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color.cpp File Reference

#include <qimage.h>
#include <qstring.h>
#include <qapplication.h>
#include "color.h"
#include "../../gui/statusWidget.h"

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Functions

QImage * improveColorBalance (QString filename, StatusWidget *status)


Function Documentation

QImage* improveColorBalance QString  filename,
StatusWidget status
 

Definition at line 21 of file color.cpp.

References b, editedImage, StatusWidget::incrementProgress(), newProgress, StatusWidget::setStatus(), StatusWidget::showProgressBar(), status, and updateIncrement.

Referenced by EditingInterface::colorBalance().

00022 {
00023   //load original image
00024   QImage* editedImage = new QImage( filename );
00025   
00026   //setup progress bar
00027   QString statusMessage = qApp->translate( "improveColorBalance", "Enhancing Color Balance:" );
00028   status->showProgressBar( statusMessage, 100 );
00029   qApp->processEvents();  
00030   
00031   //update progress bar for every 1% of completion
00032   const int updateIncrement = (int) ( 0.01 * editedImage->width() * editedImage->height() );
00033   int newProgress = 0; 
00034 
00035   //construct intensity histographs for each color channel
00036   int redVals[256];
00037   int greenVals[256];
00038   int blueVals[256];
00039   int i=0;
00040   for(i=0; i<256; i++) 
00041   {
00042     redVals[i] = 0;
00043     greenVals[i] = 0;
00044     blueVals[i] = 0;
00045   }  
00046   
00047   //populate histogram by iterating over all image pixels
00048   int numPixels = editedImage->width()*editedImage->height();  
00049   QRgb* rgb;
00050   uchar* scanLine;
00051   int x, y;
00052   for( y=0; y<editedImage->height(); y++)
00053   {   
00054     //iterate over each selected pixel in scanline
00055     scanLine = editedImage->scanLine(y);
00056     for( x=0; x<editedImage->width(); x++)
00057     {
00058       rgb = ((QRgb*)scanLine+x);
00059       redVals[qRed(*rgb)]++;
00060       greenVals[qGreen(*rgb)]++;
00061       blueVals[qBlue(*rgb)]++;
00062     } //for x
00063   } //for y
00064   
00065   //find 1% and 99% precenticles
00066   //we'll stretch these values so we avoid outliers from affecting the stretch
00067   int sumR=0;
00068   int sumG=0;
00069   int sumB=0;
00070   int indexLowR, indexHighR;
00071   int indexLowG, indexHighG;
00072   int indexLowB, indexHighB;
00073   indexLowR = -1; indexHighR = -1;
00074   indexLowG = -1; indexHighG = -1;
00075   indexLowB = -1; indexHighB = -1;
00076   for(i=0; i<256; i++)
00077   {
00078     sumR+=redVals[i];
00079     sumG+=greenVals[i];
00080     sumB+=blueVals[i];
00081     
00082     //if 1% not found yet and criteria met set index
00083     if(indexLowR < 0 && sumR >= 0.01*numPixels)
00084     { indexLowR = i; }
00085     if(indexLowG < 0 && sumG >= 0.01*numPixels)
00086     { indexLowG = i; }
00087     if(indexLowB < 0 && sumB >= 0.01*numPixels)
00088     { indexLowB = i; }
00089    
00090     //if 99% not found yet and criteria met set index
00091     if(indexHighR < 0 && sumR >= 0.99*numPixels)
00092     { indexHighR = i; }
00093     if(indexHighG < 0 && sumG >= 0.99*numPixels)
00094     { indexHighG = i; }
00095     if(indexHighB < 0 && sumB >= 0.99*numPixels)
00096     { indexHighB = i; }
00097   }
00098   
00099   //run through all image pixels a second time, this time scaling coordinates as necessary
00100   for( y=0; y<editedImage->height(); y++)
00101   {   
00102     //iterate over each selected pixel in scanline
00103     scanLine = editedImage->scanLine(y);
00104     for( x=0; x<editedImage->width(); x++)
00105     {
00106       //get color coordinates and convert to 0-1 scale
00107       rgb = ((QRgb*)scanLine+x);
00108       double r = ((double)qRed(*rgb)   );
00109       double g = ((double)qGreen(*rgb) );
00110       double b = ((double)qBlue(*rgb)  );
00111 
00112       if(indexHighR != indexLowR) { r = (255*(r-indexLowR))/(indexHighR-indexLowR); }
00113       if(indexHighG != indexLowG) { g = (255*(g-indexLowG))/(indexHighG-indexLowG); }
00114       if(indexHighB != indexLowB) { b = (255*(b-indexLowB))/(indexHighB-indexLowB); }
00115         
00116       int rp = (int) QMIN( QMAX(r, 0), 255 );
00117       int gp = (int) QMIN( QMAX(g, 0), 255 );
00118       int bp = (int) QMIN( QMAX(b, 0), 255 );
00119       
00120       //set adjusted color value
00121       *rgb = qRgb(rp,gp,bp);
00122       
00123       //update status bar if significant progress has been made since last update
00124       newProgress++;
00125       if(newProgress >= updateIncrement)
00126       {
00127         newProgress = 0;
00128         status->incrementProgress();
00129         qApp->processEvents();  
00130       }
00131       
00132     } //for x
00133   } //for y
00134   
00135   //remove status bar
00136   status->setStatus( "" );
00137   qApp->processEvents();
00138 
00139   //return pointer to edited image
00140   return editedImage;    
00141 }


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