The computed margins can be overridden by the margin commands. margin shows the current settings.
Syntax:
set bmargin {{at screen} <margin>}
set lmargin {{at screen} <margin>}
set rmargin {{at screen} <margin>}
set tmargin {{at screen} <margin>}
show margin
The default units of <margin> are character heights or widths, as appropriate. A positive value defines the absolute size of the margin. A negative value (or none) causes `gnuplot` to revert to the computed value. For 3D plots, only the left margin can be set using character units.
The keywords `at screen` indicates that the margin is specified as a fraction of the full drawing area. This can be used to precisely line up the corners of individual 2D and 3D graphs in a multiplot. This placement ignores the current values of origin and size, and is intended as an alternative method for positioning graphs within a multiplot.
Normally the margins of a plot are automatically calculated based on tics, tic labels, axis labels, the plot title, the timestamp and the size of the key if it is outside the borders. If, however, tics are attached to the axes (`set xtics axis`, for example), neither the tics themselves nor their labels will be included in either the margin calculation or the calculation of the positions of other text to be written in the margin. This can lead to tic labels overwriting other text if the axis is very close to the border.