///////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2002-2016, Open Design Alliance (the "Alliance").
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// All rights reserved.
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//
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// This software and its documentation and related materials are owned by
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// the Alliance. The software may only be incorporated into application
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// programs owned by members of the Alliance, subject to a signed
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// Membership Agreement and Supplemental Software License Agreement with the
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// Alliance. The structure and organization of this software are the valuable
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// trade secrets of the Alliance and its suppliers. The software is also
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// protected by copyright law and international treaty provisions. Application
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// programs incorporating this software must include the following statement
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// with their copyright notices:
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//
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// This application incorporates Teigha(R) software pursuant to a license
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// agreement with Open Design Alliance.
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// Teigha(R) Copyright (C) 2002-2016 by Open Design Alliance.
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// All rights reserved.
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//
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// By use of this software, its documentation or related materials, you
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// acknowledge and accept the above terms.
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///////////////////////////////////////////////////////////////////////////////
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#ifndef __OD_GE_ELLIP_ARC__
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#define __OD_GE_ELLIP_ARC__
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#include "OdRound.h"
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/** \details
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Elliptical arc helper functions.
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<group TD_Namespaces>
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*/
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namespace OdGeEllipArc
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{
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/** \details
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calibrates value, so that it is "near" input (not farther than OdaPi)
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(value and input should not be farther than OdaPi/2 modulo Oda2Pi,
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for the function to work correcly)
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*/
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inline double calibrateAngle(double val, double input)
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{
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if (input > val)
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{
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if ( (input - val) < OdaPI )
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return val;
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else
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return val + OdRound((input - val)/Oda2PI)*Oda2PI;
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}
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else
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{
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if ( (val - input) < OdaPI )
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return val;
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else
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return val - OdRound((val - input)/Oda2PI)*Oda2PI;
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}
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}
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/** \details
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Converts an elliptical parameter to an angle.
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\param param [in] Elliptical parameter.
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\param radiusRatio [in] The minorRadius:majorRadius ratio of the ellipse.
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\remarks
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The angle of a point on an ellipse corresponding to a parameter
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of the ellipse is determined by projecting a vector perpendicular to the
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major axis from the parameter point on the parameter circle. The angle from the major axis to the intersection
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of the vector with the ellipse is the desired angle.
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Library: TD_Ge
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*/
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inline double angleFromParam (
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double param,
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double radiusRatio)
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{
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if(OdZero(param))
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return 0;
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if(OdZero(param - Oda2PI))
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return Oda2PI;
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return calibrateAngle(OD_ATAN2(radiusRatio*sin(param), cos(param)), param);
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}
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/** \details
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Converts an elliptical angle to a parameter.
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\param angle [in] Elliptical angle.
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\param radiusRatio [in] The minorRadius:majorRadius ratio of the ellipse.
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\remarks
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The parameter of a point on an ellipse corresponding to the
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angle of the point is determined by projecting a vector perpendicular to the
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major axis from the point on the ellipse to the parameter circle.
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The angle from the major axis to the intersection
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of the vector with the circle is the desired parameter.
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Library: TD_Ge
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*/
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inline double paramFromAngle (
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double angle,
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double radiusRatio)
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{
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if(OdZero(angle))
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return 0;
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if(OdZero(angle - Oda2PI))
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return Oda2PI;
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return calibrateAngle(OD_ATAN2(sin(angle), radiusRatio*cos(angle)), angle);
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}
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}
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#endif // __OD_GE_ELLIP_ARC__
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