title: Paper border on plotly R graph
body: <p>Not sure if R's plot_ly function has this capability (i havent been able to find it), but figured I'd ask). Plot_ly does have a paper_bgcolor parameter that changes the color of the paper that the plot is on, as such:</p>
  
  <pre><code>mydf = data.frame(x = 1:5, y = 1:5)
  
  plot_ly(mydf) %&gt;%
    add_trace(x = ~x, y = ~x, type = 'scatter', mode = 'markers',
              marker = list(size = 24)) %&gt;%
    layout(paper_bgcolor = 'red')  
  </code></pre>
  
  <p>I am not interested in changing the paper color, but rather the paper border. That is, I'd like a red box around the outer edge of the paper. Does anybody know a simple way to do this?</p>
  
  <p>EDIT — I think I may have to use the grid package for this / it could be done with grid, but I'm curious first if it's possible without incorporating another package. </p>