qt5base-lts/examples/widgets/graphicsview/flowlayout/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."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QGraphicsLayout>

class FlowLayout : public QGraphicsLayout
{
public:
    FlowLayout(QGraphicsLayoutItem *parent = nullptr);
    inline void addItem(QGraphicsLayoutItem *item);
    void insertItem(int index, QGraphicsLayoutItem *item);
    void setSpacing(Qt::Orientations o, qreal spacing);
    qreal spacing(Qt::Orientation o) const;

    // inherited functions
    void setGeometry(const QRectF &geom) override;

    int count() const override;
    QGraphicsLayoutItem *itemAt(int index) const override;
    void removeAt(int index) override;

protected:
    QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const override;

private:
    qreal doLayout(const QRectF &geom, bool applyNewGeometry) const;
    QSizeF minSize(const QSizeF &constraint) const;
    QSizeF prefSize() const;
    QSizeF maxSize() const;

    QVector<QGraphicsLayoutItem*> m_items;
    qreal m_spacing[2] = {6, 6};
};


inline void FlowLayout::addItem(QGraphicsLayoutItem *item)
{
    insertItem(-1, item);
}