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rplot

Save a plot in an object

In ggplot2, one can easily save a graphic into a R object.

p = ggplot(...) + geom_point()      # does not display the graph
p                                   # displays the graph

The standard function plot produces the graphic as a void function and returns NULL.

p = plot(1:10)     # displays the graph
p                  # NULL

Is it possible to save a graphic created by plot in an object?

Solution

  • base graphics draw directly on a device.

    You could use

    1- recordPlot

    2- the recently introduced gridGraphics package, to convert base graphics to their grid equivalent

    Here's a minimal example,

    plot(1:10) 

p <- recordPlot()
plot.new() ## clean up device
p # redraw

## grab the scene as a grid object
library(gridGraphics)
library(grid)
grid.echo()
a <- grid.grab()

## draw it, changes optional
grid.newpage()
a <- editGrob(a, vp=viewport(width=unit(2,"in")), gp=gpar(fontsize=10))
grid.draw(a)