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#include "flowlayout.h"

#include <QtWidgets>
//! [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 {}; }
//! [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;
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
    for (const QLayoutItem *item : std::as_const(itemList))
#elif QT_VERSION >= 0x050700
    for (const QLayoutItem *item : qAsConst(itemList))
#else
    for (const QLayoutItem *item : itemList)
#endif
        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]
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
    for (QLayoutItem *item : std::as_const(itemList)) {
#elif QT_VERSION >= 0x050700
    for (QLayoutItem *item : qAsConst(itemList)) {
#else
    for (QLayoutItem *item : itemList) {
#endif
        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<int>(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]
