Add flow layout from Qt examples
ADD
src/flowlayout.cpp
+/****************************************************************************
+**
+** 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);
+ return nullptr;
+}
+//! [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;
+ for (const QLayoutItem *item : qAsConst(itemList))
+ size = size.expandedTo(item->minimumSize());
+
+ const QMargins margins = contentsMargins();
+ size += QSize(margins.left() + margins.right(), margins.top() + margins.bottom());
+ 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]
+ for (QLayoutItem *item : qAsConst(itemList)) {
+ const 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, nullptr, pw);
+ } else {
+ return static_cast<QLayout *>(parent)->spacing();
+ }
+}
+//! [12]

ADD
src/flowlayout.h
+/****************************************************************************
+**
+** 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."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef FLOWLAYOUT_H
+#define FLOWLAYOUT_H
+
+#include <QLayout>
+#include <QRect>
+#include <QStyle>
+//! [0]
+class FlowLayout : public QLayout
+{
+public:
+ explicit FlowLayout(QWidget *parent, int margin = -1, int hSpacing = -1, int vSpacing = -1);
+ explicit FlowLayout(int margin = -1, int hSpacing = -1, int vSpacing = -1);
+ ~FlowLayout();
+
+ void addItem(QLayoutItem *item) override;
+ int horizontalSpacing() const;
+ int verticalSpacing() const;
+ Qt::Orientations expandingDirections() const override;
+ bool hasHeightForWidth() const override;
+ int heightForWidth(int) const override;
+ int count() const override;
+ QLayoutItem *itemAt(int index) const override;
+ QSize minimumSize() const override;
+ void setGeometry(const QRect &rect) override;
+ QSize sizeHint() const override;
+ QLayoutItem *takeAt(int index) override;
+
+private:
+ int doLayout(const QRect &rect, bool testOnly) const;
+ int smartSpacing(QStyle::PixelMetric pm) const;
+
+ QList<QLayoutItem *> itemList;
+ int m_hSpace;
+ int m_vSpace;
+};
+//! [0]
+
+#endif // FLOWLAYOUT_H

Add flow layout from Qt examples