In thebioengineer/camcorder: Record Your Plot History

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  warning = FALSE,
  message = FALSE
)

{camcorder} overrides functions like print.ggplot or print.patchwork to capture plots. In some cases though, when other functions are used to print plots, {camcorder} cannot automatically grab them. record_polaroid() provides a way to expand the capturing capabilities of {camcorder} to other devices.

This can be achieved by adding record_polaroid() after the code used for plotting. Although record_polaroid() has to be called manually, it allows saving a plot with the settings of an existing {camcorder} setup, like width, height, or directory.

This is particularly useful when you have an ongoing recording of ggplot2 code and then start using a package that has its own printing function, like {geofacet}.

Example with `{geofacet}`

In this example, we only use the state_ranks dataset from {geofacet} but no functions from the package. Our basic {camcorder} setup works as expected.

library(ggplot2)
library(geofacet)
library(camcorder)

gg_record(device = "png", width = 8, height = 6)

ggplot(state_ranks) +
  geom_col(aes(variable, rank, fill = variable)) +
  coord_flip() +
  facet_wrap(vars(state)) +
  theme_bw()

{width=600px}

If we were to replace the facet_wrap() function with facet_geo() though, no plot would be saved, since {geofacet} uses its own printing function. This is where record_polaroid() comes in. By adding it (no arguments needed), {camcorder} saves the plot in the same directory and with the same dimensions.

library(ggplot2)
library(geofacet)
library(camcorder)

gg_record(
  dir = file.path(tempdir(), "recording"),
  device = "png",
  width = 8,
  height = 6
)

ggplot(state_ranks) +
  geom_col(aes(variable, rank, fill = variable)) +
  coord_flip() +
  facet_geo(vars(state)) +
  theme_bw()

record_polaroid()

{width=600px}

Example with base R

record_polaroid() can be used with base R plots as well. Not only does it saves the plot but it also displays the image in RStudio's Viewer pane with the desired dimensions declared in gg_record().

library(camcorder)

gg_record(
  dir = file.path(tempdir(), "recording"),
  device = "png",
  width = 8,
  height = 6
)

plot(trees)

record_polaroid()