GeEllipArc.h

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// Copyright (C) 2002-2017, Open Design Alliance (the "Alliance"). 
// All rights reserved. 
// 
// This software and its documentation and related materials are owned by 
// the Alliance. The software may only be incorporated into application 
// programs owned by members of the Alliance, subject to a signed 
// Membership Agreement and Supplemental Software License Agreement with the
// Alliance. The structure and organization of this software are the valuable  
// trade secrets of the Alliance and its suppliers. The software is also 
// protected by copyright law and international treaty provisions. Application  
// programs incorporating this software must include the following statement 
// with their copyright notices:
//   
//   This application incorporates Teigha(R) software pursuant to a license 
//   agreement with Open Design Alliance.
//   Teigha(R) Copyright (C) 2002-2017 by Open Design Alliance. 
//   All rights reserved.
//
// By use of this software, its documentation or related materials, you 
// acknowledge and accept the above terms.
 
 
#ifndef __OD_GE_ELLIP_ARC__
#define __OD_GE_ELLIP_ARC__
 
#include "OdRound.h"
 
namespace OdGeEllipArc 
{  
  inline double calibrateAngle(double val, double input)
  {
    if (input > val)
    {
      if ( (input - val) < OdaPI )
        return val;
      else 
        return val + OdRound((input - val)/Oda2PI)*Oda2PI;
    }
    else
    {
      if ( (val - input) < OdaPI )
        return val;
      else 
        return val - OdRound((val - input)/Oda2PI)*Oda2PI;
    }
  }
 
  inline double angleFromParam (
      double param, 
      double radiusRatio)
  {
    if(OdZero(param)) 
      return 0;
    if(OdZero(param - Oda2PI)) 
      return Oda2PI;
 
    return calibrateAngle(OD_ATAN2(radiusRatio*sin(param), cos(param)), param);
  }
  
  inline double paramFromAngle (
      double angle, 
      double radiusRatio)
  {
    if(OdZero(angle)) 
      return 0;
    if(OdZero(angle - Oda2PI)) 
      return Oda2PI;
  
    return calibrateAngle(OD_ATAN2(sin(angle), radiusRatio*cos(angle)), angle);
  }  
}
 
#endif // __OD_GE_ELLIP_ARC__