title: Change legend size in qplot (R)
body: <p>I have a graph of a probability density function drawn from a data.frame that looks a bit like this: </p>
  
  <pre><code>head(GroupA_long_raw)
     Block Trial TrialType  Subject variable value
  1 Block2   101   Regular Subject1       RT  1214
  2 Block2   102   Regular Subject1       RT   766
  3 Block2   103   Regular Subject1       RT   691
  4 Block2   104   Regular Subject1       RT   939
  5 Block2   105    Random Subject1       RT   829
  6 Block2   106    Random Subject1       RT  1364
  </code></pre>
  
  <p>I created the plot with the following command(s):</p>
  
  <pre><code>RawDnsty_A &lt;- qplot(value, data = GroupA_long_raw, geom = "density",color = TrialType, main="Probability Density Function of raw RTs") + scale_y_continuous("probability",limits=c(0,.007)) + scale_x_continuous("RT(ms)",limits=c(400,1500)) + scale_colour_manual(values = c("black","grey"))
  </code></pre>
  
  <p>This is the result: <a href="https://i.stack.imgur.com/g5nf5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/g5nf5.png" alt="result"></a></p>
  
  <p>The problem I have is that I am trying to use this graph for an article, but the editors consider the size of the legend, as well as the size of the x and y labels, are too small. </p>
  
  <p>I have tried modifying these with different parameters, like <code>legend</code> but I cannot get the parmeters to affect the main graph in any way.</p>
  
  <p>Any help is most appreciated. </p>