code: public Paint getFrameInteriorPaint(Shape s, int titleHeight, int topToolBarHeight, int bottomToolBarHeight) {
          return createFrameGradient(s, titleHeight, topToolBarHeight, bottomToolBarHeight, getFrameInteriorColors());
      }
docs: Get the paint for the frame interior.
  
  @param  s                   the frame interior shape.
  @param  titleHeight         the height of the title portion.
  @param  topToolBarHeight    the height of the top toolbar, or 0 if none.
  @param  bottomToolBarHeight the height of the bottom toolbar, or 0 if
  none.
  
  @return the paint.