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#include <QWidget>

#include "flowlayout.h"
//! [1]
FlowLayoutX::FlowLayoutX(QWidget *parent, int margin, int hSpacing, int vSpacing)
    : QLayout(parent), m_hSpace(hSpacing), m_vSpace(vSpacing)
{
    setContentsMargins(margin, margin, margin, margin);
}

FlowLayoutX::FlowLayoutX(int margin, int hSpacing, int vSpacing)
    : m_hSpace(hSpacing), m_vSpace(vSpacing)
{
    setContentsMargins(margin, margin, margin, margin);
}
//! [1]

//! [2]
FlowLayoutX::~FlowLayoutX()
{
    QLayoutItem *item;
    while ((item = takeAt(0)))
        delete item;
}
//! [2]

//! [3]
void FlowLayoutX::addItem(QLayoutItem *item)
{
    itemList.append(item);
}
//! [3]

//! [4]
int FlowLayoutX::horizontalSpacing() const
{
    if (m_hSpace >= 0) {
        return m_hSpace;
    } else {
        return smartSpacing(QStyle::PM_LayoutHorizontalSpacing);
    }
}

int FlowLayoutX::verticalSpacing() const
{
    if (m_vSpace >= 0) {
        return m_vSpace;
    } else {
        return smartSpacing(QStyle::PM_LayoutVerticalSpacing);
    }
}
//! [4]

//! [5]
int FlowLayoutX::count() const
{
    return itemList.size();
}

QLayoutItem *FlowLayoutX::itemAt(int index) const
{
    return itemList.value(index);
}

QLayoutItem *FlowLayoutX::takeAt(int index)
{
    if (index >= 0 && index < itemList.size())
        return itemList.takeAt(index);
    else
        return nullptr;
}
//! [5]

//! [6]
Qt::Orientations FlowLayoutX::expandingDirections() const
{
    return Qt::Orientations();
}
//! [6]

//! [7]
bool FlowLayoutX::hasHeightForWidth() const
{
    return true;
}

int FlowLayoutX::heightForWidth(int width) const
{
    int height = doLayout(QRect(0, 0, width, 0), true);
    return height;
}
//! [7]

//! [8]
void FlowLayoutX::setGeometry(const QRect &rect)
{
    QLayout::setGeometry(rect);
    doLayout(rect, false);
}

QSize FlowLayoutX::sizeHint() const
{
    return minimumSize();
}

QSize FlowLayoutX::minimumSize() const
{
    QSize size;
    QLayoutItem *item;
    foreach (item, itemList)
        size = size.expandedTo(item->minimumSize());

    int left, top, right, bottom;
    getContentsMargins(&left, &top, &right, &bottom);
    size += QSize(left+right, top+bottom);
    return size;
}
//! [8]

//! [9]
int FlowLayoutX::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;

    QLayoutItem * primaryItem = nullptr;
    int secondaryWidth = 0;
    foreach (item, itemList) {
        QWidget *wid = item->widget();
        if (!wid) continue;
        int spaceX = horizontalSpacing();
        if (spaceX == -1)
            spaceX = wid->style()->layoutSpacing( QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
        secondaryWidth += spaceX;
        if (!primaryItem && (wid->sizePolicy().horizontalPolicy() & QSizePolicy::ExpandFlag) )
          primaryItem = item;
        else
          secondaryWidth += item->sizeHint().width();
    }
    bool flow = false;
    foreach (item, itemList) {
        QWidget *wid = item->widget();
        if (!wid) continue;
        QSize size = item->sizeHint();

        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]

        if (item == primaryItem) {
          if (effectiveRect.width() - secondaryWidth < item->minimumSize().width()) {
            flow = true;
            size.setWidth( effectiveRect.width() - x - spaceX );
          } else size.setWidth( effectiveRect.width() - secondaryWidth );
        }

        int nextX = x + size.width() + spaceX;
        if (flow && 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),  size));

        x = nextX;
        lineHeight = qMax(lineHeight, item->sizeHint().height());
    }
    return y + lineHeight - rect.y() + bottom;
}
//! [11]
//! [12]
int FlowLayoutX::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]
