sclass CheckerBoard2 is G2Drawable {

  settable int w = 256;

  settable int h = 256;

  settable double shiftX;

  settable double shiftY;

  settable double cellW = 8;

  settable double cellH = 8;

  settable Color color1 = Color.lightGray;

  settable Color color2 = Color.gray;

  selfType cellSize(double cellSize) {

    ret cellW(cellSize).cellH(cellSize);

  }

  public int getWidth() { ret w; }

  public int getHeight() { ret h; }

  public void drawOn(Graphics2D g) {

    int xofs = idiv_floor(shiftX, cellW);

    int yofs = idiv_floor(shiftY, cellH);

    double x1 = mod(shiftX, cellW)-cellW;

    double y1 = mod(shiftY, cellH)-cellH;

    bool bRow = odd(yofs^xofs);

    for (double y = y1; y < h; y += cellH) {

      bRow = !bRow;

      bool b = bRow;

      for (double x = x1; x < w; x += cellW) {

        b = !b;

        g.setColor(b ? color1 : color2);

        g.fill(new Rectangle2D.Double(x, y, cellW, cellH));

      }

    }

  }

}