Decide plot panel rows, columns for graphics::par(mfrow)

Usage

decideMfrow(
  n,
  method = c("aspect", "wide", "tall"),
  doTest = FALSE,
  xyratio = 1,
  trimExtra = TRUE,
  ...
)

Arguments

n

integer number of plot panels

method

character string indicating the type of layout to favor.

"aspect"

uses the device size and aspect ratio of the plot to try to maintain roughly square plot panels.

"wide"

tries to keep the columns and rows similar, erring on the side of more columns than rows.

"tall"

tries to keep the columns and rows similar, erring on the side of more rows than columns.

doTest

logical whether to provide a visual test. Note that n is required as the number of plot panels requested.

xyratio

numeric default 1, with the desired target x-to-y ratio. For example, to have plots slightly wider (x width) than tall (y height), use xyratio=1.3. The observed device aspect ratio is divided by xyratio to determine the target aspect ratio of plot panels.

trimExtra

logical default TRUE, whether to trim blank rows or columns in the expected layout when it would be entirely blank. For example, n=4 may produce c(3, 2) output to meet the desired aspect ratio, however with trimExtra=TRUE it would be reduced to c(2, 2) to minimize unused whitespace.

...

additional parameters are ignored.

Value

numeric vector length=2, with the recommended number of plot rows and columns, respectively. It is intended to be used directly in this form: graphics::par("mfrow"=decideMfrow(n=5))

Details

This function returns the recommended rows and columns of panels to be used in graphics::par("mfrow") with R base plotting. It attempts to use the device size and plot aspect ratio to keep panels roughly square. For example, a short-wide device would have more columns of panels than rows; a tall-thin device would have more rows than columns.

The doTest=TRUE argument will create n number of panels with the recommended layout, as a visual example.

Note this function calls getPlotAspect(), therefore if no plot device is currently open, the call to graphics::par() will open a new graphics device.

See also

Examples

# display a test visualization showing 6 panels
withr::with_par(list("mar"=c(2, 2, 2, 2)), {
decideMfrow(n=6, doTest=TRUE);
})

#> [1] 3 2

# use a custom target xyratio of plot panels
withr::with_par(list("mar"=c(2, 2, 2, 2)), {
decideMfrow(n=3, xyratio=3, doTest=TRUE);
})

#> [1] 3 1

# a manual demonstration creating 6 panels
n <- 6;
withr::with_par(list(
   "mar"=c(2, 2, 2, 2),
   "mfrow"=decideMfrow(n)), {
for(i in seq_len(n)){
   nullPlot(plotAreaTitle=paste("Plot", i));
}
})