These generic functions are used to determine a location on the boundary of a grid grob.
xDetails(x, theta)
yDetails(x, theta)A grid grob.
A numeric angle, in degrees, measured
anti-clockwise from the 3 o'clock or one of
the following character strings: "north",
"east", "west", "south".
A unit object.
The location on the grob boundary is determined by taking
a line from the centre of the grob at the angle theta
and intersecting it with the convex hull of the grob
(for the basic
grob primitives, the centre is
determined as half way between the minimum and maximum values
in x and y directions).
These functions are called in the calculation of
"grobx" and "groby" units as produced by
the grobX and grobY functions.
Methods should be written for classes derived from grob or gTree
where the boundary of the grob can be determined.