qgslinearminmaxenhancementwithclip.cpp

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/* **************************************************************************
              qgslinearminmaxenhancementwithclip.cpp -  description
                       -------------------
begin                : Fri Nov 16 2007
copyright            : (C) 2007 by Peter J. Ersts
email                : ersts@amnh.org
 
****************************************************************************/
 
/* **************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#include "qgslinearminmaxenhancementwithclip.h"
 
QgsLinearMinMaxEnhancementWithClip::QgsLinearMinMaxEnhancementWithClip( Qgis::DataType qgsRasterDataType, double minimumValue, double maximumValue ) : QgsContrastEnhancementFunction( qgsRasterDataType, minimumValue, maximumValue )
{
}
 
int QgsLinearMinMaxEnhancementWithClip::enhance( double value )
{
  if ( value < mMinimumValue || value > mMaximumValue )
  {
    return -1;
  }
 
  const int myStretchedValue = static_cast<int>( ( ( value - mMinimumValue ) / ( mMinimumMaximumRange ) ) * 255.0 );
  if ( myStretchedValue < 0 )
  {
    return 0;
  }
  else if ( myStretchedValue > 255 )
  {
    return 255;
  }
 
  return myStretchedValue;
}
 
bool QgsLinearMinMaxEnhancementWithClip::isValueInDisplayableRange( double value )
{
  return !( value < mMinimumValue || value > mMaximumValue );
}