knitr: How to show two plots of different sizes next to each other?

Question

I wanted to generate two images of different sizes, but show them side-by-side. Is this possible?

This works, but then they have to be the same size:

Answer 1

Yet another option is to use a vector for out.width or out.height, if you do not mind resizing the plots, e.g.

```{r out.width=c('500px', '300px'), fig.show='hold'}
boxplot(1:10)
plot(rnorm(10))
```

Answer 2

You can also use grid.arrange from gridExtra which works with grob or ggplot objects

require(gridExtra)
pre_fig <- rasterGrob(readPNG("paper_figures/surf_0000.png"), interpolate=TRUE)
post_fig <- rasterGrob(readPNG("paper_figures/surf_0044.png"), interpolate=TRUE)
grid.arrange(pre_fig, post_fig, ncol=2)

Answer 3

One option would be to make a single wide graph with the R commands and give knitr just the one graph to deal with, maybe something like:

```{r fig.width=10, fig.height=9}
layout( cbind( c(0,0,1,1,1,1,1,0,0), rep(2,9) ) )
plot(...)
plot(...)
```

Answer 4

Another option, if you're outputting to HTML is to use the out.extra= chunk option, and set them to be float objects within a block. For example.

```{r fig.width=4, fig.height=6,echo=FALSE,out.extra='style="float:left"'}
plot(cars)
```{r fig.width=8, fig.height=6,echo=FALSE, out.extra='style="float:left"'}
plot(cars)
```