80 lines
2.9 KiB
C++
80 lines
2.9 KiB
C++
#pragma once
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#ifndef TCUBICBEZIER_INCLUDED
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#define TCUBICBEZIER_INCLUDED
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//-----------------------------------------------------------------------------
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#include "tmathutil.h"
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//#include "tcommon.h"
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#include "tgeometry.h"
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//#include <algorithm>
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using TConsts::epsilon;
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#undef DVAPI
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#undef DVVAR
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#ifdef TPARAM_EXPORTS
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#define DVAPI DV_EXPORT_API
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#define DVVAR DV_EXPORT_VAR
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#else
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#define DVAPI DV_IMPORT_API
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#define DVVAR DV_IMPORT_VAR
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#endif
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//-----------------------------------------------------------------------------
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/*!
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Find the value of the parameter u0 of the cubic Bezier curve C(u)
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for a specified value x, with C(u0) = (x,y).
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\par x the x-component of a point on the Bezier curve
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\par a first control point of the Bezier curve
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\par aSpeed the tangent vector in a (that is the first control point minus the
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second)
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\par b the third control point
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\par bSpeed the tangent vector in b (that is the third control point minus the
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fourth)
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\ret the parameter value u0 of the Bezier curve C(u) for x, that is C(u0) =
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(x,y)
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*/
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DVAPI double invCubicBezierX(double x, const TPointD &a, const TPointD &aSpeed,
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const TPointD &bSpeed, const TPointD &b);
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//-----------------------------------------------------------------------------
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/*!
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for C(u) a cubic Bezier curve, C(u0) = (x,y), find y from x.
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\par x the x-component of a point on the Bezier curve
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\par a first control point of the Bezier curve
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\par aSpeed the tangent vector in a (that is the first control point minus the
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second)
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\par b the third control point
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\par bSpeed the tangent vector in b (that is the third control point minus the
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fourth)
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\ret the y-component of a point P(x,y) on the Bezier curve, with C(u0) = P
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*/
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DVAPI double getCubicBezierY(double x, const TPointD &a, const TPointD &aSpeed,
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const TPointD &bSpeed, const TPointD &b);
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//-----------------------------------------------------------------------------
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/*!
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for C(u)=(x,y) a cubic Bezier curve, find minimum and maximum y-values of C(u)
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\par a first control point of the Bezier curve
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\par aSpeed the tangent vector in a (that is the first control point minus the
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second)
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\par b the third control point
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\par bSpeed the tangent vector in b (that is the third control point minus the
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fourth)
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\ret a pair of points which are the minimum and maximum of the cubic Bezier
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*/
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DVAPI std::pair<TPointD, TPointD> getMinMaxCubicBezierY(const TPointD &a,
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const TPointD &aSpeed,
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const TPointD &bSpeed,
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const TPointD &b);
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//-----------------------------------------------------------------------------
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#endif // TCUBICBEZIER_INCLUDED
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//-----------------------------------------------------------------------------
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