QtFlowlayout Qt流式布局器

/**************************************************************************** ** ** 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." ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include <QtWidgets> #include "flowlayout.h" //! [1] FlowLayout::FlowLayout(QWidget *parent, int margin, int hSpacing, int vSpacing) : QLayout(parent), m_hSpace(hSpacing), m_vSpace(vSpacing) { setContentsMargins(margin, margin, margin, margin); } FlowLayout::FlowLayout(int margin, int hSpacing, int vSpacing) : m_hSpace(hSpacing), m_vSpace(vSpacing) { setContentsMargins(margin, margin, margin, margin); } //! [1] //! [2] FlowLayout::~FlowLayout() { QLayoutItem *item; while ((item = takeAt(0))) delete item; } //! [2] //! [3] void FlowLayout::addItem(QLayoutItem *item) { itemList.append(item); } //! [3] //! [4] int FlowLayout::horizontalSpacing() const { if (m_hSpace >= 0) { return m_hSpace; } else { return smartSpacing(QStyle::PM_LayoutHorizontalSpacing); } } int FlowLayout::verticalSpacing() const { if (m_vSpace >= 0) { return m_vSpace; } else { return smartSpacing(QStyle::PM_LayoutVerticalSpacing); } } //! [4] //! [5] int FlowLayout::count() const { return itemList.size(); } QLayoutItem *FlowLayout::itemAt(int index) const { return itemList.value(index); } QLayoutItem *FlowLayout::takeAt(int index) { if (index >= 0 && index < itemList.size()) return itemList.takeAt(index); else return 0; } //! [5] //! [6] Qt::Orientations FlowLayout::expandingDirections() const { return 0; } //! [6] //! [7] bool FlowLayout::hasHeightForWidth() const { return true; } int FlowLayout::heightForWidth(int width) const { int height = doLayout(QRect(0, 0, width, 0), true); return height; } //! [7] //! [8] void FlowLayout::setGeometry(const QRect &rect) { QLayout::setGeometry(rect); doLayout(rect, false); } QSize FlowLayout::sizeHint() const { return minimumSize(); } QSize FlowLayout::minimumSize() const { QSize size; QLayoutItem *item; foreach (item, itemList) size = size.expandedTo(item->minimumSize()); size += QSize(2*margin(), 2*margin()); return size; } //! [8] //! [9] int FlowLayout::doLayout(const QRect &rect, bool testOnly) const { int left, top, right, bottom; getContentsMargins(&left, &top, &right, &bottom); QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom); int x = effectiveRect.x(); int y = effectiveRect.y(); int lineHeight = 0; //! [9] //! [10] QLayoutItem *item; foreach (item, itemList) { QWidget *wid = item->widget(); int spaceX = horizontalSpacing(); if (spaceX == -1) spaceX = wid->style()->layoutSpacing( QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal); int spaceY = verticalSpacing(); if (spaceY == -1) spaceY = wid->style()->layoutSpacing( QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical); //! [10] //! [11] int nextX = x + item->sizeHint().width() + spaceX; if (nextX - spaceX > effectiveRect.right() && lineHeight > 0) { x = effectiveRect.x(); y = y + lineHeight + spaceY; nextX = x + item->sizeHint().width() + spaceX; lineHeight = 0; } if (!testOnly) item->setGeometry(QRect(QPoint(x, y), item->sizeHint())); x = nextX; lineHeight = qMax(lineHeight, item->sizeHint().height()); } return y + lineHeight - rect.y() + bottom; } //! [11] //! [12] int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const { QObject *parent = this->parent(); if (!parent) { return -1; } else if (parent->isWidgetType()) { QWidget *pw = static_cast<QWidget *>(parent); return pw->style()->pixelMetric(pm, 0, pw); } else { return static_cast<QLayout *>(parent)->spacing(); } } //! [12]