title: The space above and below the legend using ggplot2
body: <p>If you look at the charts <a href="http://markthegraph.blogspot.com.au/2012/08/credit-aggregates-july-2012.html">here</a>! you can see there is a lot of white space above and below the legend. I wish to reduce the amount of space.</p>
  
  <p>Example code:</p>
  
  <pre><code>library(ggplot2)
  library(gridExtra)
  library(reshape)
  library(plyr)
  library(scales)
  
  theme_set(theme_bw())
  
  rows &lt;- 1:nrow(faithful)
  data &lt;- cbind(faithful, rows)
  molten &lt;- melt(data, id.vars='rows', measure.vars=c('eruptions', 'waiting'))
  
  p &lt;- ggplot() +
      geom_line(data=molten, 
          mapping=aes(x=rows, y=value, group=variable, colour=variable), size=0.8) +
      scale_colour_manual(values=c('red','blue')) +
      opts(title='Title') +
      xlab(NULL) + ylab('Meaningless Numbers') +
      opts(
          legend.position='bottom',
          legend.direction='horizontal',
          legend.title=theme_blank(),
          legend.key=theme_blank(),
          legend.text=theme_text(size=9),
          legend.margin = unit(0, "line"),
          legend.key.height=unit(0.6,"line"),      
          legend.background = theme_rect(colour='white', size=0)
      )
  
  ggsave(p, width=8, height=4, filename='crap.png', dpi=125)
  </code></pre>