| % File src/library/grid/man/xDetails.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2007 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{xDetails} |
| \alias{xDetails} |
| \alias{yDetails} |
| \title{ Boundary of a grid grob } |
| \description{ |
| These generic functions are used to determine a location |
| on the boundary of a grid grob. |
| } |
| \usage{ |
| xDetails(x, theta) |
| yDetails(x, theta) |
| } |
| \arguments{ |
| \item{x}{ A grid grob. } |
| \item{theta}{ A numeric angle, in degrees, measured |
| anti-clockwise from the 3 o'clock \emph{or} one of |
| the following character strings: \code{"north"}, |
| \code{"east"}, \code{"west"}, \code{"south"}.} |
| } |
| \details{ |
| The location on the grob boundary is determined by taking |
| a line from the centre of the grob at the angle \code{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 |
| \code{"grobx"} and \code{"groby"} units as produced by |
| the \code{grobX} and \code{grobY} functions. |
| Methods should be written for classes derived from grob or gTree |
| where the boundary of the grob can be determined. |
| } |
| \value{ |
| A unit object. |
| } |
| \seealso{ |
| \code{\link{grobX}}, |
| \code{\link{grobY}}. |
| } |
| \author{ Paul Murrell } |
| \keyword{ dplot } |