AlbumShaper  1.0a3
Functions
tilt.h File Reference
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Functions

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

Function Documentation

§ correctImageTilt()

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

Definition at line 103 of file tilt.cpp.

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

Referenced by EditingInterface::finishCorrectTilt().

105 {
106  //first compute distance between two points or "radius"
107  int dx = p2.x() - p1.x();
108  int dy = p2.y() - p1.y();
109 
110  //determine tilt angle
111  int delta = 0;
112 
113  //compute recirpocal of distance between points
114  double recip_r = 1.0 / sqrt( (double) (dx*dx + dy*dy) );
115 
116  //compute angle with horizontal axis
117  if( QABS(dx) > QABS(dy) )
118  {
119  delta = dy;
120  if(dx > 0) delta = -delta;
121  }
122  //compute angle with vertical axis
123  else
124  {
125  delta = dx;
126  if(dy < 0) delta = -delta;
127  }
128 
129  double sinTheta = (delta * recip_r);
130  double theta = asin( sinTheta );
131  double cosTheta = cos( theta );
132 
133  //if angle is 0 (improbable but possible) then quit now
134  if( theta == 0 )
135  return NULL;
136 
137  //load original and edited images
138  QImage originalImage( filename );
139 
140  //convert to 32-bit depth if necessary
141  if( originalImage.depth() < 32 ) { originalImage = originalImage.convertDepth( 32, Qt::AutoColor ); }
142 
143  QImage rotatedImage( originalImage.width(), originalImage.height(), originalImage.depth() );
144 
145  //setup progress bar
146  QString statusMessage = qApp->translate( "correctImageTilt", "Correcting Tilt:" );
147  status->showProgressBar( statusMessage, 200 );
148  qApp->processEvents();
149 
150  //during the first phase update the status bar for every 1% of image pixels that are processed
151  int updateIncrement = (int) ( 0.01 * originalImage.width() * originalImage.height() );
152  int newProgress = 0;
153 
154  //set each pixel to the rotated value
155  double xp, yp;
156 
157  double w2 = 0.5 * rotatedImage.width();
158  double h2 = 0.5 * rotatedImage.height();
159 
160  int x,y;
161  uchar* scanLine;
162  QRgb* rgb;
163  for( y=0; y<rotatedImage.height(); y++)
164  {
165  //iterate over each selected pixel in scanline
166  scanLine = rotatedImage.scanLine(y);
167  for( x=0; x<rotatedImage.width(); x++)
168  {
169  //compute unrotated coordinates
170  xp = cosTheta*(x-w2) + sinTheta*(y-h2) + w2;
171  yp = -sinTheta*(x-w2) + cosTheta*(y-h2) + h2;
172 
173  //set unrotated value
174  rgb = ((QRgb*)scanLine+x);
175  *rgb = interpolatedPixelValue( xp, yp, &originalImage);
176 
177  //update status bar if significant progress has been made since last update
178  newProgress++;
179  if(newProgress >= updateIncrement)
180  {
181  newProgress = 0;
182  status->incrementProgress();
183  qApp->processEvents();
184  }
185 
186  }
187  }
188 
189  //find rotated corners
190  double nTheta = -theta;
191  double sinNTheta = sin( nTheta );
192  double cosNTheta = cos( nTheta );
193 
194  DPoint topLeft = DPoint( cosNTheta*(-w2) + sinNTheta*(-h2) + w2,
195  -sinNTheta*(-w2) + cosNTheta*(-h2) + h2 );
196 
197  DPoint topRight = DPoint( cosNTheta*(w2) + sinNTheta*(-h2) + w2,
198  -sinNTheta*(w2) + cosNTheta*(-h2) + h2 );
199 
200  DPoint bottomLeft = DPoint( cosNTheta*(-w2) + sinNTheta*(h2) + w2,
201  -sinNTheta*(-w2) + cosNTheta*(h2) + h2 );
202 
203  DPoint bottomRight = DPoint( cosNTheta*(w2) + sinNTheta*(h2) + w2,
204  -sinNTheta*(w2) + cosNTheta*(h2) + h2 );
205 
206  //determine which of these points are which in their rotated form
207  DPoint top, bottom, left, right;
208  if( theta < 0 )
209  {
210  top = topRight;
211  bottom = bottomLeft;
212  left = topLeft;
213  right = bottomRight;
214  }
215  else
216  {
217  top = topLeft;
218  bottom = bottomRight;
219  left = bottomLeft;
220  right = topRight;
221  }
222 
223  //construct true corners
224  DPoint trueTopLeft ( 0, 0 );
225  DPoint trueTopRight ( rotatedImage.width()-1, 0 );
226  DPoint trueBottomLeft ( 0, rotatedImage.height()-1 );
227  DPoint trueBottomRight( rotatedImage.width()-1, rotatedImage.height()-1 );
228 
229  //find intersections with image boundary
230  DPoint topEdgeL = findTwoLineIntersection( left, top, trueTopLeft, trueTopRight );
231  DPoint topEdgeR = findTwoLineIntersection( top, right, trueTopLeft, trueTopRight );
232 
233  DPoint bottomEdgeL = findTwoLineIntersection( left, bottom, trueBottomLeft, trueBottomRight );
234  DPoint bottomEdgeR = findTwoLineIntersection( bottom, right, trueBottomLeft, trueBottomRight );
235 
236  DPoint leftEdgeT = findTwoLineIntersection( left, top, trueTopLeft, trueBottomLeft );
237  DPoint leftEdgeB = findTwoLineIntersection( left, bottom, trueTopLeft, trueBottomLeft );
238 
239  DPoint rightEdgeT = findTwoLineIntersection( right, top, trueTopRight, trueBottomRight );
240  DPoint rightEdgeB = findTwoLineIntersection( right, bottom, trueTopRight, trueBottomRight );
241 
242  //shot rays out from image center to each true corner and find intersections with clipped corners
243  DPoint center( (int)w2, (int)h2 );
244  DPoint safeTopLeft = findTwoLineIntersection( center, trueTopLeft, leftEdgeT, topEdgeL );
245  DPoint safeTopRight = findTwoLineIntersection( center, trueTopRight, rightEdgeT, topEdgeR );
246  DPoint safeBottomLeft = findTwoLineIntersection( center, trueBottomLeft, leftEdgeB, bottomEdgeL );
247  DPoint safeBottomRight = findTwoLineIntersection( center, trueBottomRight, rightEdgeB, bottomEdgeR );
248 
249  //find constrained area
250  double minY = MAX( safeTopLeft.y(), safeTopRight.y() );
251  double maxY = MIN( safeBottomLeft.y(), safeBottomRight.y() );
252 
253  double minX = MAX( safeTopLeft.x(), safeBottomLeft.x() );
254  double maxX = MIN( safeTopRight.x(), safeBottomRight.x() );
255 
256  //find contrained area in integer coordinates. this is semi-tricky.
257  //if the minimum values decimal porition is nonzero then increment by one
258  // (eg 5.37 -> 6)
259  int xMin = (int) minX;
260  int xMax = (int) maxX;
261 
262  int yMin = (int) minY;
263  int yMax = (int) maxY;
264 
265  if( xMin < minX ) xMin++;
266  if( yMin < minY ) yMin++;
267 
268  //construct cropped rotated image
269  QImage* editedImage = new QImage( xMax - xMin + 1,
270  yMax - yMin + 1,
271  rotatedImage.depth() );
272 
273  //during the second phase update the status bar for every 1% of cropped pixels that are procesed
274  updateIncrement = (int) ( 0.01 * editedImage->width() * editedImage->height() );
275  newProgress = 0;
276 
277  int x2,y2;
278  uchar* scanLine2;
279  QRgb* rgb2;
280 
281  y2 = 0;
282  for( y=yMin; y<=yMax; y++, y2++)
283  {
284  //iterate over each selected pixel in scanline
285  scanLine = rotatedImage.scanLine(y);
286  scanLine2 = editedImage->scanLine(y2);
287 
288  x2 = 0;
289  for( x=xMin; x<=xMax; x++, x2++)
290  {
291  rgb = ((QRgb*)scanLine +x );
292  rgb2 = ((QRgb*)scanLine2+x2);
293  *rgb2 = *rgb;
294 
295  //update status bar if significant progress has been made since last update
296  newProgress++;
297  if(newProgress >= updateIncrement)
298  {
299  newProgress = 0;
300  status->incrementProgress();
301  qApp->processEvents();
302  }
303 
304  }
305  }
306 
307  //remove status bar
308  status->setStatus( "" );
309  qApp->processEvents();
310 
311  //return pointer to edited image
312  return editedImage;
313 }
QRgb interpolatedPixelValue(double xp, double yp, QImage *image)
Definition: tilt.cpp:315
QPoint bottomRight
int updateIncrement
QPoint topLeft
#define MIN(x, y)
Definition: tilt.cpp:17
void incrementProgress()
Updates the progress bar by one step.
void showProgressBar(QString message, int numSteps)
Initializes the progress bar.
void setStatus(QString message)
Update message.
#define MAX(x, y)
Definition: tilt.cpp:18
double x() const
Definition: tilt.cpp:459
double y() const
Definition: tilt.cpp:460
QImage * editedImage
int newProgress
DPoint findTwoLineIntersection(DPoint p1, DPoint p2, DPoint p3, DPoint p4)
Definition: tilt.cpp:370