title: How can I manipulate a ggplot in R to allow extra room on lhs for angle=45 long x-axis labels?
body: <p>I have several geom_bar ggplots where I have long names for x-axis text.  If I plot them at angle=90, it takes a lot of room at the bottom of the graph, so I am trying angle=45.  This causes the left hand side of the first label to be cut off.  Is there a way to increase the left margin?  </p>
  
  <p>(not allowed to post an image example)</p>
  
  <pre><code>ggplot(aes(x = cm, y = ahead_aadt),
          data = sbt) + 
     geom_point( ) + geom_line() +
     ggtitle("Ahead AADT Traffic Counts On US 101 in S Santa Barbara Cty") + 
     theme(axis.text.x = element_text(angle=45, size = 9,
       color = "black", face = "plain", vjust = 1, hjust = 1), 
       panel.grid.major.x = element_line(colour = "black", linetype = "dotted")) +
    xlab("Cumulative Mileage") + ylab("Ahead AADT") +
     scale_x_continuous(breaks = sbt$cm,
                        labels =  sbt$description)
  </code></pre>