R how to change shape/size of plots save as pngs

Question

I am trying to change the size/shape of the base plots in R so they are larger and have closer to a rectangular shape than a square shape at default. Here is an example of one of my plots:

  png(file.path("plots",sets[set],"rspGREKM_vs_Star_Age.png"))
  plot(x=ages, y=growth.rates, main=paste(sets[set],"rspGREKM vs Star Age",sep=" "), pch=3, col="purple",
        xlab=expression("Star Age (days)"), ylab=expression("rspGREKM"))
  dev.off()

I tried including dev.new(width=5, height=4), but there was no noticeable change. What is the appropriate way to do this?

question from:https://stackoverflow.com/questions/65910580/r-how-to-change-shape-size-of-plots-save-as-pngs

Answer 1

The function png() has arguments for defining the width and height of the graphics device, as well as an extra argument for entering the desired units of those dimensions. Check args(png) or ?png.

here is a reproducible example, the first part will produce a rectangular plot, while the second part will produce the default square-shaped plot.

data("mtcars")
##rectangular plot
png("p1.png", width = 640, height = 420, units = "px")
plot(mtcars$mpg, type="l",  main = "p1" )
dev.off()
## default plot
png("p2.png")
plot(mtcars$mpg, type="l", main = "p2" )
dev.off()