Hi, I'm trying to figure out the formula used by ggplot2 to calculate the width of a bar in geom_bar so that I can use that elsewhere in the plot. My code looks like this: ggplot(xAll, aes(Date)) + geom_bar(subset = .(Direction == "Up"), aes(y = Change, fill Time), stat = "identity") + geom_bar(subset = .(Direction == "Down"), aes(y = Change, fill Time), stat = "identity") + geom_segment(data = xline, aes(Date, Total, xend = Date, yend = (Total - (sign(Total) * (mean(Total)/25)))), size = 5, # this is where I need to substitute in the geom_bar width color = "white") Right now, I have to manually adjust (i.e. guess) the size of geom_segment so that it matches the width of geom_bar. Can someone point me to the formula used by geom_bar to calculate bar width? I've attached an example plot for reference. Thanks, James -------------- next part -------------- A non-text attachment was scrubbed... Name: bar_plot.png Type: image/png Size: 23728 bytes Desc: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20120301/348fbfd7/attachment.png>