF
// MERCHANTABILITY ARE HEREBY DISCLAIMED.
//				
// For complete openNURBS copyright information see <http://www.opennurbs.org>.
//
////////////////////////////////////////////////////////////////
*/

#if !defined(ON_POLYLINE_INC_)
#define ON_POLYLINE_INC_

class ON_CLASS ON_Polyline : public ON_3dPointArray
{
public:
  ON_Polyline();
  ON_Polyline(const ON_3dPointArray&);
  ON_Polyline& operator=(const ON_3dPointArray&);
  ~ON_Polyline();

  // Description:
  //   Create a regular polygon inscribed in a circle.
  //   The vertices of the polygon will be on the circle.
  // Parameters:
  //   circle - [in]
  //   side_count - [in] (>=3) number of sides
  // Returns:
  //   true if successful.  false if circle is invalid or
  //   side_count < 3.
  bool CreateInscribedPolygon(
    const ON_Circle& circle,
    int side_count
    );

  // Description:
  //   Create a regular polygon circumscribe about a circle.
  //   The midpoints of the polygon's edges will be tanget to the
  //   circle.
  // Parameters:
  //   circle - [in]
  //   side_count - [in] (>=3) number of sides
  // Returns:
  //   true if successful.  false if circle is invalid or
  //   side_count < 3.
  bool CreateCircumscribedPolygon(
    const ON_Circle& circle,
    int side_count
    );

  // Description:
  //   Create a regular star polygon.
  //   The star begins at circle.PointAt(0) and the vertices alternate
  //   between being on circle and begin on a concentric circle of
  //   other_radius.
  // Parameters:
  //   circle - [in] circle star polygon starts on
  //   other_radius - [in] radius of other circle 
  //   corner_count - [in] (>=3) number of corners on circle
  //      There will be 2*corner_count sides and 2*corner_count
  //      vertices.
  // Returns:
  //   true if successful.  false if circle is invalid, other_radius < 0.0,
  //   or side_count < 3.
  bool CreateStarPolygon(
    const ON_Circle& circle,
    double other_radius,
    int side_count
    );

  // Description:
  //   Checks that polyline has at least two points
  //   and that sequential points are distinct.  If the
  //   polyline has 2 or 3 points, then the start and end
  //   point must be distinct.
  // Parameters:
  //   tolerance - [in] tolerance used to check for duplicate points.
  // Returns:
  //   true if polyline is valid.
  // See Also:
  //   ON_Polyline::Clean.
  bool IsValid(
    double tolerance = 0.0 
    ) const;

  // Description:
  //   Removes duplicate points that result in zero length segments.
  // Parameters:
  //   tolerance - [in] tolerance used to check for duplicate points.
  // Returns:
  //   Number of points removed.
  // Remarks:
  //   If the distance between points polyline[i] and polyline[i+1]
  //   is <= tolerance, then the point with index (i+1) is removed.
  int Clean( 
    double tolerance = 0.0 
    );

  // Returns:
  //   Number of points in the polyline.
  int PointCount() const;

  // Returns:
  //   Number of segments in the polyline.
  int SegmentCount() const;

  // Description:
  //   Test a polyline to see if it is closed.
  // Returns:
  //   true if polyline has 4 or more points, the distance between the
  //   start and end points is <= tolerance, and there is a
  //   point in the polyline whose distance from the start and end
  //   points is > tolerance.
  bool IsClosed(
    double tolerance = 0.0 
    ) const;


  // Returns:
  //   Length of the polyline.
  double Length() const;

  // Parameters:
  //   segment_index - [in] zero based segment index
  // Returns:
  //   vector = point[segment_index+1] - point[segment_index].
  ON_3dVector SegmentDirection (
    int segment_index
    ) const;

  // Parameters:
  //   segment_index - [in] zero based segment index
  // Returns:
  //   Unit vector in the direction of the segment
  ON_3dVector SegmentTangent (
    int segment_index
    ) const;

  // Description:
  //   Evaluate the polyline location at a parameter.
  // Parameters:
  //   t - [in] the i-th segment goes from i <= t < i+1
  ON_3dPoint PointAt( double t ) const;

  // Description:
  //   Evaluate the polyline first derivative at a parameter.
  // Parameters:
  //   t - [in] the i-th segment goes from i <= t < i+1
  ON_3dVector DerivativeAt( double t ) const;

  // Description:
  //   Evaluate the polyline unit tangent at a parameter.
  // Parameters:
  //   t - [in] the i-th segment goes from i <= t < i+1
  ON_3dVector TangentAt( double t ) const;

  // Description:
  //   Find a point on the polyline that is closest 
  //   to test_point.
  // Parameters:
  //   test_point - [in]
  //   t - [out] parameter for a point on the polyline that
  //             is closest to test_point.  If mulitple solutions
  //             exist, then the smallest solution is returned.
  // Returns:
  //   true if successful.
  bool ClosestPointTo( 
        const ON_3dPoint& test_point, 
        double* t
        ) const;

  // Description:
  //   Find a point on the polyline that is closest 
  //   to test_point.
  // Parameters:
  //   test_point - [in]
  //   t - [out] parameter for a point on the polyline that
  //             is closest to test_point.  If mulitple solutions
  //             exist, then the smallest solution is returned.
  //   segment_index0 - [in] index of segment where search begins
  //   segment_index1 - [in] index of segment where search ends
  //                         This segment is NOT searched.
  // Example:
  //   Search segments 3,4, and 5 for the point closest to (0,0,0).
  //   double t;
  //   ClosestPointTo( ON_3dPoint(0,0,0), &t, 3, 6 );
  // Returns:
  //   true if successful.
  bool ClosestPointTo( 
        const ON_3dPoint& test_point, 
        double* t, 
        int segment_index0, // index of segment where search begins
        int segment_index1 // index + 1 of segment where search stops
        ) const;

  // Description:
  //   Find a point on the polyline that is closest 
  //   to test_point.
  // Parameters:
  //   test_point - [in]
  // Returns:
  //   point on polyline.
  ON_3dPoint ClosestPointTo( 
       const ON_3dPoint& test_point
    ) const;

};

#endif
