CODEWITHSUNDEEP
pythonrplotjupyter-notebookrpy2
Harry
Harry

Reputation: 3412

Jupyter Notebook rpy2 Rmagics: How to set the default plot size?

I'm using the %%R cell magics in Jupyter notebooks. I'm aware that you can set the plot size for each cell with, e.g.:

%%R -w 800 -h 600

But I would like to set a default for the whole notebook/R session.

I've looked at the documentation, seen this blog post on the R Jupyter Notebook Kernel, and have seen Plot Size - Using ggplot2 in IPython Notebook (via rmagic) on setting the plot size by cell, but unless I've missed something obvious, there doesn't appear to be a way to set the default plot size for plots in R magics.

Is this possible? Is there a hidden setting, or must -w and -h be set for every cell individually?

Upvotes: 11

Views: 2335

Answers (2)

strank
strank

Reputation: 31

Old question, but I just had the same itch, found this page, and then managed to scratch it, so hopefully this is useful to someone.

The workaround is monkey-patching rpy2 which calls R's png method directly without a way to set default arguments. Note that this approach is usually a Bad Idea, and brittle, but cannot be avoided. It would probably be worthwhile to make a feature request for rpy2 to include a mechanism for default arguments.

So here goes the monkey-patching:

# these are the defaults we want to set:
default_units = 'in' # inch, to make it more easily comparable to matpplotlib
default_res = 100 # dpi, same as default in matplotlib
default_width = 10
default_height = 9
# try monkey-patching a function in rpy2, so we effectively get these
# default settings for the width, height, and units arguments of the %R magic command
import rpy2
old_setup_graphics = rpy2.ipython.rmagic.RMagics.setup_graphics

def new_setup_graphics(self, args):
    if getattr(args, 'units') is not None:
        if args.units != default_units: # a different units argument was passed, do not apply defaults
            return old_setup_graphics(self, args)
    args.units = default_units
    if getattr(args, 'res') is None:
        args.res = default_res
    if getattr(args, 'width') is None:
        args.width = default_width
    if getattr(args, 'height') is None:
        args.height = default_height        
    return old_setup_graphics(self, args)

rpy2.ipython.rmagic.RMagics.setup_graphics = new_setup_graphics

Upvotes: 1

lgautier
lgautier

Reputation: 11565

Good question. Currently I think that the default are the R default settings, but it would make sense to use jyputer defaults (if there are any - I'd need look that up).

The following hack would work... if "R magic" was using the default plotting settings in R. Unfortunately it does not.

%%R
my_png <- function(...) {
    lst <- as.list(...)
    if (is.null(lst$w)) {
        lst$w <- 1000 # default width
    }
    if (is.null(lst$h)) {
        lst$h <- 700 # default height
    }
    do.call("png", lst)
}
options(device=my_png)

It would make sense to open an issue on the rpy2 tracker on bitbucket to request the feature.

Upvotes: 0

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