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<h1>qwt_rect.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************</span>
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<a name="l00002"></a>00002 <span class="comment"> * Qwt Widget Library</span>
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<a name="l00003"></a>00003 <span class="comment"> * Copyright (C) 1997 Josef Wilgen</span>
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<a name="l00004"></a>00004 <span class="comment"> * Copyright (C) 2002 Uwe Rathmann</span>
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<a name="l00005"></a>00005 <span class="comment"> * </span>
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<a name="l00006"></a>00006 <span class="comment"> * This library is free software; you can redistribute it and/or</span>
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<a name="l00007"></a>00007 <span class="comment"> * modify it under the terms of the Qwt License, Version 1.0</span>
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<a name="l00008"></a>00008 <span class="comment"> *****************************************************************************/</span>
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<a name="l00009"></a>00009
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<a name="l00010"></a>00010 <span class="preprocessor">#include "qwt_math.h"</span>
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<a name="l00011"></a>00011 <span class="preprocessor">#include "qwt_rect.h"</span>
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<a name="l00012"></a>00012
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<a name="l00014"></a>00014
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<a name="l00015"></a><a class="code" href="class_qwt_rect.html#b06079fec7a47319073964ca9f3d6e08">00015</a> <a class="code" href="class_qwt_rect.html#b06079fec7a47319073964ca9f3d6e08">QwtRect::QwtRect</a>():
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<a name="l00016"></a>00016 QRect()
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<a name="l00017"></a>00017 {
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<a name="l00018"></a>00018 }
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<a name="l00019"></a>00019
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<a name="l00021"></a><a class="code" href="class_qwt_rect.html#bc5572f7565f289c6db54482933ea99c">00021</a> <a class="code" href="class_qwt_rect.html#b06079fec7a47319073964ca9f3d6e08">QwtRect::QwtRect</a>(<span class="keyword">const</span> QRect &r):
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<a name="l00022"></a>00022 QRect(r)
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<a name="l00023"></a>00023 {
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<a name="l00024"></a>00024 }
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<a name="l00025"></a>00025
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<a name="l00026"></a>00026 <span class="keyword">inline</span> <span class="keyword">static</span> <span class="keywordtype">void</span> addPoint(QwtPolygon &pa, uint pos, <span class="keyword">const</span> QPoint &point)
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<a name="l00027"></a>00027 {
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<a name="l00028"></a>00028 <span class="keywordflow">if</span> ( uint(pa.size()) <= pos )
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<a name="l00029"></a>00029 pa.resize(pos + 5);
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<a name="l00030"></a>00030
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<a name="l00031"></a>00031 pa.setPoint(pos, point);
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<a name="l00032"></a>00032 }
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<a name="l00033"></a>00033
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<a name="l00035"></a>00035
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<a name="l00036"></a><a class="code" href="class_qwt_rect.html#89bfabf3416a3b535451a83e91a12d13">00036</a> QwtPolygon <a class="code" href="class_qwt_rect.html#89bfabf3416a3b535451a83e91a12d13">QwtRect::clip</a>(<span class="keyword">const</span> QwtPolygon &pa)<span class="keyword"> const</span>
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<a name="l00037"></a>00037 <span class="keyword"></span>{
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<a name="l00038"></a>00038 <span class="keywordflow">if</span> ( contains( pa.boundingRect() ) )
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<a name="l00039"></a>00039 <span class="keywordflow">return</span> pa;
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<a name="l00040"></a>00040
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<a name="l00041"></a>00041 QwtPolygon cpa(pa.size());
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<a name="l00042"></a>00042
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<a name="l00043"></a>00043 clipEdge((Edge)0, pa, cpa);
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<a name="l00044"></a>00044
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<a name="l00045"></a>00045 <span class="keywordflow">for</span> ( uint edge = 1; edge < NEdges; edge++ )
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<a name="l00046"></a>00046 {
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<a name="l00047"></a>00047 <span class="keyword">const</span> QwtPolygon rpa = cpa;
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<a name="l00048"></a>00048 <span class="preprocessor">#if QT_VERSION < 0x040000</span>
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<a name="l00049"></a>00049 <span class="preprocessor"></span> cpa.detach();
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<a name="l00050"></a>00050 <span class="preprocessor">#endif</span>
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<a name="l00051"></a>00051 <span class="preprocessor"></span> clipEdge((Edge)edge, rpa, cpa);
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<a name="l00052"></a>00052 }
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<a name="l00053"></a>00053
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<a name="l00054"></a>00054 <span class="keywordflow">return</span> cpa;
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<a name="l00055"></a>00055 }
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<a name="l00056"></a>00056
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<a name="l00057"></a>00057 <span class="keywordtype">bool</span> QwtRect::insideEdge(<span class="keyword">const</span> QPoint &p, Edge edge)<span class="keyword"> const</span>
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<a name="l00058"></a>00058 <span class="keyword"></span>{
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<a name="l00059"></a>00059 <span class="keywordflow">switch</span>(edge)
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<a name="l00060"></a>00060 {
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<a name="l00061"></a>00061 <span class="keywordflow">case</span> Left:
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<a name="l00062"></a>00062 <span class="keywordflow">return</span> p.x() > left();
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<a name="l00063"></a>00063 <span class="keywordflow">case</span> Top:
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<a name="l00064"></a>00064 <span class="keywordflow">return</span> p.y() > top();
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<a name="l00065"></a>00065 <span class="keywordflow">case</span> Right:
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<a name="l00066"></a>00066 <span class="keywordflow">return</span> p.x() < right();
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<a name="l00067"></a>00067 <span class="keywordflow">case</span> Bottom:
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<a name="l00068"></a>00068 <span class="keywordflow">return</span> p.y() < bottom();
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<a name="l00069"></a>00069 <span class="keywordflow">default</span>:
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<a name="l00070"></a>00070 <span class="keywordflow">break</span>;
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<a name="l00071"></a>00071 }
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<a name="l00072"></a>00072
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<a name="l00073"></a>00073 <span class="keywordflow">return</span> <span class="keyword">false</span>;
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<a name="l00074"></a>00074 }
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<a name="l00075"></a>00075
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<a name="l00076"></a>00076 QPoint QwtRect::intersectEdge(<span class="keyword">const</span> QPoint &p1,
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<a name="l00077"></a>00077 <span class="keyword">const</span> QPoint &p2, Edge edge )<span class="keyword"> const</span>
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<a name="l00078"></a>00078 <span class="keyword"></span>{
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<a name="l00079"></a>00079 <span class="keywordtype">int</span> x=0, y=0;
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<a name="l00080"></a>00080 <span class="keywordtype">double</span> m = 0;
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<a name="l00081"></a>00081
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<a name="l00082"></a>00082 <span class="keyword">const</span> <span class="keywordtype">double</span> dy = p2.y() - p1.y();
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<a name="l00083"></a>00083 <span class="keyword">const</span> <span class="keywordtype">double</span> dx = p2.x() - p1.x();
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<a name="l00084"></a>00084
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<a name="l00085"></a>00085 <span class="keywordflow">switch</span> ( edge )
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<a name="l00086"></a>00086 {
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<a name="l00087"></a>00087 <span class="keywordflow">case</span> Left:
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<a name="l00088"></a>00088 x = left();
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<a name="l00089"></a>00089 m = double(qwtAbs(p1.x() - x)) / qwtAbs(dx);
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<a name="l00090"></a>00090 y = p1.y() + int(dy * m);
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<a name="l00091"></a>00091 <span class="keywordflow">break</span>;
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<a name="l00092"></a>00092 <span class="keywordflow">case</span> Top:
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<a name="l00093"></a>00093 y = top();
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<a name="l00094"></a>00094 m = double(qwtAbs(p1.y() - y)) / qwtAbs(dy);
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<a name="l00095"></a>00095 x = p1.x() + int(dx * m);
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<a name="l00096"></a>00096 <span class="keywordflow">break</span>;
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<a name="l00097"></a>00097 <span class="keywordflow">case</span> Right:
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<a name="l00098"></a>00098 x = right();
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<a name="l00099"></a>00099 m = double(qwtAbs(p1.x() - x)) / qwtAbs(dx);
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<a name="l00100"></a>00100 y = p1.y() + int(dy * m);
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<a name="l00101"></a>00101 <span class="keywordflow">break</span>;
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<a name="l00102"></a>00102 <span class="keywordflow">case</span> Bottom:
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<a name="l00103"></a>00103 y = bottom();
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<a name="l00104"></a>00104 m = double(qwtAbs(p1.y() - y)) / qwtAbs(dy);
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<a name="l00105"></a>00105 x = p1.x() + int(dx * m);
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<a name="l00106"></a>00106 <span class="keywordflow">break</span>;
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<a name="l00107"></a>00107 <span class="keywordflow">default</span>:
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<a name="l00108"></a>00108 <span class="keywordflow">break</span>;
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<a name="l00109"></a>00109 }
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<a name="l00110"></a>00110
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<a name="l00111"></a>00111 <span class="keywordflow">return</span> QPoint(x,y);
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<a name="l00112"></a>00112 }
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<a name="l00113"></a>00113
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<a name="l00114"></a>00114 <span class="keywordtype">void</span> QwtRect::clipEdge(Edge edge,
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<a name="l00115"></a>00115 <span class="keyword">const</span> QwtPolygon &pa, QwtPolygon &cpa)<span class="keyword"> const</span>
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<a name="l00116"></a>00116 <span class="keyword"></span>{
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<a name="l00117"></a>00117 <span class="keywordflow">if</span> ( pa.count() == 0 )
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<a name="l00118"></a>00118 {
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<a name="l00119"></a>00119 cpa.resize(0);
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<a name="l00120"></a>00120 <span class="keywordflow">return</span>;
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<a name="l00121"></a>00121 }
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<a name="l00122"></a>00122
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<a name="l00123"></a>00123 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> count = 0;
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<a name="l00124"></a>00124
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<a name="l00125"></a>00125 QPoint p1 = pa.point(0);
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<a name="l00126"></a>00126 <span class="keywordflow">if</span> ( insideEdge(p1, edge) )
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<a name="l00127"></a>00127 addPoint(cpa, count++, p1);
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<a name="l00128"></a>00128
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<a name="l00129"></a>00129 <span class="keyword">const</span> uint nPoints = pa.size();
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<a name="l00130"></a>00130 <span class="keywordflow">for</span> ( uint i = 1; i < nPoints; i++ )
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<a name="l00131"></a>00131 {
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<a name="l00132"></a>00132 <span class="keyword">const</span> QPoint p2 = pa.point(i);
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<a name="l00133"></a>00133 <span class="keywordflow">if</span> ( insideEdge(p2, edge) )
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<a name="l00134"></a>00134 {
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<a name="l00135"></a>00135 <span class="keywordflow">if</span> ( insideEdge(p1, edge) )
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<a name="l00136"></a>00136 addPoint(cpa, count++, p2);
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<a name="l00137"></a>00137 <span class="keywordflow">else</span>
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<a name="l00138"></a>00138 {
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<a name="l00139"></a>00139 addPoint(cpa, count++, intersectEdge(p1, p2, edge));
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<a name="l00140"></a>00140 addPoint(cpa, count++, p2);
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<a name="l00141"></a>00141 }
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<a name="l00142"></a>00142 }
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<a name="l00143"></a>00143 <span class="keywordflow">else</span>
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<a name="l00144"></a>00144 {
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<a name="l00145"></a>00145 <span class="keywordflow">if</span> ( insideEdge(p1, edge) )
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<a name="l00146"></a>00146 addPoint(cpa, count++, intersectEdge(p1, p2, edge));
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<a name="l00147"></a>00147 }
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<a name="l00148"></a>00148 p1 = p2;
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<a name="l00149"></a>00149 }
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<a name="l00150"></a>00150 cpa.resize(count);
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<a name="l00151"></a>00151 }
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</pre></div><hr size="1"><address style="align: right;"><small>Generated on Mon Jun 11 07:41:38 2007 for Qwt User's Guide by
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<a href="http://www.doxygen.org/index.html">
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<img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.4.6 </small></address>
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