public void centerString(Graphics g, Rectangle r, String s,
Font font) {
FontRenderContext frc =
new FontRenderContext(null, true, true);
Rectangle2D r2D = font.getStringBounds(s, frc);
int rWidth = (int) Math.round(r2D.getWidth());
int rHeight = (int) Math.round(r2D.getHeight());
int rX = (int) Math.round(r2D.getX());
int rY = (int) Math.round(r2D.getY());
int a = (r.width / 2) - (rWidth / 2) - rX;
int b = (r.height / 2) - (rHeight / 2) - rY;
g.setFont(font);
g.drawString(s, r.x + a, r.y + b);
}