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tilt.h File Reference

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Functions

QImage * correctImageTilt (QString filename, QPoint p1, QPoint p2, StatusWidget *status)


Function Documentation

QImage* correctImageTilt QString  filename,
QPoint  p1,
QPoint  p2,
StatusWidget status
 

Definition at line 100 of file tilt.cpp.

References bottomRight, editedImage, findTwoLineIntersection(), StatusWidget::incrementProgress(), interpolatedPixelValue(), newProgress, StatusWidget::setStatus(), StatusWidget::showProgressBar(), status, topLeft, updateIncrement, DPoint::x(), and DPoint::y().

Referenced by EditingInterface::finishCorrectTilt().

00102 {
00103   //first compute distance between two points or "radius"
00104   int dx = p2.x() - p1.x();
00105   int dy = p2.y() - p1.y();
00106   
00107   //determine tilt angle
00108   int delta = 0;
00109   
00110   //compute recirpocal of distance between points
00111   double recip_r = 1.0 / sqrt( (double) (dx*dx + dy*dy) );
00112   
00113   //compute angle with horizontal axis
00114   if( QABS(dx) > QABS(dy) )
00115   {
00116     delta = dy;
00117     if(dx > 0) delta = -delta;
00118   }
00119   //compute angle with vertical axis
00120   else
00121   {
00122     delta = dx;
00123     if(dy < 0) delta = -delta;
00124   }
00125   
00126   double sinTheta = (delta * recip_r);
00127   double theta = asin( sinTheta );
00128   double cosTheta = cos( theta );
00129   
00130   //if angle is 0 (improbable but possible) then quit now
00131   if( theta == 0 )
00132     return NULL;
00133   
00134   //load original and edited images
00135   QImage originalImage( filename );
00136   QImage rotatedImage( originalImage.width(), originalImage.height(), originalImage.depth() );
00137   
00138   //setup progress bar
00139   QString statusMessage = qApp->translate( "correctImageTilt", "Correcting Tilt:" );
00140   status->showProgressBar( statusMessage, 200 );
00141   qApp->processEvents();  
00142   
00143   //during the first phase update the status bar for every 1% of image pixels that are processed
00144   int updateIncrement = (int) ( 0.01 * originalImage.width() * originalImage.height() );
00145   int newProgress = 0;
00146   
00147   //set each pixel to the rotated value
00148   double xp, yp;
00149   
00150   double w2 = 0.5 * rotatedImage.width();
00151   double h2 = 0.5 * rotatedImage.height();
00152   
00153   int x,y;
00154   uchar* scanLine;
00155   QRgb* rgb;
00156   for( y=0; y<rotatedImage.height(); y++)
00157   {   
00158     //iterate over each selected pixel in scanline
00159     scanLine = rotatedImage.scanLine(y);
00160     for( x=0; x<rotatedImage.width(); x++)
00161     {
00162       //compute unrotated coordinates
00163       xp = cosTheta*(x-w2) + sinTheta*(y-h2) + w2;
00164       yp = -sinTheta*(x-w2) + cosTheta*(y-h2) + h2;
00165 
00166       //set unrotated value
00167       rgb = ((QRgb*)scanLine+x);
00168       *rgb = interpolatedPixelValue( xp, yp, &originalImage);
00169 
00170       //update status bar if significant progress has been made since last update
00171       newProgress++;
00172       if(newProgress >= updateIncrement)
00173       {
00174         newProgress = 0;
00175         status->incrementProgress();
00176         qApp->processEvents();  
00177       }
00178       
00179     }
00180   }
00181   
00182   //find rotated corners
00183   double nTheta = -theta;
00184   double sinNTheta = sin( nTheta );
00185   double cosNTheta = cos( nTheta );
00186   
00187   DPoint topLeft = DPoint( cosNTheta*(-w2) + sinNTheta*(-h2) + w2,
00188                            -sinNTheta*(-w2) + cosNTheta*(-h2) + h2 );
00189 
00190   DPoint topRight = DPoint( cosNTheta*(w2) + sinNTheta*(-h2) + w2,                           
00191                             -sinNTheta*(w2) + cosNTheta*(-h2) + h2 );
00192   
00193   DPoint bottomLeft = DPoint( cosNTheta*(-w2) + sinNTheta*(h2) + w2,                           
00194                               -sinNTheta*(-w2) + cosNTheta*(h2) + h2 );
00195   
00196   DPoint bottomRight = DPoint( cosNTheta*(w2) + sinNTheta*(h2) + w2,                           
00197                                -sinNTheta*(w2) + cosNTheta*(h2) + h2 );
00198   
00199   //determine which of these points are which in their rotated form
00200   DPoint top, bottom, left, right;
00201   if( theta < 0 )
00202   {
00203     top = topRight;
00204     bottom = bottomLeft;
00205     left = topLeft;
00206     right = bottomRight;
00207   }
00208   else
00209   {
00210     top = topLeft;
00211     bottom = bottomRight;    
00212     left = bottomLeft;
00213     right = topRight;
00214   }
00215   
00216   //construct true corners
00217   DPoint trueTopLeft    ( 0, 0 );
00218   DPoint trueTopRight   ( rotatedImage.width()-1, 0 );
00219   DPoint trueBottomLeft ( 0, rotatedImage.height()-1 );
00220   DPoint trueBottomRight( rotatedImage.width()-1, rotatedImage.height()-1 );
00221   
00222   //find intersections with image boundary
00223   DPoint topEdgeL = findTwoLineIntersection( left, top, trueTopLeft, trueTopRight );
00224   DPoint topEdgeR = findTwoLineIntersection( top, right, trueTopLeft, trueTopRight );
00225                                             
00226   DPoint bottomEdgeL = findTwoLineIntersection( left, bottom, trueBottomLeft, trueBottomRight );
00227   DPoint bottomEdgeR = findTwoLineIntersection( bottom, right, trueBottomLeft, trueBottomRight );
00228 
00229   DPoint leftEdgeT = findTwoLineIntersection( left, top, trueTopLeft, trueBottomLeft );
00230   DPoint leftEdgeB = findTwoLineIntersection( left, bottom, trueTopLeft, trueBottomLeft );
00231     
00232   DPoint rightEdgeT = findTwoLineIntersection( right, top, trueTopRight, trueBottomRight );
00233   DPoint rightEdgeB = findTwoLineIntersection( right, bottom, trueTopRight, trueBottomRight );
00234   
00235   //shot rays out from image center to each true corner and find intersections with clipped corners
00236   DPoint center( (int)w2, (int)h2 );
00237   DPoint safeTopLeft     = findTwoLineIntersection( center, trueTopLeft, leftEdgeT, topEdgeL );
00238   DPoint safeTopRight    = findTwoLineIntersection( center, trueTopRight, rightEdgeT, topEdgeR );
00239   DPoint safeBottomLeft  = findTwoLineIntersection( center, trueBottomLeft, leftEdgeB, bottomEdgeL );
00240   DPoint safeBottomRight = findTwoLineIntersection( center, trueBottomRight, rightEdgeB, bottomEdgeR );
00241   
00242   //find constrained area
00243   double minY = QMAX( safeTopLeft.y(), safeTopRight.y() );
00244   double maxY = QMIN( safeBottomLeft.y(), safeBottomRight.y() );
00245   
00246   double minX = QMAX( safeTopLeft.x(), safeBottomLeft.x() );
00247   double maxX = QMIN( safeTopRight.x(), safeBottomRight.x() );
00248 
00249   //find contrained area in integer coordinates. this is semi-tricky.
00250   //if the minimum values decimal porition is nonzero then increment by one 
00251   // (eg 5.37 -> 6)
00252   int xMin = (int) minX;
00253   int xMax = (int) maxX;
00254   
00255   int yMin = (int) minY;
00256   int yMax = (int) maxY;
00257   
00258   if( xMin < minX ) xMin++;
00259   if( yMin < minY ) yMin++;
00260   
00261   //construct cropped rotated image
00262   QImage* editedImage = new QImage( xMax - xMin + 1,
00263                                     yMax - yMin + 1,
00264                                     rotatedImage.depth() );    
00265 
00266   //during the second phase update the status bar for every 1% of cropped pixels that are procesed
00267   updateIncrement = (int) ( 0.01 * editedImage->width() * editedImage->height() );
00268   newProgress = 0;
00269   
00270   int x2,y2;
00271   uchar* scanLine2;
00272   QRgb* rgb2;
00273 
00274   y2 = 0;
00275   for( y=yMin; y<=yMax; y++, y2++)
00276   {   
00277     //iterate over each selected pixel in scanline
00278     scanLine = rotatedImage.scanLine(y);
00279     scanLine2 = editedImage->scanLine(y2);
00280 
00281     x2 = 0;
00282     for( x=xMin; x<=xMax; x++, x2++)
00283     {
00284       rgb  = ((QRgb*)scanLine +x );
00285       rgb2 = ((QRgb*)scanLine2+x2);
00286       *rgb2 = *rgb;      
00287 
00288       //update status bar if significant progress has been made since last update
00289       newProgress++;
00290       if(newProgress >= updateIncrement)
00291       {
00292         newProgress = 0;
00293         status->incrementProgress();
00294         qApp->processEvents();  
00295       }
00296     
00297     }
00298   }
00299   
00300   //remove status bar
00301   status->setStatus( "" );
00302   qApp->processEvents();  
00303   
00304   //return pointer to edited image
00305   return editedImage;
00306 }


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