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#include "flowlayout.h"

#include <QtGui/qwidget.h>

#include <QtCore/qmath.h>

FlowLayout::FlowLayout()

{

    m_spacing[0] = 6;

    m_spacing[1] = 6;

    QSizePolicy sp = sizePolicy();

    sp.setHeightForWidth(true);

    setSizePolicy(sp);

}

void FlowLayout::insertItem(int index, QGraphicsLayoutItem *item)

{

    item->setParentLayoutItem(this);

    if (uint(index) > uint(m_items.count()))

        index = m_items.count();

    m_items.insert(index, item);

    invalidate();

}

int FlowLayout::count() const

{

    return m_items.count();

}

QGraphicsLayoutItem *FlowLayout::itemAt(int index) const

{

    return m_items.value(index);

}

void FlowLayout::removeAt(int index)

{

    m_items.removeAt(index);

    invalidate();

}

qreal FlowLayout::spacing(Qt::Orientation o) const

{

    return m_spacing[int(o) - 1];

}

void FlowLayout::setSpacing(Qt::Orientations o, qreal spacing)

{

    if (o & Qt::Horizontal)

        m_spacing[0] = spacing;

    if (o & Qt::Vertical)

        m_spacing[1] = spacing;

}

void FlowLayout::setGeometry(const QRectF &geom)

{

    QGraphicsLayout::setGeometry(geom);

    doLayout(geom, true);

}

qreal FlowLayout::doLayout(const QRectF &geom, bool applyNewGeometry) const

{

    qreal left, top, right, bottom;

    getContentsMargins(&left, &top, &right, &bottom);

    const qreal maxw = geom.width() - left - right;

    qreal x = 0;

    qreal y = 0;

    qreal maxRowHeight = 0;

    QSizeF pref;

    for (int i = 0; i < m_items.count(); ++i) {

        QGraphicsLayoutItem *item = m_items.at(i);

        pref = item->effectiveSizeHint(Qt::PreferredSize);

        maxRowHeight = qMax(maxRowHeight, pref.height());

        qreal next_x;

        next_x = x + pref.width();

        if (next_x > maxw) {

            if (x == 0) {

                pref.setWidth(maxw);

            } else {

                x = 0;

                next_x = pref.width();

            }

            y += maxRowHeight + spacing(Qt::Vertical);

            maxRowHeight = 0;

        }

        if (applyNewGeometry)

            item->setGeometry(QRectF(QPointF(left + x, top + y), pref));

        x = next_x + spacing(Qt::Horizontal);

    }

    maxRowHeight = qMax(maxRowHeight, pref.height());

    return top + y + maxRowHeight + bottom;

}

QSizeF FlowLayout::minSize(const QSizeF &constraint) const

{

    QSizeF size(0, 0);

    qreal left, top, right, bottom;

    getContentsMargins(&left, &top, &right, &bottom);

    if (constraint.width() >= 0) {   // height for width

        const qreal height = doLayout(QRectF(QPointF(0,0), constraint), false);

        size = QSizeF(constraint.width(), height);

    } else if (constraint.height() >= 0) {  // width for height?

        // not supported

    } else {

        QGraphicsLayoutItem *item;

        foreach (item, m_items)

            size = size.expandedTo(item->effectiveSizeHint(Qt::MinimumSize));

        size += QSize(left + right, top + bottom);

    }

    return size;

}

QSizeF FlowLayout::prefSize() const

{

    qreal left, right;

    getContentsMargins(&left, 0, &right, 0);

    QGraphicsLayoutItem *item;

    qreal maxh = 0;

    qreal totalWidth = 0;

    foreach (item, m_items) {

        if (totalWidth > 0)

            totalWidth += spacing(Qt::Horizontal);

        QSizeF pref = item->effectiveSizeHint(Qt::PreferredSize);

        totalWidth += pref.width();

        maxh = qMax(maxh, pref.height());

    }

    maxh += spacing(Qt::Vertical);

    const qreal goldenAspectRatio = 1.61803399;

    qreal w = qSqrt(totalWidth * maxh * goldenAspectRatio) + left + right;

    return minSize(QSizeF(w, -1));

}

QSizeF FlowLayout::maxSize() const

{

    QGraphicsLayoutItem *item;

    qreal totalWidth = 0;

    qreal totalHeight = 0;

    foreach (item, m_items) {

        if (totalWidth > 0)

            totalWidth += spacing(Qt::Horizontal);

        if (totalHeight > 0)

            totalHeight += spacing(Qt::Vertical);

        QSizeF pref = item->effectiveSizeHint(Qt::PreferredSize);

        totalWidth += pref.width();

        totalHeight += pref.height();

    }

    qreal left, top, right, bottom;

    getContentsMargins(&left, &top, &right, &bottom);

    return QSizeF(left + totalWidth + right, top + totalHeight + bottom);

}

QSizeF FlowLayout::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const

{

    QSizeF sh = constraint;

    switch (which) {

    case Qt::PreferredSize:

        sh = prefSize();

        break;

    case Qt::MinimumSize:

        sh = minSize(constraint);

        break;

    case Qt::MaximumSize:

        sh = maxSize();

        break;

    default:

        break;

    }

    return sh;

}