A convolution function that takes a kernel and an image.

image-processing.cpp

QVector<QRgb>
MainWindow::convolveImage(QImage* img,
                         QVector<double>; kernel,
                         short kernel_size)
{
   int width = img->width();
   int height = img->height();
   int len = width * height;

   QVector<QRgb> imvec = vectorOfImagePixels(img);
   QVector>QRgb> retvec(0);

   qDebug() << "Length of image vector:" << len;

   for(int i = 0; i < len; ++i) // perform the convolution
   {
      retvec.append(convolveImageAtPixel(imvec, width,
      kernel, kernel_size,i));
   }

   return retvec;
 }

QRgb
MainWindow::convolveImageAtPixel(QVector<QRgb> img, short img_width,
                                  QVector<double> kernel, short kernel_size,
                                  int center)
{
   short y, x;
   QRgb sum = 0;
   QString out = &amp;quot;&amp;quot;;

   for(int ky = 0; ky < kernel_size; ++ky)
   {
      y = center/img_width - kernel_size/2 + ky;
      int kColFromY = kernel_size * ky;
      int imgColFromY = img_width * y; // only calculate when new

      for(int kx = 0; kx < kernel_size; ++kx)
      {
         x = center%img_width - kernel_size/2 + kx;

         if (x < 0 || y < 0 || x >= img_width)
            continue;

         double kval = kernel[kColFromY + kx];
         sum += img[imgColFromY + x] * kval;
      }
   }

   return sum;
}