/*
     Bresenham algorithm
     for line drawing.
     Requires a class to draw pixel, to build RDB color codes...
     Public domain source code, provided by scriptol.com
*/


void bresenham(int x0, int y0, int x1, int y1, Color color)
    {
        int pix = color.getRGB();
        int dy = y1 - y0;
        int dx = x1 - x0;
        int stepx, stepy;

        if (dy < 0)
            { dy = -dy;  stepy = -1; } 
        else { stepy = 1; }
        if (dx < 0)
           { dx = -dx;  stepx = -1; } 
         else
           { stepx = 1; }

        dy <<= 1;                                        
        dx <<= 1;                                        

        raster.setPixel(pix, x0, y0);
        if (dx > dy) 
        {
            int fraction = dy - (dx >> 1);    
            while (x0 != x1) 
           {
                if (fraction >= 0) 
                {
                    y0 += stepy;
                    fraction -= dx;      
                }
                x0 += stepx;
                fraction += dy;         
                raster.setPixel(pix, x0, y0);
            }
        } else 
       {
            int fraction = dx - (dy >> 1);
            while (y0 != y1) 
            {
                if (fraction >= 0) 
                {
                    x0 += stepx;
                    fraction -= dy;
                }
                y0 += stepy;
                fraction += dx;
                raster.setPixel(pix, x0, y0);
            }
        }
    }