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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><!-- InstanceBegin template="/visual/Templates/template.dwt" codeOutsideHTMLIsLocked="false" -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- InstanceBeginEditable name="doctitle" -->
<title>label</title>
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function MM_jumpMenu(targ,selObj,restore){ //v3.0
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<td width="10" height="272" valign="top" bgcolor="#DDDDDD"><p> </p> </td>
<td width="173" valign="top" bgcolor="#DDDDDD"><p class="Normal"><a href="index.html">Home</a></p>
<p class="Normal">If you're new to Python <br />
and VPython: <a href="VisualIntro.html">Introduction</a></p>
<p class="Normal">A VPython <a href="VPython_Intro.pdf" target="_blank">tutorial</a></p>
<p class="Normal"><a href="primitives.html">Pictures</a> of 3D objects</p>
<p class="Normal">Choose a 3D object:</p>
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<option>Choose an object</option>
<option value="cylinder.html">Overview</option>
<option value="arrow.html">arrow</option>
<option value="box.html">box</option>
<option value="cone.html">cone</option>
<option value="convex.html">convex</option>
<option value="curve.html">curve</option>
<option value="cylinder.html">cylinder</option>
<option value="ellipsoid.html">ellipsoid</option>
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<option value="label.html">label</option>
<option value="lights.html">lights</option>
<option value="points.html">points</option>
<option value="pyramid.html">pyramid</option>
<option value="ring.html">ring</option>
<option value="sphere.html">sphere</option>
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<td width="586" rowspan="2" valign="top"><!-- InstanceBeginEditable name="content" -->
<table width="100%" border="1">
<tr>
<td width="77%"><div align="center"><span class="style2"><font color="#0000A0">label</font></span></div></td>
<td width="23%"><div align="center"><img src="images/label.jpg" alt="label" width="131" height="127" /><a href="arrow.html"></a></div></td>
</tr>
</table>
<p class="Normal"> With the label object you can display text in a box. Here
are simple examples (in the second label statement, note the standard Python
scheme for formatting numerical values, where 1.5f means 1 figure before the
decimal point and 5 after):</p>
<p class="program"> box(pos=(0,0,0), color=color.red)<br />
label(pos=(0,0.25,0), text='This is a box')<br />
label(pos=(0,-0.25,0), text='pi = %1.5f' % pi)
<p class="Normal"><img src="VisualRef-7.gif" alt="label" align="right" /> There are many additional
label options. In the accompanying diagram, a sphere representing the Earth
(whose center is at <span class="attribute"> earth.pos</span>) has an associated
label with the text "Earth" in a box, connected to the sphere
by a line which stops at the surface of the sphere:</p>
<p class="program"> earthlabel = label(pos=earth.pos,<br />
text='Earth', xoffset=20,<br />
yoffset=12, space=earth.radius,<br />
height=10, border=6,<br />
font='sans')</p>
<p class="Normal"> A unique feature of the label object is that several attributes
are given in terms of screen pixels instead of the usual "world-space"
coordinates. For example, the height of the text is given in pixels, with
the result that the text remains readable even when the sphere object is
moved far away. Other pixel-oriented attributes include <span class="attribute">xoffset</span>, <span class="attribute">yoffset</span>, and <span class="attribute">border</span>.
Here are the label attributes:</p>
<p class="attributes"> <span class="attribute">pos</span>; <span class="attribute">x</span>,<span class="attribute">y</span>,<span class="attribute">z</span> The
point in world space being labeled. If there are no offsets (see
diagram), the center of the text is at <span class="attribute">pos</span></p>
<p class="attributes"> <span class="attribute">xoffset</span>, <span class="attribute">yoffset</span> The
x and y components of the line, in pixels (see diagram). You can <span class="style1">left
justify </span>text
by setting xoffset = 1 and line = 0 (so the 1-pixel line doesn't show),
or <strong><span class="attribute">right-justify</span></strong> text
by setting xoffset = -1 and line = 0.</p>
<p class="attributes"> <span class="attribute">text</span> The text to be
displayed, such as 'Earth'<br />
(Line breaks can be included as \n, as in label.text = "Three\nlines\nof
text")</p>
<p class="attributes"> <span class="attribute">font</span> Name of the desired
font; for example, 'sans', or 'serif', or 'monospace' (fixed-width)<br />
Python Unicode strings are supported.</p>
<p class="attributes"> <span class="attribute">height</span> Height
of the font in pixels; default is 13 pixels</p>
<p class="attributes"> <span class="attribute">color</span>, <span class="attribute">red</span>, <span class="attribute">green</span>, <span class="attribute">blue</span> Color of the text</p>
<p class="attributes"> <span class="attribute">opacity</span> Opacity of the
background of the box, default 0.66<br />
(0 transparent, 1 opaque, for objects behind the box)</p>
<p class="attributes"> <span class="attribute">border</span> Distance
in pixels from the text to the surrounding box; default is 5 pixels</p>
<p class="attributes"> <span class="attribute">box</span> True if the box should
be drawn (default), else False</p>
<p class="attributes"> <span class="attribute">line</span> True if the line from
the box to pos should be drawn (default), else False</p>
<p class="attributes"> <span class="attribute">linecolor</span> Color of the line
and box</p>
<p class="attributes"> <span class="attribute">space</span> World-space radius
of a sphere surrounding pos,<br />
into which the connecting line does not go</p>
<p class="Normal"></p>
<p class="Normal">See description of <a href="options.html">Additional
Attributes</a> available for all 3D display objects.</p>
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<tr>
<td height="16" colspan="4"></td>
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