| % File src/library/grid/man/grobCoords.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2007 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{grobCoords} |
| \alias{grobCoords} |
| \alias{grobPoints} |
| \alias{emptyCoords} |
| \alias{isEmptyCoords} |
| \title{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, \dots) |
| grobPoints(x, closed, \dots) |
| emptyCoords |
| isEmptyCoords(coords) |
| } |
| \arguments{ |
| \item{x}{A grob object.} |
| \item{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.} |
| \item{\dots}{Arguments to be used by methods.} |
| \item{coords}{A set of grob coordinates (as generated by \code{grobCoords}).} |
| } |
| \details{ |
| Custom grobs can write their own methods for \code{grobPoints}. |
| |
| The \code{emptyCoords} object can be used to return a "null" |
| result (e.g., when asking for \code{closed} coordinates on an |
| open line) and the \code{isEmptyCoords} function can be used to check for |
| "null" results. |
| } |
| \value{ |
| A list of lists with components \code{x} and \code{y}. |
| All locations are in inches relative to the current \pkg{grid} viewport. |
| } |
| \author{Paul Murrell} |
| \keyword{dplot} |