// -------------------------------------------------------------------------
// @author Leonardo Florez-Valencia (florez-l@javeriana.edu.co)
// -------------------------------------------------------------------------

#ifndef __cpExtensions__Algorithms__ImageToBoundingBoxFromThreshold__hxx__
#define __cpExtensions__Algorithms__ImageToBoundingBoxFromThreshold__hxx__

#include <limits>
#include <itkImageRegionConstIteratorWithIndex.h>

// -------------------------------------------------------------------------
template< class _TImage >
void cpExtensions::Algorithms::ImageToBoundingBoxFromThreshold< _TImage >::
Compute( )
{
  typedef itk::ImageRegionConstIteratorWithIndex< _TImage > _TIt;

  TIndex min_idx, max_idx;
  min_idx.Fill( 0 );
  max_idx.Fill( -1 );

  if( this->m_Image.IsNotNull( ) )
  {
    auto region = this->m_Image->GetRequestedRegion( );
    min_idx = max_idx = region.GetIndex( );
    min_idx += region.GetSize( );

    _TIt i( this->m_Image, region );
    for( i.GoToBegin( ); !i.IsAtEnd( ); ++i )
    {
      auto v = i.Get( );
      if( this->m_LowerThreshold <= v && v <= this->m_UpperThreshold )
      {
        auto idx = i.GetIndex( );
        for( unsigned int d = 0; d < _TImage::ImageDimension; ++d )
        {
          min_idx[ d ] = ( idx[ d ] < min_idx[ d ] )? idx[ d ]: min_idx[ d ]; 
          max_idx[ d ] = ( idx[ d ] > max_idx[ d ] )? idx[ d ]: max_idx[ d ]; 
 
        } // rof

      } // fi

    } // rof

    // Fix indices
    for( unsigned int d = 0; d < _TImage::ImageDimension; ++d )
    {
      min_idx[ d ] -= long( this->m_PAD );
      max_idx[ d ] += long( this->m_PAD );

      if( min_idx[ d ] < region.GetIndex( )[ d ] )
        min_idx[ d ] = region.GetIndex( )[ d ];
      if( max_idx[ d ] > region.GetIndex( )[ d ] + region.GetSize( )[ d ] )
        max_idx[ d ] = region.GetIndex( )[ d ] + region.GetSize( )[ d ];

    } // rof

  } // fi

  typename _TImage::SizeType size;
  for( unsigned int d = 0; d < _TImage::ImageDimension; ++d )
    size[ d ] = max_idx[ d ] - min_idx[ d ] + 1;
  
  this->m_Region.SetIndex( min_idx );
  this->m_Region.SetSize( size );
}

// -------------------------------------------------------------------------
template< class _TImage >
cpExtensions::Algorithms::ImageToBoundingBoxFromThreshold< _TImage >::
ImageToBoundingBoxFromThreshold( )
  : Superclass( ),
    m_LowerThreshold( std::numeric_limits< TPixel >::min( ) ),
    m_UpperThreshold( std::numeric_limits< TPixel >::max( ) ),
    m_PAD( 0 )
{
}

// -------------------------------------------------------------------------
template< class _TImage >
cpExtensions::Algorithms::ImageToBoundingBoxFromThreshold< _TImage >::
~ImageToBoundingBoxFromThreshold( )
{
}

#endif // __cpExtensions__Algorithms__ImageToBoundingBoxFromThreshold__hxx__

// eof - $RCSfile$