Breaks misalignment with scale_x_date

[jrowen]

I'm seeing a misalignment between the major and minor breaks when they use different units.

df=data.frame(Date=seq(from=as.Date("2008-12-15"), 
                     to=as.Date("2013-04-30"), by="day"))
df$y=rnorm(nrow(df))

ggplot(df) +
  geom_path(aes(x=Date, y=y)) +
  scale_x_date(expand=c(0, 0), breaks=date_breaks("1 year"), 
               labels=date_format("%Y"),
               minor_breaks=date_breaks("3 months"))

If everything is defined using the same units, the breaks are aligned as expected, but in this example, the axis label marks the end, instead of beginning of the period.

ggplot(df) +
  geom_path(aes(x=Date, y=y)) +
  scale_x_date(expand=c(0, 0), breaks=date_breaks("12 months"), 
               labels=date_format("%Y"),
               minor_breaks=date_breaks("3 months"))

[hadley]

This sounds like a great feature/horrible bug, but unfortunately we don't currently have the development bandwidth to support it/fix it. If you'd like to submit a pull request that implements this feature/fixes this bug, please follow the instructions in the development vignette.