static BufferedImage renderableToImage(Renderable r) {
  if (r == null) null;
  ret renderableToImage(r.preferredSize(), r);
}

static BufferedImage renderableToImage(Pt size, Color backgroundColor default white(), Renderable r) {
  var img = newImage(size.x, size.y, backgroundColor);
  r.renderOn(img, size.x, size.y);
  ret img;
}

svoid renderRenderables(Graphics2D g, int w, int h, Iterable<Renderable> renderables) {
  fOr (Renderable r : renderables)
    r.renderOn(g, w, h);
}