qheaderview.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qheaderview.h"
 
#include <qabstractitemdelegate.h>
#include <qapplication.h>
#include <qbitarray.h>
#include <qbrush.h>
#include <qdebug.h>
#include <qevent.h>
#include <qlist.h>
#include <qpainter.h>
#include <qscrollbar.h>
#include <qstyle.h>
#include <qstyleoption.h>
#if QT_CONFIG(tooltip)
#include <qtooltip.h>
#endif
#include <qvarlengtharray.h>
#include <qvariant.h>
#if QT_CONFIG(whatsthis)
#include <qwhatsthis.h>
#endif
#include <private/qheaderview_p.h>
#include <private/qabstractitemmodel_p.h>
#include <private/qabstractitemdelegate_p.h>
 
#ifndef QT_NO_DATASTREAM
#include <qdatastream.h>
#endif
 
QT_BEGIN_NAMESPACE
 
#ifndef QT_NO_DATASTREAM
QDataStream &operator<<(QDataStream &out, const QHeaderViewPrivate::SectionItem &section)
{
    section.write(out);
    return out;
}
 
QDataStream &operator>>(QDataStream &in, QHeaderViewPrivate::SectionItem &section)
{
    section.read(in);
    return in;
}
#endif // QT_NO_DATASTREAM
 
static const int maxSizeSection = 1048575; // since section size is in a bitfield (uint 20). See qheaderview_p.h
                                           // if this is changed then the docs in maximumSectionSize should be changed.
 
QHeaderView::QHeaderView(Qt::Orientation orientation, QWidget *parent)
    : QAbstractItemView(*new QHeaderViewPrivate, parent)
{
    Q_D(QHeaderView);
    d->setDefaultValues(orientation);
    initialize();
}
 
QHeaderView::QHeaderView(QHeaderViewPrivate &dd,
                         Qt::Orientation orientation, QWidget *parent)
    : QAbstractItemView(dd, parent)
{
    Q_D(QHeaderView);
    d->setDefaultValues(orientation);
    initialize();
}
 
QHeaderView::~QHeaderView()
{
    Q_D(QHeaderView);
    d->disconnectModel();
}
 
void QHeaderView::initialize()
{
    Q_D(QHeaderView);
    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setFrameStyle(NoFrame);
    setFocusPolicy(Qt::NoFocus);
    d->viewport->setMouseTracking(true);
    d->viewport->setBackgroundRole(QPalette::Button);
    d->textElideMode = Qt::ElideNone;
    delete d->itemDelegate;
}
 
void QHeaderView::setModel(QAbstractItemModel *model)
{
    if (model == this->model())
        return;
    Q_D(QHeaderView);
    d->layoutChangePersistentSections.clear();
    if (d->model && d->model != QAbstractItemModelPrivate::staticEmptyModel())
        d->disconnectModel();
 
    if (model && model != QAbstractItemModelPrivate::staticEmptyModel()) {
        const bool hor = d->orientation == Qt::Horizontal;
        d->modelConnections = {
            QObject::connect(model, hor ? &QAbstractItemModel::columnsInserted
                                        : &QAbstractItemModel::rowsInserted,
                             this, &QHeaderView::sectionsInserted),
            QObject::connect(model, hor ? &QAbstractItemModel::columnsAboutToBeRemoved
                                        : &QAbstractItemModel::rowsAboutToBeRemoved,
                             this, &QHeaderView::sectionsAboutToBeRemoved),
            QObjectPrivate::connect(model, hor ? &QAbstractItemModel::columnsRemoved
                                               : &QAbstractItemModel::rowsRemoved,
                                    d, &QHeaderViewPrivate::sectionsRemoved),
            QObjectPrivate::connect(model, hor ? &QAbstractItemModel::columnsAboutToBeMoved
                                               : &QAbstractItemModel::rowsAboutToBeMoved,
                                    d, &QHeaderViewPrivate::sectionsAboutToBeMoved),
            QObjectPrivate::connect(model, hor ? &QAbstractItemModel::columnsMoved
                                               : &QAbstractItemModel::rowsMoved,
                                    d, &QHeaderViewPrivate::sectionsMoved),
 
            QObject::connect(model, &QAbstractItemModel::headerDataChanged,
                             this, &QHeaderView::headerDataChanged),
            QObjectPrivate::connect(model, &QAbstractItemModel::layoutAboutToBeChanged,
                                    d, &QHeaderViewPrivate::sectionsAboutToBeChanged),
            QObjectPrivate::connect(model, &QAbstractItemModel::layoutChanged,
                                    d, &QHeaderViewPrivate::sectionsChanged)
        };
    }
 
    d->state = QHeaderViewPrivate::NoClear;
    QAbstractItemView::setModel(model);
    d->state = QHeaderViewPrivate::NoState;
 
    // Users want to set sizes and modes before the widget is shown.
    // Thus, we have to initialize when the model is set,
    // and not lazily like we do in the other views.
    initializeSections();
}
 
Qt::Orientation QHeaderView::orientation() const
{
    Q_D(const QHeaderView);
    return d->orientation;
}
 
int QHeaderView::offset() const
{
    Q_D(const QHeaderView);
    return d->headerOffset;
}
 
void QHeaderView::setOffset(int newOffset)
{
    Q_D(QHeaderView);
    if (d->headerOffset == newOffset)
        return;
    int ndelta = d->headerOffset - newOffset;
    d->headerOffset = newOffset;
    if (d->orientation == Qt::Horizontal)
        d->viewport->scroll(isRightToLeft() ? -ndelta : ndelta, 0);
    else
        d->viewport->scroll(0, ndelta);
    if (d->state == QHeaderViewPrivate::ResizeSection && !d->preventCursorChangeInSetOffset) {
        QPoint cursorPos = QCursor::pos();
        if (d->orientation == Qt::Horizontal)
            QCursor::setPos(cursorPos.x() + ndelta, cursorPos.y());
        else
            QCursor::setPos(cursorPos.x(), cursorPos.y() + ndelta);
        d->firstPos += ndelta;
        d->lastPos += ndelta;
    }
}
 
void QHeaderView::setOffsetToSectionPosition(int visualSectionNumber)
{
    Q_D(QHeaderView);
    if (visualSectionNumber > -1 && visualSectionNumber < d->sectionCount()) {
        int position = d->headerSectionPosition(d->adjustedVisualIndex(visualSectionNumber));
        setOffset(position);
    }
}
 
void QHeaderView::setOffsetToLastSection()
{
    Q_D(const QHeaderView);
    int size = (d->orientation == Qt::Horizontal ? viewport()->width() : viewport()->height());
    int position = length() - size;
    setOffset(position);
}
 
int QHeaderView::length() const
{
    Q_D(const QHeaderView);
    d->executePostedLayout();
    d->executePostedResize();
    //Q_ASSERT(d->headerLength() == d->length);
    return d->length;
}
 
QSize QHeaderView::sizeHint() const
{
    Q_D(const QHeaderView);
    if (d->cachedSizeHint.isValid())
        return d->cachedSizeHint;
    d->cachedSizeHint = QSize(0, 0); //reinitialize the cached size hint
    const int sectionCount = count();
 
    // get size hint for the first n sections
    int i = 0;
    for (int checked = 0; checked < 100 && i < sectionCount; ++i) {
        if (isSectionHidden(i))
            continue;
        checked++;
        QSize hint = sectionSizeFromContents(i);
        d->cachedSizeHint = d->cachedSizeHint.expandedTo(hint);
    }
    // get size hint for the last n sections
    i = qMax(i, sectionCount - 100 );
    for (int j = sectionCount - 1, checked = 0; j >= i && checked < 100; --j) {
        if (isSectionHidden(j))
            continue;
        checked++;
        QSize hint = sectionSizeFromContents(j);
        d->cachedSizeHint = d->cachedSizeHint.expandedTo(hint);
    }
    return d->cachedSizeHint;
}
 
void QHeaderView::setVisible(bool v)
{
    bool actualChange = (v != isVisible());
    QAbstractItemView::setVisible(v);
    if (actualChange) {
        QAbstractScrollArea *parent = qobject_cast<QAbstractScrollArea*>(parentWidget());
        if (parent)
            parent->updateGeometry();
    }
}
 
 
int QHeaderView::sectionSizeHint(int logicalIndex) const
{
    Q_D(const QHeaderView);
    if (isSectionHidden(logicalIndex))
        return 0;
    if (logicalIndex < 0 || logicalIndex >= count())
        return -1;
    QSize size;
    QVariant value = d->model->headerData(logicalIndex, d->orientation, Qt::SizeHintRole);
    if (value.isValid())
        size = qvariant_cast<QSize>(value);
    else
        size = sectionSizeFromContents(logicalIndex);
    int hint = d->orientation == Qt::Horizontal ? size.width() : size.height();
    return qBound(minimumSectionSize(), hint, maximumSectionSize());
}
 
int QHeaderView::visualIndexAt(int position) const
{
    Q_D(const QHeaderView);
    int vposition = position;
    d->executePostedLayout();
    d->executePostedResize();
    const int count = d->sectionCount();
    if (count < 1)
        return -1;
 
    if (d->reverse())
        vposition = d->viewport->width() - vposition - 1;
    vposition += d->headerOffset;
 
    if (vposition > d->length)
        return -1;
    int visual = d->headerVisualIndexAt(vposition);
    if (visual < 0)
        return -1;
 
    while (d->isVisualIndexHidden(visual)){
        ++visual;
        if (visual >= count)
            return -1;
    }
    return visual;
}
 
int QHeaderView::logicalIndexAt(int position) const
{
    const int visual = visualIndexAt(position);
    if (visual > -1)
        return logicalIndex(visual);
    return -1;
}
 
int QHeaderView::sectionSize(int logicalIndex) const
{
    Q_D(const QHeaderView);
    if (isSectionHidden(logicalIndex))
        return 0;
    if (logicalIndex < 0 || logicalIndex >= count())
        return 0;
    int visual = visualIndex(logicalIndex);
    if (visual == -1)
        return 0;
    d->executePostedResize();
    return d->headerSectionSize(visual);
}
 
int QHeaderView::sectionPosition(int logicalIndex) const
{
    Q_D(const QHeaderView);
    int visual = visualIndex(logicalIndex);
    // in some cases users may change the selections
    // before we have a chance to do the layout
    if (visual == -1)
        return -1;
    d->executePostedResize();
    return d->headerSectionPosition(visual);
}
 
int QHeaderView::sectionViewportPosition(int logicalIndex) const
{
    Q_D(const QHeaderView);
    if (logicalIndex >= count())
        return -1;
    int position = sectionPosition(logicalIndex);
    if (position < 0)
        return position; // the section was hidden
    int offsetPosition = position - d->headerOffset;
    if (d->reverse())
        return d->viewport->width() - (offsetPosition + sectionSize(logicalIndex));
    return offsetPosition;
}
 
template<typename Container>
static void qMoveRange(Container& c,
               typename Container::size_type rangeStart,
               typename Container::size_type rangeEnd,
               typename Container::size_type targetPosition)
{
    Q_ASSERT(targetPosition <= c.size());
    Q_ASSERT(targetPosition < rangeStart || targetPosition >= rangeEnd);
 
    const bool forwardMove = targetPosition > rangeStart;
    typename Container::size_type first = std::min(rangeStart, targetPosition);
    typename Container::size_type mid = forwardMove ? rangeEnd : rangeStart;
    typename Container::size_type last = forwardMove ? targetPosition + 1 : rangeEnd;
    std::rotate(c.begin() + first, c.begin() + mid, c.begin() + last);
}
 
void QHeaderView::moveSection(int from, int to)
{
    Q_D(QHeaderView);
 
    d->executePostedLayout();
    if (from < 0 || from >= d->sectionCount() || to < 0 || to >= d->sectionCount())
        return;
 
    if (from == to) {
        int logical = logicalIndex(from);
        Q_ASSERT(logical != -1);
        updateSection(logical);
        return;
    }
 
    d->initializeIndexMapping();
 
    int *visualIndices = d->visualIndices.data();
    int *logicalIndices = d->logicalIndices.data();
    int logical = logicalIndices[from];
    int visual = from;
 
    if (to > from) {
        while (visual < to) {
            visualIndices[logicalIndices[visual + 1]] = visual;
            logicalIndices[visual] = logicalIndices[visual + 1];
            ++visual;
        }
    } else {
        while (visual > to) {
            visualIndices[logicalIndices[visual - 1]] = visual;
            logicalIndices[visual] = logicalIndices[visual - 1];
            --visual;
        }
    }
    visualIndices[logical] = to;
    logicalIndices[to] = logical;
 
    qMoveRange(d->sectionItems, from, from + 1, to);
 
    d->sectionStartposRecalc = true;
 
    if (d->hasAutoResizeSections())
        d->doDelayedResizeSections();
    d->viewport->update();
 
    emit sectionMoved(logical, from, to);
 
    if (stretchLastSection()) {
        const int lastSectionVisualIdx = visualIndex(d->lastSectionLogicalIdx);
        if (from >= lastSectionVisualIdx || to >= lastSectionVisualIdx)
            d->maybeRestorePrevLastSectionAndStretchLast();
    }
}
 
void QHeaderView::swapSections(int first, int second)
{
    Q_D(QHeaderView);
 
    if (first == second)
        return;
    d->executePostedLayout();
    if (first < 0 || first >= d->sectionCount() || second < 0 || second >= d->sectionCount())
        return;
 
    int firstSize = d->headerSectionSize(first);
    ResizeMode firstMode = d->headerSectionResizeMode(first);
    int firstLogical = d->logicalIndex(first);
 
    int secondSize = d->headerSectionSize(second);
    ResizeMode secondMode = d->headerSectionResizeMode(second);
    int secondLogical = d->logicalIndex(second);
 
    if (d->state == QHeaderViewPrivate::ResizeSection)
        d->preventCursorChangeInSetOffset = true;
 
    d->createSectionItems(second, second, firstSize, firstMode);
    d->createSectionItems(first, first, secondSize, secondMode);
 
    d->initializeIndexMapping();
 
    d->visualIndices[firstLogical] = second;
    d->logicalIndices[second] = firstLogical;
 
    d->visualIndices[secondLogical] = first;
    d->logicalIndices[first] = secondLogical;
 
    if (!d->hiddenSectionSize.isEmpty()) {
        bool firstHidden = d->isVisualIndexHidden(first);
        bool secondHidden = d->isVisualIndexHidden(second);
        d->setVisualIndexHidden(first, secondHidden);
        d->setVisualIndexHidden(second, firstHidden);
    }
 
    d->viewport->update();
    emit sectionMoved(firstLogical, first, second);
    emit sectionMoved(secondLogical, second, first);
 
    if (stretchLastSection()) {
        const int lastSectionVisualIdx = visualIndex(d->lastSectionLogicalIdx);
        if (first >= lastSectionVisualIdx || second >= lastSectionVisualIdx)
            d->maybeRestorePrevLastSectionAndStretchLast();
    }
}
 
void QHeaderView::resizeSection(int logical, int size)
{
    Q_D(QHeaderView);
    if (logical < 0 || logical >= count() || size < 0 || size > maxSizeSection)
        return;
 
    // make sure to not exceed bounds when setting size programmatically
    if (size > 0)
        size = qBound(minimumSectionSize(), size, maximumSectionSize());
 
    if (isSectionHidden(logical)) {
        d->hiddenSectionSize.insert(logical, size);
        return;
    }
 
    int visual = visualIndex(logical);
    if (visual == -1)
        return;
 
    if (d->state == QHeaderViewPrivate::ResizeSection && !d->cascadingResizing && logical != d->section)
        d->preventCursorChangeInSetOffset = true;
 
    int oldSize = d->headerSectionSize(visual);
    if (oldSize == size)
        return;
 
    d->executePostedLayout();
    d->invalidateCachedSizeHint();
 
    if (stretchLastSection() && logical == d->lastSectionLogicalIdx)
        d->lastSectionSize = size;
 
    d->createSectionItems(visual, visual, size, d->headerSectionResizeMode(visual));
 
    if (!updatesEnabled()) {
        if (d->hasAutoResizeSections())
            d->doDelayedResizeSections();
        emit sectionResized(logical, oldSize, size);
        return;
    }
 
    int w = d->viewport->width();
    int h = d->viewport->height();
    int pos = sectionViewportPosition(logical);
    QRect r;
    if (d->orientation == Qt::Horizontal)
        if (isRightToLeft())
            r.setRect(0, 0, pos + size, h);
        else
            r.setRect(pos, 0, w - pos, h);
    else
        r.setRect(0, pos, w, h - pos);
 
    if (d->hasAutoResizeSections()) {
        d->doDelayedResizeSections();
        r = d->viewport->rect();
    }
 
    // If the parent is a QAbstractScrollArea with QAbstractScrollArea::AdjustToContents
    // then we want to change the geometry on that widget. Not doing it at once can/will
    // cause scrollbars flicker as they would be shown at first but then removed.
    // In the same situation it will also allow shrinking the whole view when stretchLastSection is set
    // (It is default on QTreeViews - and it wouldn't shrink since the last stretch was made before the
    // viewport was resized)
 
    QAbstractScrollArea *parent = qobject_cast<QAbstractScrollArea *>(parentWidget());
    if (parent && parent->sizeAdjustPolicy() == QAbstractScrollArea::AdjustToContents)
        parent->updateGeometry();
 
    d->viewport->update(r.normalized());
    emit sectionResized(logical, oldSize, size);
}
 
void QHeaderView::resizeSections(QHeaderView::ResizeMode mode)
{
    Q_D(QHeaderView);
    d->resizeSections(mode, true);
}
 
bool QHeaderView::isSectionHidden(int logicalIndex) const
{
    Q_D(const QHeaderView);
    d->executePostedLayout();
    if (d->hiddenSectionSize.isEmpty() || logicalIndex < 0 || logicalIndex >= d->sectionCount())
        return false;
    int visual = visualIndex(logicalIndex);
    Q_ASSERT(visual != -1);
    return d->isVisualIndexHidden(visual);
}
 
int QHeaderView::hiddenSectionCount() const
{
    Q_D(const QHeaderView);
    return d->hiddenSectionSize.size();
}
 
void QHeaderView::setSectionHidden(int logicalIndex, bool hide)
{
    Q_D(QHeaderView);
    if (logicalIndex < 0 || logicalIndex >= count())
        return;
 
    d->executePostedLayout();
    int visual = visualIndex(logicalIndex);
    Q_ASSERT(visual != -1);
    if (hide == d->isVisualIndexHidden(visual))
        return;
    if (hide) {
        const bool isHidingLastSection = (stretchLastSection() && logicalIndex == d->lastSectionLogicalIdx);
        if (isHidingLastSection)
            d->restoreSizeOnPrevLastSection(); // Restore here/now to get the right restore size.
        int size = d->headerSectionSize(visual);
        if (!d->hasAutoResizeSections())
            resizeSection(logicalIndex, 0);
        d->hiddenSectionSize.insert(logicalIndex, size);
        d->setVisualIndexHidden(visual, true);
        if (isHidingLastSection)
            d->setNewLastSection(d->lastVisibleVisualIndex());
        if (d->hasAutoResizeSections())
            d->doDelayedResizeSections();
    } else {
        int size = d->hiddenSectionSize.value(logicalIndex, d->defaultSectionSize);
        d->hiddenSectionSize.remove(logicalIndex);
        d->setVisualIndexHidden(visual, false);
        resizeSection(logicalIndex, size);
 
        const bool newLastSection = (stretchLastSection() && visual > visualIndex(d->lastSectionLogicalIdx));
        if (newLastSection) {
            d->restoreSizeOnPrevLastSection();
            d->setNewLastSection(visual);
        }
    }
}
 
int QHeaderView::count() const
{
    Q_D(const QHeaderView);
    //Q_ASSERT(d->sectionCount == d->headerSectionCount());
    // ### this may affect the lazy layout
    d->executePostedLayout();
    return d->sectionCount();
}
 
int QHeaderView::visualIndex(int logicalIndex) const
{
    Q_D(const QHeaderView);
    if (logicalIndex < 0)
        return -1;
    d->executePostedLayout();
    if (d->visualIndices.isEmpty()) { // nothing has been moved, so we have no mapping
        if (logicalIndex < d->sectionCount())
            return logicalIndex;
    } else if (logicalIndex < d->visualIndices.size()) {
        int visual = d->visualIndices.at(logicalIndex);
        Q_ASSERT(visual < d->sectionCount());
        return visual;
    }
    return -1;
}
 
int QHeaderView::logicalIndex(int visualIndex) const
{
    Q_D(const QHeaderView);
    if (visualIndex < 0 || visualIndex >= d->sectionCount())
        return -1;
    return d->logicalIndex(visualIndex);
}
 
void QHeaderView::setSectionsMovable(bool movable)
{
    Q_D(QHeaderView);
    d->movableSections = movable;
}
 
bool QHeaderView::sectionsMovable() const
{
    Q_D(const QHeaderView);
    return d->movableSections;
}
 
void QHeaderView::setFirstSectionMovable(bool movable)
{
    Q_D(QHeaderView);
    d->allowUserMoveOfSection0 = movable;
}
 
bool QHeaderView::isFirstSectionMovable() const
{
    Q_D(const QHeaderView);
    return d->allowUserMoveOfSection0;
}
 
void QHeaderView::setSectionsClickable(bool clickable)
{
    Q_D(QHeaderView);
    d->clickableSections = clickable;
}
 
bool QHeaderView::sectionsClickable() const
{
    Q_D(const QHeaderView);
    return d->clickableSections;
}
 
void QHeaderView::setHighlightSections(bool highlight)
{
    Q_D(QHeaderView);
    d->highlightSelected = highlight;
}
 
bool QHeaderView::highlightSections() const
{
    Q_D(const QHeaderView);
    return d->highlightSelected;
}
 
void QHeaderView::setSectionResizeMode(ResizeMode mode)
{
    Q_D(QHeaderView);
    initializeSections();
    d->stretchSections = (mode == Stretch ? count() : 0);
    d->contentsSections =  (mode == ResizeToContents ? count() : 0);
    d->setGlobalHeaderResizeMode(mode);
    if (d->hasAutoResizeSections())
        d->doDelayedResizeSections(); // section sizes may change as a result of the new mode
}
 
void QHeaderView::setSectionResizeMode(int logicalIndex, ResizeMode mode)
{
    Q_D(QHeaderView);
    int visual = visualIndex(logicalIndex);
    Q_ASSERT(visual != -1);
 
    ResizeMode old = d->headerSectionResizeMode(visual);
    d->setHeaderSectionResizeMode(visual, mode);
 
    if (mode == Stretch && old != Stretch)
        ++d->stretchSections;
    else if (mode == ResizeToContents && old != ResizeToContents)
        ++d->contentsSections;
    else if (mode != Stretch && old == Stretch)
        --d->stretchSections;
    else if (mode != ResizeToContents && old == ResizeToContents)
        --d->contentsSections;
 
    if (d->hasAutoResizeSections() && d->state == QHeaderViewPrivate::NoState)
        d->doDelayedResizeSections(); // section sizes may change as a result of the new mode
}
 
QHeaderView::ResizeMode QHeaderView::sectionResizeMode(int logicalIndex) const
{
    Q_D(const QHeaderView);
    int visual = visualIndex(logicalIndex);
    if (visual == -1)
        return Fixed; //the default value
    return d->headerSectionResizeMode(visual);
}
 
void QHeaderView::setResizeContentsPrecision(int precision)
{
    Q_D(QHeaderView);
    d->resizeContentsPrecision = precision;
}
 
int QHeaderView::resizeContentsPrecision() const
{
    Q_D(const QHeaderView);
    return d->resizeContentsPrecision;
}
 
int QHeaderView::stretchSectionCount() const
{
    Q_D(const QHeaderView);
    return d->stretchSections;
}
 
void QHeaderView::setSortIndicatorShown(bool show)
{
    Q_D(QHeaderView);
    if (d->sortIndicatorShown == show)
        return;
 
    d->sortIndicatorShown = show;
 
    if (sortIndicatorSection() < 0 || sortIndicatorSection() > count())
        return;
 
    if (d->headerSectionResizeMode(sortIndicatorSection()) == ResizeToContents)
        resizeSections();
 
    d->viewport->update();
}
 
bool QHeaderView::isSortIndicatorShown() const
{
    Q_D(const QHeaderView);
    return d->sortIndicatorShown;
}
 
void QHeaderView::setSortIndicator(int logicalIndex, Qt::SortOrder order)
{
    Q_D(QHeaderView);
 
    // This is so that people can set the position of the sort indicator before the fill the model
    int old = d->sortIndicatorSection;
    if (old == logicalIndex && order == d->sortIndicatorOrder)
        return;
    d->sortIndicatorSection = logicalIndex;
    d->sortIndicatorOrder = order;
 
    if (logicalIndex >= d->sectionCount()) {
        emit sortIndicatorChanged(logicalIndex, order);
        return; // nothing to do
    }
 
    if (old != logicalIndex
        && ((logicalIndex >= 0 && sectionResizeMode(logicalIndex) == ResizeToContents)
            || old >= d->sectionCount() || (old >= 0 && sectionResizeMode(old) == ResizeToContents))) {
        resizeSections();
        d->viewport->update();
    } else {
        if (old >= 0 && old != logicalIndex)
            updateSection(old);
        if (logicalIndex >= 0)
            updateSection(logicalIndex);
    }
 
    emit sortIndicatorChanged(logicalIndex, order);
}
 
int QHeaderView::sortIndicatorSection() const
{
    Q_D(const QHeaderView);
    return d->sortIndicatorSection;
}
 
Qt::SortOrder QHeaderView::sortIndicatorOrder() const
{
    Q_D(const QHeaderView);
    return d->sortIndicatorOrder;
}
 
void QHeaderView::setSortIndicatorClearable(bool clearable)
{
    Q_D(QHeaderView);
    if (d->sortIndicatorClearable == clearable)
        return;
    d->sortIndicatorClearable = clearable;
    emit sortIndicatorClearableChanged(clearable);
}
 
bool QHeaderView::isSortIndicatorClearable() const
{
    Q_D(const QHeaderView);
    return d->sortIndicatorClearable;
}
 
bool QHeaderView::stretchLastSection() const
{
    Q_D(const QHeaderView);
    return d->stretchLastSection;
}
 
void QHeaderView::setStretchLastSection(bool stretch)
{
    Q_D(QHeaderView);
    if (d->stretchLastSection == stretch)
        return;
    d->stretchLastSection = stretch;
    if (d->state != QHeaderViewPrivate::NoState)
        return;
    if (stretch) {
        d->setNewLastSection(d->lastVisibleVisualIndex());
        resizeSections();
    } else {
        d->restoreSizeOnPrevLastSection();
    }
}
 
bool QHeaderView::cascadingSectionResizes() const
{
    Q_D(const QHeaderView);
    return d->cascadingResizing;
}
 
void QHeaderView::setCascadingSectionResizes(bool enable)
{
    Q_D(QHeaderView);
    d->cascadingResizing = enable;
}
 
int QHeaderView::defaultSectionSize() const
{
    Q_D(const QHeaderView);
    return d->defaultSectionSize;
}
 
void QHeaderView::setDefaultSectionSize(int size)
{
    Q_D(QHeaderView);
    if (size < 0 || size > maxSizeSection)
        return;
    d->setDefaultSectionSize(size);
}
 
void QHeaderView::resetDefaultSectionSize()
{
    Q_D(QHeaderView);
    if (d->customDefaultSectionSize) {
        d->updateDefaultSectionSizeFromStyle();
        d->customDefaultSectionSize = false;
    }
}
 
int QHeaderView::minimumSectionSize() const
{
    Q_D(const QHeaderView);
    if (d->minimumSectionSize == -1) {
        int margin = 2 * style()->pixelMetric(QStyle::PM_HeaderMargin, nullptr, this);
        if (d->orientation == Qt::Horizontal)
            return fontMetrics().maxWidth() + margin;
        return fontMetrics().height() + margin;
    }
    return d->minimumSectionSize;
}
 
void QHeaderView::setMinimumSectionSize(int size)
{
    Q_D(QHeaderView);
    if (size < -1 || size > maxSizeSection)
        return;
    // larger new min size - check current section sizes
    const bool needSizeCheck = size > d->minimumSectionSize;
    d->minimumSectionSize = size;
    if (d->minimumSectionSize > maximumSectionSize())
        setMaximumSectionSize(size);
 
    if (needSizeCheck) {
        if (d->hasAutoResizeSections()) {
            d->doDelayedResizeSections();
        } else {
            for (int visual = 0; visual < d->sectionCount(); ++visual) {
                if (d->isVisualIndexHidden(visual))
                    continue;
                if (d->headerSectionSize(visual) < d->minimumSectionSize)
                    resizeSection(logicalIndex(visual), size);
            }
        }
    }
 
}
 
int QHeaderView::maximumSectionSize() const
{
    Q_D(const QHeaderView);
    if (d->maximumSectionSize == -1)
        return maxSizeSection;
    return d->maximumSectionSize;
}
 
void QHeaderView::setMaximumSectionSize(int size)
{
    Q_D(QHeaderView);
    if (size == -1) {
        d->maximumSectionSize = maxSizeSection;
        return;
    }
    if (size < 0 || size > maxSizeSection)
        return;
    if (minimumSectionSize() > size)
        d->minimumSectionSize = size;
 
    // smaller new max size - check current section sizes
    const bool needSizeCheck = size < d->maximumSectionSize;
    d->maximumSectionSize = size;
 
    if (needSizeCheck) {
        if (d->hasAutoResizeSections()) {
            d->doDelayedResizeSections();
        } else {
            for (int visual = 0; visual < d->sectionCount(); ++visual) {
                if (d->isVisualIndexHidden(visual))
                    continue;
                if (d->headerSectionSize(visual) > d->maximumSectionSize)
                    resizeSection(logicalIndex(visual), size);
            }
        }
    }
}
 
 
Qt::Alignment QHeaderView::defaultAlignment() const
{
    Q_D(const QHeaderView);
    return d->defaultAlignment;
}
 
void QHeaderView::setDefaultAlignment(Qt::Alignment alignment)
{
    Q_D(QHeaderView);
    if (d->defaultAlignment == alignment)
        return;
 
    d->defaultAlignment = alignment;
    d->viewport->update();
}
 
void QHeaderView::doItemsLayout()
{
    initializeSections();
    QAbstractItemView::doItemsLayout();
}
 
bool QHeaderView::sectionsMoved() const
{
    Q_D(const QHeaderView);
    return !d->visualIndices.isEmpty();
}
 
bool QHeaderView::sectionsHidden() const
{
    Q_D(const QHeaderView);
    return !d->hiddenSectionSize.isEmpty();
}
 
#ifndef QT_NO_DATASTREAM
QByteArray QHeaderView::saveState() const
{
    Q_D(const QHeaderView);
    QByteArray data;
    QDataStream stream(&data, QIODevice::WriteOnly);
    stream.setVersion(QDataStream::Qt_5_0);
    stream << QHeaderViewPrivate::VersionMarker;
    stream << 0; // current version is 0
    d->write(stream);
    return data;
}
 
bool QHeaderView::restoreState(const QByteArray &state)
{
    Q_D(QHeaderView);
    if (state.isEmpty())
        return false;
 
    for (const auto dataStreamVersion : {QDataStream::Qt_5_0, QDataStream::Qt_6_0}) {
 
        QByteArray data = state;
        QDataStream stream(&data, QIODevice::ReadOnly);
        stream.setVersion(dataStreamVersion);
        int marker;
        int ver;
        stream >> marker;
        stream >> ver;
        if (stream.status() != QDataStream::Ok
        || marker != QHeaderViewPrivate::VersionMarker
        || ver != 0) { // current version is 0
            return false;
        }
 
        if (d->read(stream)) {
            emit sortIndicatorChanged(d->sortIndicatorSection, d->sortIndicatorOrder );
            d->viewport->update();
            return true;
        }
    }
    return false;
}
#endif // QT_NO_DATASTREAM
 
void QHeaderView::reset()
{
    Q_D(QHeaderView);
    QAbstractItemView::reset();
    // it would be correct to call clear, but some apps rely
    // on the header keeping the sections, even after calling reset
    //d->clear();
    initializeSections();
    d->invalidateCachedSizeHint();
}
 
void QHeaderView::headerDataChanged(Qt::Orientation orientation, int logicalFirst, int logicalLast)
{
    Q_D(QHeaderView);
    if (d->orientation != orientation)
        return;
 
    if (logicalFirst < 0 || logicalLast < 0 || logicalFirst >= count() || logicalLast >= count())
        return;
 
    d->invalidateCachedSizeHint();
 
    int firstVisualIndex = INT_MAX, lastVisualIndex = -1;
 
    for (int section = logicalFirst; section <= logicalLast; ++section) {
        const int visual = visualIndex(section);
        firstVisualIndex = qMin(firstVisualIndex, visual);
        lastVisualIndex =  qMax(lastVisualIndex,  visual);
    }
 
    d->executePostedResize();
    const int first = d->headerSectionPosition(firstVisualIndex),
              last = d->headerSectionPosition(lastVisualIndex)
                        + d->headerSectionSize(lastVisualIndex);
 
    if (orientation == Qt::Horizontal) {
        d->viewport->update(first, 0, last - first, d->viewport->height());
    } else {
        d->viewport->update(0, first, d->viewport->width(), last - first);
    }
}
 
void QHeaderView::updateSection(int logicalIndex)
{
    Q_D(QHeaderView);
    if (d->orientation == Qt::Horizontal)
        d->viewport->update(QRect(sectionViewportPosition(logicalIndex),
                                  0, sectionSize(logicalIndex), d->viewport->height()));
    else
        d->viewport->update(QRect(0, sectionViewportPosition(logicalIndex),
                                  d->viewport->width(), sectionSize(logicalIndex)));
}
 
void QHeaderView::resizeSections()
{
    Q_D(QHeaderView);
    if (d->hasAutoResizeSections())
        d->resizeSections(Interactive, false); // no global resize mode
}
 
void QHeaderView::sectionsInserted(const QModelIndex &parent,
                                   int logicalFirst, int logicalLast)
{
    Q_D(QHeaderView);
    // only handle root level changes and return on no-op
    if (parent != d->root || d->modelSectionCount() == d->sectionCount())
        return;
    int oldCount = d->sectionCount();
 
    d->invalidateCachedSizeHint();
 
    if (d->state == QHeaderViewPrivate::ResizeSection)
        d->preventCursorChangeInSetOffset = true;
 
    // add the new sections
    int insertAt = logicalFirst;
    int insertCount = logicalLast - logicalFirst + 1;
 
    bool lastSectionActualChange = false;
    if (stretchLastSection()) {
 
        int visualIndexForStretch = d->lastSectionLogicalIdx;
        if (d->lastSectionLogicalIdx >= 0 && d->lastSectionLogicalIdx < d->visualIndices.size())
            visualIndexForStretch = d->visualIndices[d->lastSectionLogicalIdx]; // We cannot call visualIndex since it executes executePostedLayout()
                                                                                // and it is likely to bypass initializeSections() and we may end up here again. Doing the insert twice.
 
        if (d->lastSectionLogicalIdx < 0 || insertAt >= visualIndexForStretch)
            lastSectionActualChange = true;
 
        if (d->lastSectionLogicalIdx >= logicalFirst)
            d->lastSectionLogicalIdx += insertCount; // We do not want to emit resize before we have fixed the count
    }
 
    QHeaderViewPrivate::SectionItem section(d->defaultSectionSize, d->globalResizeMode);
    d->sectionStartposRecalc = true;
 
    if (d->sectionItems.isEmpty() || insertAt >= d->sectionItems.size()) {
        int insertLength = d->defaultSectionSize * insertCount;
        d->length += insertLength;
        d->sectionItems.insert(d->sectionItems.size(), insertCount, section); // append
    } else {
        // separate them out into their own sections
        int insertLength = d->defaultSectionSize * insertCount;
        d->length += insertLength;
        d->sectionItems.insert(insertAt, insertCount, section);
    }
 
    // update sorting column
    if (d->sortIndicatorSection >= logicalFirst)
        d->sortIndicatorSection += insertCount;
 
    // update resize mode section counts
    if (d->globalResizeMode == Stretch)
        d->stretchSections = d->sectionCount();
    else if (d->globalResizeMode == ResizeToContents)
        d->contentsSections = d->sectionCount();
 
    // clear selection cache
    d->sectionSelected.clear();
 
    // update mapping
    if (!d->visualIndices.isEmpty() && !d->logicalIndices.isEmpty()) {
        Q_ASSERT(d->visualIndices.size() == d->logicalIndices.size());
        int mappingCount = d->visualIndices.size();
        for (int i = 0; i < mappingCount; ++i) {
            if (d->visualIndices.at(i) >= logicalFirst)
               d->visualIndices[i] += insertCount;
            if (d->logicalIndices.at(i) >= logicalFirst)
                d->logicalIndices[i] += insertCount;
        }
        for (int j = logicalFirst; j <= logicalLast; ++j) {
            d->visualIndices.insert(j, j);
            d->logicalIndices.insert(j, j);
        }
    }
 
    // insert sections into hiddenSectionSize
    QHash<int, int> newHiddenSectionSize; // from logical index to section size
    for (QHash<int, int>::const_iterator it = d->hiddenSectionSize.cbegin(),
         end = d->hiddenSectionSize.cend(); it != end; ++it) {
        const int oldIndex = it.key();
        const int newIndex = (oldIndex < logicalFirst) ? oldIndex : oldIndex + insertCount;
        newHiddenSectionSize[newIndex] = it.value();
    }
    d->hiddenSectionSize.swap(newHiddenSectionSize);
 
    d->doDelayedResizeSections();
    emit sectionCountChanged(oldCount, count());
 
    if (lastSectionActualChange)
        d->maybeRestorePrevLastSectionAndStretchLast();
 
    // if the new sections were not updated by resizing, we need to update now
    if (!d->hasAutoResizeSections())
        d->viewport->update();
}
 
void QHeaderView::sectionsAboutToBeRemoved(const QModelIndex &parent,
                                           int logicalFirst, int logicalLast)
{
    Q_UNUSED(parent);
    Q_UNUSED(logicalFirst);
    Q_UNUSED(logicalLast);
}
 
void QHeaderViewPrivate::updateHiddenSections(int logicalFirst, int logicalLast)
{
    Q_Q(QHeaderView);
    const int changeCount = logicalLast - logicalFirst + 1;
 
    // remove sections from hiddenSectionSize
    QHash<int, int> newHiddenSectionSize; // from logical index to section size
    for (int i = 0; i < logicalFirst; ++i)
        if (q->isSectionHidden(i))
            newHiddenSectionSize[i] = hiddenSectionSize[i];
    for (int j = logicalLast + 1; j < sectionCount(); ++j)
        if (q->isSectionHidden(j))
            newHiddenSectionSize[j - changeCount] = hiddenSectionSize[j];
    hiddenSectionSize = newHiddenSectionSize;
}
 
void QHeaderViewPrivate::sectionsRemoved(const QModelIndex &parent,
                                         int logicalFirst, int logicalLast)
{
    Q_Q(QHeaderView);
    if (parent != root)
        return; // we only handle changes in the root level
    if (qMin(logicalFirst, logicalLast) < 0
        || qMax(logicalLast, logicalFirst) >= sectionCount())
        return;
    int oldCount = q->count();
    int changeCount = logicalLast - logicalFirst + 1;
 
    if (state == QHeaderViewPrivate::ResizeSection)
        preventCursorChangeInSetOffset = true;
 
    updateHiddenSections(logicalFirst, logicalLast);
 
    if (visualIndices.isEmpty() && logicalIndices.isEmpty()) {
        //Q_ASSERT(headerSectionCount() == sectionCount);
        removeSectionsFromSectionItems(logicalFirst, logicalLast);
    } else {
        if (logicalFirst == logicalLast) { // Remove just one index.
            int l = logicalFirst;
            int visual = visualIndices.at(l);
            Q_ASSERT(sectionCount() == logicalIndices.size());
            for (int v = 0; v < sectionCount(); ++v) {
                if (v > visual) {
                    int logical = logicalIndices.at(v);
                    --(visualIndices[logical]);
                }
                if (logicalIndex(v) > l) // no need to move the positions before l
                    --(logicalIndices[v]);
            }
            logicalIndices.remove(visual);
            visualIndices.remove(l);
            //Q_ASSERT(headerSectionCount() == sectionCount);
            removeSectionsFromSectionItems(visual, visual);
        } else {
            sectionStartposRecalc = true; // We will need to recalc positions after removing items
            for (int u = 0; u < sectionItems.size(); ++u)  // Store section info
                sectionItems.at(u).tmpLogIdx = logicalIndices.at(u);
            for (int v = sectionItems.size() - 1; v >= 0; --v) {  // Remove the sections
                if (logicalFirst <= sectionItems.at(v).tmpLogIdx && sectionItems.at(v).tmpLogIdx <= logicalLast)
                    removeSectionsFromSectionItems(v, v);
            }
            visualIndices.resize(sectionItems.size());
            logicalIndices.resize(sectionItems.size());
            int* visual_data = visualIndices.data();
            int* logical_data = logicalIndices.data();
            for (int w = 0; w < sectionItems.size(); ++w) { // Restore visual and logical indexes
                int logindex = sectionItems.at(w).tmpLogIdx;
                if (logindex > logicalFirst)
                    logindex -= changeCount;
                visual_data[logindex] = w;
                logical_data[w] = logindex;
            }
        }
        // ### handle sectionSelection (sectionHidden is handled by updateHiddenSections)
    }
 
    // update sorting column
    if (sortIndicatorSection >= logicalFirst) {
        if (sortIndicatorSection <= logicalLast)
            sortIndicatorSection = -1;
        else
            sortIndicatorSection -= changeCount;
    }
 
    // if we only have the last section (the "end" position) left, the header is empty
    if (sectionCount() <= 0)
        clear();
    invalidateCachedSizeHint();
    emit q->sectionCountChanged(oldCount, q->count());
 
    if (q->stretchLastSection()) {
        const bool lastSectionRemoved = lastSectionLogicalIdx >= logicalFirst && lastSectionLogicalIdx <= logicalLast;
        if (lastSectionRemoved)
            setNewLastSection(lastVisibleVisualIndex());
        else
            lastSectionLogicalIdx = logicalIndex(lastVisibleVisualIndex()); // Just update the last log index.
        doDelayedResizeSections();
    }
 
    viewport->update();
}
 
void QHeaderViewPrivate::sectionsAboutToBeMoved(const QModelIndex &sourceParent, int logicalStart,
                                                int logicalEnd, const QModelIndex &destinationParent,
                                                int logicalDestination)
{
    if (sourceParent != root || destinationParent != root)
        return; // we only handle changes in the root level
    Q_UNUSED(logicalStart);
    Q_UNUSED(logicalEnd);
    Q_UNUSED(logicalDestination);
    sectionsAboutToBeChanged();
}
 
void QHeaderViewPrivate::sectionsMoved(const QModelIndex &sourceParent, int logicalStart,
                                       int logicalEnd, const QModelIndex &destinationParent,
                                       int logicalDestination)
{
    if (sourceParent != root || destinationParent != root)
        return; // we only handle changes in the root level
    Q_UNUSED(logicalStart);
    Q_UNUSED(logicalEnd);
    Q_UNUSED(logicalDestination);
    sectionsChanged();
}
 
void QHeaderViewPrivate::sectionsAboutToBeChanged(const QList<QPersistentModelIndex> &,
                                                  QAbstractItemModel::LayoutChangeHint hint)
{
    if ((hint == QAbstractItemModel::VerticalSortHint && orientation == Qt::Horizontal) ||
        (hint == QAbstractItemModel::HorizontalSortHint && orientation == Qt::Vertical))
        return;
 
    //if there is no row/column we can't have mapping for columns
    //because no QModelIndex in the model would be valid
    // ### this is far from being bullet-proof and we would need a real system to
    // ### map columns or rows persistently
    if ((orientation == Qt::Horizontal && model->rowCount(root) == 0)
        || model->columnCount(root) == 0)
        return;
 
    layoutChangePersistentSections.clear();
    layoutChangePersistentSections.reserve(std::min(10, int(sectionItems.size())));
    // after layoutChanged another section can be last stretched section
    if (stretchLastSection && lastSectionLogicalIdx >= 0 && lastSectionLogicalIdx < sectionItems.size()) {
        const int visual = visualIndex(lastSectionLogicalIdx);
        if (visual >= 0 && visual < sectionItems.size()) {
            auto &itemRef = sectionItems[visual];
            if (itemRef.size != lastSectionSize) {
                length += lastSectionSize - itemRef.size;
                itemRef.size = lastSectionSize;
            }
        }
    }
    for (int i = 0; i < sectionItems.size(); ++i) {
        auto s = sectionItems.at(i);
        // only add if the section is not default and not visually moved
        if (s.size == defaultSectionSize && !s.isHidden && s.resizeMode == globalResizeMode)
            continue;
 
        const int logical = logicalIndex(i);
        if (s.isHidden)
            s.size = hiddenSectionSize.value(logical);
 
        // ### note that we are using column or row 0
        layoutChangePersistentSections.append({orientation == Qt::Horizontal
                                                  ? model->index(0, logical, root)
                                                  : model->index(logical, 0, root),
                                              s});
    }
}
 
void QHeaderViewPrivate::sectionsChanged(const QList<QPersistentModelIndex> &,
                                         QAbstractItemModel::LayoutChangeHint hint)
{
    if ((hint == QAbstractItemModel::VerticalSortHint && orientation == Qt::Horizontal) ||
        (hint == QAbstractItemModel::HorizontalSortHint && orientation == Qt::Vertical))
        return;
 
    Q_Q(QHeaderView);
    viewport->update();
 
    const auto oldPersistentSections = layoutChangePersistentSections;
    layoutChangePersistentSections.clear();
 
    const int newCount = modelSectionCount();
    const int oldCount = sectionItems.size();
    if (newCount == 0) {
        clear();
        if (oldCount != 0)
            emit q->sectionCountChanged(oldCount, 0);
        return;
    }
 
    bool hasPersistantIndexes = false;
    for (const auto &item : oldPersistentSections) {
        if (item.index.isValid()) {
            hasPersistantIndexes = true;
            break;
        }
    }
 
    // Though far from perfect we here try to retain earlier/existing behavior
    // ### See QHeaderViewPrivate::layoutAboutToBeChanged()
    // When we don't have valid hasPersistantIndexes it can be due to
    // - all sections are default sections
    // - the row/column 0 which is used for persistent indexes is gone
    // - all non-default sections were removed
    // case one is trivial, in case two we assume nothing else changed (it's the best
    // guess we can do - everything else can not be handled correctly for now)
    // case three can not be handled correctly with layoutChanged - removeSections
    // should be used instead for this
    if (!hasPersistantIndexes) {
        if (oldCount != newCount)
            q->initializeSections();
        return;
    }
 
    // adjust section size
    if (newCount != oldCount) {
        const int min = qBound(0, oldCount, newCount - 1);
        q->initializeSections(min, newCount - 1);
    }
    // reset sections
    sectionItems.fill(SectionItem(defaultSectionSize, globalResizeMode), newCount);
 
    // all hidden sections are in oldPersistentSections
    hiddenSectionSize.clear();
 
    for (const auto &item : oldPersistentSections) {
        const auto &index = item.index;
        if (!index.isValid())
            continue;
 
        const int newLogicalIndex = (orientation == Qt::Horizontal
                                     ? index.column()
                                     : index.row());
        // the new visualIndices are already adjusted / reset by initializeSections()
        const int newVisualIndex = visualIndex(newLogicalIndex);
        if (newVisualIndex < sectionItems.size()) {
            auto &newSection = sectionItems[newVisualIndex];
            newSection = item.section;
 
            if (newSection.isHidden) {
                // otherwise setSectionHidden will return without doing anything
                newSection.isHidden = false;
                q->setSectionHidden(newLogicalIndex, true);
            }
        }
    }
 
    recalcSectionStartPos();
    length = headerLength();
 
    if (stretchLastSection) {
        // force rebuild of stretched section later on
        lastSectionLogicalIdx = -1;
        maybeRestorePrevLastSectionAndStretchLast();
    }
}
 
void QHeaderView::initializeSections()
{
    Q_D(QHeaderView);
    const int oldCount = d->sectionCount();
    const int newCount = d->modelSectionCount();
    if (newCount <= 0) {
        d->clear();
        emit sectionCountChanged(oldCount, 0);
    } else if (newCount != oldCount) {
        const int min = qBound(0, oldCount, newCount - 1);
        initializeSections(min, newCount - 1);
        if (stretchLastSection())   // we've already gotten the size hint
            d->maybeRestorePrevLastSectionAndStretchLast();
 
        // make sure we update the hidden sections
        // simulate remove from newCount to oldCount
        if (newCount < oldCount)
            d->updateHiddenSections(newCount, oldCount);
    }
}
 
void QHeaderView::initializeSections(int start, int end)
{
    Q_D(QHeaderView);
 
    Q_ASSERT(start >= 0);
    Q_ASSERT(end >= 0);
 
    d->invalidateCachedSizeHint();
    int oldCount = d->sectionCount();
 
    if (end + 1 < d->sectionCount()) {
        int newCount = end + 1;
        d->removeSectionsFromSectionItems(newCount, d->sectionCount() - 1);
        if (!d->hiddenSectionSize.isEmpty()) {
            if (oldCount - newCount > d->hiddenSectionSize.size()) {
                for (int i = end + 1; i < d->sectionCount(); ++i)
                    d->hiddenSectionSize.remove(i);
            } else {
                QHash<int, int>::iterator it = d->hiddenSectionSize.begin();
                while (it != d->hiddenSectionSize.end()) {
                    if (it.key() > end)
                        it = d->hiddenSectionSize.erase(it);
                    else
                        ++it;
                }
            }
        }
    }
 
    int newSectionCount = end + 1;
 
    if (!d->logicalIndices.isEmpty()) {
        if (oldCount <= newSectionCount) {
            d->logicalIndices.resize(newSectionCount);
            d->visualIndices.resize(newSectionCount);
            for (int i = oldCount; i < newSectionCount; ++i) {
                d->logicalIndices[i] = i;
                d->visualIndices[i] = i;
            }
        } else {
            int j = 0;
            for (int i = 0; i < oldCount; ++i) {
                int v = d->logicalIndices.at(i);
                if (v < newSectionCount) {
                    d->logicalIndices[j] = v;
                    d->visualIndices[v] = j;
                    j++;
                }
            }
            d->logicalIndices.resize(newSectionCount);
            d->visualIndices.resize(newSectionCount);
        }
    }
 
    if (d->globalResizeMode == Stretch)
        d->stretchSections = newSectionCount;
    else if (d->globalResizeMode == ResizeToContents)
         d->contentsSections = newSectionCount;
 
    if (newSectionCount > oldCount)
        d->createSectionItems(start, end, d->defaultSectionSize, d->globalResizeMode);
    //Q_ASSERT(d->headerLength() == d->length);
 
    if (d->sectionCount() != oldCount)
        emit sectionCountChanged(oldCount,  d->sectionCount());
    d->viewport->update();
}
 
void QHeaderView::currentChanged(const QModelIndex &current, const QModelIndex &old)
{
    Q_D(QHeaderView);
 
    if (d->orientation == Qt::Horizontal && current.column() != old.column()) {
        if (old.isValid() && old.parent() == d->root)
            d->viewport->update(QRect(sectionViewportPosition(old.column()), 0,
                                    sectionSize(old.column()), d->viewport->height()));
        if (current.isValid() && current.parent() == d->root)
            d->viewport->update(QRect(sectionViewportPosition(current.column()), 0,
                                    sectionSize(current.column()), d->viewport->height()));
    } else if (d->orientation == Qt::Vertical && current.row() != old.row()) {
        if (old.isValid() && old.parent() == d->root)
            d->viewport->update(QRect(0, sectionViewportPosition(old.row()),
                                    d->viewport->width(), sectionSize(old.row())));
        if (current.isValid() && current.parent() == d->root)
            d->viewport->update(QRect(0, sectionViewportPosition(current.row()),
                                    d->viewport->width(), sectionSize(current.row())));
    }
}
 
 
bool QHeaderView::event(QEvent *e)
{
    Q_D(QHeaderView);
    switch (e->type()) {
    case QEvent::HoverEnter: {
        QHoverEvent *he = static_cast<QHoverEvent*>(e);
        d->hover = logicalIndexAt(he->position().toPoint());
        if (d->hover != -1)
            updateSection(d->hover);
        break; }
    case QEvent::Leave:
    case QEvent::HoverLeave: {
        if (d->hover != -1)
            updateSection(d->hover);
        d->hover = -1;
        break; }
    case QEvent::HoverMove: {
        QHoverEvent *he = static_cast<QHoverEvent*>(e);
        int oldHover = d->hover;
        d->hover = logicalIndexAt(he->position().toPoint());
        if (d->hover != oldHover) {
            if (oldHover != -1)
                updateSection(oldHover);
            if (d->hover != -1)
                updateSection(d->hover);
        }
        break; }
    case QEvent::Timer: {
        QTimerEvent *te = static_cast<QTimerEvent*>(e);
        if (te->timerId() == d->delayedResize.timerId()) {
            d->delayedResize.stop();
            resizeSections();
        }
        break; }
    case QEvent::StyleChange:
        if (!d->customDefaultSectionSize)
            d->updateDefaultSectionSizeFromStyle();
        break;
    default:
        break;
    }
    return QAbstractItemView::event(e);
}
 
void QHeaderView::paintEvent(QPaintEvent *e)
{
    Q_D(QHeaderView);
 
    if (count() == 0)
        return;
 
    QPainter painter(d->viewport);
    const QPoint offset = d->scrollDelayOffset;
    QRect translatedEventRect = e->rect();
    translatedEventRect.translate(offset);
 
    int start = -1;
    int end = -1;
    if (d->orientation == Qt::Horizontal) {
        start = visualIndexAt(translatedEventRect.left());
        end = visualIndexAt(translatedEventRect.right());
    } else {
        start = visualIndexAt(translatedEventRect.top());
        end = visualIndexAt(translatedEventRect.bottom());
    }
 
    if (d->reverse()) {
        start = (start == -1 ? count() - 1 : start);
        end = (end == -1 ? 0 : end);
    } else {
        start = (start == -1 ? 0 : start);
        end = (end == -1 ? count() - 1 : end);
    }
 
    int tmp = start;
    start = qMin(start, end);
    end = qMax(tmp, end);
 
    d->prepareSectionSelected(); // clear and resize the bit array
 
    QRect currentSectionRect;
    const int width = d->viewport->width();
    const int height = d->viewport->height();
    const int rtlHorizontalOffset = d->reverse() ? 1 : 0;
    for (int i = start; i <= end; ++i) {
        if (d->isVisualIndexHidden(i))
            continue;
        painter.save();
        const int logical = logicalIndex(i);
        if (d->orientation == Qt::Horizontal) {
            currentSectionRect.setRect(sectionViewportPosition(logical) + rtlHorizontalOffset,
                                       0, sectionSize(logical), height);
        } else {
            currentSectionRect.setRect(0, sectionViewportPosition(logical),
                                       width, sectionSize(logical));
        }
        currentSectionRect.translate(offset);
 
        QVariant variant = d->model->headerData(logical, d->orientation,
                                                Qt::FontRole);
        if (variant.isValid() && variant.canConvert<QFont>()) {
            QFont sectionFont = qvariant_cast<QFont>(variant);
            painter.setFont(sectionFont);
        }
        paintSection(&painter, currentSectionRect, logical);
        painter.restore();
    }
 
    QStyleOption opt;
    opt.initFrom(this);
    // Paint the area beyond where there are indexes
    if (d->reverse()) {
        opt.state |= QStyle::State_Horizontal;
        if (currentSectionRect.left() > translatedEventRect.left()) {
            opt.rect = QRect(translatedEventRect.left(), 0,
                             currentSectionRect.left() - translatedEventRect.left(), height);
            style()->drawControl(QStyle::CE_HeaderEmptyArea, &opt, &painter, this);
        }
    } else if (currentSectionRect.right() < translatedEventRect.right()) {
        // paint to the right
        opt.state |= QStyle::State_Horizontal;
        opt.rect = QRect(currentSectionRect.right() + 1, 0,
                         translatedEventRect.right() - currentSectionRect.right(), height);
        style()->drawControl(QStyle::CE_HeaderEmptyArea, &opt, &painter, this);
    } else if (currentSectionRect.bottom() < translatedEventRect.bottom()) {
        // paint the bottom section
        opt.state &= ~QStyle::State_Horizontal;
        opt.rect = QRect(0, currentSectionRect.bottom() + 1,
                         width, height - currentSectionRect.bottom() - 1);
        style()->drawControl(QStyle::CE_HeaderEmptyArea, &opt, &painter, this);
    }
 
#if 0
    // ### visualize sections
    for (int a = 0, i = 0; i < d->sectionItems.count(); ++i) {
        QColor color((i & 4 ? 255 : 0), (i & 2 ? 255 : 0), (i & 1 ? 255 : 0));
        if (d->orientation == Qt::Horizontal)
            painter.fillRect(a - d->headerOffset, 0, d->sectionItems.at(i).size, 4, color);
        else
            painter.fillRect(0, a - d->headerOffset, 4, d->sectionItems.at(i).size, color);
        a += d->sectionItems.at(i).size;
    }
 
#endif
}
 
void QHeaderView::mousePressEvent(QMouseEvent *e)
{
    Q_D(QHeaderView);
    if (d->state != QHeaderViewPrivate::NoState || e->button() != Qt::LeftButton)
        return;
    int pos = d->orientation == Qt::Horizontal ? e->position().toPoint().x() : e->position().toPoint().y();
    int handle = d->sectionHandleAt(pos);
    d->originalSize = -1; // clear the stored original size
    if (handle == -1) {
        d->firstPressed = d->pressed = logicalIndexAt(pos);
        if (d->clickableSections)
            emit sectionPressed(d->pressed);
 
        bool acceptMoveSection = d->movableSections;
        if (acceptMoveSection && d->pressed == 0 && !d->allowUserMoveOfSection0)
            acceptMoveSection = false; // Do not allow moving the tree nod
 
        if (acceptMoveSection) {
            d->target = -1;
            d->section = d->pressed;
            if (d->section == -1)
                return;
            d->state = QHeaderViewPrivate::MoveSection;
            d->setupSectionIndicator(d->section, pos);
        } else if (d->clickableSections && d->pressed != -1) {
            updateSection(d->pressed);
            d->state = QHeaderViewPrivate::SelectSections;
        }
    } else if (sectionResizeMode(handle) == Interactive) {
        d->originalSize = sectionSize(handle);
        d->state = QHeaderViewPrivate::ResizeSection;
        d->section = handle;
        d->preventCursorChangeInSetOffset = false;
    }
 
    d->firstPos = pos;
    d->lastPos = pos;
 
    d->clearCascadingSections();
}
 
void QHeaderView::mouseMoveEvent(QMouseEvent *e)
{
    Q_D(QHeaderView);
    const int pos = d->orientation == Qt::Horizontal ? e->position().toPoint().x() : e->position().toPoint().y();
    if (pos < 0 && d->state != QHeaderViewPrivate::SelectSections)
        return;
    if (e->buttons() == Qt::NoButton) {
        // Under Cocoa, when the mouse button is released, may include an extra
        // simulated mouse moved event. The state of the buttons when this event
        // is generated is already "no button" and the code below gets executed
        // just before the mouseReleaseEvent and resets the state. This prevents
        // column dragging from working. So this code is disabled under Cocoa.
        d->state = QHeaderViewPrivate::NoState;
        d->firstPressed = d->pressed = -1;
    }
    switch (d->state) {
        case QHeaderViewPrivate::ResizeSection: {
            Q_ASSERT(d->originalSize != -1);
            if (d->cascadingResizing) {
                int delta = d->reverse() ? d->lastPos - pos : pos - d->lastPos;
                int visual = visualIndex(d->section);
                d->cascadingResize(visual, d->headerSectionSize(visual) + delta);
            } else {
                int delta = d->reverse() ? d->firstPos - pos : pos - d->firstPos;
                int newsize = qBound(minimumSectionSize(), d->originalSize + delta, maximumSectionSize());
                resizeSection(d->section, newsize);
            }
            d->lastPos = pos;
            return;
        }
        case QHeaderViewPrivate::MoveSection: {
            if (d->shouldAutoScroll(e->position().toPoint())) {
                d->draggedPosition = e->pos() + d->offset();
                d->startAutoScroll();
            }
            if (qAbs(pos - d->firstPos) >= QApplication::startDragDistance()
#if QT_CONFIG(label)
                || !d->sectionIndicator->isHidden()
#endif
                ) {
                int visual = visualIndexAt(pos);
                if (visual == -1)
                    return;
                if (visual == 0 && logicalIndex(0) == 0 && !d->allowUserMoveOfSection0)
                    return;
 
                const int posThreshold = d->headerSectionPosition(visual) - d->headerOffset + d->headerSectionSize(visual) / 2;
                const int checkPos = d->reverse() ? d->viewport->width() - pos : pos;
                int moving = visualIndex(d->section);
                int oldTarget = d->target;
                if (visual < moving) {
                    if (checkPos < posThreshold)
                        d->target = d->logicalIndex(visual);
                    else
                        d->target = d->logicalIndex(visual + 1);
                } else if (visual > moving) {
                    if (checkPos > posThreshold)
                        d->target = d->logicalIndex(visual);
                    else
                        d->target = d->logicalIndex(visual - 1);
                } else {
                    d->target = d->section;
                }
                if (oldTarget != d->target || oldTarget == -1)
                    d->updateSectionsBeforeAfter(d->target);
                d->updateSectionIndicator(d->section, pos);
            }
            return;
        }
        case QHeaderViewPrivate::SelectSections: {
            int logical = logicalIndexAt(qMax(-d->headerOffset, pos));
            if (logical == -1 && pos > 0)
                logical = logicalIndex(d->lastVisibleVisualIndex());
            if (logical == d->pressed)
                return; // nothing to do
            else if (d->pressed != -1)
                updateSection(d->pressed);
            d->pressed = logical;
            if (d->clickableSections && logical != -1) {
                emit sectionEntered(d->pressed);
                updateSection(d->pressed);
            }
            return;
        }
        case QHeaderViewPrivate::NoState: {
#ifndef QT_NO_CURSOR
            int handle = d->sectionHandleAt(pos);
            bool hasCursor = testAttribute(Qt::WA_SetCursor);
            if (handle != -1 && (sectionResizeMode(handle) == Interactive)) {
                if (!hasCursor)
                    setCursor(d->orientation == Qt::Horizontal ? Qt::SplitHCursor : Qt::SplitVCursor);
            } else {
                if (hasCursor)
                    unsetCursor();
#ifndef QT_NO_STATUSTIP
                int logical = logicalIndexAt(pos);
                QString statusTip;
                if (logical != -1)
                    statusTip = d->model->headerData(logical, d->orientation, Qt::StatusTipRole).toString();
                if (d->shouldClearStatusTip || !statusTip.isEmpty()) {
                    QStatusTipEvent tip(statusTip);
                    QCoreApplication::sendEvent(d->parent ? d->parent : this, &tip);
                    d->shouldClearStatusTip = !statusTip.isEmpty();
                }
#endif // !QT_NO_STATUSTIP
            }
#endif
            return;
        }
        default:
            break;
    }
}
 
void QHeaderView::mouseReleaseEvent(QMouseEvent *e)
{
    Q_D(QHeaderView);
    int pos = d->orientation == Qt::Horizontal ? e->position().toPoint().x() : e->position().toPoint().y();
    switch (d->state) {
    case QHeaderViewPrivate::MoveSection:
        if (true
#if QT_CONFIG(label)
            && !d->sectionIndicator->isHidden()
#endif
      ) { // moving
            int from = visualIndex(d->section);
            Q_ASSERT(from != -1);
            int to = visualIndex(d->target);
            Q_ASSERT(to != -1);
            moveSection(from, to);
            d->section = d->target = -1;
            d->updateSectionIndicator(d->section, pos);
            if (from == to)
                d->updateSectionsBeforeAfter(from);
            break;
        } // not moving
        Q_FALLTHROUGH();
    case QHeaderViewPrivate::SelectSections:
        if (!d->clickableSections) {
            int section = logicalIndexAt(pos);
            updateSection(section);
        }
        Q_FALLTHROUGH();
    case QHeaderViewPrivate::NoState:
        if (d->clickableSections) {
            int section = logicalIndexAt(pos);
            if (section != -1 && section == d->firstPressed) {
                QRect firstPressedSectionRect;
                switch (d->orientation) {
                case Qt::Horizontal:
                    firstPressedSectionRect.setRect(sectionViewportPosition(d->firstPressed),
                                                    0,
                                                    sectionSize(d->firstPressed),
                                                    d->viewport->height());
                    break;
                case Qt::Vertical:
                    firstPressedSectionRect.setRect(0,
                                                    sectionViewportPosition(d->firstPressed),
                                                    d->viewport->width(),
                                                    sectionSize(d->firstPressed));
                    break;
                };
 
                if (firstPressedSectionRect.contains(e->position().toPoint())) {
                    d->flipSortIndicator(section);
                    emit sectionClicked(section);
                }
            }
            if (d->pressed != -1)
                updateSection(d->pressed);
        }
        break;
    case QHeaderViewPrivate::ResizeSection:
        d->originalSize = -1;
        d->clearCascadingSections();
        break;
    default:
        break;
    }
    d->state = QHeaderViewPrivate::NoState;
    d->firstPressed = d->pressed = -1;
}
 
void QHeaderView::mouseDoubleClickEvent(QMouseEvent *e)
{
    Q_D(QHeaderView);
    int pos = d->orientation == Qt::Horizontal ? e->position().toPoint().x() : e->position().toPoint().y();
    int handle = d->sectionHandleAt(pos);
    if (handle > -1 && sectionResizeMode(handle) == Interactive) {
        emit sectionHandleDoubleClicked(handle);
#ifndef QT_NO_CURSOR
        Qt::CursorShape splitCursor = (d->orientation == Qt::Horizontal)
                                      ? Qt::SplitHCursor : Qt::SplitVCursor;
        if (cursor().shape() == splitCursor) {
            // signal handlers may have changed the section size
            handle = d->sectionHandleAt(pos);
            if (!(handle > -1 && sectionResizeMode(handle) == Interactive))
                setCursor(Qt::ArrowCursor);
        }
#endif
    } else {
        emit sectionDoubleClicked(logicalIndexAt(e->position().toPoint()));
    }
}
 
bool QHeaderView::viewportEvent(QEvent *e)
{
    Q_D(QHeaderView);
    switch (e->type()) {
#if QT_CONFIG(tooltip)
    case QEvent::ToolTip: {
        QHelpEvent *he = static_cast<QHelpEvent*>(e);
        int logical = logicalIndexAt(he->pos());
        if (logical != -1) {
            QVariant variant = d->model->headerData(logical, d->orientation, Qt::ToolTipRole);
            if (variant.isValid()) {
                QToolTip::showText(he->globalPos(), variant.toString(), this);
                return true;
            }
        }
        break; }
#endif
#if QT_CONFIG(whatsthis)
    case QEvent::QueryWhatsThis: {
        QHelpEvent *he = static_cast<QHelpEvent*>(e);
        int logical = logicalIndexAt(he->pos());
        if (logical != -1
            && d->model->headerData(logical, d->orientation, Qt::WhatsThisRole).isValid())
            return true;
        break; }
    case QEvent::WhatsThis: {
        QHelpEvent *he = static_cast<QHelpEvent*>(e);
        int logical = logicalIndexAt(he->pos());
        if (logical != -1) {
             QVariant whatsthis = d->model->headerData(logical, d->orientation,
                                                      Qt::WhatsThisRole);
             if (whatsthis.isValid()) {
                 QWhatsThis::showText(he->globalPos(), whatsthis.toString(), this);
                 return true;
             }
        }
        break; }
#endif // QT_CONFIG(whatsthis)
#if QT_CONFIG(statustip)
    case QEvent::StatusTip: {
        QHelpEvent *he = static_cast<QHelpEvent*>(e);
        int logical = logicalIndexAt(he->pos());
        if (logical != -1) {
            QString statustip = d->model->headerData(logical, d->orientation,
                                                    Qt::StatusTipRole).toString();
            if (!statustip.isEmpty())
                setStatusTip(statustip);
        }
        return true; }
#endif // QT_CONFIG(statustip)
    case QEvent::Resize:
    case QEvent::FontChange:
    case QEvent::StyleChange:
        d->invalidateCachedSizeHint();
        Q_FALLTHROUGH();
    case QEvent::Hide:
    case QEvent::Show: {
        QAbstractScrollArea *parent = qobject_cast<QAbstractScrollArea *>(parentWidget());
        if (parent && parent->isVisible()) // Only resize if we have a visible parent
            resizeSections();
        emit geometriesChanged();
        break;}
    case QEvent::ContextMenu: {
        d->state = QHeaderViewPrivate::NoState;
        d->pressed = d->section = d->target = -1;
        d->updateSectionIndicator(d->section, -1);
        break; }
    case QEvent::Wheel: {
        QAbstractScrollArea *asa = qobject_cast<QAbstractScrollArea *>(parentWidget());
        if (asa)
            return QCoreApplication::sendEvent(asa->viewport(), e);
        break; }
    default:
        break;
    }
    return QAbstractItemView::viewportEvent(e);
}
 
void QHeaderView::initStyleOptionForIndex(QStyleOptionHeader *option, int logicalIndex) const
{
    Q_D(const QHeaderView);
 
    if (!option)
        return;
    QStyleOptionHeader &opt = *option;
    QStyleOptionHeaderV2 *optV2 = qstyleoption_cast<QStyleOptionHeaderV2*>(option);
 
    QStyle::State state = QStyle::State_None;
    if (window()->isActiveWindow())
        state |= QStyle::State_Active;
    if (d->clickableSections) {
        if (logicalIndex == d->hover)
            state |= QStyle::State_MouseOver;
        if (logicalIndex == d->pressed)
            state |= QStyle::State_Sunken;
        else if (d->highlightSelected) {
            if (d->sectionIntersectsSelection(logicalIndex))
                state |= QStyle::State_On;
            if (d->isSectionSelected(logicalIndex))
                state |= QStyle::State_Sunken;
        }
    }
    if (isSortIndicatorShown() && sortIndicatorSection() == logicalIndex)
        opt.sortIndicator = (sortIndicatorOrder() == Qt::AscendingOrder)
                            ? QStyleOptionHeader::SortDown : QStyleOptionHeader::SortUp;
 
    // setup the style options structure
    QVariant textAlignment = d->model->headerData(logicalIndex, d->orientation,
                                                  Qt::TextAlignmentRole);
    opt.section = logicalIndex;
    opt.state |= state;
    opt.textAlignment = textAlignment.isValid()
                        ? QtPrivate::legacyFlagValueFromModelData<Qt::Alignment>(textAlignment)
                        : d->defaultAlignment;
 
    opt.iconAlignment = Qt::AlignVCenter;
    opt.text = d->model->headerData(logicalIndex, d->orientation,
                                    Qt::DisplayRole).toString();
 
    const QVariant variant = d->model->headerData(logicalIndex, d->orientation,
                                                  Qt::DecorationRole);
    opt.icon = qvariant_cast<QIcon>(variant);
    if (opt.icon.isNull())
        opt.icon = qvariant_cast<QPixmap>(variant);
 
    QVariant var = d->model->headerData(logicalIndex, d->orientation,
                                        Qt::FontRole);
    if (var.isValid() && var.canConvert<QFont>())
        opt.fontMetrics = QFontMetrics(qvariant_cast<QFont>(var));
    if (optV2)
        optV2->textElideMode = d->textElideMode;
 
    QVariant foregroundBrush = d->model->headerData(logicalIndex, d->orientation,
                                                    Qt::ForegroundRole);
    if (foregroundBrush.canConvert<QBrush>())
        opt.palette.setBrush(QPalette::ButtonText, qvariant_cast<QBrush>(foregroundBrush));
 
    QVariant backgroundBrush = d->model->headerData(logicalIndex, d->orientation,
                                                    Qt::BackgroundRole);
    if (backgroundBrush.canConvert<QBrush>()) {
        opt.palette.setBrush(QPalette::Button, qvariant_cast<QBrush>(backgroundBrush));
        opt.palette.setBrush(QPalette::Window, qvariant_cast<QBrush>(backgroundBrush));
    }
 
    // the section position
    int visual = visualIndex(logicalIndex);
    Q_ASSERT(visual != -1);
    bool first = d->isFirstVisibleSection(visual);
    bool last = d->isLastVisibleSection(visual);
    if (first && last)
        opt.position = QStyleOptionHeader::OnlyOneSection;
    else if (first)
        opt.position = d->reverse() ? QStyleOptionHeader::End : QStyleOptionHeader::Beginning;
    else if (last)
        opt.position = d->reverse() ? QStyleOptionHeader::Beginning : QStyleOptionHeader::End;
    else
        opt.position = QStyleOptionHeader::Middle;
    opt.orientation = d->orientation;
    // the selected position
    bool previousSelected = d->isSectionSelected(this->logicalIndex(visual - 1));
    bool nextSelected =  d->isSectionSelected(this->logicalIndex(visual + 1));
    if (previousSelected && nextSelected)
        opt.selectedPosition = QStyleOptionHeader::NextAndPreviousAreSelected;
    else if (previousSelected)
        opt.selectedPosition = QStyleOptionHeader::PreviousIsSelected;
    else if (nextSelected)
        opt.selectedPosition = QStyleOptionHeader::NextIsSelected;
    else
        opt.selectedPosition = QStyleOptionHeader::NotAdjacent;
    if (optV2)
        optV2->isSectionDragTarget = d->target == logicalIndex;
}
 
void QHeaderView::paintSection(QPainter *painter, const QRect &rect, int logicalIndex) const
{
    if (!rect.isValid())
        return;
 
    QStyleOptionHeaderV2 opt;
    QPointF oldBO = painter->brushOrigin();
 
    initStyleOption(&opt);
 
    QBrush oBrushButton = opt.palette.brush(QPalette::Button);
    QBrush oBrushWindow = opt.palette.brush(QPalette::Window);
 
    initStyleOptionForIndex(&opt, logicalIndex);
    // We set rect here. If it needs to be changed it can be changed by overriding this function
    opt.rect = rect;
 
    QBrush nBrushButton = opt.palette.brush(QPalette::Button);
    QBrush nBrushWindow = opt.palette.brush(QPalette::Window);
 
    // If relevant brushes are not the same as from the regular widgets we set the brush origin
    if (oBrushButton != nBrushButton || oBrushWindow != nBrushWindow) {
        painter->setBrushOrigin(opt.rect.topLeft());
    }
 
    // draw the section.
    style()->drawControl(QStyle::CE_Header, &opt, painter, this);
    painter->setBrushOrigin(oldBO);
}
 
QSize QHeaderView::sectionSizeFromContents(int logicalIndex) const
{
    Q_D(const QHeaderView);
    Q_ASSERT(logicalIndex >= 0);
 
    ensurePolished();
 
    // use SizeHintRole
    QVariant variant = d->model->headerData(logicalIndex, d->orientation, Qt::SizeHintRole);
    if (variant.isValid())
        return qvariant_cast<QSize>(variant);
 
    // otherwise use the contents
    QStyleOptionHeaderV2 opt;
    initStyleOption(&opt);
    opt.section = logicalIndex;
    QVariant var = d->model->headerData(logicalIndex, d->orientation,
                                            Qt::FontRole);
    QFont fnt;
    if (var.isValid() && var.canConvert<QFont>())
        fnt = qvariant_cast<QFont>(var);
    else
        fnt = font();
    fnt.setBold(true);
    opt.fontMetrics = QFontMetrics(fnt);
    opt.text = d->model->headerData(logicalIndex, d->orientation,
                                    Qt::DisplayRole).toString();
    variant = d->model->headerData(logicalIndex, d->orientation, Qt::DecorationRole);
    opt.icon = qvariant_cast<QIcon>(variant);
    if (opt.icon.isNull())
        opt.icon = qvariant_cast<QPixmap>(variant);
    if (isSortIndicatorShown())
        opt.sortIndicator = QStyleOptionHeader::SortDown;
    return style()->sizeFromContents(QStyle::CT_HeaderSection, &opt, QSize(), this);
}
 
int QHeaderView::horizontalOffset() const
{
    Q_D(const QHeaderView);
    if (d->orientation == Qt::Horizontal)
        return d->headerOffset;
    return 0;
}
 
int QHeaderView::verticalOffset() const
{
    Q_D(const QHeaderView);
    if (d->orientation == Qt::Vertical)
        return d->headerOffset;
    return 0;
}
 
void QHeaderView::updateGeometries()
{
    Q_D(QHeaderView);
    d->layoutChildren();
    if (d->hasAutoResizeSections())
        d->doDelayedResizeSections();
}
 
void QHeaderView::scrollContentsBy(int dx, int dy)
{
    Q_D(QHeaderView);
    d->scrollDirtyRegion(dx, dy);
}
 
void QHeaderView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight,
                              const QList<int> &roles)
{
    Q_D(QHeaderView);
    if (!roles.isEmpty()) {
        const auto doesRoleAffectSize = [](int role) -> bool {
            switch (role) {
            case Qt::DisplayRole:
            case Qt::DecorationRole:
            case Qt::SizeHintRole:
            case Qt::FontRole:
                return true;
            default:
                // who knows what a subclass or custom style might do
                return role >= Qt::UserRole;
            }
        };
        if (std::none_of(roles.begin(), roles.end(), doesRoleAffectSize))
            return;
    }
    d->invalidateCachedSizeHint();
    if (d->hasAutoResizeSections()) {
        bool resizeRequired = d->globalResizeMode == ResizeToContents;
        int first = orientation() == Qt::Horizontal ? topLeft.column() : topLeft.row();
        int last = orientation() == Qt::Horizontal ? bottomRight.column() : bottomRight.row();
        for (int i = first; i <= last && !resizeRequired; ++i)
            resizeRequired = (sectionResizeMode(i) == ResizeToContents);
        if (resizeRequired)
            d->doDelayedResizeSections();
    }
}
 
void QHeaderView::rowsInserted(const QModelIndex &, int, int)
{
    // do nothing
}
 
QRect QHeaderView::visualRect(const QModelIndex &) const
{
    return QRect();
}
 
void QHeaderView::scrollTo(const QModelIndex &, ScrollHint)
{
    // do nothing - the header only displays sections
}
 
QModelIndex QHeaderView::indexAt(const QPoint &) const
{
    return QModelIndex();
}
 
bool QHeaderView::isIndexHidden(const QModelIndex &) const
{
    return true; // the header view has no items, just sections
}
 
QModelIndex QHeaderView::moveCursor(CursorAction, Qt::KeyboardModifiers)
{
    return QModelIndex();
}
 
void QHeaderView::setSelection(const QRect&, QItemSelectionModel::SelectionFlags)
{
    // do nothing
}
 
QRegion QHeaderView::visualRegionForSelection(const QItemSelection &selection) const
{
    Q_D(const QHeaderView);
    const int max = d->modelSectionCount();
 
    if (d->orientation == Qt::Horizontal) {
        int logicalLeft = max;
        int logicalRight = 0;
 
        if (d->visualIndices.empty()) {
            // If no reordered sections, skip redundant visual-to-logical transformations
            for (const auto &r : selection) {
                if (r.parent().isValid() || !r.isValid())
                    continue; // we only know about toplevel items and we don't want invalid ranges
                if (r.left() < logicalLeft)
                    logicalLeft = r.left();
                if (r.right() > logicalRight)
                    logicalRight = r.right();
            }
        } else {
            int left = max;
            int right = 0;
            for (const auto &r : selection) {
                if (r.parent().isValid() || !r.isValid())
                    continue; // we only know about toplevel items and we don't want invalid ranges
                for (int k = r.left(); k <= r.right(); ++k) {
                    int visual = visualIndex(k);
                    if (visual == -1)   // in some cases users may change the selections
                        continue;       // before we have a chance to do the layout
                    if (visual < left)
                        left = visual;
                    if (visual > right)
                        right = visual;
                }
            }
            logicalLeft = logicalIndex(left);
            logicalRight = logicalIndex(right);
        }
 
        if (logicalLeft < 0  || logicalLeft >= count() ||
            logicalRight < 0 || logicalRight >= count())
            return QRegion();
 
        int leftPos = sectionViewportPosition(logicalLeft);
        int rightPos = sectionViewportPosition(logicalRight);
        rightPos += sectionSize(logicalRight);
        return QRect(leftPos, 0, rightPos - leftPos, height());
    }
    // orientation() == Qt::Vertical
    int logicalTop = max;
    int logicalBottom = 0;
 
    if (d->visualIndices.empty()) {
        // If no reordered sections, skip redundant visual-to-logical transformations
        for (const auto &r : selection) {
            if (r.parent().isValid() || !r.isValid())
                continue; // we only know about toplevel items and we don't want invalid ranges
            if (r.top() < logicalTop)
                logicalTop = r.top();
            if (r.bottom() > logicalBottom)
                logicalBottom = r.bottom();
        }
    } else {
        int top = max;
        int bottom = 0;
 
        for (const auto &r : selection) {
            if (r.parent().isValid() || !r.isValid())
                continue; // we only know about toplevel items and we don't want invalid ranges
            for (int k = r.top(); k <= r.bottom(); ++k) {
                int visual = visualIndex(k);
                if (visual == -1)   // in some cases users may change the selections
                    continue;       // before we have a chance to do the layout
                if (visual < top)
                    top = visual;
                if (visual > bottom)
                    bottom = visual;
            }
        }
 
        logicalTop = logicalIndex(top);
        logicalBottom = logicalIndex(bottom);
    }
 
    if (logicalTop < 0 || logicalTop >= count() ||
        logicalBottom < 0 || logicalBottom >= count())
        return QRegion();
 
    int topPos = sectionViewportPosition(logicalTop);
    int bottomPos = sectionViewportPosition(logicalBottom) + sectionSize(logicalBottom);
 
    return QRect(0, topPos, width(), bottomPos - topPos);
}
 
 
// private implementation
 
int QHeaderViewPrivate::sectionHandleAt(int position)
{
    Q_Q(QHeaderView);
    int visual = q->visualIndexAt(position);
    if (visual == -1)
        return -1;
    int log = logicalIndex(visual);
    int pos = q->sectionViewportPosition(log);
    int grip = q->style()->pixelMetric(QStyle::PM_HeaderGripMargin, nullptr, q);
 
    bool atLeft = position < pos + grip;
    bool atRight = (position > pos + q->sectionSize(log) - grip);
    if (reverse())
        qSwap(atLeft, atRight);
 
    if (atLeft) {
        //grip at the beginning of the section
        while(visual > -1) {
            int logical = q->logicalIndex(--visual);
            if (!q->isSectionHidden(logical))
                return logical;
        }
    } else if (atRight) {
        //grip at the end of the section
        return log;
    }
    return -1;
}
 
void QHeaderViewPrivate::setupSectionIndicator(int section, int position)
{
    Q_Q(QHeaderView);
#if QT_CONFIG(label)
    if (!sectionIndicator) {
        sectionIndicator = new QLabel(viewport);
    }
#endif
 
    int w, h;
    int p = q->sectionViewportPosition(section);
    if (orientation == Qt::Horizontal) {
        w = q->sectionSize(section);
        h = viewport->height();
    } else {
        w = viewport->width();
        h = q->sectionSize(section);
    }
#if QT_CONFIG(label)
    sectionIndicator->resize(w, h);
#endif
 
    const qreal pixmapDevicePixelRatio = q->devicePixelRatio();
    QPixmap pm(QSize(w, h) * pixmapDevicePixelRatio);
    pm.setDevicePixelRatio(pixmapDevicePixelRatio);
    pm.fill(QColor(0, 0, 0, 45));
    QRect rect(0, 0, w, h);
 
    QPainter painter(&pm);
    const QVariant variant = model->headerData(section, orientation,
                                               Qt::FontRole);
    if (variant.isValid() && variant.canConvert<QFont>()) {
        const QFont sectionFont = qvariant_cast<QFont>(variant);
        painter.setFont(sectionFont);
    } else {
        painter.setFont(q->font());
    }
 
    painter.setOpacity(0.75);
    q->paintSection(&painter, rect, section);
    painter.end();
 
#if QT_CONFIG(label)
    sectionIndicator->setPixmap(pm);
#endif
    sectionIndicatorOffset = position - qMax(p, 0);
}
 
void QHeaderViewPrivate::updateSectionIndicator(int section, int position)
{
#if QT_CONFIG(label)
    if (!sectionIndicator)
        return;
 
    if (section == -1 || target == -1) {
        sectionIndicator->hide();
        return;
    }
 
    if (orientation == Qt::Horizontal)
        sectionIndicator->move(position - sectionIndicatorOffset, 0);
    else
        sectionIndicator->move(0, position - sectionIndicatorOffset);
 
    sectionIndicator->show();
#endif
}
 
void QHeaderView::initStyleOption(QStyleOptionHeader *option) const
{
    Q_D(const QHeaderView);
    option->initFrom(this);
    option->state = QStyle::State_None | QStyle::State_Raised;
    option->orientation = d->orientation;
    if (d->orientation == Qt::Horizontal)
        option->state |= QStyle::State_Horizontal;
    if (isEnabled())
        option->state |= QStyle::State_Enabled;
    option->section = 0;
}
 
void QHeaderView::initStyleOption(QStyleOptionFrame *option) const
{
    // The QFrame version is only here to avoid compiler warnings.
    // If invoked we just pass it on to the base class.
    QFrame::initStyleOption(option);
}
 
bool QHeaderViewPrivate::isSectionSelected(int section) const
{
    int i = section * 2;
    if (i < 0 || i >= sectionSelected.size())
        return false;
    if (sectionSelected.testBit(i)) // if the value was cached
        return sectionSelected.testBit(i + 1);
    bool s = false;
    if (orientation == Qt::Horizontal)
        s = isColumnSelected(section);
    else
        s = isRowSelected(section);
    sectionSelected.setBit(i + 1, s); // selection state
    sectionSelected.setBit(i, true); // cache state
    return s;
}
 
bool QHeaderViewPrivate::isFirstVisibleSection(int section) const
{
    if (sectionStartposRecalc)
        recalcSectionStartPos();
    const SectionItem &item = sectionItems.at(section);
    return item.size > 0 && item.calculated_startpos == 0;
}
 
bool QHeaderViewPrivate::isLastVisibleSection(int section) const
{
    if (sectionStartposRecalc)
        recalcSectionStartPos();
    const SectionItem &item = sectionItems.at(section);
    return item.size > 0 && item.calculatedEndPos() == length;
}
 
int QHeaderViewPrivate::lastVisibleVisualIndex() const
{
    Q_Q(const QHeaderView);
    for (int visual = q->count()-1; visual >= 0; --visual) {
        if (!q->isSectionHidden(q->logicalIndex(visual)))
            return visual;
    }
 
    //default value if no section is actually visible
    return -1;
}
 
void QHeaderViewPrivate::restoreSizeOnPrevLastSection()
{
    Q_Q(QHeaderView);
    if (lastSectionLogicalIdx < 0)
        return;
    int resizeLogIdx = lastSectionLogicalIdx;
    lastSectionLogicalIdx = -1; // We do not want resize to catch it as the last section.
    q->resizeSection(resizeLogIdx, lastSectionSize);
}
 
void QHeaderViewPrivate::setNewLastSection(int visualIndexForLastSection)
{
    Q_Q(QHeaderView);
    lastSectionSize = -1;
    lastSectionLogicalIdx = q->logicalIndex(visualIndexForLastSection);
    lastSectionSize = headerSectionSize(visualIndexForLastSection); // pick size directly since ...
    //  q->sectionSize(lastSectionLogicalIdx) may do delayed resize and stretch it before we get the value.
}
 
void QHeaderViewPrivate::maybeRestorePrevLastSectionAndStretchLast()
{
    Q_Q(const QHeaderView);
    if (!q->stretchLastSection())
        return;
 
    int nowLastVisualSection = lastVisibleVisualIndex();
    if (lastSectionLogicalIdx == q->logicalIndex(nowLastVisualSection))
        return;
 
    // restore old last section.
    restoreSizeOnPrevLastSection();
    setNewLastSection(nowLastVisualSection);
    doDelayedResizeSections(); // Do stretch of last section soon (but not now).
}
 
 
void QHeaderViewPrivate::resizeSections(QHeaderView::ResizeMode globalMode, bool useGlobalMode)
{
    Q_Q(QHeaderView);
    //stop the timer in case it is delayed
    delayedResize.stop();
 
    executePostedLayout();
    if (sectionCount() == 0)
        return;
 
    if (resizeRecursionBlock)
        return;
    resizeRecursionBlock = true;
 
    invalidateCachedSizeHint();
    const int lastSectionVisualIdx = q->visualIndex(lastSectionLogicalIdx);
 
    // find stretchLastSection if we have it
    int stretchSection = -1;
    if (stretchLastSection && !useGlobalMode)
        stretchSection = lastSectionVisualIdx;
 
    // count up the number of stretched sections and how much space left for them
    int lengthToStretch = (orientation == Qt::Horizontal ? viewport->width() : viewport->height());
    int numberOfStretchedSections = 0;
    QList<int> section_sizes;
    for (int i = 0; i < sectionCount(); ++i) {
        if (isVisualIndexHidden(i))
            continue;
 
        QHeaderView::ResizeMode resizeMode;
        if (useGlobalMode && (i != stretchSection))
            resizeMode = globalMode;
        else
            resizeMode = (i == stretchSection ? QHeaderView::Stretch : headerSectionResizeMode(i));
 
        if (resizeMode == QHeaderView::Stretch) {
            ++numberOfStretchedSections;
            section_sizes.append(headerSectionSize(i));
            continue;
        }
 
        // because it isn't stretch, determine its width and remove that from lengthToStretch
        int sectionSize = 0;
        if (resizeMode == QHeaderView::Interactive || resizeMode == QHeaderView::Fixed) {
            sectionSize = qBound(q->minimumSectionSize(), headerSectionSize(i), q->maximumSectionSize());
        } else { // resizeMode == QHeaderView::ResizeToContents
            int logicalIndex = q->logicalIndex(i);
            sectionSize = qMax(viewSectionSizeHint(logicalIndex),
                               q->sectionSizeHint(logicalIndex));
        }
        sectionSize = qBound(q->minimumSectionSize(),
                             sectionSize,
                             q->maximumSectionSize());
 
        section_sizes.append(sectionSize);
        lengthToStretch -= sectionSize;
    }
 
    // calculate the new length for all of the stretched sections
    int stretchSectionLength = -1;
    int pixelReminder = 0;
    if (numberOfStretchedSections > 0 && lengthToStretch > 0) { // we have room to stretch in
        int hintLengthForEveryStretchedSection = lengthToStretch / numberOfStretchedSections;
        stretchSectionLength = qMax(hintLengthForEveryStretchedSection, q->minimumSectionSize());
        pixelReminder = lengthToStretch % numberOfStretchedSections;
    }
 
    // ### The code below would be nicer if it was cleaned up a bit (since spans has been replaced with items)
    int spanStartSection = 0;
    int previousSectionLength = 0;
 
    QHeaderView::ResizeMode previousSectionResizeMode = QHeaderView::Interactive;
 
    // resize each section along the total length
    for (int i = 0; i < sectionCount(); ++i) {
        int oldSectionLength = headerSectionSize(i);
        int newSectionLength = -1;
        QHeaderView::ResizeMode newSectionResizeMode = headerSectionResizeMode(i);
 
        if (isVisualIndexHidden(i)) {
            newSectionLength = 0;
        } else {
            QHeaderView::ResizeMode resizeMode;
            if (useGlobalMode)
                resizeMode = globalMode;
            else
                resizeMode = (i == stretchSection
                              ? QHeaderView::Stretch
                              : newSectionResizeMode);
            if (resizeMode == QHeaderView::Stretch && stretchSectionLength != -1) {
                if (i == lastSectionVisualIdx)
                    newSectionLength = qMax(stretchSectionLength, lastSectionSize);
                else
                    newSectionLength = stretchSectionLength;
                if (pixelReminder > 0) {
                    newSectionLength += 1;
                    --pixelReminder;
                }
                section_sizes.removeFirst();
            } else {
                newSectionLength = section_sizes.takeFirst();
            }
        }
 
        //Q_ASSERT(newSectionLength > 0);
        if ((previousSectionResizeMode != newSectionResizeMode
            || previousSectionLength != newSectionLength) && i > 0) {
            createSectionItems(spanStartSection, i - 1, previousSectionLength, previousSectionResizeMode);
            //Q_ASSERT(headerLength() == length);
            spanStartSection = i;
        }
 
        if (newSectionLength != oldSectionLength)
            emit q->sectionResized(logicalIndex(i), oldSectionLength, newSectionLength);
 
        previousSectionLength = newSectionLength;
        previousSectionResizeMode = newSectionResizeMode;
    }
 
    createSectionItems(spanStartSection, sectionCount() - 1,
                       previousSectionLength, previousSectionResizeMode);
    //Q_ASSERT(headerLength() == length);
    resizeRecursionBlock = false;
    viewport->update();
}
 
void QHeaderViewPrivate::createSectionItems(int start, int end, int sizePerSection, QHeaderView::ResizeMode mode)
{
    if (end >= sectionItems.size()) {
        sectionItems.resize(end + 1);
        sectionStartposRecalc = true;
    }
    SectionItem *sectiondata = sectionItems.data();
    for (int i = start; i <= end; ++i) {
        length += (sizePerSection - sectiondata[i].size);
        sectionStartposRecalc |= (sectiondata[i].size != sizePerSection);
        sectiondata[i].size = sizePerSection;
        sectiondata[i].resizeMode = mode;
    }
}
 
void QHeaderViewPrivate::removeSectionsFromSectionItems(int start, int end)
{
    // remove sections
    sectionStartposRecalc |= (end != sectionItems.size() - 1);
    int removedlength = 0;
    for (int u = start; u <= end; ++u)
        removedlength += sectionItems.at(u).size;
    length -= removedlength;
    sectionItems.remove(start, end - start + 1);
}
 
void QHeaderViewPrivate::clear()
{
    if (state != NoClear) {
        length = 0;
        visualIndices.clear();
        logicalIndices.clear();
        sectionSelected.clear();
        hiddenSectionSize.clear();
        sectionItems.clear();
        lastSectionLogicalIdx = -1;
        invalidateCachedSizeHint();
    }
}
 
static Qt::SortOrder flipOrder(Qt::SortOrder order)
{
    switch (order) {
    case Qt::AscendingOrder:
        return Qt::DescendingOrder;
    case Qt::DescendingOrder:
        return Qt::AscendingOrder;
    };
    Q_UNREACHABLE_RETURN(Qt::AscendingOrder);
};
 
void QHeaderViewPrivate::flipSortIndicator(int section)
{
    Q_Q(QHeaderView);
    Qt::SortOrder sortOrder;
    if (sortIndicatorSection == section) {
        if (sortIndicatorClearable) {
            const Qt::SortOrder defaultSortOrder = defaultSortOrderForSection(section);
            if (sortIndicatorOrder == defaultSortOrder) {
                sortOrder = flipOrder(sortIndicatorOrder);
            } else {
                section = -1;
                sortOrder = Qt::AscendingOrder;
            }
        } else {
            sortOrder = flipOrder(sortIndicatorOrder);
        }
    } else {
        sortOrder = defaultSortOrderForSection(section);
    }
    q->setSortIndicator(section, sortOrder);
}
 
Qt::SortOrder QHeaderViewPrivate::defaultSortOrderForSection(int section) const
{
    const QVariant value = model->headerData(section, orientation, Qt::InitialSortOrderRole);
    if (value.canConvert<int>())
        return static_cast<Qt::SortOrder>(value.toInt());
    return Qt::AscendingOrder;
}
 
void QHeaderViewPrivate::cascadingResize(int visual, int newSize)
{
    Q_Q(QHeaderView);
    const int minimumSize = q->minimumSectionSize();
    const int oldSize = headerSectionSize(visual);
    int delta = newSize - oldSize;
 
    if (delta > 0) { // larger
        bool sectionResized = false;
 
        // restore old section sizes
        for (int i = firstCascadingSection; i < visual; ++i) {
            if (cascadingSectionSize.contains(i)) {
                int currentSectionSize = headerSectionSize(i);
                int originalSectionSize = cascadingSectionSize.value(i);
                if (currentSectionSize < originalSectionSize) {
                    int newSectionSize = currentSectionSize + delta;
                    resizeSectionItem(i, currentSectionSize, newSectionSize);
                    if (newSectionSize >= originalSectionSize && false)
                        cascadingSectionSize.remove(i); // the section is now restored
                    sectionResized = true;
                    break;
                }
            }
 
        }
 
        // resize the section
        if (!sectionResized) {
            newSize = qMax(newSize, minimumSize);
            if (oldSize != newSize)
                resizeSectionItem(visual, oldSize, newSize);
        }
 
        // cascade the section size change
        for (int i = visual + 1; i < sectionCount(); ++i) {
            if (isVisualIndexHidden(i))
                continue;
            if (!sectionIsCascadable(i))
                continue;
            int currentSectionSize = headerSectionSize(i);
            if (currentSectionSize <= minimumSize)
                continue;
            int newSectionSize = qMax(currentSectionSize - delta, minimumSize);
            resizeSectionItem(i, currentSectionSize, newSectionSize);
            saveCascadingSectionSize(i, currentSectionSize);
            delta = delta - (currentSectionSize - newSectionSize);
            if (delta <= 0)
                break;
        }
    } else { // smaller
        bool sectionResized = false;
 
        // restore old section sizes
        for (int i = lastCascadingSection; i > visual; --i) {
            if (!cascadingSectionSize.contains(i))
                continue;
            int currentSectionSize = headerSectionSize(i);
            int originalSectionSize = cascadingSectionSize.value(i);
            if (currentSectionSize >= originalSectionSize)
                continue;
            int newSectionSize = currentSectionSize - delta;
            resizeSectionItem(i, currentSectionSize, newSectionSize);
            if (newSectionSize >= originalSectionSize && false) {
                cascadingSectionSize.remove(i); // the section is now restored
            }
            sectionResized = true;
            break;
        }
 
        // resize the section
        resizeSectionItem(visual, oldSize, qMax(newSize, minimumSize));
 
        // cascade the section size change
        if (delta < 0 && newSize < minimumSize) {
            for (int i = visual - 1; i >= 0; --i) {
                if (isVisualIndexHidden(i))
                    continue;
                if (!sectionIsCascadable(i))
                    continue;
                int sectionSize = headerSectionSize(i);
                if (sectionSize <= minimumSize)
                    continue;
                resizeSectionItem(i, sectionSize, qMax(sectionSize + delta, minimumSize));
                saveCascadingSectionSize(i, sectionSize);
                break;
            }
        }
 
        // let the next section get the space from the resized section
        if (!sectionResized) {
            for (int i = visual + 1; i < sectionCount(); ++i) {
                if (isVisualIndexHidden(i))
                    continue;
                if (!sectionIsCascadable(i))
                    continue;
                int currentSectionSize = headerSectionSize(i);
                int newSectionSize = qMax(currentSectionSize - delta, minimumSize);
                resizeSectionItem(i, currentSectionSize, newSectionSize);
                break;
            }
        }
    }
 
    if (hasAutoResizeSections())
        doDelayedResizeSections();
 
    viewport->update();
}
 
void QHeaderViewPrivate::setDefaultSectionSize(int size)
{
    Q_Q(QHeaderView);
    size = qBound(q->minimumSectionSize(), size, q->maximumSectionSize());
    executePostedLayout();
    invalidateCachedSizeHint();
    defaultSectionSize = size;
    customDefaultSectionSize = true;
    if (state == QHeaderViewPrivate::ResizeSection)
        preventCursorChangeInSetOffset = true;
    for (int i = 0; i < sectionItems.size(); ++i) {
        QHeaderViewPrivate::SectionItem &section = sectionItems[i];
        if (hiddenSectionSize.isEmpty() || !isVisualIndexHidden(i)) { // resize on not hidden.
            const int newSize = size;
            if (newSize != section.size) {
                length += newSize - section.size; //the whole length is changed
                const int oldSectionSize = section.sectionSize();
                section.size = size;
                emit q->sectionResized(logicalIndex(i), oldSectionSize, size);
            }
        }
    }
    sectionStartposRecalc = true;
    if (hasAutoResizeSections())
        doDelayedResizeSections();
    viewport->update();
}
 
void QHeaderViewPrivate::updateDefaultSectionSizeFromStyle()
{
    Q_Q(QHeaderView);
    if (orientation == Qt::Horizontal) {
        defaultSectionSize = q->style()->pixelMetric(QStyle::PM_HeaderDefaultSectionSizeHorizontal, nullptr, q);
    } else {
        defaultSectionSize = qMax(q->minimumSectionSize(),
                                  q->style()->pixelMetric(QStyle::PM_HeaderDefaultSectionSizeVertical, nullptr, q));
    }
}
 
void QHeaderViewPrivate::recalcSectionStartPos() const // linear (but fast)
{
    int pixelpos = 0;
    for (const SectionItem &i : sectionItems) {
        i.calculated_startpos = pixelpos; // write into const mutable
        pixelpos += i.size;
    }
    sectionStartposRecalc = false;
}
 
void QHeaderViewPrivate::resizeSectionItem(int visualIndex, int oldSize, int newSize)
{
    Q_Q(QHeaderView);
    QHeaderView::ResizeMode mode = headerSectionResizeMode(visualIndex);
    createSectionItems(visualIndex, visualIndex, newSize, mode);
    emit q->sectionResized(logicalIndex(visualIndex), oldSize, newSize);
}
 
int QHeaderViewPrivate::headerSectionSize(int visual) const
{
    if (visual < sectionCount() && visual >= 0)
        return sectionItems.at(visual).sectionSize();
    return -1;
}
 
int QHeaderViewPrivate::headerSectionPosition(int visual) const
{
    if (visual < sectionCount() && visual >= 0) {
        if (sectionStartposRecalc)
            recalcSectionStartPos();
        return sectionItems.at(visual).calculated_startpos;
    }
    return -1;
}
 
int QHeaderViewPrivate::headerVisualIndexAt(int position) const
{
    if (sectionStartposRecalc)
        recalcSectionStartPos();
    int startidx = 0;
    int endidx = sectionItems.size() - 1;
    while (startidx <= endidx) {
        int middle = (endidx + startidx) / 2;
        if (sectionItems.at(middle).calculated_startpos > position) {
            endidx = middle - 1;
        } else {
            if (sectionItems.at(middle).calculatedEndPos() <= position)
                startidx = middle + 1;
            else // we found it.
                return middle;
        }
    }
    return -1;
}
 
void QHeaderViewPrivate::setHeaderSectionResizeMode(int visual, QHeaderView::ResizeMode mode)
{
    int size = headerSectionSize(visual);
    createSectionItems(visual, visual, size, mode);
}
 
QHeaderView::ResizeMode QHeaderViewPrivate::headerSectionResizeMode(int visual) const
{
    if (visual < 0 || visual >= sectionItems.size())
        return globalResizeMode;
    return static_cast<QHeaderView::ResizeMode>(sectionItems.at(visual).resizeMode);
}
 
void QHeaderViewPrivate::setGlobalHeaderResizeMode(QHeaderView::ResizeMode mode)
{
    globalResizeMode = mode;
    for (int i = 0; i < sectionItems.size(); ++i)
        sectionItems[i].resizeMode = mode;
}
 
int QHeaderViewPrivate::viewSectionSizeHint(int logical) const
{
    if (QAbstractItemView *view = qobject_cast<QAbstractItemView*>(parent)) {
        return (orientation == Qt::Horizontal
                ? view->sizeHintForColumn(logical)
                : view->sizeHintForRow(logical));
    }
    return 0;
}
 
int QHeaderViewPrivate::adjustedVisualIndex(int visualIndex) const
{
    if (!hiddenSectionSize.isEmpty()) {
        int adjustedVisualIndex = visualIndex;
        int currentVisualIndex = 0;
        for (int i = 0; i < sectionItems.size(); ++i) {
            if (isVisualIndexHidden(i))
                ++adjustedVisualIndex;
            else
                ++currentVisualIndex;
            if (currentVisualIndex >= visualIndex)
                break;
        }
        visualIndex = adjustedVisualIndex;
    }
    return visualIndex;
}
 
void QHeaderViewPrivate::setScrollOffset(const QScrollBar *scrollBar, QAbstractItemView::ScrollMode scrollMode)
{
    Q_Q(QHeaderView);
    if (scrollMode == QAbstractItemView::ScrollPerItem) {
        if (scrollBar->maximum() > 0 && scrollBar->value() == scrollBar->maximum())
            q->setOffsetToLastSection();
        else
            q->setOffsetToSectionPosition(scrollBar->value());
    } else {
        q->setOffset(scrollBar->value());
    }
}
 
void QHeaderViewPrivate::updateSectionsBeforeAfter(int logical)
{
    Q_Q(QHeaderView);
    const int visual = visualIndex(logical);
    int from = logicalIndex(visual > 1 ? visual - 1 : 0);
    int to = logicalIndex(visual + 1 >= sectionCount() ? visual : visual + 1);
    QRect updateRect;
    if (orientation == Qt::Horizontal) {
        if (reverse())
            std::swap(from, to);
        updateRect = QRect(QPoint(q->sectionViewportPosition(from), 0),
                           QPoint(q->sectionViewportPosition(to) + headerSectionSize(to), viewport->height()));
    } else {
        updateRect = QRect(QPoint(0, q->sectionViewportPosition(from)),
                           QPoint(viewport->width(), q->sectionViewportPosition(to) + headerSectionSize(to)));
    }
    viewport->update(updateRect);
}
 
#ifndef QT_NO_DATASTREAM
void QHeaderViewPrivate::write(QDataStream &out) const
{
    out << int(orientation);
    out << int(sortIndicatorOrder);
    out << sortIndicatorSection;
    out << sortIndicatorShown;
 
    out << visualIndices;
    out << logicalIndices;
 
    out << sectionsHiddenToBitVector();
    out << hiddenSectionSize;
 
    out << length;
    out << sectionCount();
    out << movableSections;
    out << clickableSections;
    out << highlightSelected;
    out << stretchLastSection;
    out << cascadingResizing;
    out << stretchSections;
    out << contentsSections;
    out << defaultSectionSize;
    out << minimumSectionSize;
 
    out << int(defaultAlignment);
    out << int(globalResizeMode);
 
    out << sectionItems;
    out << resizeContentsPrecision;
    out << customDefaultSectionSize;
    out << lastSectionSize;
    out << int(sortIndicatorClearable);
}
 
bool QHeaderViewPrivate::read(QDataStream &in)
{
    Q_Q(QHeaderView);
    int orient, order, align, global;
    int sortIndicatorSectionIn;
    bool sortIndicatorShownIn;
    int lengthIn;
    QList<int> visualIndicesIn;
    QList<int> logicalIndicesIn;
    QHash<int, int> hiddenSectionSizeIn;
    bool movableSectionsIn;
    bool clickableSectionsIn;
    bool highlightSelectedIn;
    bool stretchLastSectionIn;
    bool cascadingResizingIn;
    int stretchSectionsIn;
    int contentsSectionsIn;
    int defaultSectionSizeIn;
    int minimumSectionSizeIn;
    QList<SectionItem> sectionItemsIn;
 
    in >> orient;
    in >> order;
 
    in >> sortIndicatorSectionIn;
    in >> sortIndicatorShownIn;
 
    in >> visualIndicesIn;
    in >> logicalIndicesIn;
 
    QBitArray sectionHidden;
    in >> sectionHidden;
    in >> hiddenSectionSizeIn;
    in >> lengthIn;
 
    int unusedSectionCount; // For compatibility
    in >> unusedSectionCount;
 
    if (in.status() != QDataStream::Ok || lengthIn < 0)
        return false;
 
    in >> movableSectionsIn;
    in >> clickableSectionsIn;
    in >> highlightSelectedIn;
    in >> stretchLastSectionIn;
    in >> cascadingResizingIn;
    in >> stretchSectionsIn;
    in >> contentsSectionsIn;
    in >> defaultSectionSizeIn;
    in >> minimumSectionSizeIn;
 
    in >> align;
 
    in >> global;
 
    // Check parameter consistency
    // Global orientation out of bounds?
    if (global < 0 || global > QHeaderView::ResizeToContents)
        return false;
 
    // Alignment out of bounds?
    if (align < 0 || align > Qt::AlignVertical_Mask)
        return false;
 
    in >> sectionItemsIn;
    // In Qt4 we had a vector of spans where one span could hold information on more sections.
    // Now we have an itemvector where one items contains information about one section
    // For backward compatibility with Qt4 we do the following
    QList<SectionItem> newSectionItems;
    for (int u = 0; u < sectionItemsIn.size(); ++u) {
        int count = sectionItemsIn.at(u).tmpDataStreamSectionCount;
        if (count > 1)
            sectionItemsIn[u].size /= count;
        for (int n = 0; n < count; ++n)
            newSectionItems.append(sectionItemsIn[u]);
    }
 
    int sectionItemsLengthTotal = 0;
    for (const SectionItem &section : std::as_const(newSectionItems))
        sectionItemsLengthTotal += section.size;
    if (sectionItemsLengthTotal != lengthIn)
        return false;
 
    const int currentCount = (orient == Qt::Horizontal ? model->columnCount(root) : model->rowCount(root));
    if (newSectionItems.size() < currentCount) {
        // we have sections not in the saved state, give them default settings
        if (!visualIndicesIn.isEmpty() && !logicalIndicesIn.isEmpty()) {
            for (int i = newSectionItems.size(); i < currentCount; ++i) {
                visualIndicesIn.append(i);
                logicalIndicesIn.append(i);
            }
        }
        const int insertCount = currentCount - newSectionItems.size();
        const int insertLength = defaultSectionSizeIn * insertCount;
        lengthIn += insertLength;
        SectionItem section(defaultSectionSizeIn, globalResizeMode);
        newSectionItems.insert(newSectionItems.size(), insertCount, section); // append
    }
 
    orientation = static_cast<Qt::Orientation>(orient);
    sortIndicatorOrder = static_cast<Qt::SortOrder>(order);
    sortIndicatorSection = sortIndicatorSectionIn;
    sortIndicatorShown = sortIndicatorShownIn;
    visualIndices = visualIndicesIn;
    logicalIndices = logicalIndicesIn;
    hiddenSectionSize = hiddenSectionSizeIn;
    length = lengthIn;
 
    movableSections = movableSectionsIn;
    clickableSections = clickableSectionsIn;
    highlightSelected = highlightSelectedIn;
    stretchLastSection = stretchLastSectionIn;
    cascadingResizing = cascadingResizingIn;
    stretchSections = stretchSectionsIn;
    contentsSections = contentsSectionsIn;
    defaultSectionSize = defaultSectionSizeIn;
    minimumSectionSize = minimumSectionSizeIn;
 
    defaultAlignment = Qt::Alignment(align);
    globalResizeMode = static_cast<QHeaderView::ResizeMode>(global);
 
    sectionItems = newSectionItems;
    setHiddenSectionsFromBitVector(sectionHidden);
    recalcSectionStartPos();
 
    int tmpint;
    in >> tmpint;
    if (in.status() == QDataStream::Ok)  // we haven't read past end
        resizeContentsPrecision = tmpint;
 
    bool tmpbool;
    in >> tmpbool;
    if (in.status() == QDataStream::Ok) {  // we haven't read past end
        customDefaultSectionSize = tmpbool;
        if (!customDefaultSectionSize)
            updateDefaultSectionSizeFromStyle();
    }
 
    lastSectionSize = -1;
    int inLastSectionSize;
    in >> inLastSectionSize;
    if (in.status() == QDataStream::Ok)
        lastSectionSize = inLastSectionSize;
 
    lastSectionLogicalIdx = -1;
    if (stretchLastSection) {
        lastSectionLogicalIdx = q->logicalIndex(lastVisibleVisualIndex());
        doDelayedResizeSections();
    }
 
    int inSortIndicatorClearable;
    in >> inSortIndicatorClearable;
    if (in.status() == QDataStream::Ok)  // we haven't read past end
        sortIndicatorClearable = inSortIndicatorClearable;
 
    return true;
}
 
#endif // QT_NO_DATASTREAM
 
QT_END_NAMESPACE
 
#include "moc_qheaderview.cpp"