class="section level4">
<h4 class="hasAnchor">
<a href="#drawing-plot-and-extracting-coordinates" class="anchor"></a>1. Drawing plot and extracting coordinates</h4>
<p>The first part of the server function includes code to draw the plot and build it with <code>ggplot_build()</code>. Note that the global assignment operator <code><a href="https://rdrr.io/r/base/assignOps.html">&lt;&lt;-</a></code> is used to assign <code>node_width</code> and <code>pbuilt</code> so they are both accessible outside the <code>