public void lineDDA(int x0, int y0, int x1, int y1, Color color) {
         int pix = color.getRGB();
         int dy = y1 - y0;
         int dx = x1 - x0;
         float t = (float) 0.5;                    // offset for rounding
         raster.setPixel(pix, x0, y0);
         if (Math.abs(dx) > Math.abs(dy)) {        // slope < 1
             float m = (float) dy / (float) dx;    // compute slope
             t += y0;
             dx = (dx < 0) ? -1 : 1;
             m *= dx;
             while (x0 != x1) {
                 x0 += dx;                         // step to next x value
                 t += m;                           // add slope to y value
                 raster.setPixel(pix, x0, (int) t);
             }
         } else {                                  // slope >= 1
             float m = (float) dx / (float) dy;    // compute slope
             t += x0;
             dy = (dy < 0) ? -1 : 1;
             m *= dy;
             while (y0 != y1) {
                 y0 += dy;                         // step to next y value
                 t += m;                           // add slope to x value
                 raster.setPixel(pix, (int) t, y0);
             }
         }
     }