168 lines
5.6 KiB
HTML
168 lines
5.6 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-4.html</title>
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</head>
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<hr>
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[ <a href="pic-3.html">prev</a> | <a href="pic-5.html">next</a> | <a href="pic.html">top</a> ]
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<hr>
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<h2>4. Sizes and Spacing
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<a name="4. Sizes and Spacing"></a>
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</h2>
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<p style="margin-top: 1em">Sizes are specified in inches.
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If you don’t like inches, it’s possible to set a
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global style variable <b>scale</b> that changes the unit.
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Setting <b>scale = 2.54</b> effectively changes the internal
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unit to centimeters (all other size variable values are
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scaled correspondingly).</p>
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<h3>4.1. Default Sizes of Objects
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<a name="4.1. Default Sizes of Objects"></a>
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</h3>
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<p style="margin-top: 1em">Here are the default sizes for
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<b>pic</b> objects:</p>
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<p align="center"><img src="img/pic-8.png" alt="Image img/pic-8.png"></p>
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<p style="margin-top: 1em">The simplest way to think about
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these defaults is that they make the other basic objects fit
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snugly into a default-sized box.</p>
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<p style="margin-top: 1em"><i>pic2plot</i>(1) does not
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necessarily emit a physical inch for each virtual inch in
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its drawing coordinate system. Instead, it draws on a canvas
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8 virtual inches by 8 virtual inches wide. If its
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output page size is “letter”, these virtual
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inches will map to real ones. Specifying a different page
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size (such as, say, “a4”) will scale virtual
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inches so they are output as one eighth of the page width.
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Also, <i>pic2plot</i>(1) centers all images by default,
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though the <b>−n</b> option can be used to prevent
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this.</p>
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<h3>4.2. Objects Do Not Stretch!
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<a name="4.2. Objects Do Not Stretch!"></a>
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</h3>
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<p style="margin-top: 1em">Text is rendered in the current
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font with normal troff line spacing. Boxes, circles, and
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ellipses do <i>not</i> automatically resize to fit enclosed
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text. Thus, if you say <b>box "this text far too long
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for a default box"</b> you’ll get this:</p>
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<p align="center" style="margin-top: 1em"><img src="img/pic-9.png" alt="Image img/pic-9.png"></p>
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<p align="center" style="margin-top: 1em">F i g u r e 4 - 1
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: B o x e s d o n o t a u t o m a t i c a l l y r e s i z
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e</p>
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<p style="margin-top: 1em">which is probably not the effect
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you want.</p>
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<h3>4.3. Resizing Boxes
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<a name="4.3. Resizing Boxes"></a>
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</h3>
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<p style="margin-top: 1em">To change the box size, you can
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specify a box width with the “width”
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modifier:</p>
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<p align="center" style="margin-top: 1em"><img src="img/pic-10.png" alt="Image img/pic-10.png"></p>
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<p align="center" style="margin-top: 1em">Figure 4-2:
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Result of <b>box width 3 "text far too
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long"</b></p>
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<p style="margin-top: 1em">This modifier takes a dimension
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in inches. There is also a “height” modifier
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that changes a box’s height. The <b>width</b> keyword
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may be abbreviated to <b>wid</b>; the <b>height</b> keyword
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to <b>ht</b>.</p>
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<h3>4.4. Resizing Other Object Types
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<a name="4.4. Resizing Other Object Types"></a>
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</h3>
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<p style="margin-top: 1em">To change the size of a circle,
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give it a <b>rad[ius]</b> or <b>diam[eter]</b> modifier;
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this changes the radius or diameter of the circle, according
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to the numeric argument that follows.</p>
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<p align="center" style="margin-top: 1em"><img src="img/pic-11.png" alt="Image img/pic-11.png"></p>
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<p align="center" style="margin-top: 1em">Figure 4-3:
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Circles with increasing radii</p>
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<p style="margin-top: 1em">The <b>move</b> command can also
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take a dimension, which just tells it how many inches to
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move in the current direction.</p>
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<p style="margin-top: 1em">Ellipses are sized to fit in the
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rectangular box defined by their axes, and can be resized
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with <b>width</b> and <b>height</b> like boxes.</p>
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<p style="margin-top: 1em">You can also change the radius
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of curvature of an arc with <b>rad[ius]</b> (which specifies
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the radius of the circle of which the arc is a segment).
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Larger values yield flatter arcs.</p>
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<p align="center" style="margin-top: 1em"><img src="img/pic-12.png" alt="Image img/pic-12.png"></p>
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<p align="center" style="margin-top: 1em">Figure 4-4:
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<b>arc rad</b> with increasing radii</p>
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<p style="margin-top: 1em">Observe that because an arc is
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defined as a quarter circle, increasing the radius also
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increases the size of the arc’s bounding box.</p>
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<h3>4.5. The ‘same’ Keyword
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<a name="4.5. The ‘same’ Keyword"></a>
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</h3>
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<p style="margin-top: 1em">In place of a dimension
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specification, you can use the keyword <b>same</b>. This
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gives the object the same size as the previous one of its
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type. As an example, the program</p>
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<p style="margin-left:28%; margin-top: 1em">.PS <br>
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box; box wid 1 ht 1; box same; box <br>
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.PE</p>
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<p style="margin-top: 1em">gives you</p>
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<p align="center" style="margin-top: 1em"><img src="img/pic-13.png" alt="Image img/pic-13.png"></p>
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<p align="center" style="margin-top: 1em">Figure 4-5: The
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<b>same</b> keyword</p>
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<hr>
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[ <a href="pic-3.html">prev</a> | <a href="pic-5.html">next</a> | <a href="pic.html">top</a> ]
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<hr>
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