qgscontrastenhancementfunction.cpp

一个非常好的GIS开源新版本

/* **************************************************************************
              qgscontrastenhancementfunction.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 "qgscontrastenhancementfunction.h"

QgsContrastEnhancementFunction::QgsContrastEnhancementFunction(QgsContrastEnhancement::QgsRasterDataType theDataType, double theMinimumValue, double theMaximumValue)
{
  mQgsRasterDataType = theDataType;
  mMaximumValue = theMaximumValue;
  mMinimumValue = theMinimumValue;
  mMinimumMaximumRange = mMaximumValue - mMinimumValue;
}

void QgsContrastEnhancementFunction::setMaximumValue(double theValue)
{
  if(QgsContrastEnhancement::getMaximumPossibleValue(mQgsRasterDataType) < theValue)
  {
    mMaximumValue = QgsContrastEnhancement::getMaximumPossibleValue(mQgsRasterDataType);
  }
  else
  {
    mMaximumValue = theValue;
  }
  
  mMinimumMaximumRange = mMaximumValue - mMinimumValue;
}

void QgsContrastEnhancementFunction::setMinimumValue(double theValue)
{

  if(QgsContrastEnhancement::getMinimumPossibleValue(mQgsRasterDataType) > theValue)
  {
    mMinimumValue = QgsContrastEnhancement::getMinimumPossibleValue(mQgsRasterDataType);
  }
  else
  {
    mMinimumValue = theValue;
  }
  
  mMinimumMaximumRange = mMaximumValue - mMinimumValue;
}

int QgsContrastEnhancementFunction::enhanceValue(double theValue)
{
  if(mQgsRasterDataType == QgsContrastEnhancement::QGS_Byte)
  {
    return static_cast<int>(theValue);
  }
  else
  {
    return static_cast<int>((((theValue - QgsContrastEnhancement::getMinimumPossibleValue(mQgsRasterDataType))/(QgsContrastEnhancement::getMaximumPossibleValue(mQgsRasterDataType) - QgsContrastEnhancement::getMinimumPossibleValue(mQgsRasterDataType)))*255.0));
  }
  return 0;
}

bool QgsContrastEnhancementFunction::isValueInDisplayableRange(double theValue) {
  //A default check is to see if the provided value is with the range for the data type
  if(theValue < QgsContrastEnhancement::getMinimumPossibleValue(mQgsRasterDataType) || theValue > QgsContrastEnhancement::getMaximumPossibleValue(mQgsRasterDataType))
  {
    return false;
  }

  return true;
}