R: Record and Replay Plots

recordPlot {grDevices}

R Documentation

Record and Replay Plots

Description

Functions to save the current plot in an R variable, and to replay it.

Usage

recordPlot(load=NULL, attach=NULL)
replayPlot(x, reloadPkgs=FALSE)

Arguments

`load`	If not `NULL`, a character vector of package names, which are saved as part of the recorded plot.
`attach`	If not `NULL`, a character vector of package names, which are saved as part of the recorded plot.
`x`	A saved plot.
`reloadPkgs`	A logical indicating whether to reload and/or reattach any packages that were saved as part of the recorded plot.

Details

These functions record and replay the display list of the current graphics device. The returned object is of class "recordedplot", and replayPlot acts as a print method for that class.

The returned object is stored as a pairlist, but the usual methods for examining R objects such as deparse and str are liable to mislead.

Value

recordPlot returns an object of class "recordedplot".

replayPlot has no return value.

Warning

The format of recorded plots may change between R versions, so recorded plots should not be used as a permanent storage format for R plots.

As of R 3.3.0, it is possible (again) to replay a plot from another R session using, for example, saveRDS and readRDS. It is even possible to replay a plot from another R version, however, this will produce warnings, may produce errors, or something worse.

Note

Replay of a recorded plot may not produce the correct result (or may just fail) if the display list contains a call to recordGraphics which in turn contains an expression that calls code from a non-base package other than graphics or grid. The most well-known example of this is a plot drawn with the package ggplot2. One solution is to load the relevant package(s) before replaying the recorded plot. The load and attach arguments to recordPlot can be used to automate this - any packages named in load will be reloaded, via loadNamespace, and any packages named in attach will be reattached, via library, as long as reloadPkgs is TRUE in the call to replayPlot. This is only relevant when attempting to replay in one R session a plot that was recorded in a different R session.

References

Murrell, P., Ooms, J., Allaire, J.J. (2015), "Recording and Replaying the Graphics Engine Display List", https://stattech.wordpress.fos.auckland.ac.nz/2015/12/21/2015-07-recording-and-replaying-the-graphics-engine-display-list/