code: private void calcInnerBounds() {
          final java.awt.Insets INSETS = getInsets();
          INNER_BOUNDS.setBounds(INSETS.left, INSETS.top, (getWidth() - INSETS.left - INSETS.right), (getHeight() - INSETS.top - INSETS.bottom));
      }
docs: Calculates the rectangle that specifies the area that is available
  for painting the gauge. This means that if the component has insets
  that are larger than 0, these will be taken into account.