grid (version 3.6.0)

grobCoords: Calculate Points on the Perimeter of a Grob

Description

These functions calculate points along the perimeter (or length) of a grob.

Usage

grobCoords(x, closed, …)
grobPoints(x, closed, …)
emptyCoords
isEmptyCoords(coords)

Arguments

x

A grob object.

closed

Whether we are asking for points along the perimeter of a closed object or points along the length of an open object. Some grobs (e.g., X-splines) can do both.

Arguments to be used by methods.

coords

A set of grob coordinates (as generated by grobCoords).

Value

A list of lists with components x and y. All locations are in inches relative to the current grid viewport.

Details

Custom grobs can write their own methods for grobPoints.

The emptyCoords object can be used to return a "null" result (e.g., when asking for closed coordinates on an open line) and the isEmptyCoords function can be used to check for "null" results.