Change the width of a figure created with barplot()

Question

When I use barplot, I cannot see the names of the bars if the names are too big. For example:

barplot(as.numeric(c(2, 4, 1, 6)), col = c("lightblue"), main="Barplot",
        names.arg=c("This is bar 1...1", "This is bar 1...2",
                    "This is bar 1...3", "This is bar 1...4"), 
        xpd=TRUE, las=1, lwd=1, cex.names=0.5)

When I use horiz=TRUE, I cannot see the names on the left:

barplot(as.numeric(c(2, 4, 1, 6)), col = c("lightblue"), main="Barplot", 
        names.arg=c("This is \nbar 2...1", "This is bar 2...2",
                    "This is bar 2...3", "This is bar 2...4"), 
        xpd=TRUE, las=1, lwd=1, horiz=TRUE, space=1)

Using a line break in names (e.g. "This is \nbar 2...1") or reducing text size with, e.g., cex.names=0.5 "solves" the problem but I would prefer to add space so that the names fit.

Is there any ability to change the width of the whole figure including the plot?

Answer 1

When horiz=FALSE (the default), one option is to plot the bar names perpendicular to the x-axis with las=2, and add height to the bottom margin to accommodate the length of the names. To add space to the margin, use par(mar=c(b, l, t, r)), where b, l, t, and r are numbers giving the number of lines width/height that you want the bottom, left, top, and right margins to be, respectively.

For example:

par(mar=c(15, 3, 3, 1)) # 15 line height for bottom margin
barplot(c(2, 4, 1, 6), main="Barplot", las=2,
        names.arg=c("This is my first very long name",
                    "This is my second very long name",
                    "This is my third very long name",
                    "This is my fourth very long name"))

When horiz=TRUE, you can use las=1 and add space to the left margin instead:

par(mar=c(3, 15, 3, 1))
barplot(c(2, 4, 1, 6), main="Barplot", las=1, horiz=TRUE,
        names.arg=c("This is my first very long name",
                    "This is my second very long name",
                    "This is my third very long name",
                    "This is my fourth very long name"))