title: ggplot2: remove colour and draw borders in bar plot
body: <p>I am currently using ggplot2 to plot a barchart with too many levels in fill. As a result, I am unable tell when a bar ends and the other begin.</p>
  
  <p>Here's my sample data code of what I am doing right now.</p>
  
  <pre><code>variable&lt;-c("X1","X1","X1","X1","X1","X1","X1","X1","X1","X2","X2","X2","X2","X2","X2","X2","X2","X2","X3","X3","X3","X3","X3","X3","X3","X3","X3")
  Length.1&lt;-c(4.24,0.81,0.81,NA,NA,NA,NA,NA,NA,4.24,0.81,0.81,NA,NA,NA,NA,NA,NA,4.24,0.72,0.72,0.16,NA,NA,NA,NA,NA)
  data&lt;-data.frame(variable=as.factor(variable),value=as.factor(1:length(variable)),Length.1=Length.1)
  
  ## Plots a stacked bar chat in ggplot2 with text labels. Credit to MYaseen208
  library(ggplot2)
  p &lt;- qplot(variable, Length.1, data = data, geom = "bar", fill = value,     theme_set(theme_bw()))
  p + geom_text(aes(label = Length.1), size = 3, hjust = 0.5, vjust = 3, position =     "stack") 
  </code></pre>
  
  <p>Currently, the plot looks fine. However in my actual data set, <code>length(data$value)</code> is much higher and I can't see the differences between different bars as clearly.  So, I wish to change the colours of the bars to white and draw a black border around each one. Does anyone know how I can do that?</p>