qgslinearminmaxenhancementwithclip.cpp

来自「一个非常好的GIS开源新版本」· C++ 代码 · 共 54 行

/* **************************************************************************
              qgslinearminmaxenhancementwithclip.cpp -  description
                       -------------------
begin                : Fri Nov 16 2007
copyright            : (C) 2007 by Peter J. Ersts
email                : [e-mail]

****************************************************************************/

/* **************************************************************************
 *                                                                         *
 *   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(QgsContrastEnhancement::QgsRasterDataType theQgsRasterDataType, double theMinimumValue, double theMaximumValue) : QgsContrastEnhancementFunction(theQgsRasterDataType, theMinimumValue, theMaximumValue)
{
}

int QgsLinearMinMaxEnhancementWithClip::enhanceValue(double theValue)
{
  if(theValue < mMinimumValue || theValue > mMaximumValue)
  {
    return -1;
  }

  int myStretchedValue = static_cast<int>(((theValue - mMinimumValue)/(mMinimumMaximumRange))*255.0);
  if(myStretchedValue < 0)
  {
    return 0;
  }
  else if(myStretchedValue > 255)
  {
    return 255;
  }
  
  return myStretchedValue; 
}

bool QgsLinearMinMaxEnhancementWithClip::isValueInDisplayableRange(double theValue)
{
  if(theValue < mMinimumValue || theValue > mMaximumValue)
  {
    return false;
  }
  
  return true;
}