[TASK] Begin implementing filters with overflow modes.

imageviewer-qt4.cpp

@@ -537,7 +537,69 @@ void ImageViewer::applyBasicFilter() {
   updateImageDisplay();
 }
 
+/**
+ * Basic filter PLUS different overflow modes
+ * 
+ * @brief ImageViewer::applyBasicFilterWithOverflowHandling
+ */
+void ImageViewer::applyBasicFilterWithOverflowHandling() {
+  // TODO: Get overflow mode here
+  LazyImage::overflowMode overflowMode = LazyImage::CONSTANT; 
+  logFile << "Applying basic filter - overflow mode: " << overflowMode << std::endl;
+  renewLogging();
   
+  int* data = filter_gui->getData();
+  int filter_size = filter_gui->getSize();
+  
+  // sum up the filter weights
+  int filter_sum = 0;
+  for(int i=0; i<filter_size; i++) {
+    for(int j=0; j<filter_size; j++) {
+      int current_data = data[i*filter_size + j];
+      filter_sum += abs(current_data); // support for negativ weights using abs()
+      logFile << "[" << i << "," << j << "] -> " << current_data << "  ";
+    }
+    logFile << std::endl;
+  }
+  logFile << "Beginning calculation ... " << std::endl;
+  renewLogging();
+  
+  int h, s, l;
+  // for each pixel
+  for(int x=0; x<working_copy->getImage()->width(); x++) {
+    for(int y=0; y<working_copy->getImage()->height(); y++) {
+      int intensity_sum = 0;
+      // sum up weighted intensity for each matrix entry
+      for(int fx=0; fx<filter_size; fx++) {
+	int dx = fx - (filter_size / 2);
+        for(int fy=0; fy<filter_size; fy++) {
+	  int dy = fy - (filter_size / 2);
+	  QColor color = QColor::fromRgb(original->getPixel(x+dx, y+dy, overflowMode));
+	  color.getHsl(&h, &s, &l);
+	  //std::cout << "[" << fx << "," << fy <<"] " << l << " * " << data[fx*filter_size + fy] << " = ";
+	  intensity_sum += (l * data[fx*filter_size + fy]);
+	  //std::cout << intensity_sum << std::endl;
+        }	
+      }
+      QColor color = QColor::fromRgb(original->getImage()->pixel(x, y));
+      color.getHsl(&h, &s, &l);
+      //std::cout << "old lightness: " << l << ", filter_sum: " << filter_sum << ", intensity_sum:" << intensity_sum;
+      // divide by sum of weights
+      l = qRound((intensity_sum*1.0) / filter_sum);
+      //optional clamping for exotic stuff like negative values
+      if(l > 255) l = 255;
+      if(l < 0) l = 0;
+      //std::cout << " --> new l: " << l << std::endl;
+      color.setHsl(h, s, l);
+      // and set it.
+      working_copy->getImage()->setPixel(x, y, color.rgb());
+    }
+  }  
+  
+  logFile << "done." << std::endl;
+  renewLogging();
+  updateImageDisplay();
+}
 /**************************************************************************************** 
 *   
 *  GUI elements related to the tasks are set up here.

imageviewer-qt4.h

@@ -158,6 +158,7 @@ class ImageViewer : public QMainWindow {
     void succeedingHistogrammAdaption();
     void changeFilterSize(int s);
     void applyBasicFilter();
+    void applyBasicFilterWithOverflowHandling();
 
     void open();
     void openReference();

lazy_image.cpp

@@ -116,6 +116,8 @@ class LazyImage {
     
 
   public:
+    enum overflowMode {ZERO_PADDING, CONSTANT, MIRRORED, CONTINUOUS};
+    
     LazyImage(QImage* img) {
       this->histogramm_normal_image = NULL;
       this->histogramm_cumulative_image = NULL;
@@ -202,6 +204,56 @@ class LazyImage {
       }
     };
     
+    /**
+     * Takes coordinates and a mode about how to handle overflows.
+     * Not all modes are 100% bullet proof - it is still possible to
+     * get unexpected results out of this for very big overflows.
+     * 
+     * @brief LazyImage::getPixel 
+     */
+    QColor getPixel(int x, int y, overflowMode mode) {
+      int width = this->img->width();
+      int height = this->img->height();
+      QRgb result = NULL;
+      switch(mode) {
+	case ZERO_PADDING: // Return black for all out of bound requests
+          if(x < 0 || x >= width || y < 0 || y >= height) {
+	    result = QRgb(qRgb(0, 0, 0);
+	  }
+	  break;
+	case CONSTANT: // Simply clamp to the border it is stuck on
+	  if(x < 0) x = 0;
+	  else if(x >= width) x = width - 1;
+	  if(y < 0) y = 0;
+	  else if(y >= height) y = height - 1;
+	  break;
+	case MIRRORED: // Mirror on overflowed axis
+	  if(x < 0) x *= -1;
+	  else if(x >= width) {
+	    int delta = x - (width-1);
+	    x = (width-1) - delta;
+	  }
+	  if(y < 0) y *= -1;
+	  else if(y > (height-1)) {
+	    int delta = y - (height-1);
+	    y = (height-1) - delta;	    
+	  }
+	  break;
+	case CONTINUOUS: // simply start over at the other side again
+	  x = x % width;
+	  y = y % height;
+	  break;
+	default:
+	  std::cout << "HELP, SOMETHING WENT WRONG! I DON'T KNOW THIS MODE!" << std::endl;
+	  break; // BOOM!
+      }
+      if(result == NULL) {
+	return this->img->pixel(x, y);
+      } else {
+        return result;
+      }
+    };
+
 };