title: What customizations are possible for plot.CLD on an emmeans output?
body: <p>I am trying to figure out how to customize the plot produced by the <code>plot.CLD</code> function on the output of <code>emmeans</code>. The plot function produces a nice default plot, but it does not seem to share the customization options of <code>plot.cld</code>. Also, I cannot find any documentation of <code>plot.CLD</code>, only <code>plot.cld</code>. I specifically want to add the compact letter display as data labels on the plot. I would also like to switch the xvar and yvar variables to rotate the plot.</p>
  
  <p>I am running a <code>lmer</code> mixed effect model on some weight data. I want to compute and plot the compact letter display of the tukey-adjusted <code>emmeans</code> output. The function cld was designed for <code>glht</code>-type data, which can be visualized using <code>plot.cld</code>. The <code>cld</code> function was brought forward in the <code>emmeans</code> package as <code>CLD</code>. </p>
  
  <p>The <code>plot.CLD</code> function is active, but was not documented in the <code>emmeans</code> package. The customization of <code>plot.cld</code> has been documented, but no similar documentation of <code>plot.CLD</code> is available. I tried <code>plot.cld</code> on my <code>emmeans</code> object, but it was not compatible. The only features I have been able to modify is the <code>xlab=</code> and <code>ylab=</code>. Strangely, <code>plot.CLD</code> requires the package <code>multcompView</code> but there is no documentation about the function.</p>
  
  <pre><code>library(lme4)
  library(lmerTest)
  library(multcomp)
  library(multcompView)
  #Generating means
  attach(dataX)
  x = lmer(plant_kg_cum2~ (genotype) + (1|rep) )
  emmeans(x, list(pairwise~genotype), adjust="tukey", ddf="Satterthwaite", level = 0.95)-&gt;emmeans1
  
  #producing compact letter display
  cld(emmeans1, sort=FALSE, Letters=c("ABCDEFGHIJKL",LETTERS, letters), which=1) -&gt;CLD1
  
  #plot the compact letter display
  plot(CLD1, xlab="kg", ylab="Genotype")
  </code></pre>
  
  <p>I even tried adding a title using <code>main="title"</code>, but even that was not successful. I tried switching xvar and yvar in my dataframe to re-orient the plot by changing the columns order or using the <code>x=</code> and <code>y=</code> commands. All gave errors saying it produced NAs.</p>