/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser General Public
** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this
** file. Please review the following information to ensure the GNU Lesser
** General Public License version 2.1 requirements will be met:
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU General
** Public License version 3.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of this
** file. Please review the following information to ensure the GNU General
** Public License version 3.0 requirements will be met:
** http://www.gnu.org/copyleft/gpl.html.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
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**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qglobal.h"

#ifndef QT_NO_GRAPHICSVIEW

#include <QtCore/qdebug.h>
#include <QtCore/qnumeric.h>
#include "qgraphicswidget_p.h"
#include "qgraphicslayout.h"
#include "qgraphicsscene_p.h"
#include <QtGui/qapplication.h>
#include <QtGui/qgraphicsscene.h>
#include <QtGui/qstyleoption.h>
#include <QtGui/QStyleOptionTitleBar>
#include <QtGui/QGraphicsSceneMouseEvent>
#if defined(Q_WS_MAC) && !defined(QT_NO_STYLE_MAC)
# include <QMacStyle>
#endif

QT_BEGIN_NAMESPACE

void QGraphicsWidgetPrivate::init(QGraphicsItem *parentItem, Qt::WindowFlags wFlags)
{
    Q_Q(QGraphicsWidget);

    attributes = 0;
    isWidget = 1; // QGraphicsItem::isWidget() returns true.
    focusNext = focusPrev = q;
    focusPolicy = Qt::NoFocus;

    adjustWindowFlags(&wFlags);
    windowFlags = wFlags;

    if (parentItem)
        setParentItemHelper(parentItem, 0, 0);

    q->setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred, QSizePolicy::DefaultType));
    q->setGraphicsItem(q);

    resolveLayoutDirection();
    q->unsetWindowFrameMargins();
    flags |= QGraphicsItem::ItemUsesExtendedStyleOption;
    flags |= QGraphicsItem::ItemSendsGeometryChanges;
    if (windowFlags & Qt::Window)
        flags |= QGraphicsItem::ItemIsPanel;
}

qreal QGraphicsWidgetPrivate::titleBarHeight(const QStyleOptionTitleBar &options) const
{
    Q_Q(const QGraphicsWidget);
    int height = q->style()->pixelMetric(QStyle::PM_TitleBarHeight, &options);
#if defined(Q_WS_MAC) && !defined(QT_NO_STYLE_MAC)
    if (qobject_cast<QMacStyle*>(q->style())) {
        height -=4;
    }
#endif
    return (qreal)height;
}

/*!
    \internal
*/
QGraphicsWidgetPrivate::~QGraphicsWidgetPrivate()
{
    // Remove any lazily allocated data
    delete[] margins;
    delete[] windowFrameMargins;
    delete windowData;
}

/*!
    \internal

     Ensures that margins is allocated.
     This function must be called before any dereferencing.
*/
void QGraphicsWidgetPrivate::ensureMargins() const
{
    if (!margins) {
        margins = new qreal[4];
        for (int i = 0; i < 4; ++i)
            margins[i] = 0;
    }
}

/*!
    \internal

     Ensures that windowFrameMargins is allocated.
     This function must be called before any dereferencing.
*/
void QGraphicsWidgetPrivate::ensureWindowFrameMargins() const
{
    if (!windowFrameMargins) {
        windowFrameMargins = new qreal[4];
        for (int i = 0; i < 4; ++i)
            windowFrameMargins[i] = 0;
    }
}

/*!
    \internal

     Ensures that windowData is allocated.
     This function must be called before any dereferencing.
*/
void QGraphicsWidgetPrivate::ensureWindowData()
{
    if (!windowData)
        windowData = new WindowData;
}

void QGraphicsWidgetPrivate::setPalette_helper(const QPalette &palette)
{
    if (this->palette == palette && this->palette.resolve() == palette.resolve())
        return;
    updatePalette(palette);
}

void QGraphicsWidgetPrivate::resolvePalette(uint inheritedMask)
{
    inheritedPaletteResolveMask = inheritedMask;
    QPalette naturalPalette = naturalWidgetPalette();
    QPalette resolvedPalette = palette.resolve(naturalPalette);
    updatePalette(resolvedPalette);
}

void QGraphicsWidgetPrivate::updatePalette(const QPalette &palette)
{
    Q_Q(QGraphicsWidget);
    // Update local palette setting.
    this->palette = palette;

    // Calculate new mask.
    if (q->isWindow() && !q->testAttribute(Qt::WA_WindowPropagation))
        inheritedPaletteResolveMask = 0;
    int mask = palette.resolve() | inheritedPaletteResolveMask;

    // Propagate to children.
    for (int i = 0; i < children.size(); ++i) {
        QGraphicsItem *item = children.at(i);
        if (item->isWidget()) {
            QGraphicsWidget *w = static_cast<QGraphicsWidget *>(item);
            if (!w->isWindow() || w->testAttribute(Qt::WA_WindowPropagation))
                w->d_func()->resolvePalette(mask);
        } else {
            item->d_ptr->resolvePalette(mask);
        }
    }

    // Notify change.
    QEvent event(QEvent::PaletteChange);
    QApplication::sendEvent(q, &event);
}

void QGraphicsWidgetPrivate::setLayoutDirection_helper(Qt::LayoutDirection direction)
{
    Q_Q(QGraphicsWidget);
    if ((direction == Qt::RightToLeft) == (testAttribute(Qt::WA_RightToLeft)))
        return;
    q->setAttribute(Qt::WA_RightToLeft, (direction == Qt::RightToLeft));

    // Propagate this change to all children.
    for (int i = 0; i < children.size(); ++i) {
        QGraphicsItem *item = children.at(i);
        if (item->isWidget()) {
            QGraphicsWidget *widget = static_cast<QGraphicsWidget *>(item);
            if (widget->parentWidget() && !widget->testAttribute(Qt::WA_SetLayoutDirection))
                widget->d_func()->setLayoutDirection_helper(direction);
        }
    }

    // Send the notification event to this widget item.
    QEvent e(QEvent::LayoutDirectionChange);
    QApplication::sendEvent(q, &e);
}

void QGraphicsWidgetPrivate::resolveLayoutDirection()
{
    Q_Q(QGraphicsWidget);
    if (q->testAttribute(Qt::WA_SetLayoutDirection)) {
        return;
    }
    if (QGraphicsWidget *parentWidget = q->parentWidget()) {
        setLayoutDirection_helper(parentWidget->layoutDirection());
    } else if (scene) {
        // ### shouldn't the scene have a layoutdirection really? how does
        // ### QGraphicsWidget get changes from QApplication::layoutDirection?
        setLayoutDirection_helper(QApplication::layoutDirection());
    } else {
        setLayoutDirection_helper(QApplication::layoutDirection());
    }
}

/* private slot */
void QGraphicsWidgetPrivate::_q_relayout()
{
    --refCountInvokeRelayout;
    if (refCountInvokeRelayout == 0) {
        Q_Q(QGraphicsWidget);
        bool wasResized = q->testAttribute(Qt::WA_Resized);
        q->resize(q->size()); // this will restrict the size
        q->setAttribute(Qt::WA_Resized, wasResized);
    }
}

QPalette QGraphicsWidgetPrivate::naturalWidgetPalette() const
{
    Q_Q(const QGraphicsWidget);
    QPalette palette;
    if (QGraphicsWidget *parent = q->parentWidget()) {
        palette = parent->palette();
    } else if (scene) {
        palette = scene->palette();
    }
    palette.resolve(0);
    return palette;
}

void QGraphicsWidgetPrivate::setFont_helper(const QFont &font)
{
    if (this->font == font && this->font.resolve() == font.resolve())
        return;
    updateFont(font);
}

void QGraphicsWidgetPrivate::resolveFont(uint inheritedMask)
{
    Q_Q(QGraphicsWidget);
    inheritedFontResolveMask = inheritedMask;
    if (QGraphicsWidget *p = q->parentWidget())
        inheritedFontResolveMask |= p->d_func()->inheritedFontResolveMask;
    QFont naturalFont = naturalWidgetFont();
    QFont resolvedFont = font.resolve(naturalFont);
    updateFont(resolvedFont);
}

void QGraphicsWidgetPrivate::updateFont(const QFont &font)
{
    Q_Q(QGraphicsWidget);
    // Update the local font setting.
    this->font = font;

    // Calculate new mask.
    if (q->isWindow() && !q->testAttribute(Qt::WA_WindowPropagation))
        inheritedFontResolveMask = 0;
    int mask = font.resolve() | inheritedFontResolveMask;

    // Propagate to children.
    for (int i = 0; i < children.size(); ++i) {
        QGraphicsItem *item = children.at(i);
        if (item->isWidget()) {
            QGraphicsWidget *w = static_cast<QGraphicsWidget *>(item);
            if (!w->isWindow() || w->testAttribute(Qt::WA_WindowPropagation))
                w->d_func()->resolveFont(mask);
        } else {
            item->d_ptr->resolveFont(mask);
        }
    }

    if (!polished)
        return;
    // Notify change.
    QEvent event(QEvent::FontChange);
    QApplication::sendEvent(q, &event);
}

QFont QGraphicsWidgetPrivate::naturalWidgetFont() const
{
    Q_Q(const QGraphicsWidget);
    QFont naturalFont; // ### no application font support
    if (QGraphicsWidget *parent = q->parentWidget()) {
        naturalFont = parent->font();
    } else if (scene) {
        naturalFont = scene->font();
    }
    naturalFont.resolve(0);
    return naturalFont;
}

void QGraphicsWidgetPrivate::initStyleOptionTitleBar(QStyleOptionTitleBar *option)
{
    Q_Q(QGraphicsWidget);
    ensureWindowData();
    q->initStyleOption(option);
    option->rect.setHeight(titleBarHeight(*option));
    option->titleBarFlags = windowFlags;
    option->subControls = QStyle::SC_TitleBarCloseButton | QStyle::SC_TitleBarLabel | QStyle::SC_TitleBarSysMenu;
    option->activeSubControls = windowData->hoveredSubControl;
    bool isActive = q->isActiveWindow();
    if (isActive) {
        option->state |= QStyle::State_Active;
        option->titleBarState = Qt::WindowActive;
        option->titleBarState |= QStyle::State_Active;
    } else {
        option->state &= ~QStyle::State_Active;
        option->titleBarState = Qt::WindowNoState;
    }
    QFont windowTitleFont = QApplication::font("QWorkspaceTitleBar");
    QRect textRect = q->style()->subControlRect(QStyle::CC_TitleBar, option, QStyle::SC_TitleBarLabel, 0);
    option->text = QFontMetrics(windowTitleFont).elidedText(
        windowData->windowTitle, Qt::ElideRight, textRect.width());
}

void QGraphicsWidgetPrivate::adjustWindowFlags(Qt::WindowFlags *flags)
{
    bool customize =  (*flags & (Qt::CustomizeWindowHint
            | Qt::FramelessWindowHint
            | Qt::WindowTitleHint
            | Qt::WindowSystemMenuHint
            | Qt::WindowMinimizeButtonHint
            | Qt::WindowMaximizeButtonHint
            | Qt::WindowContextHelpButtonHint));

    uint type = (*flags & Qt::WindowType_Mask);
    if (customize)
        ;
    else if (type == Qt::Dialog || type == Qt::Sheet)
        *flags |= Qt::WindowTitleHint | Qt::WindowSystemMenuHint | Qt::WindowContextHelpButtonHint;
    else if (type == Qt::Tool)
        *flags |= Qt::WindowTitleHint | Qt::WindowSystemMenuHint;
    else if (type == Qt::Window || type == Qt::SubWindow)
        *flags |= Qt::WindowTitleHint | Qt::WindowSystemMenuHint
                  | Qt::WindowMinimizeButtonHint | Qt::WindowMaximizeButtonHint;
}

void QGraphicsWidgetPrivate::windowFrameMouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    Q_Q(QGraphicsWidget);
    ensureWindowData();
    if (windowData->grabbedSection != Qt::NoSection) {
        if (windowData->grabbedSection == Qt::TitleBarArea) {
            windowData->buttonSunken = false;
            QStyleOptionTitleBar bar;
            initStyleOptionTitleBar(&bar);
            // make sure that the coordinates (rect and pos) we send to the style are positive.
            bar.rect = q->windowFrameRect().toRect();
            bar.rect.moveTo(0,0);
            bar.rect.setHeight(q->style()->pixelMetric(QStyle::PM_TitleBarHeight, &bar));
            QPointF pos = event->pos();
            if (windowFrameMargins) {
                pos.rx() += windowFrameMargins[Left];
                pos.ry() += windowFrameMargins[Top];
            }
            bar.subControls = QStyle::SC_TitleBarCloseButton;
            if (q->style()->subControlRect(QStyle::CC_TitleBar, &bar,
                                           QStyle::SC_TitleBarCloseButton,
                                           event->widget()).contains(pos.toPoint())) {
                q->close();
            }
        }
        if (!(static_cast<QGraphicsSceneMouseEvent *>(event)->buttons()))
            windowData->grabbedSection = Qt::NoSection;
        event->accept();
    }
}

void QGraphicsWidgetPrivate::windowFrameMousePressEvent(QGraphicsSceneMouseEvent *event)
{
    Q_Q(QGraphicsWidget);
    if (event->button() != Qt::LeftButton)
        return;

    ensureWindowData();
    windowData->startGeometry = q->geometry();
    windowData->grabbedSection = q->windowFrameSectionAt(event->pos());
    ensureWindowData();
    if (windowData->grabbedSection == Qt::TitleBarArea
        && windowData->hoveredSubControl == QStyle::SC_TitleBarCloseButton) {
        windowData->buttonSunken = true;
        q->update();
    }
    event->setAccepted(windowData->grabbedSection != Qt::NoSection);
}

/*!
  Used to calculate the
  Precondition:
  \a widget should support either hfw or wfh

  If \a heightForWidth is set to false, this function will query the width for height
  instead. \a width will then be interpreted as height, \a minh and \a maxh will be interpreted
  as minimum width and maximum width.
 */
static qreal minimumHeightForWidth(qreal width, qreal minh, qreal maxh,
                                   const QGraphicsWidget *widget,
                                   bool heightForWidth = true)
{
    qreal minimumHeightForWidth = -1;
    const QSizePolicy sp = widget->layout() ? widget->layout()->sizePolicy() : widget->sizePolicy();
    const bool hasHFW = sp.hasHeightForWidth();
    if (hasHFW == heightForWidth) {
        minimumHeightForWidth = hasHFW
                                ? widget->effectiveSizeHint(Qt::MinimumSize, QSizeF(width, -1)).height()
                                : widget->effectiveSizeHint(Qt::MinimumSize, QSizeF(-1, width)).width();    //"width" is here height!
    } else {
        // widthForHeight
        const qreal constraint = width;
        while (maxh - minh > 0.1) {
            qreal middle = minh + (maxh - minh)/2;
            // ### really bad, if we are a widget with a layout it will call
            // layout->effectiveSizeHint(Qt::MiniumumSize), which again will call
            // sizeHint three times because of how the cache works
            qreal hfw = hasHFW
                        ? widget->effectiveSizeHint(Qt::MinimumSize, QSizeF(middle, -1)).height()
                        : widget->effectiveSizeHint(Qt::MinimumSize, QSizeF(-1, middle)).width();
            if (hfw > constraint) {
                minh = middle;
            } else if (hfw <= constraint) {
                maxh = middle;
            }
        }
        minimumHeightForWidth = maxh;
    }
    return minimumHeightForWidth;
}

static qreal minimumWidthForHeight(qreal height, qreal minw, qreal maxw,
                                   const QGraphicsWidget *widget)
{
    return minimumHeightForWidth(height, minw, maxw, widget, false);
}

static QSizeF closestAcceptableSize(const QSizeF &proposed,
                                    const QGraphicsWidget *widget)
{
    const QSizeF current = widget->size();

    qreal minw = proposed.width();
    qreal maxw = current.width();
    qreal minh = proposed.height();
    qreal maxh = current.height();

    qreal middlew = maxw;
    qreal middleh = maxh;
    qreal min_hfw;
    min_hfw = minimumHeightForWidth(maxw, minh, maxh, widget);

    do {
        if (maxw - minw < 0.1) {
            // we still havent found anything, cut off binary search
            minw = maxw;
            minh = maxh;
        }
        middlew = minw + (maxw - minw)/2.0;
        middleh = minh + (maxh - minh)/2.0;

        min_hfw = minimumHeightForWidth(middlew, minh, maxh, widget);

        if (min_hfw > middleh) {
            minw = middlew;
            minh = middleh;
        } else if (min_hfw <= middleh) {
            maxw = middlew;
            maxh = middleh;
        }
    } while (maxw != minw);

    min_hfw = minimumHeightForWidth(middlew, minh, maxh, widget);

    QSizeF result;
    if (min_hfw < maxh) {
        result = QSizeF(middlew, min_hfw);
    } else {
        // Needed because of the cut-off we do above.
        result = QSizeF(minimumWidthForHeight(maxh, proposed.width(), current.width(), widget), maxh);
    }
    return result;
}

static void _q_boundGeometryToSizeConstraints(const QRectF &startGeometry,
                                              QRectF *rect, Qt::WindowFrameSection section,
                                              const QSizeF &min, const QSizeF &max,
                                              const QGraphicsWidget *widget)
{
    const QRectF proposedRect = *rect;
    qreal width = qBound(min.width(), proposedRect.width(), max.width());
    qreal height = qBound(min.height(), proposedRect.height(), max.height());

    QSizePolicy sp = widget->sizePolicy();
    if (const QGraphicsLayout *l = widget->layout()) {
        sp = l->sizePolicy();
    }
    const bool hasHFW = sp.hasHeightForWidth(); // || sp.hasWidthForHeight();

    const bool widthChanged = proposedRect.width() < widget->size().width();
    const bool heightChanged = proposedRect.height() < widget->size().height();

    if (hasHFW) {
        if (widthChanged || heightChanged) {
            const qreal minh = min.height();
            const qreal maxh = max.height();
            const qreal proposedHFW = minimumHeightForWidth(width, minh, maxh, widget);
            if (proposedHFW > proposedRect.height()) {
                QSizeF effectiveSize = closestAcceptableSize(QSizeF(width, height), widget);
                width = effectiveSize.width();
                height = effectiveSize.height();
            }
        }
    }

    switch (section) {
    case Qt::LeftSection:
        rect->setRect(startGeometry.right() - qRound(width), startGeometry.top(),
                      qRound(width), startGeometry.height());
        break;
    case Qt::TopLeftSection:
        rect->setRect(startGeometry.right() - qRound(width), startGeometry.bottom() - qRound(height),
                      qRound(width), qRound(height));
        break;
    case Qt::TopSection:
        rect->setRect(startGeometry.left(), startGeometry.bottom() - qRound(height),
                      startGeometry.width(), qRound(height));
        break;
    case Qt::TopRightSection:
        rect->setTop(rect->bottom() - qRound(height));
        rect->setWidth(qRound(width));
        break;
    case Qt::RightSection:
        rect->setWidth(qRound(width));
        break;
    case Qt::BottomRightSection:
        rect->setWidth(qRound(width));
        rect->setHeight(qRound(height));
        break;
    case Qt::BottomSection:
        rect->setHeight(qRound(height));
        break;
    case Qt::BottomLeftSection:
        rect->setRect(startGeometry.right() - qRound(width), startGeometry.top(),
                      qRound(width), qRound(height));
        break;
    default:
        break;
    }
}

void QGraphicsWidgetPrivate::windowFrameMouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    Q_Q(QGraphicsWidget);
    ensureWindowData();
    if (!(event->buttons() & Qt::LeftButton) || windowData->hoveredSubControl != QStyle::SC_TitleBarLabel)
        return;

    QLineF delta(q->mapFromScene(event->buttonDownScenePos(Qt::LeftButton)), event->pos());
    QLineF parentDelta(q->mapToParent(delta.p1()), q->mapToParent(delta.p2()));
    QLineF parentXDelta(q->mapToParent(QPointF(delta.p1().x(), 0)), q->mapToParent(QPointF(delta.p2().x(), 0)));
    QLineF parentYDelta(q->mapToParent(QPointF(0, delta.p1().y())), q->mapToParent(QPointF(0, delta.p2().y())));

    QRectF newGeometry;
    switch (windowData->grabbedSection) {
    case Qt::LeftSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft()
                             + QPointF(parentXDelta.dx(), parentXDelta.dy()),
                             windowData->startGeometry.size() - QSizeF(delta.dx(), delta.dy()));
        break;
    case Qt::TopLeftSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft()
                             + QPointF(parentDelta.dx(), parentDelta.dy()),
                             windowData->startGeometry.size() - QSizeF(delta.dx(), delta.dy()));
        break;
    case Qt::TopSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft()
                             + QPointF(parentYDelta.dx(), parentYDelta.dy()),
                             windowData->startGeometry.size() - QSizeF(0, delta.dy()));
        break;
    case Qt::TopRightSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft()
                             + QPointF(parentYDelta.dx(), parentYDelta.dy()),
                             windowData->startGeometry.size() - QSizeF(-delta.dx(), delta.dy()));
        break;
    case Qt::RightSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft(),
                             windowData->startGeometry.size() + QSizeF(delta.dx(), 0));
        break;
    case Qt::BottomRightSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft(),
                             windowData->startGeometry.size() + QSizeF(delta.dx(), delta.dy()));
        break;
    case Qt::BottomSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft(),
                             windowData->startGeometry.size() + QSizeF(0, delta.dy()));
        break;
    case Qt::BottomLeftSection:
        newGeometry = QRectF(windowData->startGeometry.topLeft()
                             + QPointF(parentXDelta.dx(), parentXDelta.dy()),
                             windowData->startGeometry.size() - QSizeF(delta.dx(), -delta.dy()));
        break;
    case Qt::TitleBarArea:
        newGeometry = QRectF(windowData->startGeometry.topLeft()
                             + QPointF(parentDelta.dx(), parentDelta.dy()),
                             windowData->startGeometry.size());
        break;
    case Qt::NoSection:
        break;
    }

    if (windowData->grabbedSection != Qt::NoSection) {
        _q_boundGeometryToSizeConstraints(windowData->startGeometry, &newGeometry,
                                          windowData->grabbedSection,
                                          q->effectiveSizeHint(Qt::MinimumSize),
                                          q->effectiveSizeHint(Qt::MaximumSize),
                                          q);
        q->setGeometry(newGeometry);
    }
}

void QGraphicsWidgetPrivate::windowFrameHoverMoveEvent(QGraphicsSceneHoverEvent *event)
{
    Q_Q(QGraphicsWidget);
    if (!hasDecoration())
        return;

    ensureWindowData();

    if (q->rect().contains(event->pos())) {
        if (windowData->buttonMouseOver || windowData->hoveredSubControl != QStyle::SC_None)
            windowFrameHoverLeaveEvent(event);
        return;
    }

    bool wasMouseOver = windowData->buttonMouseOver;
    QRect oldButtonRect = windowData->buttonRect;
    windowData->buttonRect = QRect();
    windowData->buttonMouseOver = false;
    QPointF pos = event->pos();
    QStyleOptionTitleBar bar;
    // make sure that the coordinates (rect and pos) we send to the style are positive.
    if (windowFrameMargins) {
        pos.rx() += windowFrameMargins[Left];
        pos.ry() += windowFrameMargins[Top];
    }
    initStyleOptionTitleBar(&bar);
    bar.rect = q->windowFrameRect().toRect();
    bar.rect.moveTo(0,0);
    bar.rect.setHeight(int(titleBarHeight(bar)));

    Qt::CursorShape cursorShape = Qt::ArrowCursor;
    bool needsSetCursorCall = true;
    switch (q->windowFrameSectionAt(event->pos())) {
        case Qt::TopLeftSection:
        case Qt::BottomRightSection:
            cursorShape = Qt::SizeFDiagCursor;
            break;
        case Qt::TopRightSection:
        case Qt::BottomLeftSection:
            cursorShape = Qt::SizeBDiagCursor;
            break;
        case Qt::LeftSection:
        case Qt::RightSection:
            cursorShape = Qt::SizeHorCursor;
            break;
        case Qt::TopSection:
        case Qt::BottomSection:
            cursorShape = Qt::SizeVerCursor;
            break;
        case Qt::TitleBarArea:
            windowData->buttonRect = q->style()->subControlRect(
                QStyle::CC_TitleBar, &bar, QStyle::SC_TitleBarCloseButton, 0);
#ifdef Q_WS_MAC
            // On mac we should hover if we are in the 'area' of the buttons
            windowData->buttonRect |= q->style()->subControlRect(
                QStyle::CC_TitleBar, &bar, QStyle::SC_TitleBarMinButton, 0);
            windowData->buttonRect |= q->style()->subControlRect(
                QStyle::CC_TitleBar, &bar, QStyle::SC_TitleBarMaxButton, 0);
#endif
            if (windowData->buttonRect.contains(pos.toPoint()))
                windowData->buttonMouseOver = true;
            event->ignore();
            break;
        default:
            needsSetCursorCall = false;
            event->ignore();
        }
#ifndef QT_NO_CURSOR
    if (needsSetCursorCall)
        q->setCursor(cursorShape);
#endif
    // update buttons if we hover over them
    windowData->hoveredSubControl = q->style()->hitTestComplexControl(QStyle::CC_TitleBar, &bar, pos.toPoint(), 0);
    if (windowData->hoveredSubControl != QStyle::SC_TitleBarCloseButton)
        windowData->hoveredSubControl = QStyle::SC_TitleBarLabel;

    if (windowData->buttonMouseOver != wasMouseOver) {
        if (!oldButtonRect.isNull())
            q->update(QRectF(oldButtonRect).translated(q->windowFrameRect().topLeft()));
        if (!windowData->buttonRect.isNull())
            q->update(QRectF(windowData->buttonRect).translated(q->windowFrameRect().topLeft()));
    }
}

void QGraphicsWidgetPrivate::windowFrameHoverLeaveEvent(QGraphicsSceneHoverEvent *event)
{
    Q_UNUSED(event);
    Q_Q(QGraphicsWidget);
    if (hasDecoration()) {
        // ### restore the cursor, don't override it
#ifndef QT_NO_CURSOR
        q->unsetCursor();
#endif

        ensureWindowData();

        bool needsUpdate = false;
        if (windowData->hoveredSubControl == QStyle::SC_TitleBarCloseButton
            || windowData->buttonMouseOver)
            needsUpdate = true;

        // update the hover state (of buttons etc...)
        windowData->hoveredSubControl = QStyle::SC_None;
        windowData->buttonMouseOver = false;
        windowData->buttonRect = QRect();
        if (needsUpdate)
            q->update(windowData->buttonRect);
    }
}

bool QGraphicsWidgetPrivate::hasDecoration() const
{
    return (windowFlags & Qt::Window) && (windowFlags & Qt::WindowTitleHint);
}

/**
 * is called after a reparent has taken place to fix up the focus chain(s)
 */
void QGraphicsWidgetPrivate::fixFocusChainBeforeReparenting(QGraphicsWidget *newParent, QGraphicsScene *oldScene, QGraphicsScene *newScene)
{
    Q_Q(QGraphicsWidget);

    Q_ASSERT(focusNext && focusPrev);

    QGraphicsWidget *n = q;     //last one in 'new' list
    QGraphicsWidget *o = 0;     //last one in 'old' list

    QGraphicsWidget *w = focusNext;

    QGraphicsWidget *firstOld = 0;
    bool wasPreviousNew = true;

    while (w != q) {
        bool isCurrentNew = q->isAncestorOf(w);
        if (isCurrentNew) {
            if (!wasPreviousNew) {
                n->d_func()->focusNext = w;
                w->d_func()->focusPrev = n;
            }
            n = w;
        } else /*if (!isCurrentNew)*/ {
            if (wasPreviousNew) {
                if (o) {
                    o->d_func()->focusNext = w;
                    w->d_func()->focusPrev = o;
                } else {
                    firstOld = w;
                }
            }
            o = w;
        }
        w = w->d_func()->focusNext;
        wasPreviousNew = isCurrentNew;
    }

    // repair the 'old' chain
    if (firstOld) {
        o->d_func()->focusNext = firstOld;
        firstOld->d_func()->focusPrev = o;
    }

    // update tabFocusFirst for oldScene if the item is going to be removed from oldScene
    if (newParent)
        newScene = newParent->scene();

    if (oldScene && newScene != oldScene)
        oldScene->d_func()->tabFocusFirst = (firstOld && firstOld->scene() == oldScene) ? firstOld : 0;

    QGraphicsItem *topLevelItem = newParent ? newParent->topLevelItem() : 0;
    QGraphicsWidget *topLevel = 0;
    if (topLevelItem && topLevelItem->isWidget())
        topLevel = static_cast<QGraphicsWidget *>(topLevelItem);

    if (topLevel && newParent) {
        QGraphicsWidget *last = topLevel->d_func()->focusPrev;
        // link last with new chain
        last->d_func()->focusNext = q;
        focusPrev = last;

        // link last in chain with
        topLevel->d_func()->focusPrev = n;
        n->d_func()->focusNext = topLevel;
    } else {
        // q is the start of the focus chain
        n->d_func()->focusNext = q;
        focusPrev = n;
    }

}

void QGraphicsWidgetPrivate::setLayout_helper(QGraphicsLayout *l)
{
    delete (this->layout);
    layout = l;
    if (!l) {
        Q_Q(QGraphicsWidget);
        q->updateGeometry();
    }
}

qreal QGraphicsWidgetPrivate::width() const
{
    Q_Q(const QGraphicsWidget);
    return q->geometry().width();
}

void QGraphicsWidgetPrivate::setWidth(qreal w)
{
    if (qIsNaN(w))
        return;
    Q_Q(QGraphicsWidget);
    if (q->geometry().width() == w)
        return;

    QRectF oldGeom = q->geometry();

    q->setGeometry(QRectF(q->x(), q->y(), w, height()));
}

void QGraphicsWidgetPrivate::resetWidth()
{
    Q_Q(QGraphicsWidget);
    q->setGeometry(QRectF(q->x(), q->y(), 0, height()));
}

qreal QGraphicsWidgetPrivate::height() const
{
    Q_Q(const QGraphicsWidget);
    return q->geometry().height();
}

void QGraphicsWidgetPrivate::setHeight(qreal h)
{
    if (qIsNaN(h))
        return;
    Q_Q(QGraphicsWidget);
    if (q->geometry().height() == h)
        return;

    QRectF oldGeom = q->geometry();

    q->setGeometry(QRectF(q->x(), q->y(), width(), h));
}

void QGraphicsWidgetPrivate::resetHeight()
{
    Q_Q(QGraphicsWidget);
    q->setGeometry(QRectF(q->x(), q->y(), width(), 0));
}

void QGraphicsWidgetPrivate::setGeometryFromSetPos()
{
    if (inSetGeometry)
        return;
    Q_Q(QGraphicsWidget);
    inSetPos = 1;
    // Ensure setGeometry is called (avoid recursion when setPos is
    // called from within setGeometry).
    q->setGeometry(QRectF(pos, q->size()));
    inSetPos = 0 ;
}

QT_END_NAMESPACE

#include "moc_qgraphicswidget.cpp"

#endif //QT_NO_GRAPHICSVIEW