i'm trying produce png chart using ggplot2 , ggsave (with cairo) in r. i'm having issue customising theme remove margins.   currently i'm using:   ... + theme(plot.margin=unit(c(0,0,0,0),"mm"))         this seems work 2 out of 4 sides of plot, removes top , right hand side margin completely, there still large margin on left , bottom sides. there way remove these? image below illustrate problem:     if reproducible example useful let me know , i'll put 1 together.     edit:   library("ggplot2") library("scales") library("cairo") library("grid")  # set chart values line.width = 0.45 axis.font.size = 2.9  # generate random data start.date <- as.date("2011-07-01") x.month <-seq.date(start.date, = "month", length.out = 24) end.date <- max(x.month)  period.a <- rnorm(12, mean=50, sd=2) period.b <- rnorm(12, mean=55, sd=2)  x.value <- c(period.a,period.b)  # combine dataframe x.data ...