How to change where the horizontal axis crosses the vertical axis in geom_bar? The result of http://stackoverflow.com/questions/16537401/how-to-change-where-the-horizontal-axis-crosses-the-vertical-axis-in-geom-bar

plot.R

library(ggplot2)

data <- c(0.3,0.4,0.5,0.6,0.7,0.8)
qplot(x=1:6, y=data - 0.5, geom="bar", stat="identity") + 
  scale_y_continuous(breaks=c(-0.5,-0.25,0,0.25,0.5), limits=c(-0.5,0.5), labels=c(0,0.25,0.5,0.75,1.0)) + 
  labs(y="",x="")