Capture plots from other devices with record_polaroid()

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()

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()

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()