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

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: LabelImageWrapper.h,v $
  Language:  C++
  Date:      $Date: 2006/02/01 20:21:23 $
  Version:   $Revision: 1.5 $
  Copyright (c) 2003 Insight Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/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 notices for more information.
=========================================================================*/
#ifndef __LabelImageWrapper_h_
#define __LabelImageWrapper_h_

#include "itkRGBAPixel.h"
#include "ImageWrapper.h"
#include "UnaryFunctorCache.h"



// Forward references
namespace itk {
  template<class TInput, class TOutput, class TFunctor> 
    class UnaryFunctorImageFilter;
}

class ColorLabel;
class ColorLabelTable;

/**
 * \class LabelImageWrapper
 * \brief ImageWrapper for segmentation images in SNAP/IRIS.
 * 
 * An extension of the ImageWrapper class for dealing with segmentation
 * images.  Using a table of color labels, it is possible to get RGBA 
 * slices from these images.
 *
 * \sa ImageWrapper
 */
class LabelImageWrapper : public ImageWrapper<LabelType>
{
public:

  // Type of color slice returned by this class
  // typedef vnl_vector_fixed<unsigned char,4> DisplayPixelType;
  typedef itk::RGBAPixel<unsigned char> DisplayPixelType;
  typedef itk::Image<DisplayPixelType,2> DisplaySliceType;
  typedef itk::SmartPointer<DisplaySliceType> DisplaySlicePointer;

  /**
   * Set the table of color labels used to produce color slice images
   */  
  void SetLabelColorTable(ColorLabelTable *labels);

  /**
   * Get the color label table
   */
  ColorLabelTable *GetLabelColorTable() const;

  /**
   * Tell the object to update it's color mapping cache
   * TODO: Implement this with ModifiedTime stuff
   */
  void UpdateColorMappingCache();

  /**
   * Get a color slice for display purposes
   */
  DisplaySliceType *GetDisplaySlice(unsigned int dim);

  /** Constructor initializes mapper */
  LabelImageWrapper();

  /** Constructor that copies another wrapper */
  LabelImageWrapper(const LabelImageWrapper &source);

  /** Destructor */
  ~LabelImageWrapper();  

private:
  /**
   * Functor used for display caching.  This class keeps a pointer to 
   * the table of colors and maps colors to RGBA Pixels
   */
  class IntensityFunctor {
  public:    
      /** The pointer to the label table */
      ColorLabelTable *m_ColorLabelTable;

      /** The operator that maps label to color */
      DisplayPixelType operator()(const LabelType &x) const;

      // Dummy equality operators, since there is no data here
      bool operator == (const IntensityFunctor &) const { return true; }
      bool operator != (const IntensityFunctor &) const { return false; }
  };

  // Type of intensity function used to map 3D volume intensity into
  // 2D slice intensities
  typedef 
    UnaryFunctorCache<LabelType,DisplayPixelType,IntensityFunctor> CacheType;  
  typedef itk::SmartPointer<CacheType> CachePointer;
  typedef CacheType::CachingFunctor CacheFunctor;

  // Filter applied to slices
  typedef itk::Image<LabelType,2> LabelSliceType;
  typedef 
    itk::UnaryFunctorImageFilter<LabelSliceType,DisplaySliceType,CacheFunctor>
    IntensityFilterType;
  typedef itk::SmartPointer<IntensityFilterType> IntensityFilterPointer;

  /**
   * An instance of the private intensity mapper (this mapper wraps the passed
   * in list of labels
   */
  IntensityFunctor m_IntensityFunctor;

  /**
   * A cache used for the intensity mapping function
   */
  CachePointer m_IntensityMapCache;

  /**
   * Filters used to remap the intensity of the slices in this image
   * into unsigned char images
   */
  IntensityFilterPointer m_IntensityFilter[3];
};

#endif // __LabelImageWrapper_h_