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<?xml-stylesheet type="text/xsl" href="mathml.xsl"?><html xmlns="http://www.w3.org/1999/xhtml" xmlns:pref="http://www.w3.org/2002/Math/preference" pref:renderer="mathplayer-dl"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>glLineWidth</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1" /></head><body><div class="refentry"><a id="glLineWidth"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>glLineWidth — specify the width of rasterized lines</p></div><div class="refsynopsisdiv"><h2>C Specification</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <strong class="fsfunc">glLineWidth</strong>(</code></td><td>GLfloat <var class="pdparam">width</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">void <strong class="fsfunc">glLineWidthx</strong>(</code></td><td>GLfixed <var class="pdparam">width</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a id="parameters"></a><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term">
                    <em class="parameter"><code>width</code></em>
                </span></dt><dd><p>Specifies the width of rasterized lines. The
                    initial value is 1.</p></dd></dl></div></div><div class="refsect1"><a id="description"></a><h2>Description</h2><p>
        <code class="function">glLineWidth</code>
        specifies the rasterized width of both aliased and antialiased
        lines. Using a line width other than 1 has different effects,
        depending on whether line antialiasing is enabled. To enable
        and disable line antialiasing, call
        <a class="citerefentry" href="glEnable.xml"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a> and
        <a class="citerefentry" href="glDisable.xml"><span class="citerefentry"><span class="refentrytitle">glDisable</span></span></a>
        with argument <code class="constant">GL_LINE_SMOOTH</code>.
        Line antialiasing is initially disabled.</p><p>If line antialiasing is disabled, the actual width is
        determined by rounding the supplied width to the nearest
        integer. (If the rounding results in the value 0, it is as if
        the line width were 1.) If
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        <em class="parameter"><code>i</code></em>
        pixels are filled in each column that is rasterized, where
        <em class="parameter"><code>i</code></em> is the rounded value of
        <em class="parameter"><code>width</code></em>. Otherwise, <em class="parameter"><code>i</code></em>
        pixels are filled in each row that is rasterized.</p><p>If antialiasing is enabled, line rasterization produces a
        fragment for each pixel square that intersects the region lying
        within the rectangle having width equal to the current line
        width, length equal to the actual length of the line, and
        centered on the mathematical line segment. The coverage value
        for each fragment is the window coordinate area of the
        intersection of the rectangular region with the corresponding
        pixel square. This value is saved and used in the final
        rasterization step.</p><p>Not all widths can be supported when line antialiasing is
        enabled. If an unsupported width is requested, the nearest
        supported width is used. Only width 1 is guaranteed to be
        supported; others depend on the implementation. Likewise, there
        is a range for aliased line widths as well. To query the range
        of supported widths, call
        <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        with arguments
        <code class="constant">GL_ALIASED_LINE_WIDTH_RANGE</code> or
        <code class="constant">GL_SMOOTH_LINE_WIDTH_RANGE</code>.</p></div><div class="refsect1"><a id="notes"></a><h2>Notes</h2><p>Nonantialiased line width may be clamped to an
        implementation-dependent maximum. Call
        <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        with <code class="constant">GL_ALIASED_LINE_WIDTH_RANGE</code>
        to determine the maximum width.</p></div><div class="refsect1"><a id="errors"></a><h2>Errors</h2><p><code class="constant">GL_INVALID_VALUE</code> is generated if
        <em class="parameter"><code>width</code></em> is less than or equal to 0.</p></div><div class="refsect1"><a id="associatedgets"></a><h2>Associated Gets</h2><p>
        <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        with argument <code class="constant">GL_ALIASED_LINE_WIDTH_RANGE</code></p><p>
        <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        with argument <code class="constant">GL_SMOOTH_LINE_WIDTH_RANGE</code></p></div><div class="refsect1"><a id="seealso"></a><h2>See Also</h2><p>
        <a class="citerefentry" href="glEnable.xml"><span class="citerefentry"><span class="refentrytitle">glEnable</span></span></a>,
        <a class="citerefentry" href="glGet.xml"><span class="citerefentry"><span class="refentrytitle">glGet</span></span></a>
        </p></div><div class="refsect1"><a id="copyright"></a><h2>Copyright</h2><p>
            Copyright <span class="trademark"></span>© 2003-2004
            Silicon Graphics, Inc. This document is licensed under the SGI
            Free Software B License. For details, see
            <a class="ulink" href="http://oss.sgi.com/projects/FreeB/" target="_top">http://oss.sgi.com/projects/FreeB/</a>.
        </p></div></div></body></html>