blackWhite.h File Reference

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Functions
QImage *	blackWhiteEffect (QString filename, ManipulationOptions *options)

Function Documentation

blackWhiteEffect()

QImage * blackWhiteEffect	(	QString	filename,
		ManipulationOptions *	options )

Definition at line 60 of file blackWhite.cpp.

{
  //load image
  QImage* editedImage = new QImage( filename );
  
  //convert to 32-bit depth if necessary
  if( editedImage->depth() < 32 )
  {
    QImage* tmp = editedImage;
    editedImage = new QImage( tmp->convertDepth( 32, Qt::AutoColor ) );
    delete tmp; tmp=NULL;
  }
  
  //determine if busy indicators will be used
  bool useBusyIndicators = false;
  StatusWidget* status = NULL;
  if( options != NULL && options->getStatus() != NULL )
  {
    useBusyIndicators = true;
    status = options->getStatus(); 
  }
  
  //setup progress bar
  if(useBusyIndicators)
  {
    QString statusMessage = qApp->translate( "blackWhiteEffect", "Applying Black + White Effect:" );
    status->showProgressBar( statusMessage, 100 );
    qApp->processEvents();  
  }
  
  //update progress bar for every 1% of completion
  const int updateIncrement = (int) ( 0.01 * editedImage->width() * editedImage->height() );
  int newProgress = 0; 
 
  //iterate over each selected scanline 
  int x, y, grayValue;
  QRgb* rgb;
  uchar* scanLine;
  for( y=0; y<editedImage->height(); y++)
  {   
    //iterate over each selected pixel in scanline
    scanLine = editedImage->scanLine(y);
    for( x=0; x<editedImage->width(); x++)
    {
      //compute gray value based on the display luminance of color coordinates
      rgb = ((QRgb*)scanLine+x);
      grayValue = (int) (0.2125*qRed(*rgb) + 0.7154*qGreen(*rgb) + 0.0721*qBlue(*rgb));
      
      //clamp to ensure it falls in the 0-255 range
      grayValue = QMIN( QMAX( grayValue, 0 ), 255 );      
      
      //set pixel channel values using computed gray value
      *rgb = qRgb( grayValue, grayValue, grayValue );      
 
      //update status bar if significant progress has been made since last update
      if(useBusyIndicators)
      {
        newProgress++;
        if(newProgress >= updateIncrement)
        {
          newProgress = 0;
          status->incrementProgress();
          qApp->processEvents();  
        }
      }
 
    }
  }
   
  //return pointer to edited image
  return editedImage;  
}

References editedImage, ManipulationOptions::getStatus(), StatusWidget::incrementProgress(), newProgress, StatusWidget::showProgressBar(), status, and updateIncrement.

Referenced by EditingInterface::applyEffect(), and pointillismEffect().