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<title>Qwt User's Guide: QwtWeedingCurveFitter Class Reference</title>
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<div id="projectname">Qwt User's Guide <span id="projectnumber">6.0.1</span></div>
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<h1>QwtWeedingCurveFitter Class Reference</h1> </div>
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<!-- doxytag: class="QwtWeedingCurveFitter" --><!-- doxytag: inherits="QwtCurveFitter" -->
<p>A curve fitter implementing Douglas and Peucker algorithm.
<a href="#_details">More...</a></p>
<p><code>#include <<a class="el" href="qwt__curve__fitter_8h_source.html">qwt_curve_fitter.h</a>></code></p>
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Inheritance diagram for QwtWeedingCurveFitter:</div>
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<div class="center"><img src="class_qwt_weeding_curve_fitter__inherit__graph.png" border="0" usemap="#_qwt_weeding_curve_fitter_inherit__map" alt="Inheritance graph"/></div>
<map name="_qwt_weeding_curve_fitter_inherit__map" id="_qwt_weeding_curve_fitter_inherit__map">
<area shape="rect" id="node2" href="class_qwt_curve_fitter.html" title="Abstract base class for a curve fitter." alt="" coords="31,5,137,35"/></map>
<center><span class="legend">[<a href="graph_legend.html">legend</a>]</span></center></div>
<p><a href="class_qwt_weeding_curve_fitter-members.html">List of all members.</a></p>
<table class="memberdecls">
<tr><td colspan="2"><h2><a name="pub-methods"></a>
Public Member Functions</h2></td></tr>
<tr><td class="memItemLeft" align="right" valign="top">virtual QPolygonF </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_weeding_curve_fitter.html#aa316dc6c60ae0d0c74ef0bc0fc239f0b">fitCurve</a> (const QPolygonF &) const </td></tr>
<tr><td class="memItemLeft" align="right" valign="top"> </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_weeding_curve_fitter.html#a7deb4d070a329cbdee454023194898a7">QwtWeedingCurveFitter</a> (double tolerance=1.0)</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_weeding_curve_fitter.html#a62c303f6826fef2be7b7bbe82f530680">setTolerance</a> (double)</td></tr>
<tr><td class="memItemLeft" align="right" valign="top">double </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_weeding_curve_fitter.html#aa2e69ce083d02c4da0d669a082a15187">tolerance</a> () const </td></tr>
<tr><td class="memItemLeft" align="right" valign="top">virtual </td><td class="memItemRight" valign="bottom"><a class="el" href="class_qwt_weeding_curve_fitter.html#abbd30a948fc6974f881678f80a29768c">~QwtWeedingCurveFitter</a> ()</td></tr>
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<hr/><a name="_details"></a><h2>Detailed Description</h2>
<div class="textblock"><p>A curve fitter implementing Douglas and Peucker algorithm. </p>
<p>The purpose of the Douglas and Peucker algorithm is that given a 'curve' composed of line segments to find a curve not too dissimilar but that has fewer points. The algorithm defines 'too dissimilar' based on the maximum distance (tolerance) between the original curve and the smoothed curve.</p>
<p>The smoothed curve consists of a subset of the points that defined the original curve.</p>
<p>In opposite to <a class="el" href="class_qwt_spline_curve_fitter.html" title="A curve fitter using cubic splines.">QwtSplineCurveFitter</a> the Douglas and Peucker algorithm reduces the number of points. By adjusting the tolerance parameter according to the axis scales <a class="el" href="class_qwt_spline_curve_fitter.html" title="A curve fitter using cubic splines.">QwtSplineCurveFitter</a> can be used to implement different level of details to speed up painting of curves of many points. </p>
</div><hr/><h2>Constructor & Destructor Documentation</h2>
<a class="anchor" id="a7deb4d070a329cbdee454023194898a7"></a><!-- doxytag: member="QwtWeedingCurveFitter::QwtWeedingCurveFitter" ref="a7deb4d070a329cbdee454023194898a7" args="(double tolerance=1.0)" -->
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<td class="memname">QwtWeedingCurveFitter::QwtWeedingCurveFitter </td>
<td>(</td>
<td class="paramtype">double </td>
<td class="paramname"><em>tolerance</em> = <code>1.0</code></td><td>)</td>
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<p>Constructor</p>
<dl><dt><b>Parameters:</b></dt><dd>
<table class="params">
<tr><td class="paramname">tolerance</td><td>Tolerance </td></tr>
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</dd>
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<dl class="see"><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_weeding_curve_fitter.html#a62c303f6826fef2be7b7bbe82f530680">setTolerance()</a>, <a class="el" href="class_qwt_weeding_curve_fitter.html#aa2e69ce083d02c4da0d669a082a15187">tolerance()</a> </dd></dl>
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<a class="anchor" id="abbd30a948fc6974f881678f80a29768c"></a><!-- doxytag: member="QwtWeedingCurveFitter::~QwtWeedingCurveFitter" ref="abbd30a948fc6974f881678f80a29768c" args="()" -->
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<td class="memname">QwtWeedingCurveFitter::~QwtWeedingCurveFitter </td>
<td>(</td>
<td class="paramname"></td><td>)</td>
<td><code> [virtual]</code></td>
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<p>Destructor. </p>
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<hr/><h2>Member Function Documentation</h2>
<a class="anchor" id="aa316dc6c60ae0d0c74ef0bc0fc239f0b"></a><!-- doxytag: member="QwtWeedingCurveFitter::fitCurve" ref="aa316dc6c60ae0d0c74ef0bc0fc239f0b" args="(const QPolygonF &) const " -->
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<td class="memname">QPolygonF QwtWeedingCurveFitter::fitCurve </td>
<td>(</td>
<td class="paramtype">const QPolygonF & </td>
<td class="paramname"><em>points</em></td><td>)</td>
<td> const<code> [virtual]</code></td>
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<dl><dt><b>Parameters:</b></dt><dd>
<table class="params">
<tr><td class="paramname">points</td><td>Series of data points </td></tr>
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</dd>
</dl>
<dl class="return"><dt><b>Returns:</b></dt><dd>Curve points </dd></dl>
<p>Implements <a class="el" href="class_qwt_curve_fitter.html#afa9bf5b328aa553229e204533a60fec0">QwtCurveFitter</a>.</p>
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<a class="anchor" id="a62c303f6826fef2be7b7bbe82f530680"></a><!-- doxytag: member="QwtWeedingCurveFitter::setTolerance" ref="a62c303f6826fef2be7b7bbe82f530680" args="(double)" -->
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<td class="memname">void QwtWeedingCurveFitter::setTolerance </td>
<td>(</td>
<td class="paramtype">double </td>
<td class="paramname"><em>tolerance</em></td><td>)</td>
<td></td>
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<p>Assign the tolerance</p>
<p>The tolerance is the maximum distance, that is accaptable between the original curve and the smoothed curve.</p>
<p>Increasing the tolerance will reduce the number of the resulting points.</p>
<dl><dt><b>Parameters:</b></dt><dd>
<table class="params">
<tr><td class="paramname">tolerance</td><td>Tolerance</td></tr>
</table>
</dd>
</dl>
<dl class="see"><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_weeding_curve_fitter.html#aa2e69ce083d02c4da0d669a082a15187">tolerance()</a> </dd></dl>
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<a class="anchor" id="aa2e69ce083d02c4da0d669a082a15187"></a><!-- doxytag: member="QwtWeedingCurveFitter::tolerance" ref="aa2e69ce083d02c4da0d669a082a15187" args="() const " -->
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<td class="memname">double QwtWeedingCurveFitter::tolerance </td>
<td>(</td>
<td class="paramname"></td><td>)</td>
<td> const</td>
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<dl class="return"><dt><b>Returns:</b></dt><dd>Tolerance </dd></dl>
<dl class="see"><dt><b>See also:</b></dt><dd><a class="el" href="class_qwt_weeding_curve_fitter.html#a62c303f6826fef2be7b7bbe82f530680">setTolerance()</a> </dd></dl>
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