code: private Shape decodeShadow(int width, int height) {
          path.reset();
          path.moveTo(width - 1, 0);
          path.lineTo(width - 1, height - 4);
          path.lineTo(width - 4, height - 1);
          path.lineTo(0, height - 1);
  
          return path;
      }
docs: Create the shadow for the button.
  
  @param  width  the width.
  @param  height the height.
  
  @return the shape of the shadow.