<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>flowlayout.cpp Example File | Qt Widgets 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td ><a href="qtwidgets-graphicsview-flowlayout-example.html">Graphics View Flow Layout Example</a></td><td >flowlayout.cpp Example File</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtwidgets-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <div class="sidebar"><div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">flowlayout.cpp Example File</h1> <span class="subtitle">graphicsview/flowlayout/flowlayout.cpp</span> <!-- $$$graphicsview/flowlayout/flowlayout.cpp-description --> <div class="descr"> <a name="details"></a> <pre class="cpp"> <span class="comment">/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, you may use this file under the terms of the BSD license ** as follows: ** ** "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. ** ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" 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." ** ** $QT_END_LICENSE$ ** ****************************************************************************/</span> <span class="preprocessor">#include "flowlayout.h"</span> <span class="preprocessor">#include <qmath.h></span> <span class="preprocessor">#include <QWidget></span> FlowLayout<span class="operator">::</span>FlowLayout() { m_spacing<span class="operator">[</span><span class="number">0</span><span class="operator">]</span> <span class="operator">=</span> <span class="number">6</span>; m_spacing<span class="operator">[</span><span class="number">1</span><span class="operator">]</span> <span class="operator">=</span> <span class="number">6</span>; <span class="type"><a href="qsizepolicy.html">QSizePolicy</a></span> sp <span class="operator">=</span> sizePolicy(); sp<span class="operator">.</span>setHeightForWidth(<span class="keyword">true</span>); setSizePolicy(sp); } <span class="type">void</span> FlowLayout<span class="operator">::</span>insertItem(<span class="type">int</span> index<span class="operator">,</span> <span class="type"><a href="qgraphicslayoutitem.html">QGraphicsLayoutItem</a></span> <span class="operator">*</span>item) { item<span class="operator">-</span><span class="operator">></span>setParentLayoutItem(<span class="keyword">this</span>); <span class="keyword">if</span> (<span class="type"><a href="../qtcore/qtglobal.html#uint-typedef">uint</a></span>(index) <span class="operator">></span> <span class="type"><a href="../qtcore/qtglobal.html#uint-typedef">uint</a></span>(m_items<span class="operator">.</span>count())) index <span class="operator">=</span> m_items<span class="operator">.</span>count(); m_items<span class="operator">.</span>insert(index<span class="operator">,</span> item); invalidate(); } <span class="type">int</span> FlowLayout<span class="operator">::</span>count() <span class="keyword">const</span> { <span class="keyword">return</span> m_items<span class="operator">.</span>count(); } <span class="type"><a href="qgraphicslayoutitem.html">QGraphicsLayoutItem</a></span> <span class="operator">*</span>FlowLayout<span class="operator">::</span>itemAt(<span class="type">int</span> index) <span class="keyword">const</span> { <span class="keyword">return</span> m_items<span class="operator">.</span>value(index); } <span class="type">void</span> FlowLayout<span class="operator">::</span>removeAt(<span class="type">int</span> index) { m_items<span class="operator">.</span>removeAt(index); invalidate(); } <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> FlowLayout<span class="operator">::</span>spacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Orientation o) <span class="keyword">const</span> { <span class="keyword">return</span> m_spacing<span class="operator">[</span><span class="type">int</span>(o) <span class="operator">-</span> <span class="number">1</span><span class="operator">]</span>; } <span class="type">void</span> FlowLayout<span class="operator">::</span>setSpacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Orientations o<span class="operator">,</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> spacing) { <span class="keyword">if</span> (o <span class="operator">&</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Horizontal) m_spacing<span class="operator">[</span><span class="number">0</span><span class="operator">]</span> <span class="operator">=</span> spacing; <span class="keyword">if</span> (o <span class="operator">&</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Vertical) m_spacing<span class="operator">[</span><span class="number">1</span><span class="operator">]</span> <span class="operator">=</span> spacing; } <span class="type">void</span> FlowLayout<span class="operator">::</span>setGeometry(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span> <span class="operator">&</span>geom) { <span class="type"><a href="qgraphicslayout.html">QGraphicsLayout</a></span><span class="operator">::</span>setGeometry(geom); doLayout(geom<span class="operator">,</span> <span class="keyword">true</span>); } <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> FlowLayout<span class="operator">::</span>doLayout(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span> <span class="operator">&</span>geom<span class="operator">,</span> bool applyNewGeometry) <span class="keyword">const</span> { <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> left<span class="operator">,</span> top<span class="operator">,</span> right<span class="operator">,</span> bottom; getContentsMargins(<span class="operator">&</span>left<span class="operator">,</span> <span class="operator">&</span>top<span class="operator">,</span> <span class="operator">&</span>right<span class="operator">,</span> <span class="operator">&</span>bottom); <span class="keyword">const</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> maxw <span class="operator">=</span> geom<span class="operator">.</span>width() <span class="operator">-</span> left <span class="operator">-</span> right; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> x <span class="operator">=</span> <span class="number">0</span>; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> y <span class="operator">=</span> <span class="number">0</span>; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> maxRowHeight <span class="operator">=</span> <span class="number">0</span>; <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> pref; <span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator"><</span> m_items<span class="operator">.</span>count(); <span class="operator">+</span><span class="operator">+</span>i) { <span class="type"><a href="qgraphicslayoutitem.html">QGraphicsLayoutItem</a></span> <span class="operator">*</span>item <span class="operator">=</span> m_items<span class="operator">.</span>at(i); pref <span class="operator">=</span> item<span class="operator">-</span><span class="operator">></span>effectiveSizeHint(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>PreferredSize); maxRowHeight <span class="operator">=</span> <a href="../qtcore/qtglobal.html#qMax">qMax</a>(maxRowHeight<span class="operator">,</span> pref<span class="operator">.</span>height()); <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> next_x; next_x <span class="operator">=</span> x <span class="operator">+</span> pref<span class="operator">.</span>width(); <span class="keyword">if</span> (next_x <span class="operator">></span> maxw) { <span class="keyword">if</span> (x <span class="operator">=</span><span class="operator">=</span> <span class="number">0</span>) { pref<span class="operator">.</span>setWidth(maxw); } <span class="keyword">else</span> { x <span class="operator">=</span> <span class="number">0</span>; next_x <span class="operator">=</span> pref<span class="operator">.</span>width(); } y <span class="operator">+</span><span class="operator">=</span> maxRowHeight <span class="operator">+</span> spacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Vertical); maxRowHeight <span class="operator">=</span> <span class="number">0</span>; } <span class="keyword">if</span> (applyNewGeometry) item<span class="operator">-</span><span class="operator">></span>setGeometry(<span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span>(<span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span>(left <span class="operator">+</span> x<span class="operator">,</span> top <span class="operator">+</span> y)<span class="operator">,</span> pref)); x <span class="operator">=</span> next_x <span class="operator">+</span> spacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Horizontal); } maxRowHeight <span class="operator">=</span> <a href="../qtcore/qtglobal.html#qMax">qMax</a>(maxRowHeight<span class="operator">,</span> pref<span class="operator">.</span>height()); <span class="keyword">return</span> top <span class="operator">+</span> y <span class="operator">+</span> maxRowHeight <span class="operator">+</span> bottom; } <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> FlowLayout<span class="operator">::</span>minSize(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> <span class="operator">&</span>constraint) <span class="keyword">const</span> { <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> size(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span>); <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> left<span class="operator">,</span> top<span class="operator">,</span> right<span class="operator">,</span> bottom; getContentsMargins(<span class="operator">&</span>left<span class="operator">,</span> <span class="operator">&</span>top<span class="operator">,</span> <span class="operator">&</span>right<span class="operator">,</span> <span class="operator">&</span>bottom); <span class="keyword">if</span> (constraint<span class="operator">.</span>width() <span class="operator">></span><span class="operator">=</span> <span class="number">0</span>) { <span class="comment">// height for width</span> <span class="keyword">const</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> height <span class="operator">=</span> doLayout(<span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span>(<span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span>(<span class="number">0</span><span class="operator">,</span><span class="number">0</span>)<span class="operator">,</span> constraint)<span class="operator">,</span> <span class="keyword">false</span>); size <span class="operator">=</span> <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span>(constraint<span class="operator">.</span>width()<span class="operator">,</span> height); } <span class="keyword">else</span> <span class="keyword">if</span> (constraint<span class="operator">.</span>height() <span class="operator">></span><span class="operator">=</span> <span class="number">0</span>) { <span class="comment">// width for height?</span> <span class="comment">// not supported</span> } <span class="keyword">else</span> { <span class="type"><a href="qgraphicslayoutitem.html">QGraphicsLayoutItem</a></span> <span class="operator">*</span>item; foreach (item<span class="operator">,</span> m_items) size <span class="operator">=</span> size<span class="operator">.</span>expandedTo(item<span class="operator">-</span><span class="operator">></span>effectiveSizeHint(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MinimumSize)); size <span class="operator">+</span><span class="operator">=</span> <span class="type"><a href="../qtcore/qsize.html">QSize</a></span>(left <span class="operator">+</span> right<span class="operator">,</span> top <span class="operator">+</span> bottom); } <span class="keyword">return</span> size; } <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> FlowLayout<span class="operator">::</span>prefSize() <span class="keyword">const</span> { <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> left<span class="operator">,</span> right; getContentsMargins(<span class="operator">&</span>left<span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="operator">&</span>right<span class="operator">,</span> <span class="number">0</span>); <span class="type"><a href="qgraphicslayoutitem.html">QGraphicsLayoutItem</a></span> <span class="operator">*</span>item; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> maxh <span class="operator">=</span> <span class="number">0</span>; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> totalWidth <span class="operator">=</span> <span class="number">0</span>; foreach (item<span class="operator">,</span> m_items) { <span class="keyword">if</span> (totalWidth <span class="operator">></span> <span class="number">0</span>) totalWidth <span class="operator">+</span><span class="operator">=</span> spacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Horizontal); <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> pref <span class="operator">=</span> item<span class="operator">-</span><span class="operator">></span>effectiveSizeHint(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>PreferredSize); totalWidth <span class="operator">+</span><span class="operator">=</span> pref<span class="operator">.</span>width(); maxh <span class="operator">=</span> <a href="../qtcore/qtglobal.html#qMax">qMax</a>(maxh<span class="operator">,</span> pref<span class="operator">.</span>height()); } maxh <span class="operator">+</span><span class="operator">=</span> spacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Vertical); <span class="keyword">const</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> goldenAspectRatio <span class="operator">=</span> <span class="number">1.61803399</span>; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> w <span class="operator">=</span> <a href="../qtcore/qtmath.html#qSqrt">qSqrt</a>(totalWidth <span class="operator">*</span> maxh <span class="operator">*</span> goldenAspectRatio) <span class="operator">+</span> left <span class="operator">+</span> right; <span class="keyword">return</span> minSize(<span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span>(w<span class="operator">,</span> <span class="operator">-</span><span class="number">1</span>)); } <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> FlowLayout<span class="operator">::</span>maxSize() <span class="keyword">const</span> { <span class="type"><a href="qgraphicslayoutitem.html">QGraphicsLayoutItem</a></span> <span class="operator">*</span>item; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> totalWidth <span class="operator">=</span> <span class="number">0</span>; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> totalHeight <span class="operator">=</span> <span class="number">0</span>; foreach (item<span class="operator">,</span> m_items) { <span class="keyword">if</span> (totalWidth <span class="operator">></span> <span class="number">0</span>) totalWidth <span class="operator">+</span><span class="operator">=</span> spacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Horizontal); <span class="keyword">if</span> (totalHeight <span class="operator">></span> <span class="number">0</span>) totalHeight <span class="operator">+</span><span class="operator">=</span> spacing(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>Vertical); <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> pref <span class="operator">=</span> item<span class="operator">-</span><span class="operator">></span>effectiveSizeHint(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>PreferredSize); totalWidth <span class="operator">+</span><span class="operator">=</span> pref<span class="operator">.</span>width(); totalHeight <span class="operator">+</span><span class="operator">=</span> pref<span class="operator">.</span>height(); } <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> left<span class="operator">,</span> top<span class="operator">,</span> right<span class="operator">,</span> bottom; getContentsMargins(<span class="operator">&</span>left<span class="operator">,</span> <span class="operator">&</span>top<span class="operator">,</span> <span class="operator">&</span>right<span class="operator">,</span> <span class="operator">&</span>bottom); <span class="keyword">return</span> <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span>(left <span class="operator">+</span> totalWidth <span class="operator">+</span> right<span class="operator">,</span> top <span class="operator">+</span> totalHeight <span class="operator">+</span> bottom); } <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> FlowLayout<span class="operator">::</span>sizeHint(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>SizeHint which<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> <span class="operator">&</span>constraint) <span class="keyword">const</span> { <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> sh <span class="operator">=</span> constraint; <span class="keyword">switch</span> (which) { <span class="keyword">case</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>PreferredSize: sh <span class="operator">=</span> prefSize(); <span class="keyword">break</span>; <span class="keyword">case</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MinimumSize: sh <span class="operator">=</span> minSize(constraint); <span class="keyword">break</span>; <span class="keyword">case</span> <span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>MaximumSize: sh <span class="operator">=</span> maxSize(); <span class="keyword">break</span>; <span class="keyword">default</span>: <span class="keyword">break</span>; } <span class="keyword">return</span> sh; } </pre> </div> <!-- @@@graphicsview/flowlayout/flowlayout.cpp --> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>