/*=========================================================================

  Library:   ctk

  Copyright (c) Kitware Inc. 
  All rights reserved.
  Distributed under a BSD License. See LICENSE.txt file.

  This software is distributed "AS IS" WITHOUT ANY WARRANTY; without even
  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the above copyright notice for more information.

=========================================================================*/

#ifndef __ctkTransferFunction_h
#define __ctkTransferFunction_h

/// Qt includes
#include <QObject>
#include <QtGlobal>
#include <QSharedPointer>
#include <QVariant>

/// CTK includes
#include "CTKCoreExport.h"

//-----------------------------------------------------------------------------
struct CTK_CORE_EXPORT ctkPoint
{
  ctkPoint(){}
  ctkPoint(qreal x, const QVariant& v)
    :X(x),Value(v)
  {  
  }
  qreal X;
  // QColor or qreal.
  QVariant Value;
};

//-----------------------------------------------------------------------------
/// assumes the mapping is linear by default, if not, then subclasses must be 
/// used
struct CTK_CORE_EXPORT ctkControlPoint
{
  virtual ~ctkControlPoint();
  inline const qreal& x()const {return this->P.X;}
  inline const QVariant& value()const {return this->P.Value;}
  ctkPoint P;
};

//-----------------------------------------------------------------------------
struct CTK_CORE_EXPORT ctkBezierControlPoint : public ctkControlPoint
{
  virtual ~ctkBezierControlPoint();
  ctkPoint P1;
  ctkPoint P2;
};

//-----------------------------------------------------------------------------
struct CTK_CORE_EXPORT ctkNonLinearControlPoint : public ctkControlPoint
{
  virtual ~ctkNonLinearControlPoint();
  QList<ctkPoint> SubPoints;
};

//-----------------------------------------------------------------------------
class CTK_CORE_EXPORT ctkTransferFunction: public QObject
{
  Q_OBJECT
public:
  ctkTransferFunction(QObject* parent = 0);
  virtual ~ctkTransferFunction();
  
  virtual ctkControlPoint* controlPoint(int index)const = 0;
  inline QVariant value(int index)const;
  virtual QVariant value(qreal pos)const = 0;
  
  virtual int count()const = 0;
  inline void range(qreal rangeValues[2])const;
  virtual void range(qreal& minRange, qreal& maxRange)const=0;
  virtual QVariant minValue()const = 0;
  virtual QVariant maxValue()const = 0;
  ///
  virtual int insertControlPoint(const ctkControlPoint& cp) = 0;

  /// 
  /// be careful with it, as changing the value might require
  /// more changes to ctkControlPoint.
  virtual void setControlPointPos(int index, qreal pos)=0;
  /// 
  /// be careful with it, as changing the value might require
  /// more changes to ctkControlPoint.
  virtual void setControlPointValue(int index, const QVariant& value)=0;
  virtual ctkBezierControlPoint* toto();
signals:
  void changed();
};

//-----------------------------------------------------------------------------
QVariant ctkTransferFunction::value(int index)const
{
  QSharedPointer<ctkControlPoint> cp(this->controlPoint(index));
  return cp->P.Value;
}

//-----------------------------------------------------------------------------
void ctkTransferFunction::range(qreal rangeValues[2])const
{
  this->range(rangeValues[0], rangeValues[1]);
}

#endif