qlistview.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// Copyright (C) 2013 Samuel Gaist <samuel.gaist@deltech.ch>
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qlistview.h"
 
#include <qabstractitemdelegate.h>
#if QT_CONFIG(accessibility)
#include <qaccessible.h>
#endif
#include <qapplication.h>
#include <qstylepainter.h>
#include <qbitmap.h>
#include <qdebug.h>
#if QT_CONFIG(draganddrop)
#include <qdrag.h>
#endif
#include <qevent.h>
#include <qlist.h>
#if QT_CONFIG(rubberband)
#include <qrubberband.h>
#endif
#include <qscrollbar.h>
#include <qstyle.h>
#include <private/qapplication_p.h>
#include <private/qlistview_p.h>
#include <private/qscrollbar_p.h>
 
#include <algorithm>
 
QT_BEGIN_NAMESPACE
 
extern bool qt_sendSpontaneousEvent(QObject *receiver, QEvent *event);
 
QListView::QListView(QWidget *parent)
    : QAbstractItemView(*new QListViewPrivate, parent)
{
    setViewMode(ListMode);
    setSelectionMode(SingleSelection);
    setAttribute(Qt::WA_MacShowFocusRect);
    Q_D(QListView);               // We rely on a qobject_cast for PM_DefaultFrameWidth to change
    d->updateStyledFrameWidths(); // hence we have to force an update now that the object has been constructed
}
 
QListView::QListView(QListViewPrivate &dd, QWidget *parent)
    : QAbstractItemView(dd, parent)
{
    setViewMode(ListMode);
    setSelectionMode(SingleSelection);
    setAttribute(Qt::WA_MacShowFocusRect);
    Q_D(QListView);               // We rely on a qobject_cast for PM_DefaultFrameWidth to change
    d->updateStyledFrameWidths(); // hence we have to force an update now that the object has been constructed
}
 
QListView::~QListView()
{
}
 
void QListView::setMovement(Movement movement)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Movement);
    d->movement = movement;
 
#if QT_CONFIG(draganddrop)
    bool movable = (movement != Static);
    setDragEnabled(movable);
    d->viewport->setAcceptDrops(movable);
#endif
    d->doDelayedItemsLayout();
}
 
QListView::Movement QListView::movement() const
{
    Q_D(const QListView);
    return d->movement;
}
 
void QListView::setFlow(Flow flow)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Flow);
    d->flow = flow;
    d->doDelayedItemsLayout();
}
 
QListView::Flow QListView::flow() const
{
    Q_D(const QListView);
    return d->flow;
}
 
void QListView::setWrapping(bool enable)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Wrap);
    d->setWrapping(enable);
    d->doDelayedItemsLayout();
}
 
bool QListView::isWrapping() const
{
    Q_D(const QListView);
    return d->isWrapping();
}
 
void QListView::setResizeMode(ResizeMode mode)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::ResizeMode);
    d->resizeMode = mode;
}
 
QListView::ResizeMode QListView::resizeMode() const
{
    Q_D(const QListView);
    return d->resizeMode;
}
 
void QListView::setLayoutMode(LayoutMode mode)
{
    Q_D(QListView);
    d->layoutMode = mode;
}
 
QListView::LayoutMode QListView::layoutMode() const
{
    Q_D(const QListView);
    return d->layoutMode;
}
 
void QListView::setSpacing(int space)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::Spacing);
    d->setSpacing(space);
    d->doDelayedItemsLayout();
}
 
int QListView::spacing() const
{
    Q_D(const QListView);
    return d->spacing();
}
 
void QListView::setBatchSize(int batchSize)
{
    Q_D(QListView);
    if (Q_UNLIKELY(batchSize <= 0)) {
        qWarning("Invalid batchSize (%d)", batchSize);
        return;
    }
    d->batchSize = batchSize;
}
 
int QListView::batchSize() const
{
    Q_D(const QListView);
    return d->batchSize;
}
 
void QListView::setGridSize(const QSize &size)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::GridSize);
    d->setGridSize(size);
    d->doDelayedItemsLayout();
}
 
QSize QListView::gridSize() const
{
    Q_D(const QListView);
    return d->gridSize();
}
 
void QListView::setViewMode(ViewMode mode)
{
    Q_D(QListView);
    if (d->commonListView && d->viewMode == mode)
        return;
    d->viewMode = mode;
 
    delete d->commonListView;
    if (mode == ListMode) {
        d->commonListView = new QListModeViewBase(this, d);
        if (!(d->modeProperties & QListViewPrivate::Wrap))
            d->setWrapping(false);
        if (!(d->modeProperties & QListViewPrivate::Spacing))
            d->setSpacing(0);
        if (!(d->modeProperties & QListViewPrivate::GridSize))
            d->setGridSize(QSize());
        if (!(d->modeProperties & QListViewPrivate::Flow))
            d->flow = TopToBottom;
        if (!(d->modeProperties & QListViewPrivate::Movement))
            d->movement = Static;
        if (!(d->modeProperties & QListViewPrivate::ResizeMode))
            d->resizeMode = Fixed;
        if (!(d->modeProperties & QListViewPrivate::SelectionRectVisible))
            d->showElasticBand = false;
    } else {
        d->commonListView = new QIconModeViewBase(this, d);
        if (!(d->modeProperties & QListViewPrivate::Wrap))
            d->setWrapping(true);
        if (!(d->modeProperties & QListViewPrivate::Spacing))
            d->setSpacing(0);
        if (!(d->modeProperties & QListViewPrivate::GridSize))
            d->setGridSize(QSize());
        if (!(d->modeProperties & QListViewPrivate::Flow))
            d->flow = LeftToRight;
        if (!(d->modeProperties & QListViewPrivate::Movement))
            d->movement = Free;
        if (!(d->modeProperties & QListViewPrivate::ResizeMode))
            d->resizeMode = Fixed;
        if (!(d->modeProperties & QListViewPrivate::SelectionRectVisible))
            d->showElasticBand = true;
    }
 
#if QT_CONFIG(draganddrop)
    bool movable = (d->movement != Static);
    setDragEnabled(movable);
    setAcceptDrops(movable);
#endif
    d->clear();
    d->doDelayedItemsLayout();
}
 
QListView::ViewMode QListView::viewMode() const
{
    Q_D(const QListView);
    return d->viewMode;
}
 
void QListView::clearPropertyFlags()
{
    Q_D(QListView);
    d->modeProperties = 0;
}
 
bool QListView::isRowHidden(int row) const
{
    Q_D(const QListView);
    return d->isHidden(row);
}
 
void QListView::setRowHidden(int row, bool hide)
{
    Q_D(QListView);
    const bool hidden = d->isHidden(row);
    if (hide && !hidden)
        d->commonListView->appendHiddenRow(row);
    else if (!hide && hidden)
        d->commonListView->removeHiddenRow(row);
    d->doDelayedItemsLayout();
    d->viewport->update();
}
 
QRect QListView::visualRect(const QModelIndex &index) const
{
    Q_D(const QListView);
    return d->mapToViewport(rectForIndex(index));
}
 
void QListView::scrollTo(const QModelIndex &index, ScrollHint hint)
{
    Q_D(QListView);
 
    if (index.parent() != d->root || index.column() != d->column)
        return;
 
    const QRect rect = visualRect(index);
    if (!rect.isValid())
        return;
    if (hint == EnsureVisible && d->viewport->rect().contains(rect)) {
        d->viewport->update(rect);
        return;
    }
 
    if (d->flow == QListView::TopToBottom || d->isWrapping()) // vertical
        verticalScrollBar()->setValue(d->verticalScrollToValue(index, rect, hint));
 
    if (d->flow == QListView::LeftToRight || d->isWrapping()) // horizontal
        horizontalScrollBar()->setValue(d->horizontalScrollToValue(index, rect, hint));
}
 
int QListViewPrivate::horizontalScrollToValue(const QModelIndex &index, const QRect &rect,
                                              QListView::ScrollHint hint) const
{
    Q_Q(const QListView);
    const QRect area = viewport->rect();
    const bool leftOf = q->isRightToLeft()
                        ? (rect.left() < area.left()) && (rect.right() < area.right())
                        : rect.left() < area.left();
    const bool rightOf = q->isRightToLeft()
                         ? rect.right() > area.right()
                         : (rect.right() > area.right()) && (rect.left() > area.left());
    return commonListView->horizontalScrollToValue(q->visualIndex(index), hint, leftOf, rightOf, area, rect);
}
 
int QListViewPrivate::verticalScrollToValue(const QModelIndex &index, const QRect &rect,
                                            QListView::ScrollHint hint) const
{
    Q_Q(const QListView);
    const QRect area = viewport->rect();
    const bool above = (hint == QListView::EnsureVisible && rect.top() < area.top());
    const bool below = (hint == QListView::EnsureVisible && rect.bottom() > area.bottom());
    return commonListView->verticalScrollToValue(q->visualIndex(index), hint, above, below, area, rect);
}
 
void QListViewPrivate::selectAll(QItemSelectionModel::SelectionFlags command)
{
    if (!selectionModel)
        return;
 
    QItemSelection selection;
    QModelIndex topLeft;
    int row = 0;
    const int colCount = model->columnCount(root);
    for(; row < model->rowCount(root); ++row) {
        if (isHidden(row)) {
            //it might be the end of a selection range
            if (topLeft.isValid()) {
                QModelIndex bottomRight = model->index(row - 1, colCount - 1, root);
                selection.append(QItemSelectionRange(topLeft, bottomRight));
                topLeft = QModelIndex();
            }
            continue;
        }
 
        if (!topLeft.isValid()) //start of a new selection range
            topLeft = model->index(row, 0, root);
    }
 
    if (topLeft.isValid()) {
        //last selected range
        QModelIndex bottomRight = model->index(row - 1, colCount - 1, root);
        selection.append(QItemSelectionRange(topLeft, bottomRight));
    }
 
    if (!selection.isEmpty())
        selectionModel->select(selection, command);
}
 
QItemViewPaintPairs QListViewPrivate::draggablePaintPairs(const QModelIndexList &indexes, QRect *r) const
{
    Q_ASSERT(r);
    Q_Q(const QListView);
    QRect &rect = *r;
    const QRect viewportRect = viewport->rect();
    QItemViewPaintPairs ret;
    QList<QModelIndex> visibleIndexes =
            intersectingSet(viewportRect.translated(q->horizontalOffset(), q->verticalOffset()));
    std::sort(visibleIndexes.begin(), visibleIndexes.end());
    for (const auto &index : indexes) {
        if (std::binary_search(visibleIndexes.cbegin(), visibleIndexes.cend(), index)) {
            const QRect current = q->visualRect(index);
            ret.append({current, index});
            rect |= current;
        }
    }
    QRect clipped = rect & viewportRect;
    rect.setLeft(clipped.left());
    rect.setRight(clipped.right());
    return ret;
}
 
void QListView::reset()
{
    Q_D(QListView);
    d->clear();
    d->hiddenRows.clear();
    QAbstractItemView::reset();
}
 
void QListView::setRootIndex(const QModelIndex &index)
{
    Q_D(QListView);
    d->column = qMax(0, qMin(d->column, d->model->columnCount(index) - 1));
    QAbstractItemView::setRootIndex(index);
    // sometimes we get an update before reset() is called
    d->clear();
    d->hiddenRows.clear();
}
 
void QListView::scrollContentsBy(int dx, int dy)
{
    Q_D(QListView);
    d->delayedAutoScroll.stop(); // auto scroll was canceled by the user scrolling
    d->commonListView->scrollContentsBy(dx, dy, d->state == QListView::DragSelectingState);
}
 
void QListView::resizeContents(int width, int height)
{
    Q_D(QListView);
    d->setContentsSize(width, height);
}
 
QSize QListView::contentsSize() const
{
    Q_D(const QListView);
    return d->contentsSize();
}
 
void QListView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight,
                            const QList<int> &roles)
{
    d_func()->commonListView->dataChanged(topLeft, bottomRight);
    QAbstractItemView::dataChanged(topLeft, bottomRight, roles);
}
 
void QListView::rowsInserted(const QModelIndex &parent, int start, int end)
{
    Q_D(QListView);
    // ### be smarter about inserted items
    d->clear();
    d->doDelayedItemsLayout();
    QAbstractItemView::rowsInserted(parent, start, end);
}
 
void QListView::rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end)
{
    Q_D(QListView);
    // if the parent is above d->root in the tree, nothing will happen
    QAbstractItemView::rowsAboutToBeRemoved(parent, start, end);
    if (parent == d->root) {
        QSet<QPersistentModelIndex>::iterator it = d->hiddenRows.begin();
        while (it != d->hiddenRows.end()) {
            int hiddenRow = it->row();
            if (hiddenRow >= start && hiddenRow <= end) {
                it = d->hiddenRows.erase(it);
            } else {
                ++it;
            }
        }
    }
    d->clear();
    d->doDelayedItemsLayout();
}
 
void QListView::mouseMoveEvent(QMouseEvent *e)
{
    if (!isVisible())
        return;
    Q_D(QListView);
    QAbstractItemView::mouseMoveEvent(e);
    if (state() == DragSelectingState
        && d->showElasticBand
        && d->selectionMode != SingleSelection
        && d->selectionMode != NoSelection) {
        QRect rect(d->pressedPosition, e->position().toPoint() + QPoint(horizontalOffset(), verticalOffset()));
        rect = rect.normalized();
        const int margin = 2 * style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
        const QRect viewPortRect = rect.united(d->elasticBand)
                                       .adjusted(-margin, -margin, margin, margin);
        d->viewport->update(d->mapToViewport(viewPortRect));
        d->elasticBand = rect;
    }
}
 
void QListView::mouseReleaseEvent(QMouseEvent *e)
{
    Q_D(QListView);
    QAbstractItemView::mouseReleaseEvent(e);
    // #### move this implementation into a dynamic class
    if (d->showElasticBand && d->elasticBand.isValid()) {
        const int margin = 2 * style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
        const QRect viewPortRect = d->elasticBand.adjusted(-margin, -margin, margin, margin);
        d->viewport->update(d->mapToViewport(viewPortRect));
        d->elasticBand = QRect();
    }
}
 
#if QT_CONFIG(wheelevent)
void QListView::wheelEvent(QWheelEvent *e)
{
    Q_D(QListView);
    if (qAbs(e->angleDelta().y()) > qAbs(e->angleDelta().x())) {
        if (e->angleDelta().x() == 0
                && ((d->flow == TopToBottom && d->wrap) || (d->flow == LeftToRight && !d->wrap))
                && d->vbar->minimum() == 0 && d->vbar->maximum() == 0) {
            QPoint pixelDelta(e->pixelDelta().y(), e->pixelDelta().x());
            QPoint angleDelta(e->angleDelta().y(), e->angleDelta().x());
            QWheelEvent hwe(e->position(), e->globalPosition(), pixelDelta, angleDelta,
                            e->buttons(), e->modifiers(), e->phase(), e->inverted(), e->source());
            if (e->spontaneous())
                qt_sendSpontaneousEvent(d->hbar, &hwe);
            else
                QCoreApplication::sendEvent(d->hbar, &hwe);
            e->setAccepted(hwe.isAccepted());
        } else {
            QCoreApplication::sendEvent(d->vbar, e);
        }
    } else {
        QCoreApplication::sendEvent(d->hbar, e);
    }
}
#endif // QT_CONFIG(wheelevent)
 
void QListView::timerEvent(QTimerEvent *e)
{
    Q_D(QListView);
    if (e->timerId() == d->batchLayoutTimer.timerId()) {
        if (d->doItemsLayout(d->batchSize)) { // layout is done
            d->batchLayoutTimer.stop();
            updateGeometries();
            d->viewport->update();
        }
    }
    QAbstractItemView::timerEvent(e);
}
 
void QListView::resizeEvent(QResizeEvent *e)
{
    Q_D(QListView);
    if (d->delayedPendingLayout)
        return;
 
    QSize delta = e->size() - e->oldSize();
 
    if (delta.isNull())
      return;
 
    bool listWrap = (d->viewMode == ListMode) && d->wrapItemText;
    bool flowDimensionChanged = (d->flow == LeftToRight && delta.width() != 0)
                                || (d->flow == TopToBottom && delta.height() != 0);
 
    // We post a delayed relayout in the following cases :
    // - we're wrapping
    // - the state is NoState, we're adjusting and the size has changed in the flowing direction
    if (listWrap
        || (state() == NoState && d->resizeMode == Adjust && flowDimensionChanged)) {
        d->doDelayedItemsLayout(100); // wait 1/10 sec before starting the layout
    } else {
        QAbstractItemView::resizeEvent(e);
    }
}
 
#if QT_CONFIG(draganddrop)
 
void QListView::dragMoveEvent(QDragMoveEvent *e)
{
    Q_D(QListView);
    if (!d->commonListView->filterDragMoveEvent(e)) {
        if (viewMode() == QListView::ListMode && flow() == QListView::LeftToRight)
            static_cast<QListModeViewBase *>(d->commonListView)->dragMoveEvent(e);
        else
            QAbstractItemView::dragMoveEvent(e);
    }
}
 
 
void QListView::dragLeaveEvent(QDragLeaveEvent *e)
{
    if (!d_func()->commonListView->filterDragLeaveEvent(e))
        QAbstractItemView::dragLeaveEvent(e);
}
 
void QListView::dropEvent(QDropEvent *event)
{
    Q_D(QListView);
 
    if (event->source() == this && (event->dropAction() == Qt::MoveAction ||
                                    dragDropMode() == QAbstractItemView::InternalMove)) {
        QModelIndex topIndex;
        bool topIndexDropped = false;
        int col = -1;
        int row = -1;
        // check whether a subclass has already accepted the event, ie. moved the data
        if (!event->isAccepted() && d->dropOn(event, &row, &col, &topIndex)) {
            const QList<QModelIndex> selIndexes = selectedIndexes();
            QList<QPersistentModelIndex> persIndexes;
            persIndexes.reserve(selIndexes.size());
 
            for (const auto &index : selIndexes) {
                persIndexes.append(index);
                if (index == topIndex) {
                    topIndexDropped = true;
                    break;
                }
            }
 
            if (!topIndexDropped && !topIndex.isValid()) {
                std::sort(persIndexes.begin(), persIndexes.end()); // The dropped items will remain in the same visual order.
 
                QPersistentModelIndex dropRow = model()->index(row, col, topIndex);
 
                int r = row == -1 ? model()->rowCount() : (dropRow.row() >= 0 ? dropRow.row() : row);
                bool dataMoved = false;
                for (int i = 0; i < persIndexes.size(); ++i) {
                    const QPersistentModelIndex &pIndex = persIndexes.at(i);
                    // only generate a move when not same row or behind itself
                    if (r != pIndex.row() && r != pIndex.row() + 1) {
                        // try to move (preserves selection)
                        dataMoved |= model()->moveRow(QModelIndex(), pIndex.row(), QModelIndex(), r);
                        if (!dataMoved) // can't move - abort and let QAbstractItemView handle this
                            break;
                    } else {
                        // move onto itself is blocked, don't delete anything
                        dataMoved = true;
                    }
                    r = pIndex.row() + 1;   // Dropped items are inserted contiguously and in the right order.
                }
                if (dataMoved)
                    event->accept();
            }
        }
 
        // either we or a subclass accepted the move event, so assume that the data was
        // moved and that QAbstractItemView shouldn't remove the source when QDrag::exec returns
        if (event->isAccepted())
            d->dropEventMoved = true;
    }
 
    if (!d->commonListView->filterDropEvent(event) || !d->dropEventMoved) {
        // icon view didn't move the data, and moveRows not implemented, so fall back to default
        if (!d->dropEventMoved)
            event->ignore();
        QAbstractItemView::dropEvent(event);
    }
}
 
void QListView::startDrag(Qt::DropActions supportedActions)
{
    if (!d_func()->commonListView->filterStartDrag(supportedActions))
        QAbstractItemView::startDrag(supportedActions);
}
 
#endif // QT_CONFIG(draganddrop)
 
void QListView::initViewItemOption(QStyleOptionViewItem *option) const
{
    Q_D(const QListView);
    QAbstractItemView::initViewItemOption(option);
    if (!d->iconSize.isValid()) { // otherwise it was already set in abstractitemview
        int pm = (d->viewMode == QListView::ListMode
                  ? style()->pixelMetric(QStyle::PM_ListViewIconSize, nullptr, this)
                  : style()->pixelMetric(QStyle::PM_IconViewIconSize, nullptr, this));
        option->decorationSize = QSize(pm, pm);
    }
    if (d->viewMode == QListView::IconMode) {
        option->showDecorationSelected = false;
        option->decorationPosition = QStyleOptionViewItem::Top;
        option->displayAlignment = Qt::AlignCenter;
    } else {
        option->decorationPosition = QStyleOptionViewItem::Left;
    }
 
    if (d->gridSize().isValid()) {
        option->rect.setSize(d->gridSize());
    }
}
 
 
void QListView::paintEvent(QPaintEvent *e)
{
    Q_D(QListView);
    if (!d->itemDelegate)
        return;
    QStyleOptionViewItem option;
    initViewItemOption(&option);
    QStylePainter painter(d->viewport);
 
    const QList<QModelIndex> toBeRendered =
            d->intersectingSet(e->rect().translated(horizontalOffset(), verticalOffset()), false);
 
    const QModelIndex current = currentIndex();
    const QModelIndex hover = d->hover;
    const QAbstractItemModel *itemModel = d->model;
    const QItemSelectionModel *selections = d->selectionModel;
    const bool focus = (hasFocus() || d->viewport->hasFocus()) && current.isValid();
    const bool alternate = d->alternatingColors;
    const QStyle::State state = option.state;
    const QAbstractItemView::State viewState = this->state();
    const bool enabled = (state & QStyle::State_Enabled) != 0;
 
    bool alternateBase = false;
    int previousRow = -2; // trigger the alternateBase adjustment on first pass
 
    int maxSize = (flow() == TopToBottom)
        ? qMax(viewport()->size().width(), d->contentsSize().width()) - 2 * d->spacing()
        : qMax(viewport()->size().height(), d->contentsSize().height()) - 2 * d->spacing();
 
    QList<QModelIndex>::const_iterator end = toBeRendered.constEnd();
    for (QList<QModelIndex>::const_iterator it = toBeRendered.constBegin(); it != end; ++it) {
        Q_ASSERT((*it).isValid());
        option.rect = visualRect(*it);
 
        if (flow() == TopToBottom)
            option.rect.setWidth(qMin(maxSize, option.rect.width()));
        else
            option.rect.setHeight(qMin(maxSize, option.rect.height()));
 
        option.state = state;
        if (selections && selections->isSelected(*it))
            option.state |= QStyle::State_Selected;
        if (enabled) {
            QPalette::ColorGroup cg;
            if ((itemModel->flags(*it) & Qt::ItemIsEnabled) == 0) {
                option.state &= ~QStyle::State_Enabled;
                cg = QPalette::Disabled;
            } else {
                cg = QPalette::Normal;
            }
            option.palette.setCurrentColorGroup(cg);
        }
        if (focus && current == *it) {
            option.state |= QStyle::State_HasFocus;
            if (viewState == EditingState)
                option.state |= QStyle::State_Editing;
        }
        option.state.setFlag(QStyle::State_MouseOver, *it == hover);
 
        if (alternate) {
            int row = (*it).row();
            if (row != previousRow + 1) {
                // adjust alternateBase according to rows in the "gap"
                if (!d->hiddenRows.isEmpty()) {
                    for (int r = qMax(previousRow + 1, 0); r < row; ++r) {
                        if (!d->isHidden(r))
                            alternateBase = !alternateBase;
                    }
                } else {
                    alternateBase = (row & 1) != 0;
                }
            }
            option.features.setFlag(QStyleOptionViewItem::Alternate, alternateBase);
 
            // draw background of the item (only alternate row). rest of the background
            // is provided by the delegate
            QStyle::State oldState = option.state;
            option.state &= ~QStyle::State_Selected;
            painter.drawPrimitive(QStyle::PE_PanelItemViewRow, option);
            option.state = oldState;
 
            alternateBase = !alternateBase;
            previousRow = row;
        }
 
        itemDelegateForIndex(*it)->paint(&painter, option, *it);
    }
 
#if QT_CONFIG(draganddrop)
    d->commonListView->paintDragDrop(&painter);
#endif
 
#if QT_CONFIG(rubberband)
    // #### move this implementation into a dynamic class
    if (d->showElasticBand && d->elasticBand.isValid()) {
        QStyleOptionRubberBand opt;
        opt.initFrom(this);
        opt.shape = QRubberBand::Rectangle;
        opt.opaque = false;
        opt.rect = d->mapToViewport(d->elasticBand, false).intersected(
            d->viewport->rect().adjusted(-16, -16, 16, 16));
        painter.save();
        painter.drawControl(QStyle::CE_RubberBand, opt);
        painter.restore();
    }
#endif
}
 
QModelIndex QListView::indexAt(const QPoint &p) const
{
    Q_D(const QListView);
    QRect rect(p.x() + horizontalOffset(), p.y() + verticalOffset(), 1, 1);
    const QList<QModelIndex> intersectVector = d->intersectingSet(rect);
    QModelIndex index = intersectVector.size() > 0
                        ? intersectVector.last() : QModelIndex();
    if (index.isValid() && visualRect(index).contains(p))
        return index;
    return QModelIndex();
}
 
int QListView::horizontalOffset() const
{
    return d_func()->commonListView->horizontalOffset();
}
 
int QListView::verticalOffset() const
{
    return d_func()->commonListView->verticalOffset();
}
 
QModelIndex QListView::moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers)
{
    Q_D(QListView);
    Q_UNUSED(modifiers);
 
    auto findAvailableRowBackward = [d](int row) {
        while (row >= 0 && d->isHiddenOrDisabled(row))
            --row;
        return row;
    };
 
    auto findAvailableRowForward = [d](int row) {
        int rowCount = d->model->rowCount(d->root);
        if (!rowCount)
            return -1;
        while (row < rowCount && d->isHiddenOrDisabled(row))
            ++row;
        if (row >= rowCount)
            return -1;
        return row;
    };
 
    QModelIndex current = currentIndex();
    if (!current.isValid()) {
        int row = findAvailableRowForward(0);
        if (row == -1)
            return QModelIndex();
        return d->model->index(row, d->column, d->root);
    }
 
    if ((d->flow == LeftToRight && cursorAction == MoveLeft) ||
            (d->flow == TopToBottom && (cursorAction == MoveUp || cursorAction == MovePrevious))) {
        const int row = findAvailableRowBackward(current.row() - 1);
        if (row == -1)
            return current;
        return d->model->index(row, d->column, d->root);
    } else if ((d->flow == LeftToRight && cursorAction == MoveRight) ||
               (d->flow == TopToBottom && (cursorAction == MoveDown || cursorAction == MoveNext))) {
        const int row = findAvailableRowForward(current.row() + 1);
        if (row == -1)
            return current;
        return d->model->index(row, d->column, d->root);
    }
 
    const QRect initialRect = rectForIndex(current);
    QRect rect = initialRect;
    if (rect.isEmpty()) {
        return d->model->index(0, d->column, d->root);
    }
    if (d->gridSize().isValid()) rect.setSize(d->gridSize());
 
    QSize contents = d->contentsSize();
    QList<QModelIndex> intersectVector;
 
    switch (cursorAction) {
    case MoveLeft:
        while (intersectVector.isEmpty()) {
            rect.translate(-rect.width(), 0);
            if (rect.right() <= 0)
                return current;
            if (rect.left() < 0)
                rect.setLeft(0);
            intersectVector = d->intersectingSet(rect);
            d->removeCurrentAndDisabled(&intersectVector, current);
        }
        return d->closestIndex(initialRect, intersectVector);
    case MoveRight:
        while (intersectVector.isEmpty()) {
            rect.translate(rect.width(), 0);
            if (rect.left() >= contents.width())
                return current;
            if (rect.right() > contents.width())
                rect.setRight(contents.width());
            intersectVector = d->intersectingSet(rect);
            d->removeCurrentAndDisabled(&intersectVector, current);
        }
        return d->closestIndex(initialRect, intersectVector);
    case MovePageUp: {
        if (rect.height() >= d->viewport->height())
           return moveCursor(QAbstractItemView::MoveUp, modifiers);
 
        rect.moveTop(rect.top() - d->viewport->height() + 1);
        if (rect.top() < rect.height()) {
            rect.setTop(0);
            rect.setBottom(1);
        }
        QModelIndex findindex = current;
        while (intersectVector.isEmpty()
               || rectForIndex(findindex).top() <= (rectForIndex(current).bottom() - d->viewport->rect().height())
               || rect.top() <= 0) {
            rect.translate(0, 1);
            if (rect.bottom() <= 0) {
                return current;
            }
            intersectVector = d->intersectingSet(rect);
            findindex = d->closestIndex(initialRect, intersectVector);
        }
        return findindex;
    }
    case MovePrevious:
    case MoveUp:
        while (intersectVector.isEmpty()) {
            rect.translate(0, -rect.height());
            if (rect.bottom() <= 0) {
#ifdef QT_KEYPAD_NAVIGATION
                if (QApplicationPrivate::keypadNavigationEnabled()) {
                    int row = d->batchStartRow() - 1;
                    while (row >= 0 && d->isHiddenOrDisabled(row))
                        --row;
                    if (row >= 0)
                        return d->model->index(row, d->column, d->root);
                }
#endif
                return current;
            }
            if (rect.top() < 0)
                rect.setTop(0);
            intersectVector = d->intersectingSet(rect);
            d->removeCurrentAndDisabled(&intersectVector, current);
        }
        return d->closestIndex(initialRect, intersectVector);
    case MovePageDown: {
        if (rect.height() >= d->viewport->height())
           return moveCursor(QAbstractItemView::MoveDown, modifiers);
 
        rect.moveTop(rect.top() + d->viewport->height() - 1);
        if (rect.bottom() > contents.height() - rect.height()) {
            rect.setTop(contents.height() - 1);
            rect.setBottom(contents.height());
        }
        QModelIndex index = current;
        // index's bottom() - current's top() always <=  (d->viewport->rect().height()
        while (intersectVector.isEmpty()
               || rectForIndex(index).bottom() >= (d->viewport->rect().height() + rectForIndex(current).top())
               || rect.bottom() > contents.height()) {
            rect.translate(0, -1);
            if (rect.top() >= contents.height()) {
                return current;
            }
            intersectVector = d->intersectingSet(rect);
            index = d->closestIndex(initialRect, intersectVector);
        }
        return index;
    }
    case MoveNext:
    case MoveDown:
        while (intersectVector.isEmpty()) {
            rect.translate(0, rect.height());
            if (rect.top() >= contents.height()) {
#ifdef QT_KEYPAD_NAVIGATION
                if (QApplicationPrivate::keypadNavigationEnabled()) {
                    int rowCount = d->model->rowCount(d->root);
                    int row = 0;
                    while (row < rowCount && d->isHiddenOrDisabled(row))
                        ++row;
                    if (row < rowCount)
                        return d->model->index(row, d->column, d->root);
                }
#endif
                return current;
            }
            if (rect.bottom() > contents.height())
                rect.setBottom(contents.height());
            intersectVector = d->intersectingSet(rect);
            d->removeCurrentAndDisabled(&intersectVector, current);
        }
        return d->closestIndex(initialRect, intersectVector);
    case MoveHome:
        return d->model->index(0, d->column, d->root);
    case MoveEnd:
        return d->model->index(d->batchStartRow() - 1, d->column, d->root);}
 
    return current;
}
 
QRect QListView::rectForIndex(const QModelIndex &index) const
{
    return d_func()->rectForIndex(index);
}
 
void QListView::setPositionForIndex(const QPoint &position, const QModelIndex &index)
{
    Q_D(QListView);
    if (d->movement == Static
        || !d->isIndexValid(index)
        || index.parent() != d->root
        || index.column() != d->column)
        return;
 
    d->executePostedLayout();
    d->commonListView->setPositionForIndex(position, index);
}
 
void QListView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
    Q_D(QListView);
    if (!d->selectionModel)
        return;
 
    // if we are wrapping, we can only select inside the contents rectangle
    int w = qMax(d->contentsSize().width(), d->viewport->width());
    int h = qMax(d->contentsSize().height(), d->viewport->height());
    if (d->wrap && !QRect(0, 0, w, h).intersects(rect))
        return;
 
    QItemSelection selection;
 
    if (rect.width() == 1 && rect.height() == 1) {
        const QList<QModelIndex> intersectVector =
                d->intersectingSet(rect.translated(horizontalOffset(), verticalOffset()));
        QModelIndex tl;
        if (!intersectVector.isEmpty())
            tl = intersectVector.last(); // special case for mouse press; only select the top item
        if (tl.isValid() && d->isIndexEnabled(tl))
            selection.select(tl, tl);
    } else {
        if (state() == DragSelectingState) { // visual selection mode (rubberband selection)
            selection = d->selection(rect.translated(horizontalOffset(), verticalOffset()));
        } else { // logical selection mode (key and mouse click selection)
            QModelIndex tl, br;
            // get the first item
            const QRect topLeft(rect.left() + horizontalOffset(), rect.top() + verticalOffset(), 1, 1);
            QList<QModelIndex> intersectVector = d->intersectingSet(topLeft);
            if (!intersectVector.isEmpty())
                tl = intersectVector.last();
            // get the last item
            const QRect bottomRight(rect.right() + horizontalOffset(), rect.bottom() + verticalOffset(), 1, 1);
            intersectVector = d->intersectingSet(bottomRight);
            if (!intersectVector.isEmpty())
                br = intersectVector.last();
 
            // get the ranges
            if (tl.isValid() && br.isValid()
                && d->isIndexEnabled(tl)
                && d->isIndexEnabled(br)) {
                QRect first = d->cellRectForIndex(tl);
                QRect last = d->cellRectForIndex(br);
                QRect middle;
                if (d->flow == LeftToRight) {
                    QRect &top = first;
                    QRect &bottom = last;
                    // if bottom is above top, swap them
                    if (top.center().y() > bottom.center().y()) {
                        QRect tmp = top;
                        top = bottom;
                        bottom = tmp;
                    }
                    // if the rect are on different lines, expand
                    if (top.top() != bottom.top()) {
                        // top rectangle
                        if (isRightToLeft())
                            top.setLeft(0);
                        else
                            top.setRight(contentsSize().width());
                        // bottom rectangle
                        if (isRightToLeft())
                            bottom.setRight(contentsSize().width());
                        else
                            bottom.setLeft(0);
                    } else if (top.left() > bottom.right()) {
                        if (isRightToLeft())
                            bottom.setLeft(top.right());
                        else
                            bottom.setRight(top.left());
                    } else {
                        if (isRightToLeft())
                            top.setLeft(bottom.right());
                        else
                            top.setRight(bottom.left());
                    }
                    // middle rectangle
                    if (top.bottom() < bottom.top()) {
                        if (gridSize().isValid() && !gridSize().isNull())
                            middle.setTop(top.top() + gridSize().height());
                        else
                            middle.setTop(top.bottom() + 1);
                        middle.setLeft(qMin(top.left(), bottom.left()));
                        middle.setBottom(bottom.top() - 1);
                        middle.setRight(qMax(top.right(), bottom.right()));
                    }
                } else {    // TopToBottom
                    QRect &left = first;
                    QRect &right = last;
                    if (left.center().x() > right.center().x())
                        qSwap(left, right);
 
                    int ch = contentsSize().height();
                    if (left.left() != right.left()) {
                        // left rectangle
                        if (isRightToLeft())
                            left.setTop(0);
                        else
                            left.setBottom(ch);
 
                        // top rectangle
                        if (isRightToLeft())
                            right.setBottom(ch);
                        else
                            right.setTop(0);
                        // only set middle if the
                        middle.setTop(0);
                        middle.setBottom(ch);
                        if (gridSize().isValid() && !gridSize().isNull())
                            middle.setLeft(left.left() + gridSize().width());
                        else
                            middle.setLeft(left.right() + 1);
                        middle.setRight(right.left() - 1);
                    } else if (left.bottom() < right.top()) {
                        left.setBottom(right.top() - 1);
                    } else {
                        right.setBottom(left.top() - 1);
                    }
                }
 
                // do the selections
                QItemSelection topSelection = d->selection(first);
                QItemSelection middleSelection = d->selection(middle);
                QItemSelection bottomSelection = d->selection(last);
                // merge
                selection.merge(topSelection, QItemSelectionModel::Select);
                selection.merge(middleSelection, QItemSelectionModel::Select);
                selection.merge(bottomSelection, QItemSelectionModel::Select);
            }
        }
    }
 
    d->selectionModel->select(selection, command);
}
 
QRegion QListView::visualRegionForSelection(const QItemSelection &selection) const
{
    Q_D(const QListView);
    // ### NOTE: this is a potential bottleneck in non-static mode
    int c = d->column;
    QRegion selectionRegion;
    const QRect &viewportRect = d->viewport->rect();
    for (const auto &elem : selection) {
        if (!elem.isValid())
            continue;
        QModelIndex parent = elem.topLeft().parent();
        //we only display the children of the root in a listview
        //we're not interested in the other model indexes
        if (parent != d->root)
            continue;
        int t = elem.topLeft().row();
        int b = elem.bottomRight().row();
        if (d->viewMode == IconMode || d->isWrapping()) { // in non-static mode, we have to go through all selected items
            for (int r = t; r <= b; ++r) {
                const QRect &rect = visualRect(d->model->index(r, c, parent));
                if (viewportRect.intersects(rect))
                    selectionRegion += rect;
            }
        } else { // in static mode, we can optimize a bit
            while (t <= b && d->isHidden(t)) ++t;
            while (b >= t && d->isHidden(b)) --b;
            const QModelIndex top = d->model->index(t, c, parent);
            const QModelIndex bottom = d->model->index(b, c, parent);
            QRect rect(visualRect(top).topLeft(),
                       visualRect(bottom).bottomRight());
            if (viewportRect.intersects(rect))
                selectionRegion += rect;
        }
    }
 
    return selectionRegion;
}
 
QModelIndexList QListView::selectedIndexes() const
{
    Q_D(const QListView);
    if (!d->selectionModel)
        return QModelIndexList();
 
    QModelIndexList viewSelected = d->selectionModel->selectedIndexes();
    auto ignorable = [this, d](const QModelIndex &index) {
        return index.column() != d->column || index.parent() != d->root || isIndexHidden(index);
    };
    viewSelected.removeIf(ignorable);
    return viewSelected;
}
 
void QListView::doItemsLayout()
{
    Q_D(QListView);
    // showing the scroll bars will trigger a resize event,
    // so we set the state to expanding to avoid
    // triggering another layout
    QAbstractItemView::State oldState = state();
    setState(ExpandingState);
    if (d->model->columnCount(d->root) > 0) { // no columns means no contents
        d->resetBatchStartRow();
        if (layoutMode() == SinglePass) {
            d->doItemsLayout(d->model->rowCount(d->root)); // layout everything
        } else if (!d->batchLayoutTimer.isActive()) {
            if (!d->doItemsLayout(d->batchSize)) // layout is done
                d->batchLayoutTimer.start(0, this); // do a new batch as fast as possible
        }
    } else { // clear the QBspTree generated by the last layout
        d->clear();
    }
    QAbstractItemView::doItemsLayout();
    setState(oldState);        // restoring the oldState
}
 
void QListView::updateGeometries()
{
    Q_D(QListView);
    if (geometry().isEmpty() || d->model->rowCount(d->root) <= 0 || d->model->columnCount(d->root) <= 0) {
        horizontalScrollBar()->setRange(0, 0);
        verticalScrollBar()->setRange(0, 0);
    } else {
        QModelIndex index = d->model->index(0, d->column, d->root);
        QStyleOptionViewItem option;
        initViewItemOption(&option);
        QSize step = d->itemSize(option, index);
        d->commonListView->updateHorizontalScrollBar(step);
        d->commonListView->updateVerticalScrollBar(step);
    }
 
    QAbstractItemView::updateGeometries();
 
    // if the scroll bars are turned off, we resize the contents to the viewport
    if (d->movement == Static && !d->isWrapping()) {
        d->layoutChildren(); // we need the viewport size to be updated
        if (d->flow == TopToBottom) {
            if (horizontalScrollBarPolicy() == Qt::ScrollBarAlwaysOff) {
                d->setContentsSize(viewport()->width(), contentsSize().height());
                horizontalScrollBar()->setRange(0, 0); // we see all the contents anyway
            }
        } else { // LeftToRight
            if (verticalScrollBarPolicy() == Qt::ScrollBarAlwaysOff) {
                d->setContentsSize(contentsSize().width(), viewport()->height());
                verticalScrollBar()->setRange(0, 0); // we see all the contents anyway
            }
        }
    }
 
}
 
bool QListView::isIndexHidden(const QModelIndex &index) const
{
    Q_D(const QListView);
    return (d->isHidden(index.row())
            && (index.parent() == d->root)
            && index.column() == d->column);
}
 
void QListView::setModelColumn(int column)
{
    Q_D(QListView);
    if (column < 0 || column >= d->model->columnCount(d->root))
        return;
    d->column = column;
    d->doDelayedItemsLayout();
#if QT_CONFIG(accessibility)
    if (QAccessible::isActive()) {
        QAccessibleTableModelChangeEvent event(this, QAccessibleTableModelChangeEvent::ModelReset);
        QAccessible::updateAccessibility(&event);
    }
#endif
}
 
int QListView::modelColumn() const
{
    Q_D(const QListView);
    return d->column;
}
 
void QListView::setUniformItemSizes(bool enable)
{
    Q_D(QListView);
    d->uniformItemSizes = enable;
}
 
bool QListView::uniformItemSizes() const
{
    Q_D(const QListView);
    return d->uniformItemSizes;
}
 
void QListView::setWordWrap(bool on)
{
    Q_D(QListView);
    if (d->wrapItemText == on)
        return;
    d->wrapItemText = on;
    d->doDelayedItemsLayout();
}
 
bool QListView::wordWrap() const
{
    Q_D(const QListView);
    return d->wrapItemText;
}
 
void QListView::setSelectionRectVisible(bool show)
{
    Q_D(QListView);
    d->modeProperties |= uint(QListViewPrivate::SelectionRectVisible);
    d->setSelectionRectVisible(show);
}
 
bool QListView::isSelectionRectVisible() const
{
    Q_D(const QListView);
    return d->isSelectionRectVisible();
}
 
void QListView::setItemAlignment(Qt::Alignment alignment)
{
    Q_D(QListView);
    if (d->itemAlignment == alignment)
        return;
    d->itemAlignment = alignment;
    if (viewMode() == ListMode && flow() == QListView::TopToBottom && isWrapping())
        d->doDelayedItemsLayout();
}
 
Qt::Alignment QListView::itemAlignment() const
{
    Q_D(const QListView);
    return d->itemAlignment;
}
 
bool QListView::event(QEvent *e)
{
    return QAbstractItemView::event(e);
}
 
/*
 * private object implementation
 */
 
QListViewPrivate::QListViewPrivate()
    : QAbstractItemViewPrivate(),
      commonListView(nullptr),
      wrap(false),
      space(0),
      flow(QListView::TopToBottom),
      movement(QListView::Static),
      resizeMode(QListView::Fixed),
      layoutMode(QListView::SinglePass),
      viewMode(QListView::ListMode),
      modeProperties(0),
      column(0),
      uniformItemSizes(false),
      batchSize(100),
      showElasticBand(false),
      itemAlignment(Qt::Alignment())
{
}
 
QListViewPrivate::~QListViewPrivate()
{
    delete commonListView;
}
 
void QListViewPrivate::clear()
{
    // initialization of data structs
    cachedItemSize = QSize();
    commonListView->clear();
}
 
void QListViewPrivate::prepareItemsLayout()
{
    Q_Q(QListView);
    clear();
 
    //take the size as if there were scrollbar in order to prevent scrollbar to blink
    layoutBounds = QRect(QPoint(), q->maximumViewportSize());
 
    int frameAroundContents = 0;
    if (q->style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents)) {
        QStyleOption option;
        option.initFrom(q);
        frameAroundContents = q->style()->pixelMetric(QStyle::PM_DefaultFrameWidth, &option, q) * 2;
    }
 
    // maximumViewportSize() already takes scrollbar into account if policy is
    // Qt::ScrollBarAlwaysOn but scrollbar extent must be deduced if policy
    // is Qt::ScrollBarAsNeeded
    int verticalMargin = (vbarpolicy == Qt::ScrollBarAsNeeded) && (flow == QListView::LeftToRight || vbar->isVisible())
                        && !q->style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarOverlap, nullptr, vbar)
        ? q->style()->pixelMetric(QStyle::PM_ScrollBarExtent, nullptr, vbar) + frameAroundContents
        : 0;
    int horizontalMargin =  hbarpolicy==Qt::ScrollBarAsNeeded
        ? q->style()->pixelMetric(QStyle::PM_ScrollBarExtent, nullptr, hbar) + frameAroundContents
        : 0;
 
    layoutBounds.adjust(0, 0, -verticalMargin, -horizontalMargin);
 
    int rowCount = model->columnCount(root) <= 0 ? 0 : model->rowCount(root);
    commonListView->setRowCount(rowCount);
}
 
bool QListViewPrivate::doItemsLayout(int delta)
{
    int max = model->rowCount(root) - 1;
    int first = batchStartRow();
    int last = qMin(first + delta - 1, max);
 
    if (first == 0) {
        layoutChildren(); // make sure the viewport has the right size
        prepareItemsLayout();
    }
 
    if (max < 0 || last < first) {
        return true; // nothing to do
    }
 
    QListViewLayoutInfo info;
    info.bounds = layoutBounds;
    info.grid = gridSize();
    info.spacing = (info.grid.isValid() ? 0 : spacing());
    info.first = first;
    info.last = last;
    info.wrap = isWrapping();
    info.flow = flow;
    info.max = max;
 
    return commonListView->doBatchedItemLayout(info, max);
}
 
QListViewItem QListViewPrivate::indexToListViewItem(const QModelIndex &index) const
{
    if (!index.isValid() || isHidden(index.row()))
        return QListViewItem();
 
    return commonListView->indexToListViewItem(index);
}
 
QRect QListViewPrivate::mapToViewport(const QRect &rect, bool extend) const
{
    Q_Q(const QListView);
    if (!rect.isValid())
        return rect;
 
    QRect result = extend ? commonListView->mapToViewport(rect) : rect;
    int dx = -q->horizontalOffset();
    int dy = -q->verticalOffset();
    return result.adjusted(dx, dy, dx, dy);
}
 
QModelIndex QListViewPrivate::closestIndex(const QRect &target,
                                           const QList<QModelIndex> &candidates) const
{
    int distance = 0;
    int shortest = INT_MAX;
    QModelIndex closest;
    QList<QModelIndex>::const_iterator it = candidates.begin();
 
    for (; it != candidates.end(); ++it) {
        if (!(*it).isValid())
            continue;
 
        const QRect indexRect = indexToListViewItem(*it).rect();
 
        //if the center x (or y) position of an item is included in the rect of the other item,
        //we define the distance between them as the difference in x (or y) of their respective center.
        // Otherwise, we use the nahattan  length between the 2 items
        if ((target.center().x() >= indexRect.x() && target.center().x() < indexRect.right())
            || (indexRect.center().x() >= target.x() && indexRect.center().x() < target.right())) {
                //one item's center is at the vertical of the other
                distance = qAbs(indexRect.center().y() - target.center().y());
        } else if ((target.center().y() >= indexRect.y() && target.center().y() < indexRect.bottom())
            || (indexRect.center().y() >= target.y() && indexRect.center().y() < target.bottom())) {
                //one item's center is at the vertical of the other
                distance = qAbs(indexRect.center().x() - target.center().x());
        } else {
            distance = (indexRect.center() - target.center()).manhattanLength();
        }
        if (distance < shortest) {
            shortest = distance;
            closest = *it;
        }
    }
    return closest;
}
 
QSize QListViewPrivate::itemSize(const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    Q_Q(const QListView);
    if (!uniformItemSizes) {
        const QAbstractItemDelegate *delegate = q->itemDelegateForIndex(index);
        return delegate ? delegate->sizeHint(option, index) : QSize();
    }
    if (!cachedItemSize.isValid()) { // the last item is probably the largest, so we use its size
        int row = model->rowCount(root) - 1;
        QModelIndex sample = model->index(row, column, root);
        const QAbstractItemDelegate *delegate = q->itemDelegateForIndex(sample);
        cachedItemSize = delegate ? delegate->sizeHint(option, sample) : QSize();
    }
    return cachedItemSize;
}
 
QItemSelection QListViewPrivate::selection(const QRect &rect) const
{
    QItemSelection selection;
    QModelIndex tl, br;
    const QList<QModelIndex> intersectVector = intersectingSet(rect);
    QList<QModelIndex>::const_iterator it = intersectVector.begin();
    for (; it != intersectVector.end(); ++it) {
        if (!tl.isValid() && !br.isValid()) {
            tl = br = *it;
        } else if ((*it).row() == (tl.row() - 1)) {
            tl = *it; // expand current range
        } else if ((*it).row() == (br.row() + 1)) {
            br = (*it); // expand current range
        } else {
            selection.select(tl, br); // select current range
            tl = br = *it; // start new range
        }
    }
 
    if (tl.isValid() && br.isValid())
        selection.select(tl, br);
    else if (tl.isValid())
        selection.select(tl, tl);
    else if (br.isValid())
        selection.select(br, br);
 
    return selection;
}
 
#if QT_CONFIG(draganddrop)
QAbstractItemView::DropIndicatorPosition QListViewPrivate::position(const QPoint &pos, const QRect &rect, const QModelIndex &idx) const
{
    if (viewMode == QListView::ListMode && flow == QListView::LeftToRight)
        return static_cast<QListModeViewBase *>(commonListView)->position(pos, rect, idx);
    else
        return QAbstractItemViewPrivate::position(pos, rect, idx);
}
 
bool QListViewPrivate::dropOn(QDropEvent *event, int *dropRow, int *dropCol, QModelIndex *dropIndex)
{
    if (viewMode == QListView::ListMode && flow == QListView::LeftToRight)
        return static_cast<QListModeViewBase *>(commonListView)->dropOn(event, dropRow, dropCol, dropIndex);
    else
        return QAbstractItemViewPrivate::dropOn(event, dropRow, dropCol, dropIndex);
}
#endif
 
void QListViewPrivate::removeCurrentAndDisabled(QList<QModelIndex> *indexes,
                                                const QModelIndex &current) const
{
    auto isCurrentOrDisabled = [this, current](const QModelIndex &index) {
        return !isIndexEnabled(index) || index == current;
    };
    indexes->removeIf(isCurrentOrDisabled);
}
 
/*
 * Common ListView Implementation
*/
 
void QCommonListViewBase::appendHiddenRow(int row)
{
    dd->hiddenRows.insert(dd->model->index(row, 0, qq->rootIndex()));
}
 
void QCommonListViewBase::removeHiddenRow(int row)
{
    dd->hiddenRows.remove(dd->model->index(row, 0, qq->rootIndex()));
}
 
#if QT_CONFIG(draganddrop)
void QCommonListViewBase::paintDragDrop(QPainter *painter)
{
    // FIXME: Until the we can provide a proper drop indicator
    // in IconMode, it makes no sense to show it
    dd->paintDropIndicator(painter);
}
#endif
 
QSize QListModeViewBase::viewportSize(const QAbstractItemView *v)
{
    return v->contentsRect().marginsRemoved(v->viewportMargins()).size();
}
 
void QCommonListViewBase::updateHorizontalScrollBar(const QSize &step)
{
    horizontalScrollBar()->d_func()->itemviewChangeSingleStep(step.width() + spacing());
    horizontalScrollBar()->setPageStep(viewport()->width());
 
    // If both scroll bars are set to auto, we might end up in a situation with enough space
    // for the actual content. But still one of the scroll bars will become enabled due to
    // the other one using the space. The other one will become invisible in the same cycle.
    // -> Infinite loop, QTBUG-39902
    const bool bothScrollBarsAuto = qq->verticalScrollBarPolicy() == Qt::ScrollBarAsNeeded &&
                                    qq->horizontalScrollBarPolicy() == Qt::ScrollBarAsNeeded;
 
    const QSize viewportSize = QListModeViewBase::viewportSize(qq);
 
    bool verticalWantsToShow = contentsSize.height() > viewportSize.height();
    bool horizontalWantsToShow;
    if (verticalWantsToShow)
        horizontalWantsToShow = contentsSize.width() > viewportSize.width() - qq->verticalScrollBar()->width();
    else
        horizontalWantsToShow = contentsSize.width() > viewportSize.width();
 
    if (bothScrollBarsAuto && !horizontalWantsToShow) {
        // break the infinite loop described above by setting the range to 0, 0.
        // QAbstractScrollArea will then hide the scroll bar for us
        horizontalScrollBar()->setRange(0, 0);
    } else {
        horizontalScrollBar()->setRange(0, contentsSize.width() - viewport()->width());
    }
}
 
void QCommonListViewBase::updateVerticalScrollBar(const QSize &step)
{
    verticalScrollBar()->d_func()->itemviewChangeSingleStep(step.height() + spacing());
    verticalScrollBar()->setPageStep(viewport()->height());
 
    // If both scroll bars are set to auto, we might end up in a situation with enough space
    // for the actual content. But still one of the scroll bars will become enabled due to
    // the other one using the space. The other one will become invisible in the same cycle.
    // -> Infinite loop, QTBUG-39902
    const bool bothScrollBarsAuto = qq->verticalScrollBarPolicy() == Qt::ScrollBarAsNeeded &&
                                    qq->horizontalScrollBarPolicy() == Qt::ScrollBarAsNeeded;
 
    const QSize viewportSize = QListModeViewBase::viewportSize(qq);
 
    bool horizontalWantsToShow = contentsSize.width() > viewportSize.width();
    bool verticalWantsToShow;
    if (horizontalWantsToShow)
        verticalWantsToShow = contentsSize.height() > viewportSize.height() - qq->horizontalScrollBar()->height();
    else
        verticalWantsToShow = contentsSize.height() > viewportSize.height();
 
    if (bothScrollBarsAuto && !verticalWantsToShow) {
        // break the infinite loop described above by setting the range to 0, 0.
        // QAbstractScrollArea will then hide the scroll bar for us
        verticalScrollBar()->setRange(0, 0);
    } else {
        verticalScrollBar()->setRange(0, contentsSize.height() - viewport()->height());
    }
}
 
void QCommonListViewBase::scrollContentsBy(int dx, int dy, bool /*scrollElasticBand*/)
{
    dd->scrollContentsBy(isRightToLeft() ? -dx : dx, dy);
}
 
int QCommonListViewBase::verticalScrollToValue(int /*index*/, QListView::ScrollHint hint,
                                          bool above, bool below, const QRect &area, const QRect &rect) const
{
    int verticalValue = verticalScrollBar()->value();
    QRect adjusted = rect.adjusted(-spacing(), -spacing(), spacing(), spacing());
    if (hint == QListView::PositionAtTop || above)
        verticalValue += adjusted.top();
    else if (hint == QListView::PositionAtBottom || below)
        verticalValue += qMin(adjusted.top(), adjusted.bottom() - area.height() + 1);
    else if (hint == QListView::PositionAtCenter)
        verticalValue += adjusted.top() - ((area.height() - adjusted.height()) / 2);
    return verticalValue;
}
 
int QCommonListViewBase::horizontalOffset() const
{
    return (isRightToLeft() ? horizontalScrollBar()->maximum() - horizontalScrollBar()->value() : horizontalScrollBar()->value());
}
 
int QCommonListViewBase::horizontalScrollToValue(const int /*index*/, QListView::ScrollHint hint,
                                            bool leftOf, bool rightOf, const QRect &area, const QRect &rect) const
{
    int horizontalValue = horizontalScrollBar()->value();
    if (isRightToLeft()) {
        if (hint == QListView::PositionAtCenter) {
            horizontalValue += ((area.width() - rect.width()) / 2) - rect.left();
        } else {
            if (leftOf)
                horizontalValue -= rect.left();
            else if (rightOf)
                horizontalValue += qMin(rect.left(), area.width() - rect.right());
        }
    } else {
        if (hint == QListView::PositionAtCenter) {
            horizontalValue += rect.left() - ((area.width()- rect.width()) / 2);
        } else {
            if (leftOf)
                horizontalValue += rect.left();
            else if (rightOf)
                horizontalValue += qMin(rect.left(), rect.right() - area.width());
        }
    }
    return horizontalValue;
}
 
/*
 * ListMode ListView Implementation
*/
QListModeViewBase::QListModeViewBase(QListView *q, QListViewPrivate *d)
    : QCommonListViewBase(q, d)
{
#if QT_CONFIG(draganddrop)
    dd->defaultDropAction = Qt::CopyAction;
#endif
}
 
#if QT_CONFIG(draganddrop)
QAbstractItemView::DropIndicatorPosition QListModeViewBase::position(const QPoint &pos, const QRect &rect, const QModelIndex &index) const
{
    QAbstractItemView::DropIndicatorPosition r = QAbstractItemView::OnViewport;
    if (!dd->overwrite) {
        const int margin = 2;
        if (pos.x() - rect.left() < margin) {
            r = QAbstractItemView::AboveItem;   // Visually, on the left
        } else if (rect.right() - pos.x() < margin) {
            r = QAbstractItemView::BelowItem;   // Visually, on the right
        } else if (rect.contains(pos, true)) {
            r = QAbstractItemView::OnItem;
        }
    } else {
        QRect touchingRect = rect;
        touchingRect.adjust(-1, -1, 1, 1);
        if (touchingRect.contains(pos, false)) {
            r = QAbstractItemView::OnItem;
        }
    }
 
    if (r == QAbstractItemView::OnItem && (!(dd->model->flags(index) & Qt::ItemIsDropEnabled)))
        r = pos.x() < rect.center().x() ? QAbstractItemView::AboveItem : QAbstractItemView::BelowItem;
 
    return r;
}
 
void QListModeViewBase::dragMoveEvent(QDragMoveEvent *event)
{
    if (qq->dragDropMode() == QAbstractItemView::InternalMove
        && (event->source() != qq || !(event->possibleActions() & Qt::MoveAction)))
        return;
 
    // ignore by default
    event->ignore();
 
    // can't use indexAt, doesn't account for spacing.
    QPoint p = event->position().toPoint();
    QRect rect(p.x() + horizontalOffset(), p.y() + verticalOffset(), 1, 1);
    rect.adjust(-dd->spacing(), -dd->spacing(), dd->spacing(), dd->spacing());
    const QList<QModelIndex> intersectVector = dd->intersectingSet(rect);
    QModelIndex index = intersectVector.size() > 0
                        ? intersectVector.last() : QModelIndex();
    dd->hover = index;
    if (!dd->droppingOnItself(event, index)
        && dd->canDrop(event)) {
 
        if (index.isValid() && dd->showDropIndicator) {
            QRect rect = qq->visualRect(index);
            dd->dropIndicatorPosition = position(event->position().toPoint(), rect, index);
            // if spacing, should try to draw between items, not just next to item.
            switch (dd->dropIndicatorPosition) {
            case QAbstractItemView::AboveItem:
                if (dd->isIndexDropEnabled(index.parent())) {
                    dd->dropIndicatorRect = QRect(rect.left()-dd->spacing(), rect.top(), 0, rect.height());
                    event->accept();
                } else {
                    dd->dropIndicatorRect = QRect();
                }
                break;
            case QAbstractItemView::BelowItem:
                if (dd->isIndexDropEnabled(index.parent())) {
                    dd->dropIndicatorRect = QRect(rect.right()+dd->spacing(), rect.top(), 0, rect.height());
                    event->accept();
                } else {
                    dd->dropIndicatorRect = QRect();
                }
                break;
            case QAbstractItemView::OnItem:
                if (dd->isIndexDropEnabled(index)) {
                    dd->dropIndicatorRect = rect;
                    event->accept();
                } else {
                    dd->dropIndicatorRect = QRect();
                }
                break;
            case QAbstractItemView::OnViewport:
                dd->dropIndicatorRect = QRect();
                if (dd->isIndexDropEnabled(qq->rootIndex())) {
                    event->accept(); // allow dropping in empty areas
                }
                break;
            }
        } else {
            dd->dropIndicatorRect = QRect();
            dd->dropIndicatorPosition = QAbstractItemView::OnViewport;
            if (dd->isIndexDropEnabled(qq->rootIndex())) {
                event->accept(); // allow dropping in empty areas
            }
        }
        dd->viewport->update();
    } // can drop
 
    if (dd->shouldAutoScroll(event->position().toPoint()))
        qq->startAutoScroll();
}
 
bool QListModeViewBase::dropOn(QDropEvent *event, int *dropRow, int *dropCol, QModelIndex *dropIndex)
{
    if (event->isAccepted())
        return false;
 
    QModelIndex index;
    if (dd->viewport->rect().contains(event->position().toPoint())) {
        // can't use indexAt, doesn't account for spacing.
        QPoint p = event->position().toPoint();
        QRect rect(p.x() + horizontalOffset(), p.y() + verticalOffset(), 1, 1);
        rect.adjust(-dd->spacing(), -dd->spacing(), dd->spacing(), dd->spacing());
        const QList<QModelIndex> intersectVector = dd->intersectingSet(rect);
        index = intersectVector.size() > 0
            ? intersectVector.last() : QModelIndex();
        if (!index.isValid())
            index = dd->root;
    }
 
    // If we are allowed to do the drop
    if (dd->model->supportedDropActions() & event->dropAction()) {
        int row = -1;
        int col = -1;
        if (index != dd->root) {
            dd->dropIndicatorPosition = position(event->position().toPoint(), qq->visualRect(index), index);
            switch (dd->dropIndicatorPosition) {
            case QAbstractItemView::AboveItem:
                row = index.row();
                col = index.column();
                index = index.parent();
                break;
            case QAbstractItemView::BelowItem:
                row = index.row() + 1;
                col = index.column();
                index = index.parent();
                break;
            case QAbstractItemView::OnItem:
            case QAbstractItemView::OnViewport:
                break;
            }
        } else {
            dd->dropIndicatorPosition = QAbstractItemView::OnViewport;
        }
        *dropIndex = index;
        *dropRow = row;
        *dropCol = col;
        if (!dd->droppingOnItself(event, index))
            return true;
    }
    return false;
}
 
#endif //QT_CONFIG(draganddrop)
 
void QListModeViewBase::updateVerticalScrollBar(const QSize &step)
{
    if (verticalScrollMode() == QAbstractItemView::ScrollPerItem
        && ((flow() == QListView::TopToBottom && !isWrapping())
        || (flow() == QListView::LeftToRight && isWrapping()))) {
            const int steps = (flow() == QListView::TopToBottom ? scrollValueMap : segmentPositions).size() - 1;
            if (steps > 0) {
                const int pageSteps = perItemScrollingPageSteps(viewport()->height(), contentsSize.height(), isWrapping());
                verticalScrollBar()->setSingleStep(1);
                verticalScrollBar()->setPageStep(pageSteps);
                verticalScrollBar()->setRange(0, steps - pageSteps);
            } else {
                verticalScrollBar()->setRange(0, 0);
            }
            // } else if (vertical && d->isWrapping() && d->movement == Static) {
            // ### wrapped scrolling in flow direction
    } else {
        QCommonListViewBase::updateVerticalScrollBar(step);
    }
}
 
void QListModeViewBase::updateHorizontalScrollBar(const QSize &step)
{
    if (horizontalScrollMode() == QAbstractItemView::ScrollPerItem
        && ((flow() == QListView::TopToBottom && isWrapping())
        || (flow() == QListView::LeftToRight && !isWrapping()))) {
            int steps = (flow() == QListView::TopToBottom ? segmentPositions : scrollValueMap).size() - 1;
            if (steps > 0) {
                const int pageSteps = perItemScrollingPageSteps(viewport()->width(), contentsSize.width(), isWrapping());
                horizontalScrollBar()->setSingleStep(1);
                horizontalScrollBar()->setPageStep(pageSteps);
                horizontalScrollBar()->setRange(0, steps - pageSteps);
            } else {
                horizontalScrollBar()->setRange(0, 0);
            }
    } else {
        QCommonListViewBase::updateHorizontalScrollBar(step);
    }
}
 
int QListModeViewBase::verticalScrollToValue(int index, QListView::ScrollHint hint,
                                          bool above, bool below, const QRect &area, const QRect &rect) const
{
    if (verticalScrollMode() == QAbstractItemView::ScrollPerItem) {
        int value;
        if (scrollValueMap.isEmpty()) {
            value = 0;
        } else {
            int scrollBarValue = verticalScrollBar()->value();
            int numHidden = 0;
            for (const auto &idx : std::as_const(dd->hiddenRows))
                if (idx.row() <= scrollBarValue)
                    ++numHidden;
            value = qBound(0, scrollValueMap.at(verticalScrollBar()->value()) - numHidden, flowPositions.size() - 1);
        }
        if (above)
            hint = QListView::PositionAtTop;
        else if (below)
            hint = QListView::PositionAtBottom;
        if (hint == QListView::EnsureVisible)
            return value;
 
        return perItemScrollToValue(index, value, area.height(), hint, Qt::Vertical, isWrapping(), rect.height());
    }
 
    return QCommonListViewBase::verticalScrollToValue(index, hint, above, below, area, rect);
}
 
int QListModeViewBase::horizontalOffset() const
{
    if (horizontalScrollMode() == QAbstractItemView::ScrollPerItem) {
        if (isWrapping()) {
            if (flow() == QListView::TopToBottom && !segmentPositions.isEmpty()) {
                const int max = segmentPositions.size() - 1;
                int currentValue = qBound(0, horizontalScrollBar()->value(), max);
                int position = segmentPositions.at(currentValue);
                int maximumValue = qBound(0, horizontalScrollBar()->maximum(), max);
                int maximum = segmentPositions.at(maximumValue);
                return (isRightToLeft() ? maximum - position : position);
            }
        } else if (flow() == QListView::LeftToRight && !flowPositions.isEmpty()) {
            int position = flowPositions.at(scrollValueMap.at(horizontalScrollBar()->value()));
            int maximum = flowPositions.at(scrollValueMap.at(horizontalScrollBar()->maximum()));
            return (isRightToLeft() ? maximum - position : position);
        }
    }
    return QCommonListViewBase::horizontalOffset();
}
 
int QListModeViewBase::verticalOffset() const
{
    if (verticalScrollMode() == QAbstractItemView::ScrollPerItem) {
        if (isWrapping()) {
            if (flow() == QListView::LeftToRight && !segmentPositions.isEmpty()) {
                int value = verticalScrollBar()->value();
                if (value >= segmentPositions.size())
                    return 0;
                return segmentPositions.at(value) - spacing();
            }
        } else if (flow() == QListView::TopToBottom && !flowPositions.isEmpty()) {
            int value = verticalScrollBar()->value();
            if (value > scrollValueMap.size())
                return 0;
            return flowPositions.at(scrollValueMap.at(value)) - spacing();
        }
    }
    return QCommonListViewBase::verticalOffset();
}
 
int QListModeViewBase::horizontalScrollToValue(int index, QListView::ScrollHint hint,
                                            bool leftOf, bool rightOf, const QRect &area, const QRect &rect) const
{
    if (horizontalScrollMode() != QAbstractItemView::ScrollPerItem)
        return QCommonListViewBase::horizontalScrollToValue(index, hint, leftOf, rightOf, area, rect);
 
    int value;
    if (scrollValueMap.isEmpty())
        value = 0;
    else
        value = qBound(0, scrollValueMap.at(horizontalScrollBar()->value()), flowPositions.size() - 1);
    if (leftOf)
        hint = QListView::PositionAtTop;
    else if (rightOf)
        hint = QListView::PositionAtBottom;
    if (hint == QListView::EnsureVisible)
        return value;
 
    return perItemScrollToValue(index, value, area.width(), hint, Qt::Horizontal, isWrapping(), rect.width());
}
 
void QListModeViewBase::scrollContentsBy(int dx, int dy, bool scrollElasticBand)
{
    // ### reorder this logic
    const int verticalValue = verticalScrollBar()->value();
    const int horizontalValue = horizontalScrollBar()->value();
    const bool vertical = (verticalScrollMode() == QAbstractItemView::ScrollPerItem);
    const bool horizontal = (horizontalScrollMode() == QAbstractItemView::ScrollPerItem);
 
    if (isWrapping()) {
        if (segmentPositions.isEmpty())
            return;
        const int max = segmentPositions.size() - 1;
        if (horizontal && flow() == QListView::TopToBottom && dx != 0) {
            int currentValue = qBound(0, horizontalValue, max);
            int previousValue = qBound(0, currentValue + dx, max);
            int currentCoordinate = segmentPositions.at(currentValue) - spacing();
            int previousCoordinate = segmentPositions.at(previousValue) - spacing();
            dx = previousCoordinate - currentCoordinate;
        } else if (vertical && flow() == QListView::LeftToRight && dy != 0) {
            int currentValue = qBound(0, verticalValue, max);
            int previousValue = qBound(0, currentValue + dy, max);
            int currentCoordinate = segmentPositions.at(currentValue) - spacing();
            int previousCoordinate = segmentPositions.at(previousValue) - spacing();
            dy = previousCoordinate - currentCoordinate;
        }
    } else {
        if (flowPositions.isEmpty())
            return;
        const int max = scrollValueMap.size() - 1;
        if (vertical && flow() == QListView::TopToBottom && dy != 0) {
            int currentValue = qBound(0, verticalValue, max);
            int previousValue = qBound(0, currentValue + dy, max);
            int currentCoordinate = flowPositions.at(scrollValueMap.at(currentValue));
            int previousCoordinate = flowPositions.at(scrollValueMap.at(previousValue));
            dy = previousCoordinate - currentCoordinate;
        } else if (horizontal && flow() == QListView::LeftToRight && dx != 0) {
            int currentValue = qBound(0, horizontalValue, max);
            int previousValue = qBound(0, currentValue + dx, max);
            int currentCoordinate = flowPositions.at(scrollValueMap.at(currentValue));
            int previousCoordinate = flowPositions.at(scrollValueMap.at(previousValue));
            dx = previousCoordinate - currentCoordinate;
        }
    }
    QCommonListViewBase::scrollContentsBy(dx, dy, scrollElasticBand);
}
 
bool QListModeViewBase::doBatchedItemLayout(const QListViewLayoutInfo &info, int max)
{
    doStaticLayout(info);
    return batchStartRow > max; // returning true stops items layout
}
 
QListViewItem QListModeViewBase::indexToListViewItem(const QModelIndex &index) const
{
    if (flowPositions.isEmpty()
        || segmentPositions.isEmpty()
        || index.row() >= flowPositions.size() - 1)
        return QListViewItem();
 
    const int segment = qBinarySearch<int>(segmentStartRows, index.row(),
                                           0, segmentStartRows.size() - 1);
 
 
    QStyleOptionViewItem options;
    initViewItemOption(&options);
    options.rect.setSize(contentsSize);
    QSize size = (uniformItemSizes() && cachedItemSize().isValid())
                 ? cachedItemSize() : itemSize(options, index);
    QSize cellSize = size;
 
    QPoint pos;
    if (flow() == QListView::LeftToRight) {
        pos.setX(flowPositions.at(index.row()));
        pos.setY(segmentPositions.at(segment));
    } else { // TopToBottom
        pos.setY(flowPositions.at(index.row()));
        pos.setX(segmentPositions.at(segment));
        if (isWrapping()) { // make the items as wide as the segment
            int right = (segment + 1 >= segmentPositions.size()
                     ? contentsSize.width()
                     : segmentPositions.at(segment + 1));
            cellSize.setWidth(right - pos.x());
        } else { // make the items as wide as the viewport
            cellSize.setWidth(qMax(size.width(), viewport()->width() - 2 * spacing()));
        }
    }
 
    if (dd->itemAlignment & Qt::AlignHorizontal_Mask) {
        size.setWidth(qMin(size.width(), cellSize.width()));
        if (dd->itemAlignment & Qt::AlignRight)
            pos.setX(pos.x() + cellSize.width() - size.width());
        if (dd->itemAlignment & Qt::AlignHCenter)
            pos.setX(pos.x() + (cellSize.width() - size.width()) / 2);
    } else {
        size.setWidth(cellSize.width());
    }
 
    return QListViewItem(QRect(pos, size), index.row());
}
 
QPoint QListModeViewBase::initStaticLayout(const QListViewLayoutInfo &info)
{
    int x, y;
    if (info.first == 0) {
        flowPositions.clear();
        segmentPositions.clear();
        segmentStartRows.clear();
        segmentExtents.clear();
        scrollValueMap.clear();
        x = info.bounds.left() + info.spacing;
        y = info.bounds.top() + info.spacing;
        segmentPositions.append(info.flow == QListView::LeftToRight ? y : x);
        segmentStartRows.append(0);
    } else if (info.wrap) {
        if (info.flow == QListView::LeftToRight) {
            x = batchSavedPosition;
            y = segmentPositions.constLast();
        } else { // flow == QListView::TopToBottom
            x = segmentPositions.constLast();
            y = batchSavedPosition;
        }
    } else { // not first and not wrap
        if (info.flow == QListView::LeftToRight) {
            x = batchSavedPosition;
            y = info.bounds.top() + info.spacing;
        } else { // flow == QListView::TopToBottom
            x = info.bounds.left() + info.spacing;
            y = batchSavedPosition;
        }
    }
    return QPoint(x, y);
}
 
void QListModeViewBase::doStaticLayout(const QListViewLayoutInfo &info)
{
    const bool useItemSize = !info.grid.isValid();
    const QPoint topLeft = initStaticLayout(info);
    QStyleOptionViewItem option;
    initViewItemOption(&option);
    option.rect = info.bounds;
    option.rect.adjust(info.spacing, info.spacing, -info.spacing, -info.spacing);
 
    // The static layout data structures are as follows:
    // One vector contains the coordinate in the direction of layout flow.
    // Another vector contains the coordinates of the segments.
    // A third vector contains the index (model row) of the first item
    // of each segment.
 
    int segStartPosition;
    int segEndPosition;
    int deltaFlowPosition;
    int deltaSegPosition;
    int deltaSegHint;
    int flowPosition;
    int segPosition;
 
    if (info.flow == QListView::LeftToRight) {
        segStartPosition = info.bounds.left();
        segEndPosition = info.bounds.width();
        flowPosition = topLeft.x();
        segPosition = topLeft.y();
        deltaFlowPosition = info.grid.width(); // dx
        deltaSegPosition = useItemSize ? batchSavedDeltaSeg : info.grid.height(); // dy
        deltaSegHint = info.grid.height();
    } else { // flow == QListView::TopToBottom
        segStartPosition = info.bounds.top();
        segEndPosition = info.bounds.height();
        flowPosition = topLeft.y();
        segPosition = topLeft.x();
        deltaFlowPosition = info.grid.height(); // dy
        deltaSegPosition = useItemSize ? batchSavedDeltaSeg : info.grid.width(); // dx
        deltaSegHint = info.grid.width();
    }
 
    for (int row = info.first; row <= info.last; ++row) {
        if (isHidden(row)) { // ###
            flowPositions.append(flowPosition);
        } else {
            // if we are not using a grid, we need to find the deltas
            if (useItemSize) {
                QSize hint = itemSize(option, modelIndex(row));
                if (info.flow == QListView::LeftToRight) {
                    deltaFlowPosition = hint.width() + info.spacing;
                    deltaSegHint = hint.height() + info.spacing;
                } else { // TopToBottom
                    deltaFlowPosition = hint.height() + info.spacing;
                    deltaSegHint = hint.width() + info.spacing;
                }
            }
            // create new segment
            if (info.wrap && (flowPosition + deltaFlowPosition >= segEndPosition)) {
                segmentExtents.append(flowPosition);
                flowPosition = info.spacing + segStartPosition;
                segPosition += info.spacing + deltaSegPosition;
                segmentPositions.append(segPosition);
                segmentStartRows.append(row);
                deltaSegPosition = 0;
            }
            // save the flow position of this item
            scrollValueMap.append(flowPositions.size());
            flowPositions.append(flowPosition);
            // prepare for the next item
            deltaSegPosition = qMax(deltaSegHint, deltaSegPosition);
            flowPosition += info.spacing + deltaFlowPosition;
        }
    }
    // used when laying out next batch
    batchSavedPosition = flowPosition;
    batchSavedDeltaSeg = deltaSegPosition;
    batchStartRow = info.last + 1;
    if (info.last == info.max)
        flowPosition -= info.spacing; // remove extra spacing
    // set the contents size
    QRect rect = info.bounds;
    if (info.flow == QListView::LeftToRight) {
        rect.setRight(segmentPositions.size() == 1 ? flowPosition : info.bounds.right());
        rect.setBottom(segPosition + deltaSegPosition);
    } else { // TopToBottom
        rect.setRight(segPosition + deltaSegPosition);
        rect.setBottom(segmentPositions.size() == 1 ? flowPosition : info.bounds.bottom());
    }
    contentsSize = QSize(rect.right(), rect.bottom());
    // if it is the last batch, save the end of the segments
    if (info.last == info.max) {
        segmentExtents.append(flowPosition);
        scrollValueMap.append(flowPositions.size());
        flowPositions.append(flowPosition);
        segmentPositions.append(info.wrap ? segPosition + deltaSegPosition : INT_MAX);
    }
    // if the new items are visible, update the viewport
    QRect changedRect(topLeft, rect.bottomRight());
    if (clipRect().intersects(changedRect))
        viewport()->update();
}
 
QList<QModelIndex> QListModeViewBase::intersectingSet(const QRect &area) const
{
    QList<QModelIndex> ret;
    int segStartPosition;
    int segEndPosition;
    int flowStartPosition;
    int flowEndPosition;
    if (flow() == QListView::LeftToRight) {
        segStartPosition = area.top();
        segEndPosition = area.bottom();
        flowStartPosition = area.left();
        flowEndPosition = area.right();
    } else {
        segStartPosition = area.left();
        segEndPosition = area.right();
        flowStartPosition = area.top();
        flowEndPosition = area.bottom();
    }
    if (segmentPositions.size() < 2 || flowPositions.isEmpty())
        return ret;
    // the last segment position is actually the edge of the last segment
    const int segLast = segmentPositions.size() - 2;
    int seg = qBinarySearch<int>(segmentPositions, segStartPosition, 0, segLast + 1);
    for (; seg <= segLast && segmentPositions.at(seg) <= segEndPosition; ++seg) {
        int first = segmentStartRows.at(seg);
        int last = (seg < segLast ? segmentStartRows.at(seg + 1) : batchStartRow) - 1;
        if (segmentExtents.at(seg) < flowStartPosition)
            continue;
        int row = qBinarySearch<int>(flowPositions, flowStartPosition, first, last);
        for (; row <= last && flowPositions.at(row) <= flowEndPosition; ++row) {
            if (isHidden(row))
                continue;
            QModelIndex index = modelIndex(row);
            if (index.isValid()) {
                if (flow() == QListView::LeftToRight || dd->itemAlignment == Qt::Alignment()) {
                    ret += index;
                } else {
                    const auto viewItem = indexToListViewItem(index);
                    const int iw = viewItem.width();
                    const int startPos = qMax(segStartPosition, segmentPositions.at(seg));
                    const int endPos = qMin(segmentPositions.at(seg + 1), segEndPosition);
                    if (endPos >= viewItem.x && startPos < viewItem.x + iw)
                        ret += index;
                }
            }
#if 0 // for debugging
            else
                qWarning("intersectingSet: row %d was invalid", row);
#endif
        }
    }
    return ret;
}
 
void QListModeViewBase::dataChanged(const QModelIndex &, const QModelIndex &)
{
    dd->doDelayedItemsLayout();
}
 
 
QRect QListModeViewBase::mapToViewport(const QRect &rect) const
{
    if (isWrapping())
        return rect;
    // If the listview is in "listbox-mode", the items are as wide as the view.
    // But we don't shrink the items.
    QRect result = rect;
    if (flow() == QListView::TopToBottom) {
        result.setLeft(spacing());
        result.setWidth(qMax(rect.width(), qMax(contentsSize.width(), viewport()->width()) - 2 * spacing()));
    } else { // LeftToRight
        result.setTop(spacing());
        result.setHeight(qMax(rect.height(), qMax(contentsSize.height(), viewport()->height()) - 2 * spacing()));
    }
    return result;
}
 
int QListModeViewBase::perItemScrollingPageSteps(int length, int bounds, bool wrap) const
{
    QList<int> positions;
    if (wrap)
        positions = segmentPositions;
    else if (!flowPositions.isEmpty()) {
        positions.reserve(scrollValueMap.size());
        for (int itemShown : scrollValueMap)
            positions.append(flowPositions.at(itemShown));
    }
    if (positions.isEmpty() || bounds <= length)
        return positions.size();
    if (uniformItemSizes()) {
        for (int i = 1; i < positions.size(); ++i)
            if (positions.at(i) > 0)
                return length / positions.at(i);
        return 0; // all items had height 0
    }
    int pageSteps = 0;
    int steps = positions.size() - 1;
    int max = qMax(length, bounds);
    int min = qMin(length, bounds);
    int pos = min - (max - positions.constLast());
 
    while (pos >= 0 && steps > 0) {
        pos -= (positions.at(steps) - positions.at(steps - 1));
        if (pos >= 0) //this item should be visible
            ++pageSteps;
        --steps;
    }
 
    // at this point we know that positions has at least one entry
    return qMax(pageSteps, 1);
}
 
int QListModeViewBase::perItemScrollToValue(int index, int scrollValue, int viewportSize,
                                                 QAbstractItemView::ScrollHint hint,
                                                 Qt::Orientation orientation, bool wrap, int itemExtent) const
{
    if (index < 0)
        return scrollValue;
 
    itemExtent += spacing();
    QList<int> hiddenRows = dd->hiddenRowIds();
    std::sort(hiddenRows.begin(), hiddenRows.end());
    int hiddenRowsBefore = 0;
    for (int i = 0; i < hiddenRows.size() - 1; ++i)
        if (hiddenRows.at(i) > index + hiddenRowsBefore)
            break;
        else
            ++hiddenRowsBefore;
    if (!wrap) {
        int topIndex = index;
        const int bottomIndex = topIndex;
        const int bottomCoordinate = flowPositions.at(index + hiddenRowsBefore);
        while (topIndex > 0 &&
               (bottomCoordinate - flowPositions.at(topIndex + hiddenRowsBefore - 1) + itemExtent) <= (viewportSize)) {
            topIndex--;
            // will the next one be a hidden row -> skip
            while (hiddenRowsBefore > 0 && hiddenRows.at(hiddenRowsBefore - 1) >= topIndex + hiddenRowsBefore - 1)
                hiddenRowsBefore--;
        }
 
        const int itemCount = bottomIndex - topIndex + 1;
        switch (hint) {
        case QAbstractItemView::PositionAtTop:
            return index;
        case QAbstractItemView::PositionAtBottom:
            return index - itemCount + 1;
        case QAbstractItemView::PositionAtCenter:
            return index - (itemCount / 2);
        default:
            break;
        }
    } else { // wrapping
        Qt::Orientation flowOrientation = (flow() == QListView::LeftToRight
                                           ? Qt::Horizontal : Qt::Vertical);
        if (flowOrientation == orientation) { // scrolling in the "flow" direction
            // ### wrapped scrolling in the flow direction
            return flowPositions.at(index + hiddenRowsBefore); // ### always pixel based for now
        } else if (!segmentStartRows.isEmpty()) { // we are scrolling in the "segment" direction
            int segment = qBinarySearch<int>(segmentStartRows, index, 0, segmentStartRows.size() - 1);
            int leftSegment = segment;
            const int rightSegment = leftSegment;
            const int bottomCoordinate = segmentPositions.at(segment);
 
            while (leftSegment > scrollValue &&
                (bottomCoordinate - segmentPositions.at(leftSegment-1) + itemExtent) <= (viewportSize)) {
                    leftSegment--;
            }
 
            const int segmentCount = rightSegment - leftSegment + 1;
            switch (hint) {
            case QAbstractItemView::PositionAtTop:
                return segment;
            case QAbstractItemView::PositionAtBottom:
                return segment - segmentCount + 1;
            case QAbstractItemView::PositionAtCenter:
                return segment - (segmentCount / 2);
            default:
                break;
            }
        }
    }
    return scrollValue;
}
 
void QListModeViewBase::clear()
{
    flowPositions.clear();
    segmentPositions.clear();
    segmentStartRows.clear();
    segmentExtents.clear();
    batchSavedPosition = 0;
    batchStartRow = 0;
    batchSavedDeltaSeg = 0;
}
 
/*
 * IconMode ListView Implementation
*/
 
void QIconModeViewBase::setPositionForIndex(const QPoint &position, const QModelIndex &index)
{
    if (index.row() >= items.size())
        return;
    const QSize oldContents = contentsSize;
    qq->update(index); // update old position
    moveItem(index.row(), position);
    qq->update(index); // update new position
 
    if (contentsSize != oldContents)
        dd->viewUpdateGeometries(); // update the scroll bars
}
 
void QIconModeViewBase::appendHiddenRow(int row)
{
    if (row >= 0 && row < items.size()) //remove item
        tree.removeLeaf(items.at(row).rect(), row);
    QCommonListViewBase::appendHiddenRow(row);
}
 
void QIconModeViewBase::removeHiddenRow(int row)
{
    QCommonListViewBase::removeHiddenRow(row);
    if (row >= 0 && row < items.size()) //insert item
        tree.insertLeaf(items.at(row).rect(), row);
}
 
#if QT_CONFIG(draganddrop)
bool QIconModeViewBase::filterStartDrag(Qt::DropActions supportedActions)
{
    // This function does the same thing as in QAbstractItemView::startDrag(),
    // plus adding viewitems to the draggedItems list.
    // We need these items to draw the drag items
    QModelIndexList indexes = dd->selectionModel->selectedIndexes();
    if (indexes.size() > 0 ) {
        if (viewport()->acceptDrops()) {
            QModelIndexList::ConstIterator it = indexes.constBegin();
            for (; it != indexes.constEnd(); ++it)
                if (dd->model->flags(*it) & Qt::ItemIsDragEnabled
                    && (*it).column() == dd->column)
                    draggedItems.push_back(*it);
        }
 
        QRect rect;
        QPixmap pixmap = dd->renderToPixmap(indexes, &rect);
        rect.adjust(horizontalOffset(), verticalOffset(), 0, 0);
        QDrag *drag = new QDrag(qq);
        drag->setMimeData(dd->model->mimeData(indexes));
        drag->setPixmap(pixmap);
        drag->setHotSpot(dd->pressedPosition - rect.topLeft());
        dd->dropEventMoved = false;
        Qt::DropAction action = drag->exec(supportedActions, dd->defaultDropAction);
        draggedItems.clear();
        // delete item, unless it has already been moved internally (see filterDropEvent)
        if (action == Qt::MoveAction && !dd->dropEventMoved) {
            if (dd->dragDropMode != QAbstractItemView::InternalMove || drag->target() == qq->viewport())
                dd->clearOrRemove();
        }
        dd->dropEventMoved = false;
    }
    return true;
}
 
bool QIconModeViewBase::filterDropEvent(QDropEvent *e)
{
    if (e->source() != qq)
        return false;
 
    const QSize contents = contentsSize;
    QPoint offset(horizontalOffset(), verticalOffset());
    QPoint end = e->position().toPoint() + offset;
    if (qq->acceptDrops()) {
        const Qt::ItemFlags dropableFlags = Qt::ItemIsDropEnabled|Qt::ItemIsEnabled;
        const QList<QModelIndex> &dropIndices = intersectingSet(QRect(end, QSize(1, 1)));
        for (const QModelIndex &index : dropIndices)
            if ((index.flags() & dropableFlags) == dropableFlags)
                return false;
    }
    QPoint start = dd->pressedPosition;
    QPoint delta = (dd->movement == QListView::Snap ? snapToGrid(end) - snapToGrid(start) : end - start);
    const QList<QModelIndex> indexes = dd->selectionModel->selectedIndexes();
    for (const auto &index : indexes) {
        QRect rect = dd->rectForIndex(index);
        viewport()->update(dd->mapToViewport(rect, false));
        QPoint dest = rect.topLeft() + delta;
        if (qq->isRightToLeft())
            dest.setX(dd->flipX(dest.x()) - rect.width());
        moveItem(index.row(), dest);
        qq->update(index);
    }
    dd->stopAutoScroll();
    draggedItems.clear();
    dd->emitIndexesMoved(indexes);
    // do not delete item on internal move, see filterStartDrag()
    dd->dropEventMoved = true;
    e->accept(); // we have handled the event
    // if the size has not grown, we need to check if it has shrunk
    if (contentsSize != contents) {
        if ((contentsSize.width() <= contents.width()
            || contentsSize.height() <= contents.height())) {
                updateContentsSize();
        }
        dd->viewUpdateGeometries();
    }
    return true;
}
 
bool QIconModeViewBase::filterDragLeaveEvent(QDragLeaveEvent *e)
{
    viewport()->update(draggedItemsRect()); // erase the area
    draggedItemsPos = QPoint(-1, -1); // don't draw the dragged items
    return QCommonListViewBase::filterDragLeaveEvent(e);
}
 
bool QIconModeViewBase::filterDragMoveEvent(QDragMoveEvent *e)
{
    const bool wasAccepted = e->isAccepted();
 
    // ignore by default
    e->ignore();
 
    if (e->source() != qq || !dd->canDrop(e)) {
        // restore previous acceptance on failure
        e->setAccepted(wasAccepted);
        return false;
    }
 
    // get old dragged items rect
    QRect itemsRect = this->itemsRect(draggedItems);
    viewport()->update(itemsRect.translated(draggedItemsDelta()));
    // update position
    draggedItemsPos = e->position().toPoint();
    // get new items rect
    viewport()->update(itemsRect.translated(draggedItemsDelta()));
    // set the item under the cursor to current
    QModelIndex index;
    if (movement() == QListView::Snap) {
        QRect rect(snapToGrid(e->position().toPoint() + offset()), gridSize());
        const QList<QModelIndex> intersectVector = intersectingSet(rect);
        index = intersectVector.size() > 0 ? intersectVector.last() : QModelIndex();
    } else {
        index = qq->indexAt(e->position().toPoint());
    }
    // check if we allow drops here
    if (draggedItems.contains(index))
        e->accept(); // allow changing item position
    else if (dd->model->flags(index) & Qt::ItemIsDropEnabled)
        e->accept(); // allow dropping on dropenabled items
    else if (!index.isValid())
        e->accept(); // allow dropping in empty areas
 
    // the event was treated. do autoscrolling
    if (dd->shouldAutoScroll(e->position().toPoint()))
        dd->startAutoScroll();
    return true;
}
#endif // QT_CONFIG(draganddrop)
 
void QIconModeViewBase::setRowCount(int rowCount)
{
    tree.create(qMax(rowCount - hiddenCount(), 0));
}
 
void QIconModeViewBase::scrollContentsBy(int dx, int dy, bool scrollElasticBand)
{
    if (scrollElasticBand)
        dd->scrollElasticBandBy(isRightToLeft() ? -dx : dx, dy);
 
    QCommonListViewBase::scrollContentsBy(dx, dy, scrollElasticBand);
    if (!draggedItems.isEmpty())
        viewport()->update(draggedItemsRect().translated(dx, dy));
}
 
void QIconModeViewBase::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight)
{
    if (column() >= topLeft.column() && column() <= bottomRight.column())  {
        QStyleOptionViewItem option;
        initViewItemOption(&option);
        const int bottom = qMin(items.size(), bottomRight.row() + 1);
        const bool useItemSize = !dd->grid.isValid();
        for (int row = topLeft.row(); row < bottom; ++row)
        {
            QSize s = itemSize(option, modelIndex(row));
            if (!useItemSize)
            {
                s.setWidth(qMin(dd->grid.width(), s.width()));
                s.setHeight(qMin(dd->grid.height(), s.height()));
            }
            items[row].resize(s);
        }
    }
}
 
bool QIconModeViewBase::doBatchedItemLayout(const QListViewLayoutInfo &info, int max)
{
    if (info.last >= items.size()) {
        //first we create the items
        QStyleOptionViewItem option;
        initViewItemOption(&option);
        for (int row = items.size(); row <= info.last; ++row) {
            QSize size = itemSize(option, modelIndex(row));
            QListViewItem item(QRect(0, 0, size.width(), size.height()), row); // default pos
            items.append(item);
        }
        doDynamicLayout(info);
    }
    return (batchStartRow > max); // done
}
 
QListViewItem QIconModeViewBase::indexToListViewItem(const QModelIndex &index) const
{
    if (index.isValid() && index.row() < items.size())
        return items.at(index.row());
    return QListViewItem();
}
 
void QIconModeViewBase::initBspTree(const QSize &contents)
{
    // remove all items from the tree
    int leafCount = tree.leafCount();
    for (int l = 0; l < leafCount; ++l)
        tree.leaf(l).clear();
    // we have to get the bounding rect of the items before we can initialize the tree
    QBspTree::Node::Type type = QBspTree::Node::Both; // 2D
    // simple heuristics to get better bsp
    if (contents.height() / contents.width() >= 3)
        type = QBspTree::Node::HorizontalPlane;
    else if (contents.width() / contents.height() >= 3)
        type = QBspTree::Node::VerticalPlane;
    // build tree for the bounding rect (not just the contents rect)
    tree.init(QRect(0, 0, contents.width(), contents.height()), type);
}
 
QPoint QIconModeViewBase::initDynamicLayout(const QListViewLayoutInfo &info)
{
    int x, y;
    if (info.first == 0) {
        x = info.bounds.x() + info.spacing;
        y = info.bounds.y() + info.spacing;
        items.reserve(rowCount() - hiddenCount());
    } else {
        int idx = info.first - 1;
        while (idx > 0 && !items.at(idx).isValid())
            --idx;
        const QListViewItem &item = items.at(idx);
        x = item.x;
        y = item.y;
        if (info.flow == QListView::LeftToRight)
            x += (info.grid.isValid() ? info.grid.width() : item.w) + info.spacing;
        else
            y += (info.grid.isValid() ? info.grid.height() : item.h) + info.spacing;
    }
    return QPoint(x, y);
}
 
void QIconModeViewBase::doDynamicLayout(const QListViewLayoutInfo &info)
{
    const bool useItemSize = !info.grid.isValid();
    const QPoint topLeft = initDynamicLayout(info);
 
    int segStartPosition;
    int segEndPosition;
    int deltaFlowPosition;
    int deltaSegPosition;
    int deltaSegHint;
    int flowPosition;
    int segPosition;
 
    if (info.flow == QListView::LeftToRight) {
        segStartPosition = info.bounds.left() + info.spacing;
        segEndPosition = info.bounds.right();
        deltaFlowPosition = info.grid.width(); // dx
        deltaSegPosition = (useItemSize ? batchSavedDeltaSeg : info.grid.height()); // dy
        deltaSegHint = info.grid.height();
        flowPosition = topLeft.x();
        segPosition = topLeft.y();
    } else { // flow == QListView::TopToBottom
        segStartPosition = info.bounds.top() + info.spacing;
        segEndPosition = info.bounds.bottom();
        deltaFlowPosition = info.grid.height(); // dy
        deltaSegPosition = (useItemSize ? batchSavedDeltaSeg : info.grid.width()); // dx
        deltaSegHint = info.grid.width();
        flowPosition = topLeft.y();
        segPosition = topLeft.x();
    }
 
    if (moved.size() != items.size())
        moved.resize(items.size());
 
    QRect rect(QPoint(), topLeft);
    QListViewItem *item = nullptr;
    Q_ASSERT(info.first <= info.last);
    for (int row = info.first; row <= info.last; ++row) {
        item = &items[row];
        if (isHidden(row)) {
            item->invalidate();
        } else {
            // if we are not using a grid, we need to find the deltas
            if (useItemSize) {
                if (info.flow == QListView::LeftToRight)
                    deltaFlowPosition = item->w + info.spacing;
                else
                    deltaFlowPosition = item->h + info.spacing;
            } else {
                item->w = qMin<int>(info.grid.width(), item->w);
                item->h = qMin<int>(info.grid.height(), item->h);
            }
 
            // create new segment
            if (info.wrap
                && flowPosition + deltaFlowPosition > segEndPosition
                && flowPosition > segStartPosition) {
                flowPosition = segStartPosition;
                segPosition += deltaSegPosition;
                if (useItemSize)
                    deltaSegPosition = 0;
            }
            // We must delay calculation of the seg adjustment, as this item
            // may have caused a wrap to occur
            if (useItemSize) {
                if (info.flow == QListView::LeftToRight)
                    deltaSegHint = item->h + info.spacing;
                else
                    deltaSegHint = item->w + info.spacing;
                deltaSegPosition = qMax(deltaSegPosition, deltaSegHint);
            }
 
            // set the position of the item
            // ### idealy we should have some sort of alignment hint for the item
            // ### (normally that would be a point between the icon and the text)
            if (!moved.testBit(row)) {
                if (info.flow == QListView::LeftToRight) {
                    if (useItemSize) {
                        item->x = flowPosition;
                        item->y = segPosition;
                    } else { // use grid
                        item->x = flowPosition + ((deltaFlowPosition - item->w) / 2);
                        item->y = segPosition;
                    }
                } else { // TopToBottom
                    if (useItemSize) {
                        item->y = flowPosition;
                        item->x = segPosition;
                    } else { // use grid
                        item->y = flowPosition + ((deltaFlowPosition - item->h) / 2);
                        item->x = segPosition;
                    }
                }
            }
 
            // let the contents contain the new item
            if (useItemSize)
                rect |= item->rect();
            else if (info.flow == QListView::LeftToRight)
                rect |= QRect(flowPosition, segPosition, deltaFlowPosition, deltaSegPosition);
            else // flow == TopToBottom
                rect |= QRect(segPosition, flowPosition, deltaSegPosition, deltaFlowPosition);
 
            // prepare for next item
            flowPosition += deltaFlowPosition; // current position + item width + gap
        }
    }
    Q_ASSERT(item);
    batchSavedDeltaSeg = deltaSegPosition;
    batchStartRow = info.last + 1;
    bool done = (info.last >= rowCount() - 1);
    // resize the content area
    if (done || !info.bounds.contains(item->rect())) {
        contentsSize = rect.size();
        if (info.flow == QListView::LeftToRight)
            contentsSize.rheight() += info.spacing;
        else
            contentsSize.rwidth() += info.spacing;
    }
    if (rect.size().isEmpty())
        return;
    // resize tree
    int insertFrom = info.first;
    if (done || info.first == 0) {
        initBspTree(rect.size());
        insertFrom = 0;
    }
    // insert items in tree
    for (int row = insertFrom; row <= info.last; ++row)
        tree.insertLeaf(items.at(row).rect(), row);
    // if the new items are visible, update the viewport
    QRect changedRect(topLeft, rect.bottomRight());
    if (clipRect().intersects(changedRect))
        viewport()->update();
}
 
QList<QModelIndex> QIconModeViewBase::intersectingSet(const QRect &area) const
{
    QIconModeViewBase *that = const_cast<QIconModeViewBase*>(this);
    QBspTree::Data data(static_cast<void*>(that));
    QList<QModelIndex> res;
    that->interSectingVector = &res;
    that->tree.climbTree(area, &QIconModeViewBase::addLeaf, data);
    that->interSectingVector = nullptr;
    return res;
}
 
QRect QIconModeViewBase::itemsRect(const QList<QModelIndex> &indexes) const
{
    QRect rect;
    for (const auto &index : indexes)
        rect |= viewItemRect(indexToListViewItem(index));
    return rect;
}
 
int QIconModeViewBase::itemIndex(const QListViewItem &item) const
{
    if (!item.isValid())
        return -1;
    int i = item.indexHint;
    if (i < items.size()) {
        if (items.at(i) == item)
            return i;
    } else {
        i = items.size() - 1;
    }
 
    int j = i;
    int c = items.size();
    bool a = true;
    bool b = true;
 
    while (a || b) {
        if (a) {
            if (items.at(i) == item) {
                items.at(i).indexHint = i;
                return i;
            }
            a = ++i < c;
        }
        if (b) {
            if (items.at(j) == item) {
                items.at(j).indexHint = j;
                return j;
            }
            b = --j > -1;
        }
    }
    return -1;
}
 
void QIconModeViewBase::addLeaf(QList<int> &leaf, const QRect &area, uint visited,
                                QBspTree::Data data)
{
    QListViewItem *vi;
    QIconModeViewBase *_this = static_cast<QIconModeViewBase *>(data.ptr);
    for (int i = 0; i < leaf.size(); ++i) {
        int idx = leaf.at(i);
        if (idx < 0 || idx >= _this->items.size())
            continue;
        vi = &_this->items[idx];
        Q_ASSERT(vi);
        if (vi->isValid() && vi->rect().intersects(area) && vi->visited != visited) {
            QModelIndex index  = _this->dd->listViewItemToIndex(*vi);
            Q_ASSERT(index.isValid());
            _this->interSectingVector->append(index);
            vi->visited = visited;
        }
    }
}
 
void QIconModeViewBase::moveItem(int index, const QPoint &dest)
{
    // does not impact on the bintree itself or the contents rect
    QListViewItem *item = &items[index];
    QRect rect = item->rect();
 
    // move the item without removing it from the tree
    tree.removeLeaf(rect, index);
    item->move(dest);
    tree.insertLeaf(QRect(dest, rect.size()), index);
 
    // resize the contents area
    contentsSize = (QRect(QPoint(0, 0), contentsSize)|QRect(dest, rect.size())).size();
 
    // mark the item as moved
    if (moved.size() != items.size())
        moved.resize(items.size());
    moved.setBit(index, true);
}
 
QPoint QIconModeViewBase::snapToGrid(const QPoint &pos) const
{
    int x = pos.x() - (pos.x() % gridSize().width());
    int y = pos.y() - (pos.y() % gridSize().height());
    return QPoint(x, y);
}
 
QPoint QIconModeViewBase::draggedItemsDelta() const
{
    if (movement() == QListView::Snap) {
        QPoint snapdelta = QPoint((offset().x() % gridSize().width()),
                                  (offset().y() % gridSize().height()));
        return snapToGrid(draggedItemsPos + snapdelta) - snapToGrid(pressedPosition()) - snapdelta;
    }
    return draggedItemsPos - pressedPosition();
}
 
QRect QIconModeViewBase::draggedItemsRect() const
{
    QRect rect = itemsRect(draggedItems);
    rect.translate(draggedItemsDelta());
    return rect;
}
 
void QListViewPrivate::scrollElasticBandBy(int dx, int dy)
{
    if (dx > 0) // right
        elasticBand.moveRight(elasticBand.right() + dx);
    else if (dx < 0) // left
        elasticBand.moveLeft(elasticBand.left() - dx);
    if (dy > 0) // down
        elasticBand.moveBottom(elasticBand.bottom() + dy);
    else if (dy < 0) // up
        elasticBand.moveTop(elasticBand.top() - dy);
}
 
void QIconModeViewBase::clear()
{
    tree.destroy();
    items.clear();
    moved.clear();
    batchStartRow = 0;
    batchSavedDeltaSeg = 0;
}
 
void QIconModeViewBase::updateContentsSize()
{
    QRect bounding;
    for (int i = 0; i < items.size(); ++i)
        bounding |= items.at(i).rect();
    contentsSize = bounding.size();
}
 
void QListView::currentChanged(const QModelIndex &current, const QModelIndex &previous)
{
    QAbstractItemView::currentChanged(current, previous);
#if QT_CONFIG(accessibility)
    if (QAccessible::isActive()) {
        if (current.isValid() && hasFocus()) {
            int entry = visualIndex(current);
            QAccessibleEvent event(this, QAccessible::Focus);
            event.setChild(entry);
            QAccessible::updateAccessibility(&event);
        }
    }
#endif
}
 
void QListView::selectionChanged(const QItemSelection &selected,
                                 const QItemSelection &deselected)
{
#if QT_CONFIG(accessibility)
    if (QAccessible::isActive()) {
        // ### does not work properly for selection ranges.
        QModelIndex sel = selected.indexes().value(0);
        if (sel.isValid()) {
            int entry = visualIndex(sel);
            QAccessibleEvent event(this, QAccessible::SelectionAdd);
            event.setChild(entry);
            QAccessible::updateAccessibility(&event);
        }
        QModelIndex desel = deselected.indexes().value(0);
        if (desel.isValid()) {
            int entry = visualIndex(desel);
            QAccessibleEvent event(this, QAccessible::SelectionRemove);
            event.setChild(entry);
            QAccessible::updateAccessibility(&event);
        }
    }
#endif
    QAbstractItemView::selectionChanged(selected, deselected);
}
 
int QListView::visualIndex(const QModelIndex &index) const
{
    Q_D(const QListView);
    d->executePostedLayout();
    QListViewItem itm = d->indexToListViewItem(index);
    int visualIndex = d->commonListView->itemIndex(itm);
    for (const auto &idx : std::as_const(d->hiddenRows)) {
        if (idx.row() <= index.row())
            --visualIndex;
    }
    return visualIndex;
}
 
 
QSize QListView::viewportSizeHint() const
{
    Q_D(const QListView);
    // We don't have a nice simple size hint for invalid or wrapping list views.
    if (!d->model)
        return QAbstractItemView::viewportSizeHint();
    const int rc = d->model->rowCount();
    if (rc == 0 || isWrapping())
        return QAbstractItemView::viewportSizeHint();
 
    QStyleOptionViewItem option;
    initViewItemOption(&option);
 
    if (uniformItemSizes()) {
        QSize sz = d->cachedItemSize;
        if (!sz.isValid()) {
            QModelIndex idx = d->model->index(0, d->column, d->root);
            sz = d->itemSize(option, idx);
        }
        sz.setHeight(rc * sz.height());
        return sz;
    }
 
    // Using AdjustToContents with a high number of rows will normally not make sense, so we limit
    // this to default 1000 (that is btw the default for QHeaderView::resizeContentsPrecision())
    // (By setting the property _q_resizeContentPrecision the user can however override this).
    int maximumRows = 1000;
    const QVariant userOverrideValue = property("_q_resizeContentPrecision");
    if (userOverrideValue.isValid() && userOverrideValue.toInt() > 0) {
      maximumRows = userOverrideValue.toInt();
    }
    const int rowCount = qMin(rc, maximumRows);
 
    int h = 0;
    int w = 0;
 
    for (int row = 0; row < rowCount; ++row) {
        QModelIndex idx = d->model->index(row, d->column, d->root);
        QSize itemSize = d->itemSize(option, idx);
        h += itemSize.height();
        w = qMax(w, itemSize.width());
    }
    return QSize(w, h);
}
 
QT_END_NAMESPACE
 
#include "moc_qlistview.cpp"