    <td><p>Colour title string for the legend. Defaults to NULL.</p></td>
    </tr>
    <tr>
      <th>caption</th>
      <td><p>Caption title string. Defaults to NULL.</p></td>
    </tr>
    <tr>
      <th>legend_labels</th>
      <td><p>A vector of manual legend label values. Defaults to NULL, which results in automatic labels.</p></td>
    </tr>
    <tr>
      <th>font_family</th>
      <td><p>Font family to use. Defaults to "Helvetica".</p></td>
    </tr>
    <tr>
      <th>font_size_title</th>
      <t