title: Rotate labels in a chordDiagram (R circlize)
body: <p>Here is some code from the <code>circlize</code> package for creating a chord diagram.Right now the labels are parallel to the edge of the circle.  Is it possible to rotate the labels 90 degrees to they are perpendicular to the circle?</p>
  <pre><code>library(circlize)
  set.seed(999)
  mat = matrix(sample(18, 18), 3, 6)
  rownames(mat) = paste0(&quot;Start&quot;, 1:3)
  colnames(mat) = paste0(&quot;End&quot;, 1:6)
  chordDiagram(mat)
  </code></pre>
  <p>In the figure below I manually inserted a few labels to show what I hope to accomplish (End5, End6, End7).  Thanks.</p>
  <p><a href="https://i.stack.imgur.com/5ylUP.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5ylUP.jpg" alt="enter image description here" /></a></p>