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<h1 class="title">arrow.cpp Example File</h1>
<span class="small-subtitle">graphicsview/diagramscene/arrow.cpp</span>
<!-- $$$graphicsview/diagramscene/arrow.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp"> <span class="comment">/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** &quot;Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of The Qt Company Ltd nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
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**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
**
** $QT_END_LICENSE$
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****************************************************************************/</span>
<span class="preprocessor">#include &lt;QtGui&gt;</span>
<span class="preprocessor">#include &quot;arrow.h&quot;</span>
<span class="preprocessor">#include &lt;math.h&gt;</span>
<span class="keyword">const</span> <span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> Pi <span class="operator">=</span> <span class="number">3.14</span>;
Arrow<span class="operator">::</span>Arrow(DiagramItem <span class="operator">*</span>startItem<span class="operator">,</span> DiagramItem <span class="operator">*</span>endItem<span class="operator">,</span>
<span class="type"><a href="qgraphicsitem.html">QGraphicsItem</a></span> <span class="operator">*</span>parent<span class="operator">,</span> <span class="type"><a href="qgraphicsscene.html">QGraphicsScene</a></span> <span class="operator">*</span>scene)
: <span class="type"><a href="qgraphicslineitem.html">QGraphicsLineItem</a></span>(parent<span class="operator">,</span> scene)
{
myStartItem <span class="operator">=</span> startItem;
myEndItem <span class="operator">=</span> endItem;
setFlag(<span class="type"><a href="qgraphicsitem.html">QGraphicsItem</a></span><span class="operator">::</span>ItemIsSelectable<span class="operator">,</span> <span class="keyword">true</span>);
myColor <span class="operator">=</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>black;
setPen(<span class="type"><a href="qpen.html">QPen</a></span>(myColor<span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>SolidLine<span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>RoundCap<span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>RoundJoin));
}
<span class="type"><a href="qrectf.html">QRectF</a></span> Arrow<span class="operator">::</span>boundingRect() <span class="keyword">const</span>
{
<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> extra <span class="operator">=</span> (pen()<span class="operator">.</span>width() <span class="operator">+</span> <span class="number">20</span>) <span class="operator">/</span> <span class="number">2.0</span>;
<span class="keyword">return</span> <span class="type"><a href="qrectf.html">QRectF</a></span>(line()<span class="operator">.</span>p1()<span class="operator">,</span> <span class="type"><a href="qsizef.html">QSizeF</a></span>(line()<span class="operator">.</span>p2()<span class="operator">.</span>x() <span class="operator">-</span> line()<span class="operator">.</span>p1()<span class="operator">.</span>x()<span class="operator">,</span>
line()<span class="operator">.</span>p2()<span class="operator">.</span>y() <span class="operator">-</span> line()<span class="operator">.</span>p1()<span class="operator">.</span>y()))
<span class="operator">.</span>normalized()
<span class="operator">.</span>adjusted(<span class="operator">-</span>extra<span class="operator">,</span> <span class="operator">-</span>extra<span class="operator">,</span> extra<span class="operator">,</span> extra);
}
<span class="type"><a href="qpainterpath.html">QPainterPath</a></span> Arrow<span class="operator">::</span>shape() <span class="keyword">const</span>
{
<span class="type"><a href="qpainterpath.html">QPainterPath</a></span> path <span class="operator">=</span> <span class="type"><a href="qgraphicslineitem.html">QGraphicsLineItem</a></span><span class="operator">::</span>shape();
path<span class="operator">.</span>addPolygon(arrowHead);
<span class="keyword">return</span> path;
}
<span class="type">void</span> Arrow<span class="operator">::</span>updatePosition()
{
<span class="type"><a href="qlinef.html">QLineF</a></span> line(mapFromItem(myStartItem<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span>)<span class="operator">,</span> mapFromItem(myEndItem<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span>));
setLine(line);
}
<span class="type">void</span> Arrow<span class="operator">::</span>paint(<span class="type"><a href="qpainter.html">QPainter</a></span> <span class="operator">*</span>painter<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="qstyleoptiongraphicsitem.html">QStyleOptionGraphicsItem</a></span> <span class="operator">*</span><span class="operator">,</span>
<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>)
{
<span class="keyword">if</span> (myStartItem<span class="operator">-</span><span class="operator">&gt;</span>collidesWithItem(myEndItem))
<span class="keyword">return</span>;
<span class="type"><a href="qpen.html">QPen</a></span> myPen <span class="operator">=</span> pen();
myPen<span class="operator">.</span>setColor(myColor);
<span class="type"><a href="qtglobal.html#qreal-typedef">qreal</a></span> arrowSize <span class="operator">=</span> <span class="number">20</span>;
painter<span class="operator">-</span><span class="operator">&gt;</span>setPen(myPen);
painter<span class="operator">-</span><span class="operator">&gt;</span>setBrush(myColor);
<span class="type"><a href="qlinef.html">QLineF</a></span> centerLine(myStartItem<span class="operator">-</span><span class="operator">&gt;</span>pos()<span class="operator">,</span> myEndItem<span class="operator">-</span><span class="operator">&gt;</span>pos());
<span class="type"><a href="qpolygonf.html">QPolygonF</a></span> endPolygon <span class="operator">=</span> myEndItem<span class="operator">-</span><span class="operator">&gt;</span>polygon();
<span class="type"><a href="qpointf.html">QPointF</a></span> p1 <span class="operator">=</span> endPolygon<span class="operator">.</span>first() <span class="operator">+</span> myEndItem<span class="operator">-</span><span class="operator">&gt;</span>pos();
<span class="type"><a href="qpointf.html">QPointF</a></span> p2;
<span class="type"><a href="qpointf.html">QPointF</a></span> intersectPoint;
<span class="type"><a href="qlinef.html">QLineF</a></span> polyLine;
<span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">1</span>; i <span class="operator">&lt;</span> endPolygon<span class="operator">.</span>count(); <span class="operator">+</span><span class="operator">+</span>i) {
p2 <span class="operator">=</span> endPolygon<span class="operator">.</span>at(i) <span class="operator">+</span> myEndItem<span class="operator">-</span><span class="operator">&gt;</span>pos();
polyLine <span class="operator">=</span> <span class="type"><a href="qlinef.html">QLineF</a></span>(p1<span class="operator">,</span> p2);
<span class="type"><a href="qlinef.html">QLineF</a></span><span class="operator">::</span>IntersectType intersectType <span class="operator">=</span>
polyLine<span class="operator">.</span>intersect(centerLine<span class="operator">,</span> <span class="operator">&amp;</span>intersectPoint);
<span class="keyword">if</span> (intersectType <span class="operator">=</span><span class="operator">=</span> <span class="type"><a href="qlinef.html">QLineF</a></span><span class="operator">::</span>BoundedIntersection)
<span class="keyword">break</span>;
p1 <span class="operator">=</span> p2;
}
setLine(<span class="type"><a href="qlinef.html">QLineF</a></span>(intersectPoint<span class="operator">,</span> myStartItem<span class="operator">-</span><span class="operator">&gt;</span>pos()));
<span class="type">double</span> angle <span class="operator">=</span> <span class="operator">::</span>acos(line()<span class="operator">.</span>dx() <span class="operator">/</span> line()<span class="operator">.</span>length());
<span class="keyword">if</span> (line()<span class="operator">.</span>dy() <span class="operator">&gt;</span><span class="operator">=</span> <span class="number">0</span>)
angle <span class="operator">=</span> (Pi <span class="operator">*</span> <span class="number">2</span>) <span class="operator">-</span> angle;
<span class="type"><a href="qpointf.html">QPointF</a></span> arrowP1 <span class="operator">=</span> line()<span class="operator">.</span>p1() <span class="operator">+</span> <span class="type"><a href="qpointf.html">QPointF</a></span>(sin(angle <span class="operator">+</span> Pi <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize<span class="operator">,</span>
cos(angle <span class="operator">+</span> Pi <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize);
<span class="type"><a href="qpointf.html">QPointF</a></span> arrowP2 <span class="operator">=</span> line()<span class="operator">.</span>p1() <span class="operator">+</span> <span class="type"><a href="qpointf.html">QPointF</a></span>(sin(angle <span class="operator">+</span> Pi <span class="operator">-</span> Pi <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize<span class="operator">,</span>
cos(angle <span class="operator">+</span> Pi <span class="operator">-</span> Pi <span class="operator">/</span> <span class="number">3</span>) <span class="operator">*</span> arrowSize);
arrowHead<span class="operator">.</span>clear();
arrowHead <span class="operator">&lt;</span><span class="operator">&lt;</span> line()<span class="operator">.</span>p1() <span class="operator">&lt;</span><span class="operator">&lt;</span> arrowP1 <span class="operator">&lt;</span><span class="operator">&lt;</span> arrowP2;
painter<span class="operator">-</span><span class="operator">&gt;</span>drawLine(line());
painter<span class="operator">-</span><span class="operator">&gt;</span>drawPolygon(arrowHead);
<span class="keyword">if</span> (isSelected()) {
painter<span class="operator">-</span><span class="operator">&gt;</span>setPen(<span class="type"><a href="qpen.html">QPen</a></span>(myColor<span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>DashLine));
<span class="type"><a href="qlinef.html">QLineF</a></span> myLine <span class="operator">=</span> line();
myLine<span class="operator">.</span>translate(<span class="number">0</span><span class="operator">,</span> <span class="number">4.0</span>);
painter<span class="operator">-</span><span class="operator">&gt;</span>drawLine(myLine);
myLine<span class="operator">.</span>translate(<span class="number">0</span><span class="operator">,</span><span class="operator">-</span><span class="number">8.0</span>);
painter<span class="operator">-</span><span class="operator">&gt;</span>drawLine(myLine);
}
}</pre>
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<!-- @@@graphicsview/diagramscene/arrow.cpp -->
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