Stefan Röttger

// Naive algorithm
//  int xstart, ystart = start point of line segment
//  int xend, yend = end point of line segment
//  double dx = xend - xstart;
//  double dy = yend - ystart;

   double slope = dy/dx;

   double x = xstart;
   double y = ystart;

   for (int t=0; t<dx; t++)
   {
      setPixel(x,y);
      x++;
      y+=slope;
   }

// Bresenham algorithm for 1. octant, 0<=slope<=1
//  int xstart, ystart = start point of line segment
//  int xend, yend = end point of line segment
//  int dx = xend - xstart;
//  int dy = yend - ystart;
//  double slope = dy/dx;
// other octants similar

   int x = xstart;
   int y = ystart;

   int err = 2*dy-dx;

   for (int t=0; t<dx; t++)
   {
      setPixel(x,y);
      x++;

      if (err<0)
      {
          err += 2*dy;
      }
      else
      {
          y++;
          err += 2*(dy-dx);
      }
   }