code: public void paintArrowButtonBackground(SynthContext context, Graphics g, int x, int y, int w, int h) {
          if (context.getComponent().getComponentOrientation().isLeftToRight()) {
              paintBackground(context, g, x, y, w, h, null);
          } else {
              AffineTransform transform = new AffineTransform();
  
              transform.translate(x, y);
              transform.scale(-1, 1);
              transform.translate(-w, 0);
              paintBackground(context, g, 0, 0, w, h, transform);
          }
      }
docs: Paints the background of an arrow button. Arrow buttons are created by
  some components, such as <code>JScrollBar</code>.
  
  @param context SynthContext identifying the <code>JComponent</code> and
  <code>Region</code> to paint to
  @param g       <code>Graphics</code> to paint to
  @param x       X coordinate of the area to paint to
  @param y       Y coordinate of the area to paint to
  @param w       Width of the area to paint to
  @param h       Height of the area to paint to