Saving a dark-themed plot using ggsave() creates white bordering panels - r

Question

I need my charts to have a dark gray theme to match a presentation style. I also need them to be fixed height, but the widths may vary depending on the length of the labels on the y-axis. When I try to export or save, there are always white side bars in the .jpg or .png file.
Here's some sample code that I use to create the chart (there are some extra theming controls in here that are superfluous to the simplified example, but the resulting chart is basically what I am generating):
library(ggplot2)
bar.font <- 8
title <- "Example"
l_labs <- c("")
x_labs <- c("A","B","C")
ests <- c(.5,.3,.2)
nerrs <- c(.05, .05, .05)
perrs <- nerrs
barchart.data <- data.frame(l_labs, x_labs, ests, nerrs, perrs)
p <- ggplot(barchart.data, aes(x=x_labs, y=ests*100)) +
geom_bar(stat="identity", color="#808080", position=position_dodge(), width=0.85, fill="#808080") +
geom_text(aes(y=ests*100+perrs*100+1.5, label=sprintf("%1.1f%%", 100*ests)), vjust=0.5, hjust=0, size=bar.font, color="white") +
geom_errorbar(aes(ymin=ests*100-nerrs*100, ymax=ests*100+perrs*100), width=.2, position=position_dodge(.9), color="white", size=0.25) +
labs(title=title, x="", y = "") + theme_classic() +
scale_y_continuous(expand = c(0,0),limits = c(0,115), breaks=c(0, 20, 40, 60, 80, 100)) +
theme(legend.position="none", legend.text = element_text(color = "white")) +
theme(title = element_text(size=18, colour = "white")) +
theme(axis.text = element_text(size=20, color = "white"), axis.line = element_line(color = "white")) +
theme(axis.text.x = element_text(margin=margin(9,0,0,0)),axis.text.y = element_text(margin=margin(0,9,0,0))) +
theme(axis.title = element_text(size=20, color = "white")) +
theme(axis.title.x = element_text(margin = margin(10,0,0,0))) +
theme(axis.ticks = element_line(colour = 'white', size = .5)) +
coord_flip() +
theme(aspect.ratio = 1) +
theme(panel.background = element_rect(fill = "#1e1e1e")) +
theme(legend.justification=c(1,0), legend.position=c(1,0)) +
theme(plot.background = element_rect(fill = "#1e1e1e", color = "#1e1e1e")) +
theme(panel.grid.major.x = element_line(colour = "white",size=0.1, linetype = "dotted"))
ggsave("test.jpg", height=10, units="in")
And here is what the exported .jpg looks like. I cannot specify an exact width because I do not know what it will be for each chart as the widths vary. Thanks for any guidance.

Answer 1

You can set the background color to whatever value you like:
ggsave("test.jpg", height=10, units="in", bg = "#1e1e1e")
This takes care of the white bars.
It may be a bit confusing that the bg option is not mentioned in the ggsave() documentation. That's because it's part of the graphics device, here jpeg(). It is mentioned in the jpeg() documentation.
The reason why there are white bars in the first place is discussed in depth in this post.