[feature request] vector of fig.width and fig.height

[baptiste]

I'm setting dev = c('pdf', 'png') to produce a markdown report that will get converted with Pandoc into both html and pdf (via latex). Since both formats have quite a different purpose -- latex pdf is good for print documents, html for online viewing, I would like to specify a different figure size for either device, which is currently not possible (scalar fig.width). The idea is that a html page seen in a web browser can easily accommodate a 12 inches wide figure, but this large width will currently shrink the font size when fitted into the latex version, which should therefore be limited to 8 inches, say.

[yihui]

Actually this is a little bit tricky. In certain cases, a plot can be distorted if you save it to different sizes.

Besides, I have to open one (and only one) device before drawing plots, and only one set of fig.width and fig.width can be used for this device. If you provide vectors, I'm not sure which elements I should use.

Anyway, I'll think about it.

You can also consider other approaches, e.g.

HTML_VERSION = TRUE
fs = function(size) {
  if (HTML_VERSION) 1.5 * size else size
}
opts_chunk$set(dev = if (HTML_VERSION) 'png' else 'pdf')

```{r fig.width=fs(7), fig.height=fs(5)}
```

Then you can control the device and fig.width/fig.height using a single variable HTML_VERSION.

[baptiste]

I see how it's hard to implement, but it does offer benefits: one doesn't have to run the document twice to get both versions of the plots, which can be a good time-saver. Thanks for considering it anyway!

[yihui]

It is not hard to implement at all, and I think I will do it.

[baptiste]

Great, thanks!

[yihui]

Done.

[github-actions]

This old thread has been automatically locked. If you think you have found something related to this, please open a new issue by following the issue guide (https://yihui.org/issue/), and link to this old issue if necessary.