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Adding GIF animations

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This post will show you how to include GIFs in a blogdown post from a website, and how to make new GIFs from R plots (base R and ggplot2) using knitr chunk options.

Embed plot GIFs using R

To create a GIF animation of a plot made in R, you need to install FFmpeg on your computer. If you are on a macOS, you can install FFmpeg through Homebrew using the formula brew install ffmpeg.

You can make a GIF animation using knitr starting in version 1.15. A GIF animation of the plots in a code chunk will be generated for HTML output when you use the chunk options fig.show = 'animate', ffmpeg.format = 'gif', and dev = 'jpeg'.

Here is an example knitr chunk with options:

```{r chunk-label, fig.show='animate', ffmpeg.format='gif', dev='jpeg'}
for (i in 1:10) plot(runif(100), ylim = c(0, 1)) # for example

Which would produce the GIF below…

Let’s break those chunk options down:

  • fig.show = 'animate': how to show/arrange the plots; animate wraps all plots into an animation if there are mutiple plots in a chunk

  • ffmpeg.format = 'gif': the filename of the extension video you want to create. This .gif file is also saved in your /static/post/ directory.

  • dev = 'jpeg': the function name which will be used as a graphical device to record the individual plots that make up the above. These .jpeg files are each saved in your /static/post/ directory.

You can also create GIFs using the purrr and ggplot2 packages.

library(repurrrsive) # for the example data below

Below is some sample code from an awesome purrr tutorial by Charlotte Wickham. From her map2() example code:

gap_split_small <- gap_split[1:10]
countries <- names(gap_split_small)
# For all countries
plots <- map2(gap_split_small, countries, 
  ~ ggplot(.x, aes(year, lifeExp)) + 
      geom_line() +
      labs(title = .y) +
      coord_cartesian(ylim = c(0, 100))) 

To show these plots as an animation, we would use this code chunk:

```{r gapgif, fig.show='animate', ffmpeg.format='gif', dev='jpeg'}
# Display all plots
walk(plots, print)

Which produces the GIF below…