ggplot2 plot scaling in R Markdown or Quarto

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1

When you save ggplot2 plots, the output will be different depending on the image size. There is a nice blog post on plot scaling on the tidyverse blog. The final example they use is:

pngfile <- fs::path(knitr::fig_path(),  "downscaling.png")
ggsave(
  pngfile, 
  p, 
  device = agg_png, 
  width = 10, height = 6, units = "cm", res = 300,
  scaling = 0.5
)
knitr::include_graphics(pngfile)

They are saving the plot and then displaying that image with knitr::include_graphics(). If you are using R Markdown or Quarto, is there a more elegant way to display a scaled plot (something that does not involve saving the plot and then loading that image)?

2

I'm guessing it's question of setting the options of the code chunk that creates the plot, and that the details here should help:
https://r4ds.hadley.nz/quarto#sec-figures

3

You could set the fig-width, but you would have to define the width in an earlier chunk if you want it to be a variable. That's not particularly clean either.

4

To clarify on this, with any other method you would use, it would end up doing that. When setting fig-width or any other option, at some point R graphic device will be used to save an image file on disk, and then include it using the right syntax.

So doing ggsave + include_graphics() is exactly the same, just with more control for you on the two steps, which are usually done automatically internally by knitr.

Hope this helps understand

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