qgsrastertransparency.cpp

一个非常好的GIS开源新版本

/* **************************************************************************
                qgsrastertransparency.cpp -  description
                       -------------------
begin                : Mon Nov 30 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 <QList>

#include "qgsrastertransparency.h"

QgsRasterTransparency::QgsRasterTransparency()
{

}

/** 
  Accessor for transparentSingleValuePixelList
*/
QList<QgsRasterTransparency::TransparentSingleValuePixel> QgsRasterTransparency::getTransparentSingleValuePixelList()
{
  return mTransparentSingleValuePixelList;
}

/** 
  Accessor for transparentThreeValuePixelList
*/
QList<QgsRasterTransparency::TransparentThreeValuePixel> QgsRasterTransparency::getTransparentThreeValuePixelList()
{
  return mTransparentThreeValuePixelList;
}

/** 
  Reset to the transparency list to a single value 
*/
void QgsRasterTransparency::initializeTransparentPixelList(double theValue)
{
  //clear the existing list
  mTransparentSingleValuePixelList.clear();
  
  //add the initial value
  TransparentSingleValuePixel myTransparentSingleValuePixel;
  myTransparentSingleValuePixel.pixelValue = theValue;
  myTransparentSingleValuePixel.percentTransparent = 100.0;
  mTransparentSingleValuePixelList.append(myTransparentSingleValuePixel);
}

/** 
  Reset to the transparency list to a single value 
*/
void QgsRasterTransparency::initializeTransparentPixelList(double theRedValue, double theGreenValue, double theBlueValue)
{
  //clearn the existing list
  mTransparentThreeValuePixelList.clear();
  
  //add the initial values
  TransparentThreeValuePixel myTransparentThreeValuePixel;
  myTransparentThreeValuePixel.red = theRedValue;
  myTransparentThreeValuePixel.green = theGreenValue;
  myTransparentThreeValuePixel.blue = theBlueValue;
  myTransparentThreeValuePixel.percentTransparent = 100.0;
  mTransparentThreeValuePixelList.append(myTransparentThreeValuePixel);
}


/** 
  Mutator for transparentSingleValuePixelList, , replaces the whole list 
*/
void QgsRasterTransparency::setTransparentSingleValuePixelList(QList<QgsRasterTransparency::TransparentSingleValuePixel> theNewList)
{
  mTransparentSingleValuePixelList = theNewList;
}

/** 
  Mutator for transparentThreeValuePixelList, , replaces the whole list 
*/
void QgsRasterTransparency::setTransparentThreeValuePixelList(QList<QgsRasterTransparency::TransparentThreeValuePixel> theNewList)
{
  mTransparentThreeValuePixelList = theNewList;
}

/**
  Searches throught the transparency list, if a match is found, the global transparency value is scaled
  by the stored transparency value.
  @param theValue the needle to search for in the transparency hay stack
  @param theGlobalTransparency  the overal transparency level for the layer
*/
int QgsRasterTransparency::getAlphaValue(double theValue, int theGlobalTransparency)
{
  //if NaN return 0, transparent 
  if(theValue != theValue)
  {
    return 0;
  }
  
  //Search throught he transparency list looking for a match
  bool myTransparentPixelFound = false;
  TransparentSingleValuePixel myTransparentPixel;
  for(int myListRunner = 0; myListRunner < mTransparentSingleValuePixelList.count(); myListRunner++)
  {
    myTransparentPixel = mTransparentSingleValuePixelList[myListRunner];
    if(myTransparentPixel.pixelValue == theValue)
    {
      myTransparentPixelFound = true;
      break;
    }
  }
  
  //if a match was found use the stored transparency percentage
  if(myTransparentPixelFound)
  {
    return (int)((float)theGlobalTransparency * (1.0 - (myTransparentPixel.percentTransparent/100.0)));
  }

  return theGlobalTransparency;
}

/**
  Searches throught the transparency list, if a match is found, the global transparency value is scaled
  by the stored transparency value.
  @param theRedValue the red portion of the needle to search for in the transparency hay stack
  @param theGreenValue  the green portion of the needle to search for in the transparency hay stack
  @param theBlueValue the green portion of the needle to search for in the transparency hay stack
  @param theGlobalTransparency  the overal transparency level for the layer
*/
int QgsRasterTransparency::getAlphaValue(double theRedValue, double theGreenValue, double theBlueValue, int theGlobalTransparency)
{
  //if NaN return 0, transparent 
  if(theRedValue != theRedValue || theGreenValue != theGreenValue || theBlueValue != theBlueValue)
  {
    return 0;
  }
  
  //Search throught he transparency list looking for a match
  bool myTransparentPixelFound = false;
  TransparentThreeValuePixel myTransparentPixel;
  for(int myListRunner = 0; myListRunner < mTransparentThreeValuePixelList.count(); myListRunner++)
  {
    myTransparentPixel = mTransparentThreeValuePixelList[myListRunner];
    if(myTransparentPixel.red == theRedValue)
    {
      if(myTransparentPixel.green == theGreenValue)
      {
        if(myTransparentPixel.blue == theBlueValue)
        {
          myTransparentPixelFound = true;
          break;
        }
      }
    }
  }
  
  //if a match was found use the stored transparency percentage
  if(myTransparentPixelFound)
  {
    return  (int)((float)theGlobalTransparency * (1.0 - (myTransparentPixel.percentTransparent/100.0)));
  }
  
  return theGlobalTransparency;
}