code: @Override
      protected void doPaint(Graphics2D g, JComponent c, int width, int height, Object[] extendedCacheKeys) {
          g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
  
          int size = width < height ? width : height;
          int x    = (width - size) / 2;
          int y    = (height - size) / 2;
  
          Shape s;
  
          if (focused) {
              boolean useToolBarFocus = isInToolBar(c);
  
              s = shapeGenerator.createRoundRectangle(x, y, size, size, CornerSize.CHECKBOX_OUTER_FOCUS);
              g.setPaint(getFocusPaint(s, FocusType.OUTER_FOCUS, useToolBarFocus));
              g.fill(s);
              s = shapeGenerator.createRoundRectangle(x + 1, y + 1, size - 2, size - 2, CornerSize.CHECKBOX_INNER_FOCUS);
              g.setPaint(getFocusPaint(s, FocusType.INNER_FOCUS, useToolBarFocus));
              g.fill(s);
          }
  
          s = shapeGenerator.createRoundRectangle(x + 2, y + 2, size - 4, size - 4, CornerSize.CHECKBOX_BORDER);
  
          if (!focused) {
              dropShadow.fill(g, s);
          }
  
          g.setPaint(getCommonBorderPaint(s, type));
          g.fill(s);
  
          s = shapeGenerator.createRoundRectangle(x + 3, y + 3, size - 6, size - 6, CornerSize.CHECKBOX_INTERIOR);
          g.setPaint(getCommonInteriorPaint(s, type));
          g.fill(s);
  
          if (selected) {
              s = createCheckMark(x, y, size);
              g.setPaint(getCheckBoxBulletPaint(s, type));
              g.fill(s);
          }
      }
docs: {@inheritDoc}