title: R - ggplot - Rounded extremity for geom_bar
body: <p>This is a simple example of what my barplot look like : </p>
  
  <pre><code>x &lt;- data.frame(aa=c(0.2,0.6,0.1), dd = c(1,2,3))
  x &lt;- melt(x, "dd")
  y &lt;- data.frame(bb=c(0.4,0.5), dd = c(1,2))
  y &lt;- melt(y, "dd")
  z &lt;- data.frame(cc=c(0.5,0.25,0.1,0.05), dd = c(1,2,3,4))
  z &lt;- melt(z, "dd")
  
  x=rbind(x,y,z)
  
  col=c("white","grey","blue","white","red","white","green","blue","green")
  ggplot(x, aes(x = variable, y = value)) + geom_bar(stat = "identity", fill = col)
  </code></pre>
  
  <p>I'm wondering if there is a way to have rounded ends for my bars, like with the lineend option for a line (<a href="http://sape.inf.usi.ch/quick-reference/ggplot2/lineend" rel="noreferrer">http://sape.inf.usi.ch/quick-reference/ggplot2/lineend</a>) ? </p>