>


<dt>alpha</dt>
<dd><p>A factor modifying the opacity alpha 
(as <code>alpha.f</code> in <code><a href="https://rdrr.io/r/grDevices/adjustcolor.html" class="external-link">adjustcolor</a></code>) to a value in <code>[0, 1]</code>. 
Default: <code>alpha = NA</code> (i.e., no modification of opacity).</p></dd>

</dl></div>
    <div id="details">
    <h2>Details</h2>
    <p>By default, the color gradient returned contains <code>n = 5</code> colors 
that range from the initial color <code>col_1 = "black"</co