static new ThreadLocal<Color> renderText_fg;
static new ThreadLocal<Color> renderText_bg;

sbool renderText_withLeading = true;

static BufferedImage renderText(S fontName, float fontSize, S text) {
  ret renderText(loadFont_cached(fontName), fontSize, text);
}

static BufferedImage renderText(Font font default sansSerif(), float fontSize, S text) {
  ret renderText(font.deriveFont(fontSize), text);
}
  
static BufferedImage renderText(Font font default sansSerif(), O _text) {
  S text = str(_text);
  
  Color background = optPar(renderText_bg, Color.white);
  Color foreground = optPar(renderText_fg, Color.black);

  // for font metrics
  FontMetrics fm = fontMetrics(font);
  int width = fm.stringWidth(text);
  if (width <= 0) null;
  int height = fm.getHeight();
  int y = renderText_withLeading
    ? fm.getLeading() + fm.getMaxAscent()
    : fm.getAscent();
  
  BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    
  Graphics g = imageGraphics(img);
  g.setColor(background);
  g.fillRect(0, 0, width, height);
  g.setColor(foreground);
  g.setFont(font);
  g.drawString(text, 0, y);
  g.dispose();
  
  return img;
}