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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><title>R: Create a Unit Describing a Grob Boundary Location</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<table width="100%" summary="page for grobX {grid}"><tr><td>grobX {grid}</td><td align="right">R Documentation</td></tr></table>
<h2>Create a Unit Describing a Grob Boundary Location</h2>
<h3>Description</h3>
<p>
These functions create a unit object describing a location somewhere
on the boundary of
a grob. They are generic.
</p>
<h3>Usage</h3>
<pre>
grobX(x, theta)
grobY(x, theta)
</pre>
<h3>Arguments</h3>
<table summary="R argblock">
<tr valign="top"><td><code>x</code></td>
<td>
A grob, or gList, or gTree, or gPath.</td></tr>
<tr valign="top"><td><code>theta</code></td>
<td>
An angle indicating where the location is
on the grob boundary. Can be one of <code>"east"</code>,
<code>"north"</code>, <code>"west"</code>, or <code>"south"</code>,
which correspond to angles 0, 90, 180, and 270,
respectively.</td></tr>
</table>
<h3>Details</h3>
<p>
The angle is anti-clockwise with zero corresponding to a line
with an origin centred between the extreme
points of the shape, and pointing at 3 o'clock.
</p>
<p>
If the grob describes a single shape, the boundary value should
correspond to the exact edge of the shape.
</p>
<p>
If the grob describes multiple shapes, in most cases, the boundary
value will correspond to the edge of a bounding box around all of
the shapes. The exception to this is a polygon grob describing
multiple polygons; in that case, the edge corresponds to a
convex hull around all points of all polygons described by the grob.
</p>
<h3>Value</h3>
<p>
A unit object.</p>
<h3>Author(s)</h3>
<p>
Paul Murrell
</p>
<h3>See Also</h3>
<p>
<code><a href="unit.html">unit</a></code> and
<code><a href="grobWidth.html">grobWidth</a></code>
</p>
<hr><div align="center">[Package <em>grid</em> version 2.5.1 <a href="00Index.html">Index]</a></div>
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