102 lines
3.3 KiB
HTML
102 lines
3.3 KiB
HTML
<!-- Creator : groff version 1.24.1 -->
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<!-- CreationDate: Mon Mar 16 21:28:01 2026 -->
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
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"http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta name="generator" content="groff -Thtml, see www.gnu.org">
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
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<meta name="Content-Style" content="text/css">
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<style type="text/css">
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p { margin-top: 0; margin-bottom: 0; vertical-align: top }
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pre { margin-top: 0; margin-bottom: 0; vertical-align: top }
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table { margin-top: 0; margin-bottom: 0; vertical-align: top }
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h1 { text-align: center }
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</style>
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<title>pic-8.html</title>
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</head>
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<hr>
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[ <a href="pic-7.html">prev</a> | <a href="pic-9.html">next</a> | <a href="pic.html">top</a> ]
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<hr>
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<h2>8. More About Direction Changes
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<a name="8. More About Direction Changes"></a>
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</h2>
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<p style="margin-top: 1em"><font color="#000000">We’ve
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already seen how to change the direction in which objects
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are composed from rightward to downward. Here are some more
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illustrative examples:</font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000"><img src="img/pic-27.png" alt="Image img/pic-27.png"></font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000">Figure
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8-1: Effects of different motion directions (right and
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left)</font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000"><img src="img/pic-28.png" alt="Image img/pic-28.png"></font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000">Figure
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8-2: Effects of different motion directions (up and
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down)</font></p>
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<p style="margin-top: 1em"><font color="#000000">Something
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that may appear surprising happens if you change directions
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in the obvious way:</font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000"><img src="img/pic-29.png" alt="Image img/pic-29.png"></font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000">Figure
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8-3: <b>box; arrow; circle; down; arrow;
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ellipse</b></font></p>
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<p style="margin-top: 1em"><font color="#000000">You might
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have expected that program to yield this:</font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000"><img src="img/pic-30.png" alt="Image img/pic-30.png"></font></p>
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<p align="center" style="margin-top: 1em"><font color="#000000">Figure
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8-4: More intuitive?</font></p>
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<p style="margin-top: 1em"><font color="#000000">But, in
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fact, to get Figure 8.3 you have to do this:</font></p>
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<p style="margin-left:28%; margin-top: 1em"><font color="#000000">.PS
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<br>
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box; <br>
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arrow; <br>
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circle; <br>
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move to last circle .s; <br>
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down; <br>
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arrow; <br>
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ellipse <br>
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.PE</font></p>
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<p style="margin-top: 1em"><font color="#000000">Why is
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this? Because the exit point for the current direction is
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already set when you draw the object. The second arrow in
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Figure 8.2 dropped downward from the circle’s
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attachment point for an object to be joined to the
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right.</font></p>
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<p style="margin-top: 1em"><font color="#000000">The
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meaning of the command <b>move to last circle .s</b> should
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be obvious. In order to see how it generalizes, we’ll
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need to go into detail on two important topics; locations
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and object names.</font></p>
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<hr>
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[ <a href="pic-7.html">prev</a> | <a href="pic-9.html">next</a> | <a href="pic.html">top</a> ]
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<hr>
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