/usr/share/doc/python-visual/html/arrow.html is in python-visual 1:5.12-1.6build1.
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<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>arrow</title>
<!-- InstanceEndEditable -->
<!-- InstanceBeginEditable name="head" -->
<link href="VisualRef.css" rel="stylesheet" type="text/css" />
<style type="text/css">
<!--
.style1 {font-size: x-large}
-->
</style>
<style type="text/css">
<!--
.style2 {font-size: xx-large}
-->
</style>
<!-- InstanceEndEditable -->
<script type="text/javascript">
<!--
function MM_jumpMenu(targ,selObj,restore){ //v3.0
eval(targ+".location='"+selObj.options[selObj.selectedIndex].value+"'");
if (restore) selObj.selectedIndex=0;
}
//-->
</script>
<link href="VisualRef.css" rel="stylesheet" type="text/css" />
</head>
<body>
<table width="800" border="0" cellpadding="0" cellspacing="0">
<!--DWLayoutDefaultTable-->
<tr>
<td width="10" valign="top" bgcolor="#FFFFFF"><!--DWLayoutEmptyCell--> </td>
<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>
<select name="jumpMenu4" id="jumpMenu4" onchange="MM_jumpMenu('parent',this,0)">
<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>
<option value="faces.html">faces</option>
<option value="frame.html">frame</option>
<option value="helix.html">helix</option>
<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>
</select>
<p class="Normal">Work with 3D objects:</p>
<select name="jumpMenu4" id="jumpMenu5" onchange="MM_jumpMenu('parent',this,0)">
<option>Choose an option</option>
<option value="color.html">Color & Opacity</option>
<option value="lights.html">Lighting</option>
<option value="materials.html">Materials & Textures</option>
<option value="defaults.html">Defaults</option>
<option value="rate.html">Animation Speed</option>
<option value="rotation.html">Rotations</option>
<option value="options.html">Additional Options</option>
<option value="delete.html">Delete an Object</option>
<option value="float.html">3/4 = 0?</option>
</select>
<p class="Normal">Windows, Events, & Files:</p>
<select name="jumpMenu4" id="jumpMenu6" onchange="MM_jumpMenu('parent',this,0)">
<option>Choose a topic</option>
<option value="display.html">Windows</option>
<option value="lights.html">Lighting</option>
<option value="mouse.html">Mouse Events</option>
<option value="mouse_click.html"> Mouse Click</option>
<option value="mouse_drag.html"> Mouse Drag</option>
<option value="keyboard.html">Keyboard Events</option>
<option value="controls.html">Buttons and Sliders</option>
<option value="files.html">Reading/Writing Files</option>
</select>
<p class="Normal"><a href="vector.html">Vector operations </a></p>
<p class="Normal"><a href="graph.html">Graphs</a></p>
<p class="Normal"><a href="factorial.html">factorial/combin</a></p>
<p class="Normal">What's new in <a href="new_features.html">Visual 5</a></p>
<p class="Normal"><a href="http://vpython.org" target="_blank">VPython web site</a><br />
<a href="license.txt" target="_blank">Visual license</a><br />
<a href="http://www.python.org" target="_blank">Python web site</a> <br />
<a href="http://www.python.org/doc/2.5.2/lib/module-math.html" target="_blank">Math module</a> (sqrt etc.)<br />
<a href="http://www.scipy.org/Documentation" target="_blank">Numpy module</a> (arrays) </p></td>
<td width="21" valign="top" bgcolor="#FFFFFF"><!--DWLayoutEmptyCell--> </td>
<td width="586" rowspan="2" valign="top"><!-- InstanceBeginEditable name="content" -->
<table width="100%" border="1">
<tr>
<td width="77%"><div align="center"><span class="style1 style2"><font color="#0000A0">arrow</font></span></div></td>
<td width="23%"><img src="images/arrow.jpg" alt="arrow" width="130" height="127" /></td>
</tr>
</table>
<div></div>
<div>
<p class="Normal"> <img src="VisualRef-2.gif" alt="arrow" align="right" /> The arrow object has a straight box-shaped shaft with an arrowhead at one end. The following statement will display an arrow pointing parallel to the x axis:</p>
<div>
<p class="program"> pointer = arrow(pos=(0,2,1), axis=(5,0,0), shaftwidth=1)</p>
<p class="Normal"> The arrow object has the following attributes and
default values, like those for cylinders: <span class="attribute">pos<font color="#000000"> (0,0,0)</font></span>, <span class="attribute">x</span><span class="attribute"><font color="#000000"> (0)</font></span>, <span class="attribute">y<font color="#000000">(0)</font></span>, <span class="attribute">z<font color="#000000">(0)</font></span>, <span class="attribute">axis<font color="#000000"> (1,0,0)</font></span>, <span class="attribute">length<font color="#000000"> (1)</font></span>, <span class="attribute">color<font color="#000000"> (1,1,1)
which is color.white</font></span>, <span class="attribute">red<font color="#000000"> (1)</font></span>, <span class="attribute">green<font color="#000000"> (1)</font></span>, <span class="attribute">blue<font color="#000000"> (1)</font></span>,
<span class="attribute">opacity</span> (1), <a href="materials.html">material</a>,
and <span class="attribute">up<font color="#000000"> (0,1,0)</font></span>.
As with <a href="box.html">box</a>, the <span class="attribute">up</span> attribute
is significant for arrow because the shaft and head have square
cross sections, and setting the <em class="program"> </em><span class="attribute">up</span> attribute
rotates the arrow about its axis. Additional arrow attributes:</p>
<p class="attributes"> <span class="attribute">shaftwidth</span> By default, shaftwidth
= 0.1*(length of arrow)</p>
<p class="attributes"> <span class="attribute">headwidth</span> By default, headwidth
= 2*shaftwidth</p>
<p class="attributes"> <span class="attribute">headlength</span> By default, headlength
= 3*shaftwidth</p>
<p class="Normal"> Assigning <span class="attribute">shaftwidth = 0</span> makes it be the default (0.1 times the length of the arrow). If you don't explicitly set <span class="attribute">headwidth</span> or <span class="attribute">headlength</span>, its length is based as shown above on <span class="attribute">shaftwidth</span> (either the default or whatever value you specify for <span class="attribute">shaftwidth</span>). If <span class="attribute">headlength</span> becomes larger than half the length of the arrow, or the shaft becomes thinner
than 1/50 the length, the entire arrow is scaled accordingly.</p>
<p class="Normal">This default behavior makes the widths of very short arrows
shrink, and the widths of very long arrows grow (while displaying the correct
total length). If you prefer that <span class="attribute">shaftwidth</span> and <span class="attribute">headwidth</span> not change as the arrow gets
very short or very long, set <span class="attribute">fixedwidth = 1</span>.
In this case the only adjustment that is made is that <span class="attribute">headlength</span> is adjusted so that it never gets longer than half the total length, so
that the total length of the arrow is correct. This means that very short,
thick arrows look similar to a thumbtack, with a nearly flat head.</p>
<p class="Normal">Note that the <span class="attribute">pos</span> attribute
for cylinder, arrow, cone, and pyramid corresponds to one end of the object,
whereas for a box, sphere, or ring it corresponds to the center of the object. </p>
<p class="Normal">See description of <a href="options.html">Additional
Attributes</a> available for all 3D display objects.</p>
<p class="Normal"> </p>
</div>
</div>
<div> </div>
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</tr>
<tr>
<td height="16" colspan="4"></td>
</tr>
</table>
</body>
<!-- InstanceEnd --></html>
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