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

  Program:   Visualization Toolkit
  Module:    vtkScalarsToColors.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

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

=========================================================================*/
// .NAME vtkScalarsToColors - Superclass for mapping scalar values into 
//  colors
// .SECTION Description
// vtkScalarsToColors is a general purpose superclass for objects that
// convert scalars to colors. This include vtkLookupTable classes and
// color transfer functions.
//
// The scalars to color mapping can be augmented with an additional
// uniform alpha blend. This is used, for example, to blend a vtkActor's
// opacity with the lookup table values.
//
// .SECTION See Also
// vtkLookupTable vtkColorTransferFunction

#ifndef __vtkScalarsToColors_h
#define __vtkScalarsToColors_h

#include "vtkObject.h"

class vtkDataArray;
class vtkUnsignedCharArray;

class VTK_COMMON_EXPORT vtkScalarsToColors : public vtkObject
{
public:
  vtkTypeMacro(vtkScalarsToColors,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent);
  
  // Description:
  // Return true if all of the values defining the mapping have an opacity
  // equal to 1. Default implementation return true.
  virtual int IsOpaque();
  
  // Description:
  // Perform any processing required (if any) before processing 
  // scalars.
  virtual void Build() {};
  
  // Description:
  // Sets/Gets the range of scalars which will be mapped.
  virtual double *GetRange() = 0;
  virtual void SetRange(double min, double max) = 0;
  void SetRange(double rng[2]) 
    {this->SetRange(rng[0],rng[1]);}
  
  // Description:
  // Map one value through the lookup table and return a color defined
  // as a RGBA unsigned char tuple (4 bytes).
  virtual unsigned char *MapValue(double v) = 0;

  // Description:
  // Map one value through the lookup table and return the color as
  // an RGB array of doubles between 0 and 1.
  virtual void GetColor(double v, double rgb[3]) = 0;

  // Description:
  // Map one value through the lookup table and return the color as
  // an RGB array of doubles between 0 and 1.
  double *GetColor(double v)
    {this->GetColor(v,this->RGB); return this->RGB;}
 
  // Description:
  // Map one value through the lookup table and return the alpha value
  // (the opacity) as a double between 0 and 1.
  virtual double GetOpacity(double vtkNotUsed(v)) 
    {return 1.0;}

  // Description:
  // Map one value through the lookup table and return the luminance
  // 0.3*red + 0.59*green + 0.11*blue as a double between 0 and 1.
  // Returns the luminance value for the specified scalar value.
  double GetLuminance(double x) 
    {double rgb[3]; this->GetColor(x,rgb);
    return static_cast<double>(rgb[0]*0.30 + rgb[1]*0.59 + rgb[2]*0.11);}

  // Description:
  // Specify an additional opacity (alpha) value to blend with. Values
  // != 1 modify the resulting color consistent with the requested
  // form of the output. This is typically used by an actor in order to
  // blend its opacity.
  virtual void SetAlpha(double alpha);
  vtkGetMacro(Alpha,double);

  // Description:
  // An internal method maps a data array into a 4-component, unsigned char
  // RGBA array. The color mode determines the behavior of mapping. If 
  // VTK_COLOR_MODE_DEFAULT is set, then unsigned char data arrays are
  // treated as colors (and converted to RGBA if necessary); otherwise, 
  // the data is mapped through this instance of ScalarsToColors. The offset
  // is used for data arrays with more than one component; it indicates 
  // which component to use to do the blending.
  // When the component argument is -1, then the this object uses its
  // own selected technique to change a vector into a scalar to map.
  virtual vtkUnsignedCharArray *MapScalars(vtkDataArray *scalars, int colorMode,
                                   int component);

  // Description:
  // Change mode that maps vectors by magnitude vs. component.
  vtkSetMacro(VectorMode, int);
  vtkGetMacro(VectorMode, int);
  void SetVectorModeToMagnitude();
  void SetVectorModeToComponent();

//BTX
  enum VectorModes {
    MAGNITUDE=0,
    COMPONENT=1
  };
//ETX


  // Description:
  // If the mapper does not select which component of a vector
  // to map to colors, you can specify it here.
  vtkSetMacro(VectorComponent, int);
  vtkGetMacro(VectorComponent, int);
  
  // Description:
  // Map a set of scalars through the lookup table in a single operation. 
  // The output format can be set to VTK_RGBA (4 components), 
  // VTK_RGB (3 components), VTK_LUMINANCE (1 component, greyscale),
  // or VTK_LUMINANCE_ALPHA (2 components)
  // If not supplied, the output format defaults to RGBA.
  void MapScalarsThroughTable(vtkDataArray *scalars, 
                              unsigned char *output,
                              int outputFormat);
  void MapScalarsThroughTable(vtkDataArray *scalars, 
                              unsigned char *output) 
    {this->MapScalarsThroughTable(scalars,output,VTK_RGBA);}


  // Description:
  // An internal method typically not used in applications.
  virtual void MapScalarsThroughTable2(void *input, unsigned char *output,
                                       int inputDataType, int numberOfValues,
                                       int inputIncrement, 
                                       int outputFormat) = 0;

  // Description:
  // An internal method used to convert a color array to RGBA. The
  // method instantiates a vtkUnsignedCharArray and returns it. The user is
  // responsible for managing the memory.
  virtual vtkUnsignedCharArray *ConvertUnsignedCharToRGBA(
    vtkUnsignedCharArray *colors, int numComp, int numTuples);

  // Description:
  // This should return 1 is the subclass is using log scale for mapping scalars
  // to colors. Default implementation returns 0.
  virtual int UsingLogScale()
    { return 0; }

  // Description:
  // Get the number of available colors for mapping to.
  virtual vtkIdType GetNumberOfAvailableColors() = 0;

protected:
  vtkScalarsToColors();
  ~vtkScalarsToColors() {}

  double Alpha;

  // How to map arrays with multiple components.
  int VectorMode;
  // Internal flag used to togle between vector and component mode.
  // We need this flag because the mapper can override our mode, and
  // I do not want to change the interface to the map scalars methods.
  int UseMagnitude;
  int VectorComponent;

private:
  double RGB[3];

  vtkScalarsToColors(const vtkScalarsToColors&);  // Not implemented.
  void operator=(const vtkScalarsToColors&);  // Not implemented.
};

#endif