qtabbar.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 "private/qlayoutengine_p.h"
#if QT_CONFIG(itemviews)
#include "qabstractitemdelegate.h"
#endif
#include "qapplication.h"
#include "qevent.h"
#include "qpainter.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qstylepainter.h"
#if QT_CONFIG(tabwidget)
#include "qtabwidget.h"
#endif
#if QT_CONFIG(tooltip)
#include "qtooltip.h"
#endif
#if QT_CONFIG(whatsthis)
#include "qwhatsthis.h"
#endif
#include "private/qtextengine_p.h"
#if QT_CONFIG(accessibility)
#include "qaccessible.h"
#endif
#ifdef Q_OS_MACOS
#include <qpa/qplatformnativeinterface.h>
#endif
 
#include "qdebug.h"
#include "private/qapplication_p.h"
#include "private/qtabbar_p.h"
 
QT_BEGIN_NAMESPACE
 
using namespace Qt::StringLiterals;
 
namespace {
class CloseButton : public QAbstractButton
{
    Q_OBJECT
 
public:
    explicit CloseButton(QWidget *parent = nullptr);
 
    QSize sizeHint() const override;
    QSize minimumSizeHint() const override
        { return sizeHint(); }
    void enterEvent(QEnterEvent *event) override;
    void leaveEvent(QEvent *event) override;
    void paintEvent(QPaintEvent *event) override;
};
}
 
QMovableTabWidget::QMovableTabWidget(QWidget *parent)
    : QWidget(parent)
{
}
 
void QMovableTabWidget::setPixmap(const QPixmap &pixmap)
{
    m_pixmap = pixmap;
    update();
}
 
void QMovableTabWidget::paintEvent(QPaintEvent *e)
{
    Q_UNUSED(e);
    QPainter p(this);
    p.drawPixmap(0, 0, m_pixmap);
}
 
void QTabBarPrivate::updateMacBorderMetrics()
{
#if defined(Q_OS_MACOS)
    Q_Q(QTabBar);
    // Extend the unified title and toolbar area to cover the tab bar iff
    // 1) the tab bar is in document mode
    // 2) the tab bar is directly below an "unified" area.
    // The extending itself is done in the Cocoa platform plugin and Mac style,
    // this function registers geometry and visibility state for the tab bar.
 
    // Calculate geometry
    int upper, lower;
    if (documentMode) {
        QPoint windowPos = q->mapTo(q->window(), QPoint(0,0));
        upper = windowPos.y();
        int tabStripHeight = q->tabSizeHint(0).height();
        int pixelTweak = -3;
        lower = upper + tabStripHeight + pixelTweak;
    } else {
        upper = 0;
        lower = 0;
    }
 
    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
    if (!nativeInterface)
        return;
    quintptr identifier = reinterpret_cast<quintptr>(q);
 
    // Set geometry
    QPlatformNativeInterface::NativeResourceForIntegrationFunction function =
        nativeInterface->nativeResourceFunctionForIntegration("registerContentBorderArea");
    if (!function)
        return; // Not Cocoa platform plugin.
    typedef void (*RegisterContentBorderAreaFunction)(QWindow *window, quintptr identifier, int upper, int lower);
    (reinterpret_cast<RegisterContentBorderAreaFunction>(function))(q->window()->windowHandle(), identifier, upper, lower);
 
    // Set visibility state
    function = nativeInterface->nativeResourceFunctionForIntegration("setContentBorderAreaEnabled");
    if (!function)
        return;
    typedef void (*SetContentBorderAreaEnabledFunction)(QWindow *window, quintptr identifier, bool enable);
    (reinterpret_cast<SetContentBorderAreaEnabledFunction>(function))(q->window()->windowHandle(), identifier, q->isVisible());
#endif
}
 
void QTabBarPrivate::initBasicStyleOption(QStyleOptionTab *option, int tabIndex) const
{
    Q_Q(const QTabBar);
    const int totalTabs = tabList.size();
 
    if (!option || (tabIndex < 0 || tabIndex >= totalTabs))
        return;
 
    const QTabBarPrivate::Tab &tab = *tabList.at(tabIndex);
    option->initFrom(q);
    option->state &= ~(QStyle::State_HasFocus | QStyle::State_MouseOver);
    option->rect = q->tabRect(tabIndex);
    const bool isCurrent = tabIndex == currentIndex;
    option->row = 0;
    if (tabIndex == pressedIndex)
        option->state |= QStyle::State_Sunken;
    if (isCurrent)
        option->state |= QStyle::State_Selected;
    if (isCurrent && q->hasFocus())
        option->state |= QStyle::State_HasFocus;
    if (!tab.enabled)
        option->state &= ~QStyle::State_Enabled;
    if (q->isActiveWindow())
        option->state |= QStyle::State_Active;
    if (!dragInProgress && option->rect == hoverRect)
        option->state |= QStyle::State_MouseOver;
    option->shape = shape;
    option->text = tab.text;
 
    if (tab.textColor.isValid())
        option->palette.setColor(q->foregroundRole(), tab.textColor);
    option->icon = tab.icon;
    option->iconSize = q->iconSize();  // Will get the default value then.
 
    option->leftButtonSize = tab.leftWidget ? tab.leftWidget->size() : QSize();
    option->rightButtonSize = tab.rightWidget ? tab.rightWidget->size() : QSize();
    option->documentMode = documentMode;
 
    if (tabIndex > 0 && tabIndex - 1 == currentIndex)
        option->selectedPosition = QStyleOptionTab::PreviousIsSelected;
    else if (tabIndex + 1 < totalTabs && tabIndex + 1 == currentIndex)
        option->selectedPosition = QStyleOptionTab::NextIsSelected;
    else
        option->selectedPosition = QStyleOptionTab::NotAdjacent;
 
    const bool paintBeginning = (tabIndex == firstVisible) || (dragInProgress && tabIndex == pressedIndex + 1);
    const bool paintEnd = (tabIndex == lastVisible) || (dragInProgress && tabIndex == pressedIndex - 1);
    if (paintBeginning) {
        if (paintEnd)
            option->position = QStyleOptionTab::OnlyOneTab;
        else
            option->position = QStyleOptionTab::Beginning;
    } else if (paintEnd) {
        option->position = QStyleOptionTab::End;
    } else {
        option->position = QStyleOptionTab::Middle;
    }
 
#if QT_CONFIG(tabwidget)
    if (const QTabWidget *tw = qobject_cast<const QTabWidget *>(q->parentWidget())) {
        option->features |= QStyleOptionTab::HasFrame;
        if (tw->cornerWidget(Qt::TopLeftCorner) || tw->cornerWidget(Qt::BottomLeftCorner))
            option->cornerWidgets |= QStyleOptionTab::LeftCornerWidget;
        if (tw->cornerWidget(Qt::TopRightCorner) || tw->cornerWidget(Qt::BottomRightCorner))
            option->cornerWidgets |= QStyleOptionTab::RightCornerWidget;
    }
#endif
    option->tabIndex = tabIndex;
}
 
void QTabBar::initStyleOption(QStyleOptionTab *option, int tabIndex) const
{
    Q_D(const QTabBar);
    d->initBasicStyleOption(option, tabIndex);
 
    QRect textRect = style()->subElementRect(QStyle::SE_TabBarTabText, option, this);
    option->text = fontMetrics().elidedText(option->text, d->elideMode, textRect.width(),
                        Qt::TextShowMnemonic);
}
 
void QTabBarPrivate::init()
{
    Q_Q(QTabBar);
    leftB = new QToolButton(q);
    leftB->setObjectName(u"ScrollLeftButton"_s);
    leftB->setAutoRepeat(true);
    QObject::connect(leftB, SIGNAL(clicked()), q, SLOT(_q_scrollTabs()));
    leftB->hide();
    rightB = new QToolButton(q);
    rightB->setObjectName(u"ScrollRightButton"_s);
    rightB->setAutoRepeat(true);
    QObject::connect(rightB, SIGNAL(clicked()), q, SLOT(_q_scrollTabs()));
    rightB->hide();
#ifdef QT_KEYPAD_NAVIGATION
    if (QApplicationPrivate::keypadNavigationEnabled()) {
        leftB->setFocusPolicy(Qt::NoFocus);
        rightB->setFocusPolicy(Qt::NoFocus);
        q->setFocusPolicy(Qt::NoFocus);
    } else
#endif
        q->setFocusPolicy(Qt::TabFocus);
 
#if QT_CONFIG(accessibility)
    leftB->setAccessibleName(QTabBar::tr("Scroll Left"));
    rightB->setAccessibleName(QTabBar::tr("Scroll Right"));
#endif
    q->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
    elideMode = Qt::TextElideMode(q->style()->styleHint(QStyle::SH_TabBar_ElideMode, nullptr, q));
    useScrollButtons = !q->style()->styleHint(QStyle::SH_TabBar_PreferNoArrows, nullptr, q);
}
 
int QTabBarPrivate::indexAtPos(const QPoint &p) const
{
    Q_Q(const QTabBar);
    if (q->tabRect(currentIndex).contains(p))
        return currentIndex;
    for (int i = 0; i < tabList.size(); ++i)
        if (tabList.at(i)->enabled && q->tabRect(i).contains(p))
            return i;
    return -1;
}
 
void QTabBarPrivate::layoutTabs()
{
    Q_Q(QTabBar);
    layoutDirty = false;
    QSize size = q->size();
    int last, available;
    int maxExtent;
    bool vertTabs = verticalTabs(shape);
    int tabChainIndex = 0;
    int hiddenTabs = 0;
 
    Qt::Alignment tabAlignment = Qt::Alignment(q->style()->styleHint(QStyle::SH_TabBar_Alignment, nullptr, q));
    QList<QLayoutStruct> tabChain(tabList.size() + 2);
 
    // We put an empty item at the front and back and set its expansive attribute
    // depending on tabAlignment and expanding.
    tabChain[tabChainIndex].init();
    tabChain[tabChainIndex].expansive = (!expanding)
                                        && (tabAlignment != Qt::AlignLeft)
                                        && (tabAlignment != Qt::AlignJustify);
    tabChain[tabChainIndex].empty = true;
    ++tabChainIndex;
 
    // We now go through our list of tabs and set the minimum size and the size hint
    // This will allow us to elide text if necessary. Since we don't set
    // a maximum size, tabs will EXPAND to fill up the empty space.
    // Since tab widget is rather *ahem* strict about keeping the geometry of the
    // tab bar to its absolute minimum, this won't bleed through, but will show up
    // if you use tab bar on its own (a.k.a. not a bug, but a feature).
    // Update: if expanding is false, we DO set a maximum size to prevent the tabs
    // being wider than necessary.
    if (!vertTabs) {
        int minx = 0;
        int x = 0;
        int maxHeight = 0;
        for (int i = 0; i < tabList.size(); ++i) {
            const auto tab = tabList.at(i);
            if (!tab->visible) {
                ++hiddenTabs;
                continue;
            }
            QSize sz = q->tabSizeHint(i);
            tab->maxRect = QRect(x, 0, sz.width(), sz.height());
            x += sz.width();
            maxHeight = qMax(maxHeight, sz.height());
            sz = q->minimumTabSizeHint(i);
            tab->minRect = QRect(minx, 0, sz.width(), sz.height());
            minx += sz.width();
            tabChain[tabChainIndex].init();
            tabChain[tabChainIndex].sizeHint = tab->maxRect.width();
            tabChain[tabChainIndex].minimumSize = sz.width();
            tabChain[tabChainIndex].empty = false;
            tabChain[tabChainIndex].expansive = true;
 
            if (!expanding)
                tabChain[tabChainIndex].maximumSize = tabChain[tabChainIndex].sizeHint;
            ++tabChainIndex;
        }
 
        last = minx;
        available = size.width();
        maxExtent = maxHeight;
    } else {
        int miny = 0;
        int y = 0;
        int maxWidth = 0;
        for (int i = 0; i < tabList.size(); ++i) {
            auto tab = tabList.at(i);
            if (!tab->visible) {
                ++hiddenTabs;
                continue;
            }
            QSize sz = q->tabSizeHint(i);
            tab->maxRect = QRect(0, y, sz.width(), sz.height());
            y += sz.height();
            maxWidth = qMax(maxWidth, sz.width());
            sz = q->minimumTabSizeHint(i);
            tab->minRect = QRect(0, miny, sz.width(), sz.height());
            miny += sz.height();
            tabChain[tabChainIndex].init();
            tabChain[tabChainIndex].sizeHint = tab->maxRect.height();
            tabChain[tabChainIndex].minimumSize = sz.height();
            tabChain[tabChainIndex].empty = false;
            tabChain[tabChainIndex].expansive = true;
 
            if (!expanding)
                tabChain[tabChainIndex].maximumSize = tabChain[tabChainIndex].sizeHint;
            ++tabChainIndex;
        }
 
        last = miny;
        available = size.height();
        maxExtent = maxWidth;
    }
 
    // Mirror our front item.
    tabChain[tabChainIndex].init();
    tabChain[tabChainIndex].expansive = (!expanding)
                                        && (tabAlignment != Qt::AlignRight)
                                        && (tabAlignment != Qt::AlignJustify);
    tabChain[tabChainIndex].empty = true;
    Q_ASSERT(tabChainIndex == tabChain.size() - 1 - hiddenTabs); // add an assert just to make sure.
 
    // Do the calculation
    qGeomCalc(tabChain, 0, tabChain.size(), 0, qMax(available, last), 0);
 
    // Use the results
    hiddenTabs = 0;
    for (int i = 0; i < tabList.size(); ++i) {
        auto tab = tabList.at(i);
        if (!tab->visible) {
            tab->rect = QRect();
            ++hiddenTabs;
            continue;
        }
        const QLayoutStruct &lstruct = tabChain.at(i + 1 - hiddenTabs);
        if (!vertTabs)
            tab->rect.setRect(lstruct.pos, 0, lstruct.size, maxExtent);
        else
            tab->rect.setRect(0, lstruct.pos, maxExtent, lstruct.size);
    }
 
    if (useScrollButtons && tabList.size() && last > available) {
        const QRect scrollRect = normalizedScrollRect(0);
 
        Q_Q(QTabBar);
        QStyleOption opt;
        opt.initFrom(q);
        QRect scrollButtonLeftRect = q->style()->subElementRect(QStyle::SE_TabBarScrollLeftButton, &opt, q);
        QRect scrollButtonRightRect = q->style()->subElementRect(QStyle::SE_TabBarScrollRightButton, &opt, q);
        int scrollButtonWidth = q->style()->pixelMetric(QStyle::PM_TabBarScrollButtonWidth, &opt, q);
 
        // Normally SE_TabBarScrollLeftButton should have the same width as PM_TabBarScrollButtonWidth.
        // But if that is not the case, we set the actual button width to PM_TabBarScrollButtonWidth, and
        // use the extra space from SE_TabBarScrollLeftButton as margins towards the tabs.
        if (vertTabs) {
            scrollButtonLeftRect.setHeight(scrollButtonWidth);
            scrollButtonRightRect.setY(scrollButtonRightRect.bottom() + 1 - scrollButtonWidth);
            scrollButtonRightRect.setHeight(scrollButtonWidth);
            leftB->setArrowType(Qt::UpArrow);
            rightB->setArrowType(Qt::DownArrow);
        } else if (q->layoutDirection() == Qt::RightToLeft) {
            scrollButtonRightRect.setWidth(scrollButtonWidth);
            scrollButtonLeftRect.setX(scrollButtonLeftRect.right() + 1 - scrollButtonWidth);
            scrollButtonLeftRect.setWidth(scrollButtonWidth);
            leftB->setArrowType(Qt::RightArrow);
            rightB->setArrowType(Qt::LeftArrow);
        } else {
            scrollButtonLeftRect.setWidth(scrollButtonWidth);
            scrollButtonRightRect.setX(scrollButtonRightRect.right() + 1 - scrollButtonWidth);
            scrollButtonRightRect.setWidth(scrollButtonWidth);
            leftB->setArrowType(Qt::LeftArrow);
            rightB->setArrowType(Qt::RightArrow);
        }
 
        leftB->setGeometry(scrollButtonLeftRect);
        leftB->setEnabled(false);
        leftB->show();
 
        rightB->setGeometry(scrollButtonRightRect);
        rightB->setEnabled(last + scrollRect.left() > scrollRect.x() + scrollRect.width());
        rightB->show();
    } else {
        rightB->hide();
        leftB->hide();
    }
 
    layoutWidgets();
    q->tabLayoutChange();
}
 
QRect QTabBarPrivate::normalizedScrollRect(int index)
{
    // "Normalized scroll rect" means return the free space on the tab bar
    // that doesn't overlap with scroll buttons or tear indicators, and
    // always return the rect as horizontal Qt::LeftToRight, even if the
    // tab bar itself is in a different orientation.
 
    Q_Q(QTabBar);
    // If scrollbuttons are not visible, then there's no tear either, and
    // the entire widget is the scroll rect.
    if (leftB->isHidden())
        return verticalTabs(shape) ? q->rect().transposed() : q->rect();
 
    QStyleOptionTab opt;
    q->initStyleOption(&opt, currentIndex);
    opt.rect = q->rect();
 
    QRect scrollButtonLeftRect = q->style()->subElementRect(QStyle::SE_TabBarScrollLeftButton, &opt, q);
    QRect scrollButtonRightRect = q->style()->subElementRect(QStyle::SE_TabBarScrollRightButton, &opt, q);
    QRect tearLeftRect = q->style()->subElementRect(QStyle::SE_TabBarTearIndicatorLeft, &opt, q);
    QRect tearRightRect = q->style()->subElementRect(QStyle::SE_TabBarTearIndicatorRight, &opt, q);
 
    if (verticalTabs(shape)) {
        int topEdge, bottomEdge;
        bool leftButtonIsOnTop = scrollButtonLeftRect.y() < q->height() / 2;
        bool rightButtonIsOnTop = scrollButtonRightRect.y() < q->height() / 2;
 
        if (leftButtonIsOnTop && rightButtonIsOnTop) {
            topEdge = scrollButtonRightRect.bottom() + 1;
            bottomEdge = q->height();
        } else if (!leftButtonIsOnTop && !rightButtonIsOnTop) {
            topEdge = 0;
            bottomEdge = scrollButtonLeftRect.top();
        } else {
            topEdge = scrollButtonLeftRect.bottom() + 1;
            bottomEdge = scrollButtonRightRect.top();
        }
 
        bool tearTopVisible = index != 0 && topEdge != -scrollOffset;
        bool tearBottomVisible = index != tabList.size() - 1 && bottomEdge != tabList.constLast()->rect.bottom() + 1 - scrollOffset;
        if (tearTopVisible && !tearLeftRect.isNull())
            topEdge = tearLeftRect.bottom() + 1;
        if (tearBottomVisible && !tearRightRect.isNull())
            bottomEdge = tearRightRect.top();
 
        return QRect(topEdge, 0, bottomEdge - topEdge, q->height());
    } else {
        if (q->layoutDirection() == Qt::RightToLeft) {
            scrollButtonLeftRect = QStyle::visualRect(Qt::RightToLeft, q->rect(), scrollButtonLeftRect);
            scrollButtonRightRect = QStyle::visualRect(Qt::RightToLeft, q->rect(), scrollButtonRightRect);
            tearLeftRect = QStyle::visualRect(Qt::RightToLeft, q->rect(), tearLeftRect);
            tearRightRect = QStyle::visualRect(Qt::RightToLeft, q->rect(), tearRightRect);
        }
 
        int leftEdge, rightEdge;
        bool leftButtonIsOnLeftSide = scrollButtonLeftRect.x() < q->width() / 2;
        bool rightButtonIsOnLeftSide = scrollButtonRightRect.x() < q->width() / 2;
 
        if (leftButtonIsOnLeftSide && rightButtonIsOnLeftSide) {
            leftEdge = scrollButtonRightRect.right() + 1;
            rightEdge = q->width();
        } else if (!leftButtonIsOnLeftSide && !rightButtonIsOnLeftSide) {
            leftEdge = 0;
            rightEdge = scrollButtonLeftRect.left();
        } else {
            leftEdge = scrollButtonLeftRect.right() + 1;
            rightEdge = scrollButtonRightRect.left();
        }
 
        bool tearLeftVisible = index != 0 && leftEdge != -scrollOffset;
        bool tearRightVisible = index != tabList.size() - 1 && rightEdge != tabList.constLast()->rect.right() + 1 - scrollOffset;
        if (tearLeftVisible && !tearLeftRect.isNull())
            leftEdge = tearLeftRect.right() + 1;
        if (tearRightVisible && !tearRightRect.isNull())
            rightEdge = tearRightRect.left();
 
        return QRect(leftEdge, 0, rightEdge - leftEdge, q->height());
    }
}
 
int QTabBarPrivate::hoveredTabIndex() const
{
    if (dragInProgress)
        return currentIndex;
    if (hoverIndex >= 0)
        return hoverIndex;
    return -1;
}
 
void QTabBarPrivate::makeVisible(int index)
{
    Q_Q(QTabBar);
    if (!validIndex(index))
        return;
 
    const QRect tabRect = tabList.at(index)->rect;
    const int oldScrollOffset = scrollOffset;
    const bool horiz = !verticalTabs(shape);
    const int available = horiz ? q->width() : q->height();
    const int tabStart = horiz ? tabRect.left() : tabRect.top();
    const int tabEnd = horiz ? tabRect.right() : tabRect.bottom();
    const int lastTabEnd = horiz ? tabList.constLast()->rect.right() : tabList.constLast()->rect.bottom();
    const QRect scrollRect = normalizedScrollRect(index);
    const QRect entireScrollRect = normalizedScrollRect(0); // ignore tears
    const int scrolledTabBarStart = qMax(1, scrollRect.left() + scrollOffset);
    const int scrolledTabBarEnd = qMin(lastTabEnd - 1, scrollRect.right() + scrollOffset);
 
    if (tabStart < scrolledTabBarStart) {
        // Tab is outside on the left, so scroll left.
        scrollOffset = tabStart - scrollRect.left();
    } else if (tabEnd > scrolledTabBarEnd) {
        // Tab is outside on the right, so scroll right.
        scrollOffset = qMax(0, tabEnd - scrollRect.right());
    } else if (scrollOffset + entireScrollRect.width() > lastTabEnd + 1) {
        // fill any free space on the right without overshooting
        scrollOffset = qMax(0, lastTabEnd - entireScrollRect.width() + 1);
    } else if (available >= lastTabEnd) {
        // the entire tabbar fits, reset scroll
        scrollOffset = 0;
    }
 
    leftB->setEnabled(scrollOffset > -scrollRect.left());
    rightB->setEnabled(scrollOffset < lastTabEnd - scrollRect.right());
 
    if (oldScrollOffset != scrollOffset) {
        q->update();
        layoutWidgets();
    }
}
 
void QTabBarPrivate::killSwitchTabTimer()
{
    Q_Q(QTabBar);
    if (switchTabTimerId) {
        q->killTimer(switchTabTimerId);
        switchTabTimerId = 0;
    }
    switchTabCurrentIndex = -1;
}
 
void QTabBarPrivate::layoutTab(int index)
{
    Q_Q(QTabBar);
    Q_ASSERT(index >= 0);
 
    const Tab *tab = tabList.at(index);
    bool vertical = verticalTabs(shape);
    if (!(tab->leftWidget || tab->rightWidget))
        return;
 
    QStyleOptionTab opt;
    q->initStyleOption(&opt, index);
    if (tab->leftWidget) {
        QRect rect = q->style()->subElementRect(QStyle::SE_TabBarTabLeftButton, &opt, q);
        QPoint p = rect.topLeft();
        if ((index == pressedIndex) || paintWithOffsets) {
            if (vertical)
                p.setY(p.y() + tab->dragOffset);
            else
                p.setX(p.x() + tab->dragOffset);
        }
        tab->leftWidget->move(p);
    }
    if (tab->rightWidget) {
        QRect rect = q->style()->subElementRect(QStyle::SE_TabBarTabRightButton, &opt, q);
        QPoint p = rect.topLeft();
        if ((index == pressedIndex) || paintWithOffsets) {
            if (vertical)
                p.setY(p.y() + tab->dragOffset);
            else
                p.setX(p.x() + tab->dragOffset);
        }
        tab->rightWidget->move(p);
    }
}
 
void QTabBarPrivate::layoutWidgets(int start)
{
    Q_Q(QTabBar);
    for (int i = start; i < q->count(); ++i) {
        layoutTab(i);
    }
}
 
void QTabBarPrivate::autoHideTabs()
{
    Q_Q(QTabBar);
 
    if (autoHide)
        q->setVisible(q->count() > 1);
}
 
void QTabBarPrivate::_q_closeTab()
{
    Q_Q(QTabBar);
    QObject *object = q->sender();
    int tabToClose = -1;
    QTabBar::ButtonPosition closeSide = (QTabBar::ButtonPosition)q->style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, nullptr, q);
    for (int i = 0; i < tabList.size(); ++i) {
        if (closeSide == QTabBar::LeftSide) {
            if (tabList.at(i)->leftWidget == object) {
                tabToClose = i;
                break;
            }
        } else {
            if (tabList.at(i)->rightWidget == object) {
                tabToClose = i;
                break;
            }
        }
    }
    if (tabToClose != -1)
        emit q->tabCloseRequested(tabToClose);
}
 
void QTabBarPrivate::_q_scrollTabs()
{
    Q_Q(QTabBar);
    const QObject *sender = q->sender();
    const bool horizontal = !verticalTabs(shape);
    const QRect scrollRect = normalizedScrollRect().translated(scrollOffset, 0);
 
    int i = -1;
 
    if (sender == leftB) {
        for (i = tabList.size() - 1; i >= 0; --i) {
            int start = horizontal ? tabList.at(i)->rect.left() : tabList.at(i)->rect.top();
            if (start < scrollRect.left()) {
                makeVisible(i);
                return;
            }
        }
    } else if (sender == rightB) {
        for (i = 0; i < tabList.size(); ++i) {
            const auto tabRect = tabList.at(i)->rect;
            int start = horizontal ? tabRect.left() : tabRect.top();
            int end = horizontal ? tabRect.right() : tabRect.bottom();
            if (end > scrollRect.right() && start > scrollOffset) {
                makeVisible(i);
                return;
            }
        }
    }
}
 
void QTabBarPrivate::refresh()
{
    Q_Q(QTabBar);
 
    // be safe in case a subclass is also handling move with the tabs
    if (pressedIndex != -1
        && movable
        && mouseButtons == Qt::NoButton) {
        moveTabFinished(pressedIndex);
        if (!validIndex(pressedIndex))
            pressedIndex = -1;
    }
 
    if (!q->isVisible()) {
        layoutDirty = true;
    } else {
        layoutTabs();
        makeVisible(currentIndex);
        q->update();
        q->updateGeometry();
    }
}
 
QTabBar::QTabBar(QWidget* parent)
    :QWidget(*new QTabBarPrivate, parent, { })
{
    Q_D(QTabBar);
    d->init();
}
 
 
QTabBar::~QTabBar()
{
}
 
QTabBar::Shape QTabBar::shape() const
{
    Q_D(const QTabBar);
    return d->shape;
}
 
void QTabBar::setShape(Shape shape)
{
    Q_D(QTabBar);
    if (d->shape == shape)
        return;
    d->shape = shape;
    d->refresh();
}
 
void QTabBar::setDrawBase(bool drawBase)
{
    Q_D(QTabBar);
    if (d->drawBase == drawBase)
        return;
    d->drawBase = drawBase;
    update();
}
 
bool QTabBar::drawBase() const
{
    Q_D(const QTabBar);
    return d->drawBase;
}
 
int QTabBar::addTab(const QString &text)
{
    return insertTab(-1, text);
}
 
int QTabBar::addTab(const QIcon& icon, const QString &text)
{
    return insertTab(-1, icon, text);
}
 
int QTabBar::insertTab(int index, const QString &text)
{
    return insertTab(index, QIcon(), text);
}
 
int QTabBar::insertTab(int index, const QIcon& icon, const QString &text)
{
    Q_D(QTabBar);
    if (!d->validIndex(index)) {
        index = d->tabList.size();
        d->tabList.append(new QTabBarPrivate::Tab(icon, text));
    } else {
        d->tabList.insert(index, new QTabBarPrivate::Tab(icon, text));
    }
#ifndef QT_NO_SHORTCUT
    d->tabList.at(index)->shortcutId = grabShortcut(QKeySequence::mnemonic(text));
#endif
    d->firstVisible = qMax(qMin(index, d->firstVisible), 0);
    d->refresh();
    if (d->tabList.size() == 1)
        setCurrentIndex(index);
    else if (index <= d->currentIndex)
        ++d->currentIndex;
 
    if (index <= d->lastVisible)
        ++d->lastVisible;
    else
        d->lastVisible = index;
 
    if (d->closeButtonOnTabs) {
        QStyleOptionTab opt;
        initStyleOption(&opt, index);
        ButtonPosition closeSide = (ButtonPosition)style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, nullptr, this);
        QAbstractButton *closeButton = new CloseButton(this);
        connect(closeButton, SIGNAL(clicked()), this, SLOT(_q_closeTab()));
        setTabButton(index, closeSide, closeButton);
    }
 
    for (const auto tab : std::as_const(d->tabList)) {
        if (tab->lastTab >= index)
            ++tab->lastTab;
    }
 
    if (tabAt(d->mousePosition) == index) {
        d->hoverIndex = index;
        d->hoverRect = tabRect(index);
    }
 
    tabInserted(index);
    d->autoHideTabs();
    return index;
}
 
 
void QTabBar::removeTab(int index)
{
    Q_D(QTabBar);
    if (d->validIndex(index)) {
        auto removedTab = d->tabList.at(index);
        if (d->dragInProgress)
            d->moveTabFinished(d->pressedIndex);
 
#ifndef QT_NO_SHORTCUT
        releaseShortcut(d->tabList.at(index)->shortcutId);
#endif
        if (removedTab->leftWidget) {
            removedTab->leftWidget->hide();
            removedTab->leftWidget->deleteLater();
            removedTab->leftWidget = nullptr;
        }
        if (removedTab->rightWidget) {
            removedTab->rightWidget->hide();
            removedTab->rightWidget->deleteLater();
            removedTab->rightWidget = nullptr;
        }
 
        int newIndex = removedTab->lastTab;
        d->tabList.removeAt(index);
        delete removedTab;
        for (auto tab : std::as_const(d->tabList)) {
            if (tab->lastTab == index)
                tab->lastTab = -1;
            if (tab->lastTab > index)
                --tab->lastTab;
        }
 
        d->calculateFirstLastVisible(index, false, true);
 
        if (index == d->currentIndex) {
            // The current tab is going away, in order to make sure
            // we emit that "current has changed", we need to reset this
            // around.
            d->currentIndex = -1;
            if (d->tabList.size() > 0) {
                switch(d->selectionBehaviorOnRemove) {
                case SelectPreviousTab:
                    if (newIndex > index)
                        newIndex--;
                    if (d->validIndex(newIndex) && d->tabList.at(newIndex)->visible)
                        break;
                    Q_FALLTHROUGH();
                case SelectRightTab:
                    newIndex = qBound(d->firstVisible, index, d->lastVisible);
                    break;
                case SelectLeftTab:
                    newIndex = qBound(d->firstVisible, index-1, d->lastVisible);
                    break;
                default:
                    break;
                }
 
                if (d->validIndex(newIndex)) {
                    // don't loose newIndex's old through setCurrentIndex
                    int bump = d->tabList.at(newIndex)->lastTab;
                    setCurrentIndex(newIndex);
                    d->tabList.at(newIndex)->lastTab = bump;
                } else {
                    // we had a valid current index, but there are no visible tabs left
                    emit currentChanged(-1);
                }
            } else {
                emit currentChanged(-1);
            }
        } else if (index < d->currentIndex) {
            setCurrentIndex(d->currentIndex - 1);
        }
        d->refresh();
        d->autoHideTabs();
        if (d->hoverRect.isValid()) {
            update(d->hoverRect);
            d->hoverIndex = tabAt(d->mousePosition);
            if (d->validIndex(d->hoverIndex)) {
                d->hoverRect = tabRect(d->hoverIndex);
                update(d->hoverRect);
            } else {
                d->hoverRect = QRect();
            }
        }
        tabRemoved(index);
    }
}
 
 
bool QTabBar::isTabEnabled(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->enabled;
    return false;
}
 
void QTabBar::setTabEnabled(int index, bool enabled)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index)) {
        tab->enabled = enabled;
#ifndef QT_NO_SHORTCUT
        setShortcutEnabled(tab->shortcutId, enabled);
#endif
        update();
        if (!enabled && index == d->currentIndex)
            setCurrentIndex(d->selectNewCurrentIndexFrom(index+1));
        else if (enabled && !isTabVisible(d->currentIndex))
            setCurrentIndex(d->selectNewCurrentIndexFrom(index));
    }
}
 
 
bool QTabBar::isTabVisible(int index) const
{
    Q_D(const QTabBar);
    if (d->validIndex(index))
        return d->tabList.at(index)->visible;
    return false;
}
 
void QTabBar::setTabVisible(int index, bool visible)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index)) {
        d->layoutDirty = (visible != tab->visible);
        if (!d->layoutDirty)
            return;
        tab->visible = visible;
        if (tab->leftWidget)
            tab->leftWidget->setVisible(visible);
        if (tab->rightWidget)
            tab->rightWidget->setVisible(visible);
#ifndef QT_NO_SHORTCUT
        setShortcutEnabled(tab->shortcutId, visible);
#endif
        d->calculateFirstLastVisible(index, visible, false);
        if (!visible && index == d->currentIndex) {
            const int newindex = d->selectNewCurrentIndexFrom(index+1);
            setCurrentIndex(newindex);
        }
        update();
    }
}
 
 
QString QTabBar::tabText(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->text;
    return QString();
}
 
void QTabBar::setTabText(int index, const QString &text)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index)) {
        d->textSizes.remove(tab->text);
        tab->text = text;
#ifndef QT_NO_SHORTCUT
        releaseShortcut(tab->shortcutId);
        tab->shortcutId = grabShortcut(QKeySequence::mnemonic(text));
        setShortcutEnabled(tab->shortcutId, tab->enabled);
#endif
        d->refresh();
    }
}
 
QColor QTabBar::tabTextColor(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->textColor;
    return QColor();
}
 
void QTabBar::setTabTextColor(int index, const QColor &color)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index)) {
        tab->textColor = color;
        update(tabRect(index));
    }
}
 
QIcon QTabBar::tabIcon(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->icon;
    return QIcon();
}
 
void QTabBar::setTabIcon(int index, const QIcon & icon)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index)) {
        bool simpleIconChange = (!icon.isNull() && !tab->icon.isNull());
        tab->icon = icon;
        if (simpleIconChange)
            update(tabRect(index));
        else
            d->refresh();
    }
}
 
#if QT_CONFIG(tooltip)
void QTabBar::setTabToolTip(int index, const QString & tip)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index))
        tab->toolTip = tip;
}
 
QString QTabBar::tabToolTip(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->toolTip;
    return QString();
}
#endif // QT_CONFIG(tooltip)
 
#if QT_CONFIG(whatsthis)
void QTabBar::setTabWhatsThis(int index, const QString &text)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index))
        tab->whatsThis = text;
}
 
QString QTabBar::tabWhatsThis(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->whatsThis;
    return QString();
}
 
#endif // QT_CONFIG(whatsthis)
 
void QTabBar::setTabData(int index, const QVariant & data)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index))
        tab->data = data;
}
 
QVariant QTabBar::tabData(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->data;
    return QVariant();
}
 
QRect QTabBar::tabRect(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index)) {
        if (d->layoutDirty)
            const_cast<QTabBarPrivate*>(d)->layoutTabs();
        if (!tab->visible)
            return QRect();
        QRect r = tab->rect;
        if (verticalTabs(d->shape))
            r.translate(0, -d->scrollOffset);
        else
            r.translate(-d->scrollOffset, 0);
        if (!verticalTabs(d->shape))
            r = QStyle::visualRect(layoutDirection(), rect(), r);
        return r;
    }
    return QRect();
}
 
int QTabBar::tabAt(const QPoint &position) const
{
    Q_D(const QTabBar);
    if (d->validIndex(d->currentIndex)
        && tabRect(d->currentIndex).contains(position)) {
        return d->currentIndex;
    }
    const int max = d->tabList.size();
    for (int i = 0; i < max; ++i) {
        if (tabRect(i).contains(position)) {
            return i;
        }
    }
    return -1;
}
 
int QTabBar::currentIndex() const
{
    Q_D(const QTabBar);
    if (d->validIndex(d->currentIndex))
        return d->currentIndex;
    return -1;
}
 
 
void QTabBar::setCurrentIndex(int index)
{
    Q_D(QTabBar);
    if (d->dragInProgress && d->pressedIndex != -1)
        return;
    if (d->currentIndex == index)
        return;
 
    int oldIndex = d->currentIndex;
    if (auto tab = d->at(index)) {
        d->currentIndex = index;
        // If the size hint depends on whether the tab is selected (for instance a style
        // sheet rule that sets a bold font on the 'selected' tab) then we need to
        // re-layout the entire tab bar. To minimize the cost, do that only if the
        // size hint changes for the tab that becomes the current tab (the old current tab
        // will most certainly do the same). QTBUG-6905
        if (tabRect(index).size() != tabSizeHint(index))
            d->layoutTabs();
        update();
        d->makeVisible(index);
        if (d->validIndex(oldIndex)) {
            tab->lastTab = oldIndex;
            d->layoutTab(oldIndex);
        }
        d->layoutTab(index);
#if QT_CONFIG(accessibility)
        if (QAccessible::isActive()) {
            if (hasFocus()) {
                QAccessibleEvent focusEvent(this, QAccessible::Focus);
                focusEvent.setChild(index);
                QAccessible::updateAccessibility(&focusEvent);
            }
            QAccessibleEvent selectionEvent(this, QAccessible::Selection);
            selectionEvent.setChild(index);
            QAccessible::updateAccessibility(&selectionEvent);
        }
#endif
        emit currentChanged(index);
    }
}
 
QSize QTabBar::iconSize() const
{
    Q_D(const QTabBar);
    if (d->iconSize.isValid())
        return d->iconSize;
    int iconExtent = style()->pixelMetric(QStyle::PM_TabBarIconSize, nullptr, this);
    return QSize(iconExtent, iconExtent);
 
}
 
void QTabBar::setIconSize(const QSize &size)
{
    Q_D(QTabBar);
    d->iconSize = size;
    d->layoutDirty = true;
    update();
    updateGeometry();
}
 
int QTabBar::count() const
{
    Q_D(const QTabBar);
    return d->tabList.size();
}
 
 
QSize QTabBar::sizeHint() const
{
    Q_D(const QTabBar);
    if (d->layoutDirty)
        const_cast<QTabBarPrivate*>(d)->layoutTabs();
    QRect r;
    for (const auto tab : d->tabList) {
        if (tab->visible)
            r = r.united(tab->maxRect);
    }
    return r.size();
}
 
QSize QTabBar::minimumSizeHint() const
{
    Q_D(const QTabBar);
    if (d->layoutDirty)
        const_cast<QTabBarPrivate*>(d)->layoutTabs();
    if (!d->useScrollButtons) {
        QRect r;
        for (const auto tab : d->tabList) {
            if (tab->visible)
                r = r.united(tab->minRect);
        }
        return r.size();
    }
    if (verticalTabs(d->shape))
        return QSize(sizeHint().width(), d->rightB->sizeHint().height() * 2 + 75);
    else
        return QSize(d->rightB->sizeHint().width() * 2 + 75, sizeHint().height());
}
 
// Compute the most-elided possible text, for minimumSizeHint
static QString computeElidedText(Qt::TextElideMode mode, const QString &text)
{
    if (text.size() <= 3)
        return text;
 
    static const auto Ellipses = "..."_L1;
    QString ret;
    switch (mode) {
    case Qt::ElideRight:
        ret = QStringView{text}.left(2) + Ellipses;
        break;
    case Qt::ElideMiddle:
        ret = QStringView{text}.left(1) + Ellipses + QStringView{text}.right(1);
        break;
    case Qt::ElideLeft:
        ret = Ellipses + QStringView{text}.right(2);
        break;
    case Qt::ElideNone:
        ret = text;
        break;
    }
    return ret;
}
 
QSize QTabBar::minimumTabSizeHint(int index) const
{
    Q_D(const QTabBar);
    QTabBarPrivate::Tab *tab = d->tabList.at(index);
    QString oldText = tab->text;
    tab->text = computeElidedText(d->elideMode, oldText);
    QSize size = tabSizeHint(index);
    tab->text = oldText;
    return size;
}
 
QSize QTabBar::tabSizeHint(int index) const
{
    //Note: this must match with the computations in QCommonStylePrivate::tabLayout
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index)) {
        QStyleOptionTab opt;
        d->initBasicStyleOption(&opt, index);
        opt.text = tab->text;
        QSize iconSize = tab->icon.isNull() ? QSize(0, 0) : opt.iconSize;
        int hframe = style()->pixelMetric(QStyle::PM_TabBarTabHSpace, &opt, this);
        int vframe = style()->pixelMetric(QStyle::PM_TabBarTabVSpace, &opt, this);
        const QFontMetrics fm = fontMetrics();
 
        int maxWidgetHeight = qMax(opt.leftButtonSize.height(), opt.rightButtonSize.height());
        int maxWidgetWidth = qMax(opt.leftButtonSize.width(), opt.rightButtonSize.width());
 
        int widgetWidth = 0;
        int widgetHeight = 0;
        int padding = 0;
        if (!opt.leftButtonSize.isEmpty()) {
            padding += 4;
            widgetWidth += opt.leftButtonSize.width();
            widgetHeight += opt.leftButtonSize.height();
        }
        if (!opt.rightButtonSize.isEmpty()) {
            padding += 4;
            widgetWidth += opt.rightButtonSize.width();
            widgetHeight += opt.rightButtonSize.height();
        }
        if (!opt.icon.isNull())
            padding += 4;
 
        QHash<QString, QSize>::iterator it = d->textSizes.find(tab->text);
        if (it == d->textSizes.end())
           it = d->textSizes.insert(tab->text, fm.size(Qt::TextShowMnemonic, tab->text));
        const int textWidth = it.value().width();
        QSize csz;
        if (verticalTabs(d->shape)) {
            csz = QSize( qMax(maxWidgetWidth, qMax(fm.height(), iconSize.height())) + vframe,
                         textWidth + iconSize.width() + hframe + widgetHeight + padding);
        } else {
            csz = QSize(textWidth + iconSize.width() + hframe + widgetWidth + padding,
                  qMax(maxWidgetHeight, qMax(fm.height(), iconSize.height())) + vframe);
        }
 
        QSize retSize = style()->sizeFromContents(QStyle::CT_TabBarTab, &opt, csz, this);
        return retSize;
    }
    return QSize();
}
 
void QTabBar::tabInserted(int index)
{
    Q_UNUSED(index);
}
 
void QTabBar::tabRemoved(int index)
{
    Q_UNUSED(index);
}
 
void QTabBar::tabLayoutChange()
{
}
 
 
void QTabBar::showEvent(QShowEvent *)
{
    Q_D(QTabBar);
    if (d->layoutDirty)
        d->refresh();
    if (!d->validIndex(d->currentIndex))
        setCurrentIndex(0);
    else
        d->makeVisible(d->currentIndex);
    d->updateMacBorderMetrics();
}
 
void QTabBar::hideEvent(QHideEvent *)
{
    Q_D(QTabBar);
    d->updateMacBorderMetrics();
}
 
bool QTabBar::event(QEvent *event)
{
    Q_D(QTabBar);
    switch (event->type()) {
    case QEvent::HoverMove:
    case QEvent::HoverEnter: {
        QHoverEvent *he = static_cast<QHoverEvent *>(event);
        d->mousePosition = he->position().toPoint();
        if (!d->hoverRect.contains(d->mousePosition)) {
            if (d->hoverRect.isValid())
                update(d->hoverRect);
            d->hoverIndex = tabAt(d->mousePosition);
            if (d->validIndex(d->hoverIndex)) {
                d->hoverRect = tabRect(d->hoverIndex);
                update(d->hoverRect);
            } else {
                d->hoverRect = QRect();
            }
        }
        return true;
    }
    case QEvent::HoverLeave: {
        d->mousePosition = {-1, -1};
        if (d->hoverRect.isValid())
            update(d->hoverRect);
        d->hoverIndex = -1;
        d->hoverRect = QRect();
#if QT_CONFIG(wheelevent)
        d->accumulatedAngleDelta = QPoint();
#endif
        return true;
    }
#if QT_CONFIG(tooltip)
    case QEvent::ToolTip:
        if (const QTabBarPrivate::Tab *tab = d->at(tabAt(static_cast<QHelpEvent*>(event)->pos()))) {
            if (!tab->toolTip.isEmpty()) {
                QToolTip::showText(static_cast<QHelpEvent*>(event)->globalPos(), tab->toolTip, this);
                return true;
            }
        }
        break;
#endif // QT_CONFIG(tooltip)
#if QT_CONFIG(whatsthis)
    case QEvent::QEvent::QueryWhatsThis: {
        const QTabBarPrivate::Tab *tab = d->at(d->indexAtPos(static_cast<QHelpEvent*>(event)->pos()));
        if (!tab || tab->whatsThis.isEmpty())
            event->ignore();
        return true;
    }
    case QEvent::WhatsThis:
        if (const QTabBarPrivate::Tab *tab = d->at(d->indexAtPos(static_cast<QHelpEvent*>(event)->pos()))) {
            if (!tab->whatsThis.isEmpty()) {
                QWhatsThis::showText(static_cast<QHelpEvent*>(event)->globalPos(),
                                     tab->whatsThis, this);
                return true;
            }
        }
        break;
#endif // QT_CONFIG(whatsthis)
#ifndef QT_NO_SHORTCUT
 
    case QEvent::Shortcut: {
        QShortcutEvent *se = static_cast<QShortcutEvent *>(event);
        for (int i = 0; i < d->tabList.size(); ++i) {
            const QTabBarPrivate::Tab *tab = d->tabList.at(i);
            if (tab->shortcutId == se->shortcutId()) {
                setCurrentIndex(i);
                return true;
            }
        }
    }
        break;
#endif
    case QEvent::Move:
        d->updateMacBorderMetrics();
        break;
#if QT_CONFIG(draganddrop)
 
    case QEvent::DragEnter:
        if (d->changeCurrentOnDrag)
            event->accept();
        break;
    case QEvent::DragMove:
        if (d->changeCurrentOnDrag) {
            const int tabIndex = tabAt(static_cast<QDragMoveEvent *>(event)->position().toPoint());
            if (isTabEnabled(tabIndex) && d->switchTabCurrentIndex != tabIndex) {
                d->switchTabCurrentIndex = tabIndex;
                if (d->switchTabTimerId)
                    killTimer(d->switchTabTimerId);
                d->switchTabTimerId = startTimer(style()->styleHint(QStyle::SH_TabBar_ChangeCurrentDelay));
            }
            event->ignore();
        }
        break;
    case QEvent::DragLeave:
    case QEvent::Drop:
        d->killSwitchTabTimer();
        event->ignore();
        break;
#endif
    case QEvent::MouseButtonPress:
    case QEvent::MouseButtonRelease:
    case QEvent::MouseMove:
        d->mousePosition = static_cast<QMouseEvent *>(event)->position().toPoint();
        d->mouseButtons = static_cast<QMouseEvent *>(event)->buttons();
        break;
    default:
        break;
    }
 
    return QWidget::event(event);
}
 
void QTabBar::resizeEvent(QResizeEvent *)
{
    Q_D(QTabBar);
    if (d->layoutDirty)
        updateGeometry();
 
    // when resizing, we want to keep the scroll offset as much as possible
    d->layoutTabs();
 
    d->makeVisible(d->currentIndex);
}
 
void QTabBar::paintEvent(QPaintEvent *)
{
    Q_D(QTabBar);
 
    QStyleOptionTabBarBase optTabBase;
    QTabBarPrivate::initStyleBaseOption(&optTabBase, this, size());
 
    QStylePainter p(this);
    int selected = -1;
    int cutLeft = -1;
    int cutRight = -1;
    bool vertical = verticalTabs(d->shape);
    QStyleOptionTab cutTabLeft;
    QStyleOptionTab cutTabRight;
    selected = d->currentIndex;
    if (d->dragInProgress)
        selected = d->pressedIndex;
    const QRect scrollRect = d->normalizedScrollRect();
 
    for (int i = 0; i < d->tabList.size(); ++i)
         optTabBase.tabBarRect |= tabRect(i);
 
    optTabBase.selectedTabRect = tabRect(selected);
 
    if (d->drawBase)
        p.drawPrimitive(QStyle::PE_FrameTabBarBase, optTabBase);
 
    // the buttons might be semi-transparent or not fill their rect, but we don't
    // want the tab underneath to shine through, so clip the button area; QTBUG-50866
    if (d->leftB->isVisible() || d->rightB->isVisible()) {
        QStyleOption opt;
        opt.initFrom(this);
        QRegion buttonRegion;
        if (d->leftB->isVisible())
            buttonRegion |= style()->subElementRect(QStyle::SE_TabBarScrollLeftButton, &opt, this);
        if (d->rightB->isVisible())
            buttonRegion |= style()->subElementRect(QStyle::SE_TabBarScrollRightButton, &opt, this);
        if (!buttonRegion.isEmpty())
            p.setClipRegion(QRegion(rect()) - buttonRegion);
    }
 
    for (int i = 0; i < d->tabList.size(); ++i) {
        const auto tab = d->tabList.at(i);
        if (!tab->visible)
            continue;
        QStyleOptionTab tabOption;
        initStyleOption(&tabOption, i);
        if (d->paintWithOffsets && tab->dragOffset != 0) {
            if (vertical) {
                tabOption.rect.moveTop(tabOption.rect.y() + tab->dragOffset);
            } else {
                tabOption.rect.moveLeft(tabOption.rect.x() + tab->dragOffset);
            }
        }
        if (!(tabOption.state & QStyle::State_Enabled)) {
            tabOption.palette.setCurrentColorGroup(QPalette::Disabled);
        }
 
        // If this tab is partially obscured, make a note of it so that we can pass the information
        // along when we draw the tear.
        QRect tabRect = tab->rect;
        int tabStart = vertical ? tabRect.top() : tabRect.left();
        int tabEnd = vertical ? tabRect.bottom() : tabRect.right();
        if (tabStart < scrollRect.left() + d->scrollOffset) {
            cutLeft = i;
            cutTabLeft = tabOption;
        } else if (tabEnd > scrollRect.right() + d->scrollOffset) {
            cutRight = i;
            cutTabRight = tabOption;
        }
 
        // Don't bother drawing a tab if the entire tab is outside of the visible tab bar.
        if ((!vertical && (tabOption.rect.right() < 0 || tabOption.rect.left() > width()))
            || (vertical && (tabOption.rect.bottom() < 0 || tabOption.rect.top() > height())))
            continue;
 
        optTabBase.tabBarRect |= tabOption.rect;
        if (i == selected)
            continue;
 
        p.drawControl(QStyle::CE_TabBarTab, tabOption);
    }
 
    // Draw the selected tab last to get it "on top"
    if (selected >= 0) {
        QStyleOptionTab tabOption;
        const auto tab = d->tabList.at(selected);
        initStyleOption(&tabOption, selected);
 
        if (d->paintWithOffsets && tab->dragOffset != 0) {
            // if the drag offset is != 0, a move is in progress (drag or animation)
            // => set the tab position to Moving to preserve the rect
            tabOption.position = QStyleOptionTab::TabPosition::Moving;
 
            if (vertical)
                tabOption.rect.moveTop(tabOption.rect.y() + tab->dragOffset);
            else
                tabOption.rect.moveLeft(tabOption.rect.x() + tab->dragOffset);
        }
 
        // Calculate the rect of a moving tab
        const int taboverlap = style()->pixelMetric(QStyle::PM_TabBarTabOverlap, nullptr, this);
        const QRect &movingRect = verticalTabs(d->shape)
                ? tabOption.rect.adjusted(0, -taboverlap, 0, taboverlap)
                : tabOption.rect.adjusted(-taboverlap, 0, taboverlap, 0);
 
        // If a drag is in process, set the moving tab's geometry here
        // (in an animation, it is already set)
        if (d->dragInProgress)
            d->movingTab->setGeometry(movingRect);
 
        p.drawControl(QStyle::CE_TabBarTab, tabOption);
    }
 
    // Only draw the tear indicator if necessary. Most of the time we don't need too.
    if (d->leftB->isVisible() && cutLeft >= 0) {
        cutTabLeft.rect = rect();
        cutTabLeft.rect = style()->subElementRect(QStyle::SE_TabBarTearIndicatorLeft, &cutTabLeft, this);
        p.drawPrimitive(QStyle::PE_IndicatorTabTearLeft, cutTabLeft);
    }
 
    if (d->rightB->isVisible() && cutRight >= 0) {
        cutTabRight.rect = rect();
        cutTabRight.rect = style()->subElementRect(QStyle::SE_TabBarTearIndicatorRight, &cutTabRight, this);
        p.drawPrimitive(QStyle::PE_IndicatorTabTearRight, cutTabRight);
    }
}
 
/*
    When index changes visibility, we have to find first & last visible indexes.
    If remove is set, we force both
 */
void QTabBarPrivate::calculateFirstLastVisible(int index, bool visible, bool remove)
{
    if (visible) {
        firstVisible = qMin(index, firstVisible);
        lastVisible  = qMax(index, lastVisible);
    } else {
        if (remove || (index == firstVisible)) {
            firstVisible = -1;
            for (int i = 0; i < tabList.size(); ++i) {
                if (tabList.at(i)->visible) {
                    firstVisible = i;
                    break;
                }
            }
        }
        if (remove || (index == lastVisible)) {
            lastVisible = -1;
            for (int i = tabList.size() - 1; i >= 0; --i) {
                if (tabList.at(i)->visible) {
                    lastVisible = i;
                    break;
                }
            }
        }
    }
}
 
/*
    Selects the new current index starting at "fromIndex". If "fromIndex" is visible we're done.
    Else it tries any index AFTER fromIndex, then any BEFORE fromIndex and, if everything fails,
    it returns -1 indicating that no index is available
 */
int QTabBarPrivate::selectNewCurrentIndexFrom(int fromIndex)
{
    int newindex = -1;
    for (int i = fromIndex; i < tabList.size(); ++i) {
        if (at(i)->visible && at(i)->enabled) {
          newindex = i;
          break;
        }
    }
    if (newindex < 0) {
        for (int i = fromIndex-1; i > -1; --i) {
            if (at(i)->visible && at(i)->enabled) {
              newindex = i;
              break;
            }
        }
    }
 
    return newindex;
}
 
/*
    Given that index at position from moved to position to where return where index goes.
 */
int QTabBarPrivate::calculateNewPosition(int from, int to, int index) const
{
    if (index == from)
        return to;
 
    int start = qMin(from, to);
    int end = qMax(from, to);
    if (index >= start && index <= end)
        index += (from < to) ? -1 : 1;
    return index;
}
 
void QTabBar::moveTab(int from, int to)
{
    Q_D(QTabBar);
    if (from == to
        || !d->validIndex(from)
        || !d->validIndex(to))
        return;
 
    auto &fromTab = *d->tabList.at(from);
    auto &toTab = *d->tabList.at(to);
 
    bool vertical = verticalTabs(d->shape);
    int oldPressedPosition = 0;
    if (d->pressedIndex != -1) {
        // Record the position of the pressed tab before reordering the tabs.
        oldPressedPosition = vertical ? d->tabList.at(d->pressedIndex)->rect.y()
                                      : d->tabList.at(d->pressedIndex)->rect.x();
    }
 
    // Update the locations of the tabs first
    int start = qMin(from, to);
    int end = qMax(from, to);
    int width = vertical ? fromTab.rect.height() : fromTab.rect.width();
    if (from < to)
        width *= -1;
    bool rtl = isRightToLeft();
    for (int i = start; i <= end; ++i) {
        if (i == from)
            continue;
        auto &tab = *d->tabList.at(i);
        if (vertical)
            tab.rect.moveTop(tab.rect.y() + width);
        else
            tab.rect.moveLeft(tab.rect.x() + width);
        int direction = -1;
        if (rtl && !vertical)
            direction *= -1;
        if (tab.dragOffset != 0)
            tab.dragOffset += (direction * width);
    }
 
    if (vertical) {
        if (from < to)
            fromTab.rect.moveTop(toTab.rect.bottom() + 1);
        else
            fromTab.rect.moveTop(toTab.rect.top() - width);
    } else {
        if (from < to)
            fromTab.rect.moveLeft(toTab.rect.right() + 1);
        else
            fromTab.rect.moveLeft(toTab.rect.left() - width);
    }
 
    // Move the actual data structures
    d->tabList.move(from, to);
 
    // update lastTab locations
    for (const auto tab : std::as_const(d->tabList))
        tab->lastTab = d->calculateNewPosition(from, to, tab->lastTab);
 
    // update external variables
    int previousIndex = d->currentIndex;
    d->currentIndex = d->calculateNewPosition(from, to, d->currentIndex);
 
    // If we are in the middle of a drag update the dragStartPosition
    if (d->pressedIndex != -1) {
        d->pressedIndex = d->calculateNewPosition(from, to, d->pressedIndex);
        const auto pressedTab = d->tabList.at(d->pressedIndex);
        int newPressedPosition = vertical ? pressedTab->rect.top() : pressedTab->rect.left();
        int diff = oldPressedPosition - newPressedPosition;
        if (isRightToLeft() && !vertical)
            diff *= -1;
        if (vertical)
            d->dragStartPosition.setY(d->dragStartPosition.y() - diff);
        else
            d->dragStartPosition.setX(d->dragStartPosition.x() - diff);
    }
 
    d->layoutWidgets(start);
    update();
    emit tabMoved(from, to);
    if (previousIndex != d->currentIndex)
        emit currentChanged(d->currentIndex);
    emit tabLayoutChange();
}
 
void QTabBarPrivate::slide(int from, int to)
{
    Q_Q(QTabBar);
    if (from == to
            || !validIndex(from)
            || !validIndex(to))
        return;
    bool vertical = verticalTabs(shape);
    int preLocation = vertical ? q->tabRect(from).y() : q->tabRect(from).x();
    q->setUpdatesEnabled(false);
    q->moveTab(from, to);
    q->setUpdatesEnabled(true);
    int postLocation = vertical ? q->tabRect(to).y() : q->tabRect(to).x();
    int length = postLocation - preLocation;
    tabList.at(to)->dragOffset -= length;
    tabList.at(to)->startAnimation(this, ANIMATION_DURATION);
}
 
void QTabBarPrivate::moveTab(int index, int offset)
{
    if (!validIndex(index))
        return;
    tabList.at(index)->dragOffset = offset;
    layoutTab(index); // Make buttons follow tab
    q_func()->update();
}
 
void QTabBar::mousePressEvent(QMouseEvent *event)
{
    Q_D(QTabBar);
 
    const QPoint pos = event->position().toPoint();
    const bool isEventInCornerButtons = (!d->leftB->isHidden() && d->leftB->geometry().contains(pos))
                                     || (!d->rightB->isHidden() && d->rightB->geometry().contains(pos));
    if (!isEventInCornerButtons) {
        const int index = d->indexAtPos(pos);
        emit tabBarClicked(index);
    }
 
    if (event->button() != Qt::LeftButton) {
        event->ignore();
        return;
    }
    // Be safe!
    if (d->pressedIndex != -1 && d->movable)
        d->moveTabFinished(d->pressedIndex);
 
    d->pressedIndex = d->indexAtPos(event->position().toPoint());
 
    if (d->validIndex(d->pressedIndex)) {
        QStyleOptionTabBarBase optTabBase;
        optTabBase.initFrom(this);
        optTabBase.documentMode = d->documentMode;
        if (event->type() == style()->styleHint(QStyle::SH_TabBar_SelectMouseType, &optTabBase, this))
            setCurrentIndex(d->pressedIndex);
        else
            repaint(tabRect(d->pressedIndex));
        if (d->movable) {
            d->dragStartPosition = event->position().toPoint();
        }
    }
}
 
void QTabBar::mouseMoveEvent(QMouseEvent *event)
{
    Q_D(QTabBar);
    if (d->movable) {
        // Be safe!
        if (d->pressedIndex != -1
            && event->buttons() == Qt::NoButton)
            d->moveTabFinished(d->pressedIndex);
 
        // Start drag
        if (!d->dragInProgress && d->pressedIndex != -1) {
            if ((event->position().toPoint() - d->dragStartPosition).manhattanLength() > QApplication::startDragDistance()) {
                d->dragInProgress = true;
                d->setupMovableTab();
            }
        }
 
        if (event->buttons() == Qt::LeftButton
            && d->dragInProgress
            && d->validIndex(d->pressedIndex)) {
            bool vertical = verticalTabs(d->shape);
            int dragDistance;
            if (vertical) {
                dragDistance = (event->position().toPoint().y() - d->dragStartPosition.y());
            } else {
                dragDistance = (event->position().toPoint().x() - d->dragStartPosition.x());
            }
            d->tabList.at(d->pressedIndex)->dragOffset = dragDistance;
 
            QRect startingRect = tabRect(d->pressedIndex);
            if (vertical)
                startingRect.moveTop(startingRect.y() + dragDistance);
            else
                startingRect.moveLeft(startingRect.x() + dragDistance);
 
            int overIndex;
            if (dragDistance < 0)
                overIndex = tabAt(startingRect.topLeft());
            else
                overIndex = tabAt(startingRect.topRight());
 
            if (overIndex != d->pressedIndex && overIndex != -1) {
                int offset = 1;
                if (isRightToLeft() && !vertical)
                    offset *= -1;
                if (dragDistance < 0) {
                    dragDistance *= -1;
                    offset *= -1;
                }
                for (int i = d->pressedIndex;
                     offset > 0 ? i < overIndex : i > overIndex;
                     i += offset) {
                    QRect overIndexRect = tabRect(overIndex);
                    int needsToBeOver = (vertical ? overIndexRect.height() : overIndexRect.width()) / 2;
                    if (dragDistance > needsToBeOver)
                        d->slide(i + offset, d->pressedIndex);
                }
            }
            // Buttons needs to follow the dragged tab
            if (d->pressedIndex != -1)
                d->layoutTab(d->pressedIndex);
 
            update();
        }
    }
 
    if (event->buttons() != Qt::LeftButton) {
        event->ignore();
        return;
    }
}
 
void QTabBarPrivate::setupMovableTab()
{
    Q_Q(QTabBar);
    if (!movingTab)
        movingTab = new QMovableTabWidget(q);
 
    int taboverlap = q->style()->pixelMetric(QStyle::PM_TabBarTabOverlap, nullptr ,q);
    QRect grabRect = q->tabRect(pressedIndex);
    if (verticalTabs(shape))
        grabRect.adjust(0, -taboverlap, 0, taboverlap);
    else
        grabRect.adjust(-taboverlap, 0, taboverlap, 0);
 
    QPixmap grabImage(grabRect.size() * q->devicePixelRatio());
    grabImage.setDevicePixelRatio(q->devicePixelRatio());
    grabImage.fill(Qt::transparent);
    QStylePainter p(&grabImage, q);
 
    QStyleOptionTab tab;
    q->initStyleOption(&tab, pressedIndex);
    tab.position = QStyleOptionTab::OnlyOneTab;
    if (verticalTabs(shape))
        tab.rect.moveTopLeft(QPoint(0, taboverlap));
    else
        tab.rect.moveTopLeft(QPoint(taboverlap, 0));
    p.drawControl(QStyle::CE_TabBarTab, tab);
    p.end();
 
    movingTab->setPixmap(grabImage);
    movingTab->setGeometry(grabRect);
    movingTab->raise();
 
    // Re-arrange widget order to avoid overlaps
    const auto &pressedTab = *tabList.at(pressedIndex);
    if (pressedTab.leftWidget)
        pressedTab.leftWidget->raise();
    if (pressedTab.rightWidget)
        pressedTab.rightWidget->raise();
    if (leftB)
        leftB->raise();
    if (rightB)
        rightB->raise();
    movingTab->setVisible(true);
}
 
void QTabBarPrivate::moveTabFinished(int index)
{
    Q_Q(QTabBar);
    bool cleanup = (pressedIndex == index) || (pressedIndex == -1) || !validIndex(index);
    bool allAnimationsFinished = true;
#if QT_CONFIG(animation)
    for (const auto tab : std::as_const(tabList)) {
        if (tab->animation && tab->animation->state() == QAbstractAnimation::Running) {
            allAnimationsFinished = false;
            break;
        }
    }
#endif // animation
    if (allAnimationsFinished && cleanup) {
        if (movingTab)
            movingTab->setVisible(false); // We might not get a mouse release
        for (auto tab : std::as_const(tabList)) {
            tab->dragOffset = 0;
        }
        if (pressedIndex != -1 && movable) {
            pressedIndex = -1;
            dragInProgress = false;
            dragStartPosition = QPoint();
        }
        layoutWidgets();
    } else {
        if (!validIndex(index))
            return;
        tabList.at(index)->dragOffset = 0;
    }
    q->update();
}
 
void QTabBar::mouseReleaseEvent(QMouseEvent *event)
{
    Q_D(QTabBar);
    if (event->button() != Qt::LeftButton) {
        event->ignore();
        return;
    }
 
    if (d->movable && d->dragInProgress && d->validIndex(d->pressedIndex)) {
        int length = d->tabList.at(d->pressedIndex)->dragOffset;
        int width = verticalTabs(d->shape)
            ? tabRect(d->pressedIndex).height()
            : tabRect(d->pressedIndex).width();
        int duration = qMin(ANIMATION_DURATION,
                (qAbs(length) * ANIMATION_DURATION) / width);
        d->tabList.at(d->pressedIndex)->startAnimation(d, duration);
        d->dragInProgress = false;
        d->movingTab->setVisible(false);
        d->dragStartPosition = QPoint();
    }
 
    // mouse release event might happen outside the tab, so keep the pressed index
    int oldPressedIndex = d->pressedIndex;
    int i = d->indexAtPos(event->position().toPoint()) == d->pressedIndex ? d->pressedIndex : -1;
    d->pressedIndex = -1;
    QStyleOptionTabBarBase optTabBase;
    optTabBase.initFrom(this);
    optTabBase.documentMode = d->documentMode;
    const bool selectOnRelease =
            (style()->styleHint(QStyle::SH_TabBar_SelectMouseType, &optTabBase, this) == QEvent::MouseButtonRelease);
    if (selectOnRelease)
        setCurrentIndex(i);
    if (d->validIndex(oldPressedIndex))
        update(tabRect(oldPressedIndex));
}
 
void QTabBar::mouseDoubleClickEvent(QMouseEvent *event)
{
    Q_D(QTabBar);
    const QPoint pos = event->position().toPoint();
    const bool isEventInCornerButtons = (!d->leftB->isHidden() && d->leftB->geometry().contains(pos))
                                        || (!d->rightB->isHidden() && d->rightB->geometry().contains(pos));
    if (!isEventInCornerButtons)
        emit tabBarDoubleClicked(tabAt(pos));
 
    mousePressEvent(event);
}
 
void QTabBar::keyPressEvent(QKeyEvent *event)
{
    Q_D(QTabBar);
    if (event->key() != Qt::Key_Left && event->key() != Qt::Key_Right) {
        event->ignore();
        return;
    }
    int offset = event->key() == (isRightToLeft() ? Qt::Key_Right : Qt::Key_Left) ? -1 : 1;
    d->setCurrentNextEnabledIndex(offset);
}
 
#if QT_CONFIG(wheelevent)
void QTabBar::wheelEvent(QWheelEvent *event)
{
    Q_D(QTabBar);
    if (style()->styleHint(QStyle::SH_TabBar_AllowWheelScrolling)) {
        const bool wheelVertical = qAbs(event->angleDelta().y()) > qAbs(event->angleDelta().x());
        const bool tabsVertical = verticalTabs(d->shape);
        if (event->device()->capabilities().testFlag(QInputDevice::Capability::PixelScroll)) {
            // For wheels/touch pads with pixel precision, scroll the tab bar if
            // it has the right orientation.
            int delta = 0;
            if (tabsVertical == wheelVertical)
                delta = wheelVertical ? event->pixelDelta().y() : event->pixelDelta().x();
            if (layoutDirection() == Qt::RightToLeft)
                delta = -delta;
            if (delta && d->validIndex(d->lastVisible)) {
                const int oldScrollOffset = d->scrollOffset;
                const QRect lastTabRect = d->tabList.at(d->lastVisible)->rect;
                const QRect scrollRect = d->normalizedScrollRect(d->lastVisible);
                int scrollRectExtent = scrollRect.right();
                if (!d->leftB->isVisible())
                    scrollRectExtent += tabsVertical ? d->leftB->height() : d->leftB->width();
                if (!d->rightB->isVisible())
                    scrollRectExtent += tabsVertical ? d->rightB->height() : d->rightB->width();
 
                const int maxScrollOffset = qMax((tabsVertical ?
                                                  lastTabRect.bottom() :
                                                  lastTabRect.right()) - scrollRectExtent, 0);
                d->scrollOffset = qBound(0, d->scrollOffset - delta, maxScrollOffset);
                d->leftB->setEnabled(d->scrollOffset > -scrollRect.left());
                d->rightB->setEnabled(maxScrollOffset > d->scrollOffset);
                if (oldScrollOffset != d->scrollOffset) {
                    event->accept();
                    update();
                    return;
                }
            }
        } else {
            d->accumulatedAngleDelta += event->angleDelta();
            const int xSteps = d->accumulatedAngleDelta.x() / QWheelEvent::DefaultDeltasPerStep;
            const int ySteps = d->accumulatedAngleDelta.y() / QWheelEvent::DefaultDeltasPerStep;
            int offset = 0;
            if (xSteps > 0 || ySteps > 0) {
                offset = -1;
                d->accumulatedAngleDelta = QPoint();
            } else if (xSteps < 0 || ySteps < 0) {
                offset = 1;
                d->accumulatedAngleDelta = QPoint();
            }
            const int oldCurrentIndex = d->currentIndex;
            d->setCurrentNextEnabledIndex(offset);
            if (oldCurrentIndex != d->currentIndex) {
                event->accept();
                return;
            }
        }
        QWidget::wheelEvent(event);
    }
}
#endif // QT_CONFIG(wheelevent)
 
void QTabBarPrivate::setCurrentNextEnabledIndex(int offset)
{
    Q_Q(QTabBar);
    for (int index = currentIndex + offset; validIndex(index); index += offset) {
        if (tabList.at(index)->enabled) {
            q->setCurrentIndex(index);
            break;
        }
    }
}
 
void QTabBar::changeEvent(QEvent *event)
{
    Q_D(QTabBar);
    switch (event->type()) {
    case QEvent::StyleChange:
        if (!d->elideModeSetByUser)
            d->elideMode = Qt::TextElideMode(style()->styleHint(QStyle::SH_TabBar_ElideMode, nullptr, this));
        if (!d->useScrollButtonsSetByUser)
            d->useScrollButtons = !style()->styleHint(QStyle::SH_TabBar_PreferNoArrows, nullptr, this);
        Q_FALLTHROUGH();
    case QEvent::FontChange:
        d->textSizes.clear();
        d->refresh();
        break;
    default:
        break;
    }
 
    QWidget::changeEvent(event);
}
 
void QTabBar::timerEvent(QTimerEvent *event)
{
    Q_D(QTabBar);
    if (event->timerId() == d->switchTabTimerId) {
        killTimer(d->switchTabTimerId);
        d->switchTabTimerId = 0;
        setCurrentIndex(d->switchTabCurrentIndex);
        d->switchTabCurrentIndex = -1;
    }
    QWidget::timerEvent(event);
}
 
Qt::TextElideMode QTabBar::elideMode() const
{
    Q_D(const QTabBar);
    return d->elideMode;
}
 
void QTabBar::setElideMode(Qt::TextElideMode mode)
{
    Q_D(QTabBar);
    d->elideMode = mode;
    d->elideModeSetByUser = true;
    d->textSizes.clear();
    d->refresh();
}
 
bool QTabBar::usesScrollButtons() const
{
    return d_func()->useScrollButtons;
}
 
void QTabBar::setUsesScrollButtons(bool useButtons)
{
    Q_D(QTabBar);
    d->useScrollButtonsSetByUser = true;
    if (d->useScrollButtons == useButtons)
        return;
    d->useScrollButtons = useButtons;
    d->refresh();
}
 
bool QTabBar::tabsClosable() const
{
    Q_D(const QTabBar);
    return d->closeButtonOnTabs;
}
 
void QTabBar::setTabsClosable(bool closable)
{
    Q_D(QTabBar);
    if (d->closeButtonOnTabs == closable)
        return;
    d->closeButtonOnTabs = closable;
    ButtonPosition closeSide = (ButtonPosition)style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, nullptr, this);
    if (!closable) {
        for (auto tab : std::as_const(d->tabList)) {
            if (closeSide == LeftSide && tab->leftWidget) {
                tab->leftWidget->deleteLater();
                tab->leftWidget = nullptr;
            }
            if (closeSide == RightSide && tab->rightWidget) {
                tab->rightWidget->deleteLater();
                tab->rightWidget = nullptr;
            }
        }
    } else {
        bool newButtons = false;
        for (int i = 0; i < d->tabList.size(); ++i) {
            if (tabButton(i, closeSide))
                continue;
            newButtons = true;
            QAbstractButton *closeButton = new CloseButton(this);
            connect(closeButton, SIGNAL(clicked()), this, SLOT(_q_closeTab()));
            setTabButton(i, closeSide, closeButton);
        }
        if (newButtons)
            d->layoutTabs();
    }
    update();
}
 
QTabBar::SelectionBehavior QTabBar::selectionBehaviorOnRemove() const
{
    Q_D(const QTabBar);
    return d->selectionBehaviorOnRemove;
}
 
void QTabBar::setSelectionBehaviorOnRemove(QTabBar::SelectionBehavior behavior)
{
    Q_D(QTabBar);
    d->selectionBehaviorOnRemove = behavior;
}
 
bool QTabBar::expanding() const
{
    Q_D(const QTabBar);
    return d->expanding;
}
 
void QTabBar::setExpanding(bool enabled)
{
    Q_D(QTabBar);
    if (d->expanding == enabled)
        return;
    d->expanding = enabled;
    d->layoutTabs();
}
 
bool QTabBar::isMovable() const
{
    Q_D(const QTabBar);
    return d->movable;
}
 
void QTabBar::setMovable(bool movable)
{
    Q_D(QTabBar);
    d->movable = movable;
}
 
 
bool QTabBar::documentMode() const
{
    return d_func()->documentMode;
}
 
void QTabBar::setDocumentMode(bool enabled)
{
    Q_D(QTabBar);
 
    d->documentMode = enabled;
    d->updateMacBorderMetrics();
}
 
bool QTabBar::autoHide() const
{
    Q_D(const QTabBar);
    return d->autoHide;
}
 
void QTabBar::setAutoHide(bool hide)
{
    Q_D(QTabBar);
    if (d->autoHide == hide)
        return;
 
    d->autoHide = hide;
    if (hide)
        d->autoHideTabs();
    else
        setVisible(true);
}
 
bool QTabBar::changeCurrentOnDrag() const
{
    Q_D(const QTabBar);
    return d->changeCurrentOnDrag;
}
 
void QTabBar::setChangeCurrentOnDrag(bool change)
{
    Q_D(QTabBar);
    d->changeCurrentOnDrag = change;
    if (!change)
        d->killSwitchTabTimer();
}
 
void QTabBar::setTabButton(int index, ButtonPosition position, QWidget *widget)
{
    Q_D(QTabBar);
    if (index < 0 || index >= d->tabList.size())
        return;
    if (widget) {
        widget->setParent(this);
        // make sure our left and right widgets stay on top
        widget->lower();
        widget->show();
    }
    auto &tab = *d->tabList.at(index);
    if (position == LeftSide) {
        if (tab.leftWidget)
            tab.leftWidget->hide();
        tab.leftWidget = widget;
    } else {
        if (tab.rightWidget)
            tab.rightWidget->hide();
        tab.rightWidget = widget;
    }
    d->layoutTabs();
    d->refresh();
    update();
}
 
QWidget *QTabBar::tabButton(int index, ButtonPosition position) const
{
    Q_D(const QTabBar);
    if (const auto tab = d->at(index)) {
        return position == LeftSide ? tab->leftWidget
                                    : tab->rightWidget;
    }
    return nullptr;
}
 
#if QT_CONFIG(accessibility)
void QTabBar::setAccessibleTabName(int index, const QString &name)
{
    Q_D(QTabBar);
    if (QTabBarPrivate::Tab *tab = d->at(index)) {
        tab->accessibleName = name;
        QAccessibleEvent event(this, QAccessible::NameChanged);
        event.setChild(index);
        QAccessible::updateAccessibility(&event);
    }
}
 
QString QTabBar::accessibleTabName(int index) const
{
    Q_D(const QTabBar);
    if (const QTabBarPrivate::Tab *tab = d->at(index))
        return tab->accessibleName;
    return QString();
}
#endif // QT_CONFIG(accessibility)
 
CloseButton::CloseButton(QWidget *parent)
    : QAbstractButton(parent)
{
    setFocusPolicy(Qt::NoFocus);
#ifndef QT_NO_CURSOR
    setCursor(Qt::ArrowCursor);
#endif
#if QT_CONFIG(tooltip)
    setToolTip(tr("Close Tab"));
#endif
    resize(sizeHint());
}
 
QSize CloseButton::sizeHint() const
{
    ensurePolished();
    int width = style()->pixelMetric(QStyle::PM_TabCloseIndicatorWidth, nullptr, this);
    int height = style()->pixelMetric(QStyle::PM_TabCloseIndicatorHeight, nullptr, this);
    return QSize(width, height);
}
 
void CloseButton::enterEvent(QEnterEvent *event)
{
    if (isEnabled())
        update();
    QAbstractButton::enterEvent(event);
}
 
void CloseButton::leaveEvent(QEvent *event)
{
    if (isEnabled())
        update();
    QAbstractButton::leaveEvent(event);
}
 
void CloseButton::paintEvent(QPaintEvent *)
{
    QPainter p(this);
    QStyleOption opt;
    opt.initFrom(this);
    opt.state |= QStyle::State_AutoRaise;
    if (isEnabled() && underMouse() && !isChecked() && !isDown())
        opt.state |= QStyle::State_Raised;
    if (isChecked())
        opt.state |= QStyle::State_On;
    if (isDown())
        opt.state |= QStyle::State_Sunken;
 
    if (const QTabBar *tb = qobject_cast<const QTabBar *>(parent())) {
        int index = tb->currentIndex();
        QTabBar::ButtonPosition position = (QTabBar::ButtonPosition)style()->styleHint(QStyle::SH_TabBar_CloseButtonPosition, nullptr, tb);
        if (tb->tabButton(index, position) == this)
            opt.state |= QStyle::State_Selected;
    }
 
    style()->drawPrimitive(QStyle::PE_IndicatorTabClose, &opt, &p, this);
}
 
#if QT_CONFIG(animation)
void QTabBarPrivate::Tab::TabBarAnimation::updateCurrentValue(const QVariant &current)
{
    priv->moveTab(priv->tabList.indexOf(tab), current.toInt());
}
 
void QTabBarPrivate::Tab::TabBarAnimation::updateState(QAbstractAnimation::State newState, QAbstractAnimation::State)
{
    if (newState == Stopped) priv->moveTabFinished(priv->tabList.indexOf(tab));
}
#endif
 
QT_END_NAMESPACE
 
#include "moc_qtabbar.cpp"
#include "qtabbar.moc"