number of rows for laying out plots in a grid-like structure.
Only used if no domain is already specified.
widths
relative width of each column on a 0-1 scale. By default all
columns have an equal relative width.
heights
relative height of each row on a 0-1 scale. By default all
rows have an equal relative height.
margin
either a single value or four values (all between 0 and 1).
If four values are provided, the first is used as the left margin, the second
is used as the right margin, the third is used as the top margin, and the
fourth is used as the bottom margin.
If a single value is provided, it will be used as all four margins.
shareX
should the x-axis be shared amongst the subplots?
shareY
should the y-axis be shared amongst the subplots?
titleX
should x-axis titles be retained?
titleY
should y-axis titles be retained?
which_layout
adopt the layout of which plot? If the default value of
"merge" is used, layout options found later in the sequence of plots will
override options found earlier in the sequence. This argument also accepts a
numeric vector specifying which plots to consider when merging.