title: ggplot2 increase space between legend keys
body: <p>How can I increase the space between the keys of the legend of <code>ggplot2</code> plot?</p>
  
  <pre><code>library(ggplot2)
  ggplot(aes(mpg, wt, colour = factor(cyl)),
         , data = mtcars) +
        geom_point() +
    theme(legend.direction = "horizontal", 
          legend.position = "bottom") +
    guides(color = guide_legend(nrow=2))
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/ApLwH.png"><img src="https://i.stack.imgur.com/ApLwH.png" alt="enter image description here"></a></p>
  
  <p>I am looking for a ggplot2 option that add a kind of vertical adjustment between (key 4 and key 6) in the plot above? Should I create a custom legend key? </p>
  
  <p>PS: I want to increase the blank space between boxes not between labels.</p>
  
  <p>the desired plot is : </p>
  
  <p><a href="https://i.stack.imgur.com/MVLot.png"><img src="https://i.stack.imgur.com/MVLot.png" alt="enter image description here"></a></p>
  
  <p>NOTE: <strong>No the question is not duplicated of the other question. We want here to add a vertical spacing between items that are already in multiple rows. In the other question we have 1-row legend and we want to add spaces (horizontal) between items.</strong></p>