path: root/src/gui/graphicsview/qgraphicsitem.cpp

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/*!
    \class QGraphicsItem
    \brief The QGraphicsItem class is the base class for all graphical
    items in a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    It provides a light-weight foundation for writing your own custom items.
    This includes defining the item's geometry, collision detection, its
    painting implementation and item interaction through its event handlers.
    QGraphicsItem is part of \l{The Graphics View Framework}

    \img graphicsview-items.png

    For convenience, Qt provides a set of standard graphics items for the most
    common shapes. These are:

    \list
    \o QGraphicsEllipseItem provides an ellipse item
    \o QGraphicsLineItem provides a line item
    \o QGraphicsPathItem provides an arbitrary path item
    \o QGraphicsPixmapItem provides a pixmap item
    \o QGraphicsPolygonItem provides a polygon item
    \o QGraphicsRectItem provides a rectangular item
    \o QGraphicsSimpleTextItem provides a simple text label item
    \o QGraphicsTextItem provides an advanced text browser item
    \endlist

    All of an item's geometric information is based on its local coordinate
    system. The item's position, pos(), is the only function that does not
    operate in local coordinates, as it returns a position in parent
    coordinates. \l {The Graphics View Coordinate System} describes the coordinate
    system in detail.

    You can set whether an item should be visible (i.e., drawn, and accepting
    events), by calling setVisible(). Hiding an item will also hide its
    children. Similarly, you can enable or disable an item by calling
    setEnabled(). If you disable an item, all its children will also be
    disabled. By default, items are both visible and enabled. To toggle
    whether an item is selected or not, first enable selection by setting
    the ItemIsSelectable flag, and then call setSelected(). Normally,
    selection is toggled by the scene, as a result of user interaction.

    To write your own graphics item, you first create a subclass of
    QGraphicsItem, and then start by implementing its two pure virtual public
    functions: boundingRect(), which returns an estimate of the area painted
    by the item, and paint(), which implements the actual painting. For
    example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 0

    The boundingRect() function has many different purposes. QGraphicsScene
    bases its item index on boundingRect(), and QGraphicsView uses it both for
    culling invisible items, and for determining the area that needs to be
    recomposed when drawing overlapping items. In addition, QGraphicsItem's
    collision detection mechanisms use boundingRect() to provide an efficient
    cut-off. The fine grained collision algorithm in collidesWithItem() is based
    on calling shape(), which returns an accurate outline of the item's shape
    as a QPainterPath.

    QGraphicsScene expects all items boundingRect() and shape() to remain
    unchanged unless it is notified. If you want to change an item's geometry
    in any way, you must first call prepareGeometryChange() to allow
    QGraphicsScene to update its bookkeeping.

    Collision detection can be done in two ways:

    \list 1

    \o Reimplement shape() to return an accurate shape for your item, and rely
    on the default implementation of collidesWithItem() to do shape-shape
    intersection. This can be rather expensive if the shapes are complex.

    \o Reimplement collidesWithItem() to provide your own custom item and shape
    collision algorithm.

    \endlist

    The contains() function can be called to determine whether the item \e
    contains a point or not. This function can also be reimplemented by the
    item. The default behavior of contains() is based on calling shape().

    Items can contain other items, and also be contained by other items. All
    items can have a parent item and a list of children. Unless the item has
    no parent, its position is in \e parent coordinates (i.e., the parent's
    local coordinates). Parent items propagate both their position and their
    transformation to all children.

    \img graphicsview-parentchild.png

    QGraphicsItem supports affine transformations in addition to its base
    position, pos(). To change the item's transformation, you can either pass
    a transformation matrix to setTransform(), or call one of the convenience
    functions rotate(), scale(), translate(), or shear(). Item transformations
    accumulate from parent to child, so if both a parent and child item are
    rotated 90 degrees, the child's total transformation will be 180 degrees.
    Similarly, if the item's parent is scaled to 2x its original size, its
    children will also be twice as large. An item's transformation does not
    affect its own local geometry; all geometry functions (e.g., contains(),
    update(), and all the mapping functions) still operate in local
    coordinates. For convenience, QGraphicsItem provides the functions
    sceneTransform(), which returns the item's total transformation matrix
    (including its position and all parents' positions and transformations),
    and scenePos(), which returns its position in scene coordinates. To reset
    an item's matrix, call resetTransform().

    The paint() function is called by QGraphicsView to paint the item's
    contents. The item has no background or default fill of its own; whatever
    is behind the item will shine through all areas that are not explicitly
    painted in this function.  You can call update() to schedule a repaint,
    optionally passing the rectangle that needs a repaint. Depending on
    whether or not the item is visible in a view, the item may or may not be
    repainted; there is no equivalent to QWidget::repaint() in QGraphicsItem.

    Items are painted by the view, starting with the parent items and then
    drawing children, in ascending stacking order. You can set an item's
    stacking order by calling setZValue(), and test it by calling
    zValue(), where items with low z-values are painted before items with
    high z-values. Stacking order applies to sibling items; parents are always
    drawn before their children.

    QGraphicsItem receives events from QGraphicsScene through the virtual
    function sceneEvent(). This function distributes the most common events
    to a set of convenience event handlers:

    \list
    \o contextMenuEvent() handles context menu events
    \o focusInEvent() and focusOutEvent() handle focus in and out events
    \o hoverEnterEvent(), hoverMoveEvent(), and hoverLeaveEvent() handles
    hover enter, move and leave events
    \o inputMethodEvent() handles input events, for accessibility support
    \o keyPressEvent() and keyReleaseEvent handle key press and release events
    \o mousePressEvent(), mouseMoveEvent(), mouseReleaseEvent(), and
    mouseDoubleClickEvent() handles mouse press, move, release, click and
    doubleclick events
    \endlist

    You can filter events for any other item by installing event
    filters. This functionaly is separate from from Qt's regular
    event filters (see QObject::installEventFilter()), which only
    work on subclasses of QObject. After installing your item as an
    event filter for another item by calling
    installSceneEventFilter(), the filtered events will be received
    by the virtual function sceneEventFilter(). You can remove item
    event filters by calling removeSceneEventFilter().

    Sometimes it's useful to register custom data with an item, be it a custom
    item, or a standard item. You can call setData() on any item to store data
    in it using a key-value pair (the key being an integer, and the value is a
    QVariant). To get custom data from an item, call data(). This
    functionality is completely untouched by Qt itself; it is provided for the
    user's convenience.

    \sa QGraphicsScene, QGraphicsView, {The Graphics View Framework}
*/

/*!
    \variable QGraphicsItem::UserType

    The lowest permitted type value for custom items (subclasses
    of QGraphicsItem or any of the standard items). This value is
    used in conjunction with a reimplementation of QGraphicsItem::type()
    and declaring a Type enum value. Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 1
*/

/*!
    \enum QGraphicsItem::GraphicsItemFlag

    This enum describes different flags that you can set on an item to
    toggle different features in the item's behavior.

    All flags are disabled by default.

    \value ItemIsMovable The item supports interactive movement using
    the mouse. By clicking on the item and then dragging, the item
    will move together with the mouse cursor. If the item has
    children, all children are also moved. If the item is part of a
    selection, all selected items are also moved. This feature is
    provided as a convenience through the base implementation of
    QGraphicsItem's mouse event handlers.

    \value ItemIsSelectable The item supports selection. Enabling this
    feature will enable setSelected() to toggle selection for the
    item. It will also let the item be selected automatically as a
    result of calling QGraphicsScene::setSelectionArea(), by clicking
    on an item, or by using rubber band selection in QGraphicsView.

    \value ItemIsFocusable The item supports keyboard input focus (i.e., it is
    an input item). Enabling this flag will allow the item to accept focus,
    which again allows the delivery of key events to
    QGraphicsItem::keyPressEvent() and QGraphicsItem::keyReleaseEvent().

    \value ItemClipsToShape The item clips to its own shape. The item cannot
    draw or receive mouse, tablet, drag and drop or hover events outside ts
    shape. It is disabled by default. This behavior is enforced by
    QGraphicsView::drawItems() or QGraphicsScene::drawItems(). This flag was
    introduced in Qt 4.3.

    \value ItemClipsChildrenToShape The item clips the painting of all its
    descendants to its own shape. Items that are either direct or indirect
    children of this item cannot draw outside this item's shape. By default,
    this flag is disabled; children can draw anywhere. This behavior is
    enforced by QGraphicsView::drawItems() or
    QGraphicsScene::drawItems(). This flag was introduced in Qt 4.3.

    \value ItemIgnoresTransformations The item ignores inherited
    transformations (i.e., its position is still anchored to its parent, but
    the parent or view rotation, zoom or shear transformations are ignored).
    This flag is useful for keeping text label items horizontal and unscaled,
    so they will still be readable if the view is transformed.  When set, the
    item's view geometry and scene geometry will be maintained separately. You
    must call deviceTransform() to map coordinates and detect collisions in
    the view. By default, this flag is disabled. This flag was introduced in
    Qt 4.3. \note With this flag set you can still scale the item itself, and
    that scale transformation will influence the item's children.

    \value ItemIgnoresParentOpacity The item ignores its parent's opacity. The
    item's effective opacity is the same as its own; it does not combine with
    the parent's opacity. This flags allows your item to keep its absolute
    opacity even if the parent is semitransparent. This flag was introduced in
    Qt 4.5.

    \value ItemDoesntPropagateOpacityToChildren The item doesn't propagate its
    opacity to its children. This flag allows you to create a semitransparent
    item that does not affect the opacity of its children. This flag was
    introduced in Qt 4.5.

    \value ItemStacksBehindParent The item is stacked behind its parent. By
    default, child items are stacked on top of the parent item. But setting
    this flag, the child will be stacked behind it. This flag is useful for
    drop shadow effects and for decoration objects that follow the parent
    item's geometry without drawing on top of it.
*/

/*!
    \enum QGraphicsItem::GraphicsItemChange

        ItemVisibleHasChanged,
        ItemEnabledHasChanged,
        ItemSelectedHasChanged,
        ItemParentHasChanged,
        ItemSceneHasChanged

    This enum describes the state changes that are notified by
    QGraphicsItem::itemChange(). The notifications are sent as the state
    changes, and in some cases, adjustments can be made (see the documentation
    for each change for details).

    Note: Be careful with calling functions on the QGraphicsItem itself inside
    itemChange(), as certain function calls can lead to unwanted
    recursion. For example, you cannot call setPos() in itemChange() on an
    ItemPositionChange notification, as the setPos() function will again call
    itemChange(ItemPositionChange). Instead, you can return the new, adjusted
    position from itemChange().

    \value ItemEnabledChange The item's enabled state changes. If the item is
    presently enabled, it will become disabled, and vice verca. The value
    argument is the new enabled state (i.e., true or false). Do not call
    setEnabled() in itemChange() as this notification is delivered. Instead,
    you can return the new state from itemChange().

    \value ItemEnabledHasChanged The item's enabled state has changed. The
    value argument is the new enabled state (i.e., true or false). Do not call
    setEnabled() in itemChange() as this notification is delivered. The return
    value is ignored.

    \value ItemMatrixChange The item's affine transformation matrix is
    changing. This value is obsolete; you can use ItemTransformChange instead.

    \value ItemPositionChange The item's position changes. This notification
    is only sent when the item's local position changes, relative to its
    parent, has changed (i.e., as a result of calling setPos() or
    moveBy()). The value argument is the new position (i.e., a QPointF).  You
    can call pos() to get the original position. Do not call setPos() or
    moveBy() in itemChange() as this notification is delivered; instead, you
    can return the new, adjusted position from itemChange(). After this
    notification, QGraphicsItem immediately sends the ItemPositionHasChanged
    notification if the position changed.

    \value ItemPositionHasChanged The item's position has changed. This
    notification is only sent after the item's local position, relative to its
    parent, has changed. The value argument is the new position (the same as
    pos()), and QGraphicsItem ignores the return value for this notification
    (i.e., a read-only notification).

    \value ItemTransformChange The item's transformation matrix changes. This
    notification is only sent when the item's local transformation matrix
    changes (i.e., as a result of calling setTransform(), or one of the
    convenience transformation functions, such as rotate()). The value
    argument is the new matrix (i.e., a QTransform); to get the old matrix,
    call transform(). Do not call setTransform() or any of the transformation
    convenience functions in itemChange() as this notification is delivered;
    instead, you can return the new matrix from itemChange().

    \value ItemTransformHasChanged The item's transformation matrix has
    changed.  This notification is only sent after the item's local
    trasformation matrix has changed. The value argument is the new matrix
    (same as transform()), and QGraphicsItem ignores the return value for this
    notification (i.e., a read-only notification).

    \value ItemSelectedChange The item's selected state changes. If the item
    is presently selected, it will become unselected, and vice verca. The
    value argument is the new selected state (i.e., true or false). Do not
    call setSelected() in itemChange() as this notification is delivered();
    instead, you can return the new selected state from itemChange().

    \value ItemSelectedHasChanged The item's selected state has changed. The
    value argument is the new selected state (i.e., true or false). Do not
    call setSelected() in itemChange() as this notification is delivered. The
    return value is ignored.

    \value ItemVisibleChange The item's visible state changes. If the item is
    presently visible, it will become invisible, and vice verca. The value
    argument is the new visible state (i.e., true or false). Do not call
    setVisible() in itemChange() as this notification is delivered; instead,
    you can return the new visible state from itemChange().

    \value ItemVisibleHasChanged The item's visible state has changed. The
    value argument is the new visible state (i.e., true or false). Do not call
    setVisible() in itemChange() as this notification is delivered. The return
    value is ignored.

    \value ItemParentChange The item's parent changes. The value argument is
    the new parent item (i.e., a QGraphicsItem pointer).  Do not call
    setParentItem() in itemChange() as this notification is delivered;
    instead, you can return the new parent from itemChange().

    \value ItemParentHasChanged The item's parent has changed. The value
    argument is the new parent (i.e., a pointer to a QGraphicsItem). Do not
    call setParentItem() in itemChange() as this notification is
    delivered. The return value is ignored.

    \value ItemChildAddedChange A child is added to this item. The value
    argument is the new child item (i.e., a QGraphicsItem pointer). Do not
    pass this item to any item's setParentItem() function as this notification
    is delivered. The return value is unused; you cannot adjust anything in
    this notification. Note that the new child might not be fully constructed
    when this notification is sent; calling pure virtual functions on
    the child can lead to a crash.

    \value ItemChildRemovedChange A child is removed from this item. The value
    argument is the child item that is about to be removed (i.e., a
    QGraphicsItem pointer). The return value is unused; you cannot adjust
    anything in this notification.

    \value ItemSceneChange The item is moved to a new scene. This notification
    is also sent when the item is added to its initial scene, and when it is
    removed. The value argument is the new scene (i.e., a QGraphicsScene
    pointer), or a null pointer if the item is removed from a scene. Do not
    override this change by passing this item to QGraphicsScene::addItem() as
    this notification is delivered; instead, you can return the new scene from
    itemChange(). Use this feature with caution; objecting to a scene change can
    quickly lead to unwanted recursion.

    \value ItemSceneHasChanged The item's scene has changed. The value
    argument is the new scene (i.e., a pointer to a QGraphicsScene). Do not
    call setScene() in itemChange() as this notification is delivered. The
    return value is ignored.

    \value ItemCursorChange The item's cursor changes. The value argument is
    the new cursor (i.e., a QCursor). Do not call setCursor() in itemChange()
    as this notification is delivered. Instead, you can return a new cursor
    from itemChange().

    \value ItemCursorHasChanged The item's cursor has changed. The value
    argument is the new cursor (i.e., a QCursor). Do not call setCursor() as
    this notification is delivered. The return value is ignored.

    \value ItemToolTipChange The item's tooltip changes. The value argument is
    the new tooltip (i.e., a QToolTip). Do not call setToolTip() in
    itemChange() as this notification is delivered. Instead, you can return a
    new tooltip from itemChange().

    \value ItemToolTipHasChanged The item's tooltip has changed. The value
    argument is the new tooltip (i.e., a QToolTip). Do not call setToolTip()
    as this notification is delivered. The return value is ignored.

    \value ItemFlagsChange The item's flags change. The value argument is the
    new flags (i.e., a quint32). Do not call setFlags() in itemChange() as
    this notification is delivered. Instead, you can return the new flags from
    itemChange().

    \value ItemFlagsHaveChanged The item's flags have changed. The value
    argument is the new flags (i.e., a quint32). Do not call setFlags() in
    itemChange() as this notification is delivered. The return value is
    ignored.

    \value ItemZValueChange The item's Z-value changes. The value argument is
    the new Z-value (i.e., a double). Do not call setZValue() in itemChange()
    as this notification is delivered. Instead, you can return a new Z-value
    from itemChange().

    \value ItemZValueHasChanged The item's Z-value has changed. The value
    argument is the new Z-value (i.e., a double). Do not call setZValue() as
    this notification is delivered. The return value is ignored.

    \value ItemOpacityChange The item's opacity changes. The value argument is
    the new opacity (i.e., a double). Do not call setOpacity() in itemChange()
    as this notification is delivered. Instead, you can return a new opacity
    from itemChange().

    \value ItemOpacityHasChanged The item's opacity has changed. The value
    argument is the new opacity (i.e., a double). Do not call setOpacity() as
    this notification is delivered. The return value is ignored.
*/

/*!
    \enum QGraphicsItem::CacheMode
    \since 4.4

    This enum describes QGraphicsItem's cache modes. Caching is used to speed
    up rendering by allocating and rendering to an off-screen pixel buffer,
    which can be reused when the item requires redrawing. For some paint
    devices, the cache is stored directly in graphics memory, which makes
    rendering very quick.

    \value NoCache The default; all item caching is
    disabled. QGraphicsItem::paint() is called every time the item needs
    redrawing.

    \value ItemCoordinateCache Caching is enabled for the item's logical
    (local) coordinate system. QGraphicsItem creates an off-screen pixel
    buffer with a configurable size / resolution that you can pass to
    QGraphicsItem::setCacheMode(). Rendering quality will typically degrade,
    depending on the resolution of the cache and the item transformation.  The
    first time the item is redrawn, it will render itself into the cache, and
    the cache is then reused for every subsequent expose. The cache is also
    reused as the item is transformed. To adjust the resolution of the cache,
    you can call setCacheMode() again.

    \value DeviceCoordinateCache Caching is enabled at the paint device level,
    in device coordinates. This mode is for items that can move, but are not
    rotated, scaled or sheared. If the item is transformed directly or
    indirectly, the cache will be regenerated automatically. Unlike
    ItemCoordinateCacheMode, DeviceCoordinateCache always renders at maximum
    quality.

    \sa QGraphicsItem::setCacheMode()
*/

/*!
    \enum QGraphicsItem::Extension
    \internal

    Note: This is provided as a hook to avoid future problems related
    to adding virtual functions. See also extension(),
    supportsExtension() and setExtension().
*/

#include "qgraphicsitem.h"

#ifndef QT_NO_GRAPHICSVIEW

#include "qgraphicsscene.h"
#include "qgraphicsscene_p.h"
#include "qgraphicssceneevent.h"
#include "qgraphicsview.h"
#include "qgraphicswidget.h"
#include "qgraphicsproxywidget.h"
#include <QtCore/qbitarray.h>
#include <QtCore/qdebug.h>
#include <QtCore/qpoint.h>
#include <QtCore/qstack.h>
#include <QtCore/qtimer.h>
#include <QtCore/qvariant.h>
#include <QtCore/qvarlengtharray.h>
#include <QtGui/qapplication.h>
#include <QtGui/qbitmap.h>
#include <QtGui/qpainter.h>
#include <QtGui/qpainterpath.h>
#include <QtGui/qpixmapcache.h>
#include <QtGui/qstyleoption.h>
#include <QtGui/qevent.h>

#include <private/qgraphicsitem_p.h>
#include <private/qgraphicswidget_p.h>
#include <private/qtextcontrol_p.h>
#include <private/qtextdocumentlayout_p.h>
#include <private/qtextengine_p.h>
#include <private/qgesturemanager_p.h>

#ifdef Q_WS_X11
#include <private/qt_x11_p.h>
#include <private/qpixmap_x11_p.h>
#endif

#include <math.h>

QT_BEGIN_NAMESPACE

// QRectF::intersects() returns false always if either the source or target
// rectangle's width or height are 0. This works around that problem.
static inline void _q_adjustRect(QRectF *rect)
{
    Q_ASSERT(rect);
    if (!rect->width())
        rect->adjust(-0.00001, 0, 0.00001, 0);
    if (!rect->height())
        rect->adjust(0, -0.00001, 0, 0.00001);
}

static inline void _q_adjustRect(QRect *rect)
{
    Q_ASSERT(rect);
    if (!rect->width())
        rect->adjust(0, 0, 1, 0);
    if (!rect->height())
        rect->adjust(0, 0, 0, 1);
}

/*
    ### Move this into QGraphicsItemPrivate
 */
class QGraphicsItemCustomDataStore
{
public:
    QMap<const QGraphicsItem *, QMap<int, QVariant> > data;
};
Q_GLOBAL_STATIC(QGraphicsItemCustomDataStore, qt_dataStore)

QString qt_getStandardGestureTypeName(Qt::GestureType type);

/*!
    \internal

    Returns a QPainterPath of \a path when stroked with the \a pen.
    Ignoring dash pattern.
*/
static QPainterPath qt_graphicsItem_shapeFromPath(const QPainterPath &path, const QPen &pen)
{
    // We unfortunately need this hack as QPainterPathStroker will set a width of 1.0
    // if we pass a value of 0.0 to QPainterPathStroker::setWidth()
    const qreal penWidthZero = qreal(0.00000001);

    if (path == QPainterPath())
        return path;
    QPainterPathStroker ps;
    ps.setCapStyle(pen.capStyle());
    if (pen.widthF() <= 0.0)
        ps.setWidth(penWidthZero);
    else
        ps.setWidth(pen.widthF());
    ps.setJoinStyle(pen.joinStyle());
    ps.setMiterLimit(pen.miterLimit());
    QPainterPath p = ps.createStroke(path);
    p.addPath(path);
    return p;
}

/*!
    \internal

    Propagates the ancestor flag \a flag with value \a enabled to all this
    item's children. If \a root is false, the flag is also set on this item
    (default is true).
*/
void QGraphicsItemPrivate::updateAncestorFlag(QGraphicsItem::GraphicsItemFlag childFlag,
                                           AncestorFlag flag, bool enabled, bool root)
{
    Q_Q(QGraphicsItem);
    if (root) {
        // For root items only. This is the item that has either enabled or
        // disabled \a childFlag, or has been reparented.
        switch (int(childFlag)) {
        case -1:
            flag = AncestorHandlesChildEvents;
            enabled = q->handlesChildEvents();
            break;
        case QGraphicsItem::ItemClipsChildrenToShape:
            flag = AncestorClipsChildren;
            enabled = flags & QGraphicsItem::ItemClipsChildrenToShape;
            invalidateCachedClipPathRecursively(/*childrenOnly=*/true);
            break;
        case QGraphicsItem::ItemIgnoresTransformations:
            flag = AncestorIgnoresTransformations;
            enabled = flags & QGraphicsItem::ItemIgnoresTransformations;
            break;
        default:
            return;
        }

        // Inherit the enabled-state from our parents.
        if ((parent && ((parent->d_ptr->ancestorFlags & flag)
                        || (int(parent->d_ptr->flags & childFlag) == childFlag)
                        || (childFlag == -1 && parent->d_ptr->handlesChildEvents)))) {
            enabled = true;
            ancestorFlags |= flag;
        }

        // Top-level root items don't have any ancestors, so there are no
        // ancestor flags either.
        if (!parent)
            ancestorFlags = 0;
    } else {
        // Don't set or propagate the ancestor flag if it's already correct.
        if (((ancestorFlags & flag) && enabled) || (!(ancestorFlags & flag) && !enabled))
            return;

        // Set the flag.
        if (enabled)
            ancestorFlags |= flag;
        else
            ancestorFlags &= ~flag;

        // Don't process children if the item has the main flag set on itself.
        if ((childFlag != -1 &&  int(flags & childFlag) == childFlag) || (int(childFlag) == -1 && handlesChildEvents))
            return;
    }

    foreach (QGraphicsItem *child, children)
        child->d_ptr->updateAncestorFlag(childFlag, flag, enabled, false);
}

/*!
    \internal

    Propagates item group membership.
*/
void QGraphicsItemPrivate::setIsMemberOfGroup(bool enabled)
{
    Q_Q(QGraphicsItem);
    isMemberOfGroup = enabled;
    if (!qgraphicsitem_cast<QGraphicsItemGroup *>(q)) {
        foreach (QGraphicsItem *child, children)
            child->d_func()->setIsMemberOfGroup(enabled);
    }
}

/*!
    \internal

    Maps any item pos properties of \a event to \a item's coordinate system.
*/
void QGraphicsItemPrivate::remapItemPos(QEvent *event, QGraphicsItem *item)
{
    Q_Q(QGraphicsItem);
    switch (event->type()) {
    case QEvent::GraphicsSceneMouseMove:
    case QEvent::GraphicsSceneMousePress:
    case QEvent::GraphicsSceneMouseRelease:
    case QEvent::GraphicsSceneMouseDoubleClick: {
        QGraphicsSceneMouseEvent *mouseEvent = static_cast<QGraphicsSceneMouseEvent *>(event);
        mouseEvent->setPos(item->mapFromItem(q, mouseEvent->pos()));
        mouseEvent->setLastPos(item->mapFromItem(q, mouseEvent->pos()));
        for (int i = 0x1; i <= 0x10; i <<= 1) {
            if (mouseEvent->buttons() & i) {
                Qt::MouseButton button = Qt::MouseButton(i);
                mouseEvent->setButtonDownPos(button, item->mapFromItem(q, mouseEvent->buttonDownPos(button)));
            }
        }
        break;
    }
    case QEvent::GraphicsSceneWheel: {
        QGraphicsSceneWheelEvent *wheelEvent = static_cast<QGraphicsSceneWheelEvent *>(event);
        wheelEvent->setPos(item->mapFromItem(q, wheelEvent->pos()));
        break;
    }
    case QEvent::GraphicsSceneContextMenu: {
        QGraphicsSceneContextMenuEvent *contextEvent = static_cast<QGraphicsSceneContextMenuEvent *>(event);
        contextEvent->setPos(item->mapFromItem(q, contextEvent->pos()));
        break;
    }
    case QEvent::GraphicsSceneHoverMove: {
        QGraphicsSceneHoverEvent *hoverEvent = static_cast<QGraphicsSceneHoverEvent *>(event);
        hoverEvent->setPos(item->mapFromItem(q, hoverEvent->pos()));
        break;
    }
    default:
        break;
    }
}

/*!
    \internal

    Maps the point \a pos from scene to item coordinates. If \a view is passed and the item
    is untransformable, this function will correctly map \a pos from the scene using the
    view's transformation.
*/
QPointF QGraphicsItemPrivate::genericMapFromScene(const QPointF &pos,
                                                  const QWidget *viewport) const
{
    Q_Q(const QGraphicsItem);
    if (!itemIsUntransformable())
        return q->mapFromScene(pos);
    QGraphicsView *view = 0;
    if (viewport)
        view = qobject_cast<QGraphicsView *>(viewport->parentWidget());
    if (!view)
        return q->mapFromScene(pos);
    // ### More ping pong than needed.
    return q->deviceTransform(view->viewportTransform()).inverted().map(view->mapFromScene(pos));
}

/*!
    \internal

    Returns true if this item or any of its ancestors are untransformable.
*/
bool QGraphicsItemPrivate::itemIsUntransformable() const
{
    return (flags & QGraphicsItem::ItemIgnoresTransformations)
        || (ancestorFlags & AncestorIgnoresTransformations);
}

/*!
    \internal

    This helper function helped us add input method query support in
    Qt 4.4.1 without having to reimplement the inputMethodQuery()
    function in QGraphicsProxyWidget. ### Qt 5: Remove. We cannot
    remove it in 4.5+ even if we do reimplement the function properly,
    because apps compiled with 4.4 will not be able to call the
    reimplementation.
*/
QVariant QGraphicsItemPrivate::inputMethodQueryHelper(Qt::InputMethodQuery query) const
{
    Q_UNUSED(query);
    return QVariant();
}

/*!
    \internal

    If \a deleting is true, then this item is being deleted, and \a parent is
    null. Make sure not to trigger any pure virtual function calls (e.g.,
    prepareGeometryChange).
*/
void QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem *newParent, bool deleting)
{
    Q_Q(QGraphicsItem);
    if (newParent == q) {
        qWarning("QGraphicsItem::setParentItem: cannot assign %p as a parent of itself", this);
        return;
    }
    if (newParent == parent)
        return;

    const QVariant newParentVariant(q->itemChange(QGraphicsItem::ItemParentChange,
                                                  qVariantFromValue<QGraphicsItem *>(newParent)));
    newParent = qVariantValue<QGraphicsItem *>(newParentVariant);
    if (newParent == parent)
        return;

    if (QGraphicsWidget *w = isWidget ? static_cast<QGraphicsWidget *>(q) : q->parentWidget()) {
        // Update the child focus chain; when reparenting a widget that has a
        // focus child, ensure that that focus child clears its focus child
        // chain from our parents before it's reparented.
        if (QGraphicsWidget *focusChild = w->focusWidget())
            focusChild->clearFocus();
    }

    // We anticipate geometry changes. If the item is deleted, it will be
    // removed from the index at a later stage, and the whole scene will be
    // updated.
    if (!deleting)
        q_ptr->prepareGeometryChange();

    const QVariant thisPointerVariant(qVariantFromValue<QGraphicsItem *>(q));
    if (parent) {
        // Remove from current parent
        parent->d_ptr->removeChild(q);
        parent->itemChange(QGraphicsItem::ItemChildRemovedChange, thisPointerVariant);
    }

    // Update toplevelitem list. If this item is being deleted, its parent
    // will be 0 but we don't want to register/unregister it in the TLI list.
    if (scene && !deleting) {
        if (parent && !newParent) {
            scene->d_func()->registerTopLevelItem(q);
        } else if (!parent && newParent) {
            scene->d_func()->unregisterTopLevelItem(q);
        }
    }

    if ((parent = newParent)) {
        bool implicitUpdate = false;
        if (parent->d_func()->scene && parent->d_func()->scene != scene) {
            // Move this item to its new parent's scene
            parent->d_func()->scene->addItem(q);
            implicitUpdate = true;
        } else if (!parent->d_func()->scene && scene) {
            // Remove this item from its former scene
            scene->removeItem(q);
        }

        parent->d_ptr->addChild(q);
        parent->itemChange(QGraphicsItem::ItemChildAddedChange, thisPointerVariant);
        if (!implicitUpdate)
            updateHelper(QRectF(), false, true);

        // Inherit ancestor flags from the new parent.
        updateAncestorFlag(QGraphicsItem::GraphicsItemFlag(-1));
        updateAncestorFlag(QGraphicsItem::ItemClipsChildrenToShape);
        updateAncestorFlag(QGraphicsItem::ItemIgnoresTransformations);

        // Update item visible / enabled.
        if (parent->isVisible() != visible) {
            if (!parent->isVisible() || !explicitlyHidden)
                setVisibleHelper(parent->isVisible(), /* explicit = */ false, /* update = */ !implicitUpdate);
        }
        if (parent->isEnabled() != enabled) {
            if (!parent->isEnabled() || !explicitlyDisabled)
                setEnabledHelper(parent->isEnabled(), /* explicit = */ false, /* update = */ !implicitUpdate);
        }

    } else {
        // Inherit ancestor flags from the new parent.
        updateAncestorFlag(QGraphicsItem::GraphicsItemFlag(-1));
        updateAncestorFlag(QGraphicsItem::ItemClipsChildrenToShape);
        updateAncestorFlag(QGraphicsItem::ItemIgnoresTransformations);

        if (!deleting) {
            // Update item visible / enabled.
            if (!visible && !explicitlyHidden)
                setVisibleHelper(true, /* explicit = */ false);
            if (!enabled && !explicitlyDisabled)
                setEnabledHelper(true, /* explicit = */ false);

            // If the item is being deleted, the whole scene will be updated.
            updateHelper(QRectF(), false, true);
        }
    }

    if (scene) {
        // Invalidate any sort caching; arrival of a new item means we need to
        // resort.
        scene->d_func()->invalidateSortCache();
    }

    // Resolve opacity.
    updateEffectiveOpacity();

    // Resolve depth.
    resolveDepth(parent ? parent->d_ptr->depth : -1);

    // Invalidate transform cache.
    invalidateSceneTransformCache();

    // Deliver post-change notification
    q->itemChange(QGraphicsItem::ItemParentHasChanged, newParentVariant);
}

/*!
    \internal

    Returns the bounding rect of this item's children (excluding itself).
*/
void QGraphicsItemPrivate::childrenBoundingRectHelper(QTransform *x, QRectF *rect)
{
    for (int i = 0; i < children.size(); ++i) {
        QGraphicsItem *child = children.at(i);
        QGraphicsItemPrivate *childd = child->d_ptr;
        bool hasX = childd->hasTransform;
        bool hasPos = !childd->pos.isNull();
        if (hasPos || hasX) {
            QTransform matrix;
            if (hasX)
                matrix = child->transform();
            if (hasPos) {
                const QPointF &p = childd->pos;
                matrix *= QTransform::fromTranslate(p.x(), p.y());
            }
            matrix *= *x;
            *rect |= matrix.mapRect(child->boundingRect());
            if (!childd->children.isEmpty())
                childd->childrenBoundingRectHelper(&matrix, rect);
        } else {
            *rect |= x->mapRect(child->boundingRect());
            if (!childd->children.isEmpty())
                childd->childrenBoundingRectHelper(x, rect);
        }
    }
}

/*!
    \internal

    Empty all cached pixmaps from the pixmap cache.
*/
void QGraphicsItemCache::purge()
{
    QPixmapCache::remove(key);
    QMutableMapIterator<QPaintDevice *, DeviceData> it(deviceData);
    while (it.hasNext()) {
        DeviceData &data = it.next().value();
        QPixmapCache::remove(data.key);
        data.cacheIndent = QPoint();
    }
    deviceData.clear();
    allExposed = true;
    exposed.clear();
}

/*!
    Constructs a QGraphicsItem with the given \a parent.

    If \a parent is 0, you can add the item to a scene by calling
    QGraphicsScene::addItem(). The item will then become a top-level item.

    \sa QGraphicsScene::addItem(), setParentItem()
*/
QGraphicsItem::QGraphicsItem(QGraphicsItem *parent
#ifndef Q_QDOC
                             // obsolete argument
                             , QGraphicsScene *scene
#endif
    )
    : d_ptr(new QGraphicsItemPrivate)
{
    d_ptr->q_ptr = this;
    setParentItem(parent);

    if (scene && parent && parent->scene() != scene) {
        qWarning("QGraphicsItem::QGraphicsItem: ignoring scene (%p), which is"
                 " different from parent's scene (%p)",
                 scene, parent->scene());
        return;
    }
    if (scene && !parent)
        scene->addItem(this);
}

/*!
    \internal
*/
QGraphicsItem::QGraphicsItem(QGraphicsItemPrivate &dd, QGraphicsItem *parent,
                             QGraphicsScene *scene)
    : d_ptr(&dd)
{
    d_ptr->q_ptr = this;
    setParentItem(parent);

    if (scene && parent && parent->scene() != scene) {
        qWarning("QGraphicsItem::QGraphicsItem: ignoring scene (%p), which is"
                 " different from parent's scene (%p)",
                 scene, parent->scene());
        return;
    }
    if (scene && !parent)
        scene->addItem(this);
}

/*!
    Destroys the QGraphicsItem and all its children. If this item is currently
    associated with a scene, the item will be removed from the scene before it
    is deleted.
*/
QGraphicsItem::~QGraphicsItem()
{
    if (d_ptr->scene && !d_ptr->parent)
        d_ptr->scene->d_func()->unregisterTopLevelItem(this);

    clearFocus();

    d_ptr->removeExtraItemCache();
    QList<QGraphicsItem *> oldChildren = d_ptr->children;
    qDeleteAll(oldChildren);
    Q_ASSERT(d_ptr->children.isEmpty());

    d_ptr->setParentItemHelper(0, /* deleting = */ true);
    if (d_ptr->scene)
        d_ptr->scene->d_func()->_q_removeItemLater(this);

    delete d_ptr;

    qt_dataStore()->data.remove(this);
}

/*!
    Returns the current scene for the item, or 0 if the item is not stored in
    a scene.

    To add or move an item to a scene, call QGraphicsScene::addItem().
*/
QGraphicsScene *QGraphicsItem::scene() const
{
    return d_ptr->scene;
}

/*!
    Returns a pointer to this item's item group, or 0 if this item is not
    member of a group.

    \sa QGraphicsItemGroup, QGraphicsScene::createItemGroup()
*/
QGraphicsItemGroup *QGraphicsItem::group() const
{
    if (!d_ptr->isMemberOfGroup)
        return 0;
    QGraphicsItem *parent = const_cast<QGraphicsItem *>(this);
    while ((parent = parent->d_ptr->parent)) {
        if (QGraphicsItemGroup *group = qgraphicsitem_cast<QGraphicsItemGroup *>(parent))
            return group;
    }
    // Unreachable; if d_ptr->isMemberOfGroup is != 0, then one parent of this
    // item is a group item.
    return 0;
}

/*!
    Adds this item to the item group \a group. If \a group is 0, this item is
    removed from any current group and added as a child of the previous
    group's parent.

    \sa group(), QGraphicsScene::createItemGroup()
*/
void QGraphicsItem::setGroup(QGraphicsItemGroup *group)
{
    if (!group) {
        if (QGraphicsItemGroup *group = this->group())
            group->removeFromGroup(this);
    } else {
        group->addToGroup(this);
    }
}

/*!
    Returns a pointer to this item's parent item. If this item does not have a
    parent, 0 is returned.

    \sa setParentItem(), children()
*/
QGraphicsItem *QGraphicsItem::parentItem() const
{
    return d_ptr->parent;
}

/*!
    Returns this item's top-level item. The top-level item is the item's
    topmost ancestor item whose parent is 0. If an item has no parent, its own
    pointer is returned (i.e., a top-level item is its own top-level item).

    \sa parentItem()
*/
QGraphicsItem *QGraphicsItem::topLevelItem() const
{
    QGraphicsItem *parent = const_cast<QGraphicsItem *>(this);
    while (QGraphicsItem *grandPa = parent->parentItem())
        parent = grandPa;
    return parent;
}

/*!
    \since 4.4

    Returns a pointer to the item's parent widget. The item's parent widget is
    the closest parent item that is a widget.

    \sa parentItem(), childItems()
*/
QGraphicsWidget *QGraphicsItem::parentWidget() const
{
    QGraphicsItem *p = parentItem();
    while (p && !p->isWidget())
        p = p->parentItem();
    return (p && p->isWidget()) ? static_cast<QGraphicsWidget *>(p) : 0;
}

/*!
    \since 4.4

    Returns a pointer to the item's top level widget (i.e., the item's
    ancestor whose parent is 0, or whose parent is not a widget), or 0 if this
    item does not have a top level widget. If the item is its own top level
    widget, this function returns a pointer to the item itself.
*/
QGraphicsWidget *QGraphicsItem::topLevelWidget() const
{
    if (const QGraphicsWidget *p = parentWidget())
        return p->topLevelWidget();
    return isWidget() ? static_cast<QGraphicsWidget *>(const_cast<QGraphicsItem *>(this)) : 0;
}

/*!
    \since 4.4

    Returns the item's window, or 0 if this item does not have a window. If
    the item is a window, it will return itself.  Otherwise it will return the
    closest ancestor that is a window.

    \sa QGraphicsWidget::isWindow()
*/
QGraphicsWidget *QGraphicsItem::window() const
{
    if (isWidget() && static_cast<const QGraphicsWidget *>(this)->isWindow())
        return static_cast<QGraphicsWidget *>(const_cast<QGraphicsItem *>(this));
    if (QGraphicsWidget *parent = parentWidget())
        return parent->window();
    return 0;
}

/*!
    Sets this item's parent item to \a parent. If this item already has a
    parent, it is first removed from the previous parent. If \a parent is 0,
    this item will become a top-level item.

    Note that this implicitly adds this graphics item to the scene of
    the parent. You should not \l{QGraphicsScene::addItem()}{add} the
    item to the scene yourself.

    \sa parentItem(), children()
*/
void QGraphicsItem::setParentItem(QGraphicsItem *parent)
{
    d_ptr->setParentItemHelper(parent, /* deleting = */ false);
}

/*!
    \obsolete

    Use childItems() instead.

    \sa setParentItem()
*/
QList<QGraphicsItem *> QGraphicsItem::children() const
{
    return childItems();
}

/*!
    \since 4.4

    Returns a list of this item's children. The items are returned in no
    particular order.

    \sa setParentItem()
*/
QList<QGraphicsItem *> QGraphicsItem::childItems() const
{
    return d_ptr->children;
}

/*!
    \since 4.4
    Returns true if this item is a widget (i.e., QGraphicsWidget); otherwise,
    returns false.
*/
bool QGraphicsItem::isWidget() const
{
    return d_ptr->isWidget;
}

/*!
    \since 4.4
    Returns true if the item is a QGraphicsWidget window, otherwise returns
    false.

    \sa QGraphicsWidget::windowFlags()
*/
bool QGraphicsItem::isWindow() const
{
    return isWidget() && (static_cast<const QGraphicsWidget *>(this)->windowType() & Qt::Window);
}

/*!
    Returns this item's flags. The flags describe what configurable features
    of the item are enabled and not. For example, if the flags include
    ItemIsFocusable, the item can accept input focus.

    By default, no flags are enabled.

    \sa setFlags(), setFlag()
*/
QGraphicsItem::GraphicsItemFlags QGraphicsItem::flags() const
{
    return GraphicsItemFlags(d_ptr->flags);
}

/*!
    If \a enabled is true, the item flag \a flag is enabled; otherwise, it is
    disabled.

    \sa flags(), setFlags()
*/
void QGraphicsItem::setFlag(GraphicsItemFlag flag, bool enabled)
{
    if (enabled)
        setFlags(flags() | flag);
    else
        setFlags(flags() & ~flag);
}

/*!
    \internal

    Sets the flag \a flag on \a item and all its children, to \a enabled.
*/
static void _q_qgraphicsItemSetFlag(QGraphicsItem *item, QGraphicsItem::GraphicsItemFlag flag,
                                    bool enabled)
{
    if (item->flags() & flag) {
        // If this item already has the correct flag set, we don't have to
        // propagate it.
        return;
    }
    item->setFlag(flag, enabled);
    foreach (QGraphicsItem *child, item->children())
        _q_qgraphicsItemSetFlag(child, flag, enabled);
}

/*!
    Sets the item flags to \a flags. All flags in \a flags are enabled; all
    flags not in \a flags are disabled.

    If the item had focus and \a flags does not enable ItemIsFocusable, the
    item loses focus as a result of calling this function. Similarly, if the
    item was selected, and \a flags does not enabled ItemIsSelectable, the
    item is automatically unselected.

    By default, no flags are enabled.

    \sa flags(), setFlag()
*/
void QGraphicsItem::setFlags(GraphicsItemFlags flags)
{
    // Notify change and check for adjustment.
    if (quint32(d_ptr->flags) == quint32(flags))
        return;
    flags = GraphicsItemFlags(itemChange(ItemFlagsChange, quint32(flags)).toUInt());
    if (quint32(d_ptr->flags) == quint32(flags))
        return;

    // Flags that alter the geometry of the item (or its children).
    const quint32 geomChangeFlagsMask = (ItemClipsChildrenToShape | ItemClipsToShape | ItemIgnoresTransformations);
    bool fullUpdate = (quint32(flags) & geomChangeFlagsMask) != (d_ptr->flags & geomChangeFlagsMask);
    if (fullUpdate)
        d_ptr->fullUpdateHelper(false, true);

    // Keep the old flags to compare the diff.
    GraphicsItemFlags oldFlags = this->flags();

    // Update flags.
    d_ptr->flags = flags;

    // Reresolve effective opacity if the opacity flags change.
    static const quint32 opacityFlagsMask = ItemIgnoresParentOpacity | ItemDoesntPropagateOpacityToChildren;
    if ((flags & opacityFlagsMask) != (oldFlags & opacityFlagsMask))
        d_ptr->updateEffectiveOpacity();

    if (!(d_ptr->flags & ItemIsFocusable) && hasFocus()) {
        // Clear focus on the item if it has focus when the focusable flag
        // is unset.
        clearFocus();
    }

    if (!(d_ptr->flags & ItemIsSelectable) && isSelected()) {
        // Unselect the item if it is selected when the selectable flag is
        // unset.
        setSelected(false);
    }

    if ((flags & ItemClipsChildrenToShape) != (oldFlags & ItemClipsChildrenToShape)) {
        // Item children clipping changes. Propagate the ancestor flag to
        // all children.
        d_ptr->updateAncestorFlag(ItemClipsChildrenToShape);
    }

    if ((flags & ItemClipsToShape) != (oldFlags & ItemClipsToShape))
        d_ptr->invalidateCachedClipPath();

    if ((flags & ItemIgnoresTransformations) != (oldFlags & ItemIgnoresTransformations)) {
        // Item children clipping changes. Propagate the ancestor flag to
        // all children.
        d_ptr->updateAncestorFlag(ItemIgnoresTransformations);
    }

    // ### Why updateHelper?
    d_ptr->updateHelper(QRectF(), false, true);

    // Notify change.
    itemChange(ItemFlagsHaveChanged, quint32(flags));
}

/*!
    \since 4.4
    Returns the cache mode for this item. The default mode is NoCache (i.e.,
    cache is disabled and all painting is immediate).

    \sa setCacheMode()
*/
QGraphicsItem::CacheMode QGraphicsItem::cacheMode() const
{
    return QGraphicsItem::CacheMode(d_ptr->cacheMode);
}

/*!
    \since 4.4
    Sets the item's cache mode to \a mode.

    The optional \a logicalCacheSize argument is used only by
    ItemCoordinateCache mode, and describes the resolution of the cache
    buffer; if \a logicalCacheSize is (100, 100), QGraphicsItem will fit the
    item into 100x100 pixels in graphics memory, regardless of the logical
    size of the item itself. By default QGraphicsItem uses the size of
    boundingRect(). For all other cache modes than ItemCoordinateCache, \a
    logicalCacheSize is ignored.

    Caching can speed up rendering if your item spends a significant time
    redrawing itself. In some cases the cache can also slow down rendering, in
    particular when the item spends less time redrawing than QGraphicsItem
    spends redrawing from the cache. When enabled, the item's paint() function
    will be called only once for each call to update(); for any subsequent
    repaint requests, the Graphics View framework will redraw from the
    cache. This approach works particularly well with QGLWidget, which stores
    all the cache as OpenGL textures.

    Be aware that QPixmapCache's cache limit may need to be changed to obtain
    optimal performance.

    You can read more about the different cache modes in the CacheMode
    documentation.

    \sa CacheMode, QPixmapCache::setCacheLimit()
*/
void QGraphicsItem::setCacheMode(CacheMode mode, const QSize &logicalCacheSize)
{
    CacheMode lastMode = CacheMode(d_ptr->cacheMode);
    d_ptr->cacheMode = mode;
    bool noVisualChange = (mode == NoCache && lastMode == NoCache)
                          || (mode == NoCache && lastMode == DeviceCoordinateCache)
                          || (mode == DeviceCoordinateCache && lastMode == NoCache);
    if (mode == NoCache) {
        d_ptr->removeExtraItemCache();
    } else {
        QGraphicsItemCache *cache = d_ptr->extraItemCache();

        // Reset old cache
        cache->purge();

        if (mode == ItemCoordinateCache) {
            if (cache->key.isEmpty()) {
                // Generate new simple pixmap cache key.
                QString tmp;
                tmp.sprintf("qgv-%p", this);
                cache->key = tmp;
            }
            if (lastMode == mode && cache->fixedSize == logicalCacheSize)
                noVisualChange = true;
            cache->fixedSize = logicalCacheSize;
        }
    }
    if (!noVisualChange)
        update();
}

#ifndef QT_NO_TOOLTIP
/*!
    Returns the item's tool tip, or an empty QString if no tool tip has been
    set.

    \sa setToolTip(), QToolTip
*/
QString QGraphicsItem::toolTip() const
{
    return d_ptr->extra(QGraphicsItemPrivate::ExtraToolTip).toString();
}

/*!
    Sets the item's tool tip to \a toolTip. If \a toolTip is empty, the item's
    tool tip is cleared.

    \sa toolTip(), QToolTip
*/
void QGraphicsItem::setToolTip(const QString &toolTip)
{
    const QVariant toolTipVariant(itemChange(ItemToolTipChange, toolTip));
    d_ptr->setExtra(QGraphicsItemPrivate::ExtraToolTip, toolTipVariant.toString());
    itemChange(ItemToolTipHasChanged, toolTipVariant);
}
#endif // QT_NO_TOOLTIP

#ifndef QT_NO_CURSOR
/*!
    Returns the current cursor shape for the item. The mouse cursor
    will assume this shape when it's over this item. See the \link
    Qt::CursorShape list of predefined cursor objects\endlink for a
    range of useful shapes.

    An editor item might want to use an I-beam cursor:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 2

    If no cursor has been set, the parent's cursor is used.

    \sa setCursor(), hasCursor(), unsetCursor(), QWidget::cursor,
    QApplication::overrideCursor()
*/
QCursor QGraphicsItem::cursor() const
{
    return qVariantValue<QCursor>(d_ptr->extra(QGraphicsItemPrivate::ExtraCursor));
}

/*!
    Sets the current cursor shape for the item to \a cursor. The mouse cursor
    will assume this shape when it's over this item. See the \link
    Qt::CursorShape list of predefined cursor objects\endlink for a range of
    useful shapes.

    An editor item might want to use an I-beam cursor:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 3

    If no cursor has been set, the cursor of the item beneath is used.

    \sa cursor(), hasCursor(), unsetCursor(), QWidget::cursor,
    QApplication::overrideCursor()
*/
void QGraphicsItem::setCursor(const QCursor &cursor)
{
    const QVariant cursorVariant(itemChange(ItemCursorChange, qVariantFromValue<QCursor>(cursor)));
    d_ptr->setExtra(QGraphicsItemPrivate::ExtraCursor, qVariantValue<QCursor>(cursorVariant));
    d_ptr->hasCursor = 1;
    if (d_ptr->scene) {
        d_ptr->scene->d_func()->allItemsUseDefaultCursor = false;
        foreach (QGraphicsView *view, d_ptr->scene->views()) {
            view->viewport()->setMouseTracking(true);
            // Note: Some of this logic is duplicated in QGraphicsView's mouse events.
            if (view->underMouse()) {
                foreach (QGraphicsItem *itemUnderCursor, view->items(view->mapFromGlobal(QCursor::pos()))) {
                    if (itemUnderCursor->hasCursor()) {
                        QMetaObject::invokeMethod(view, "_q_setViewportCursor",
                                                  Q_ARG(QCursor, itemUnderCursor->cursor()));
                        break;
                    }
                }
                break;
            }
        }
    }
    itemChange(ItemCursorHasChanged, cursorVariant);
}

/*!
    Returns true if this item has a cursor set; otherwise, false is returned.

    By default, items don't have any cursor set. cursor() will return a
    standard pointing arrow cursor.

    \sa unsetCursor()
*/
bool QGraphicsItem::hasCursor() const
{
    return d_ptr->hasCursor;
}

/*!
    Clears the cursor from this item.

    \sa hasCursor(), setCursor()
*/
void QGraphicsItem::unsetCursor()
{
    d_ptr->unsetExtra(QGraphicsItemPrivate::ExtraCursor);
    d_ptr->hasCursor = 0;
    if (d_ptr->scene) {
        foreach (QGraphicsView *view, d_ptr->scene->views()) {
            if (view->underMouse() && view->itemAt(view->mapFromGlobal(QCursor::pos())) == this) {
                QMetaObject::invokeMethod(view, "_q_unsetViewportCursor");
                break;
            }
        }
    }
}

#endif // QT_NO_CURSOR

/*!
   Returns true if the item is visible; otherwise, false is returned.

   Note that the item's general visibility is unrelated to whether or not it
   is actually being visualized by a QGraphicsView.

   \sa setVisible()
*/
bool QGraphicsItem::isVisible() const
{
    return d_ptr->visible;
}

/*!
    \since 4.4
    Returns true if the item is visible to \a parent; otherwise, false is
    returned. \a parent can be 0, in which case this function will return
    whether the item is visible to the scene or not.

    An item may not be visible to its ancestors even if isVisible() is true. If
    any ancestor is hidden, the item itself will be implicitly hidden, in which
    case this function will return false.

    \sa isVisible(), setVisible()
*/
bool QGraphicsItem::isVisibleTo(const QGraphicsItem *parent) const
{
    if (!d_ptr->visible)
        return false;
    if (parent == this)
        return true;
    if (parentItem() && parentItem()->isVisibleTo(parent))
        return true;
    if (!parent && !parentItem())
        return true;
    return false;
}

/*!
    \internal

    Sets this item's visibility to \a newVisible. If \a explicitly is true,
    this item will be "explicitly" \a newVisible; otherwise, it.. will not be.
*/
void QGraphicsItemPrivate::setVisibleHelper(bool newVisible, bool explicitly, bool update)
{
    Q_Q(QGraphicsItem);

    // Update explicit bit.
    if (explicitly)
        explicitlyHidden = newVisible ? 0 : 1;

    // Check if there's nothing to do.
    if (visible == quint32(newVisible))
        return;

    // Modify the property.
    const QVariant newVisibleVariant(q_ptr->itemChange(QGraphicsItem::ItemVisibleChange,
                                                       quint32(newVisible)));
    newVisible = newVisibleVariant.toBool();
    if (visible == quint32(newVisible))
        return;
    visible = newVisible;

    // Schedule redrawing
    if (update) {
        QGraphicsItemCache *c = (QGraphicsItemCache *)qVariantValue<void *>(extra(ExtraCacheData));
        if (c)
            c->purge();
        updateHelper(QRectF(), /* force = */ true);
    }

    // Certain properties are dropped as an item becomes invisible.
    if (!newVisible) {
        if (scene) {
            if (scene->d_func()->mouseGrabberItems.contains(q))
                q->ungrabMouse();
            if (scene->d_func()->keyboardGrabberItems.contains(q))
                q->ungrabKeyboard();
        }
        if (q_ptr->hasFocus() && scene) {
            // Hiding the closest non-window ancestor of the focus item
            QGraphicsItem *focusItem = scene->focusItem();
            bool clear = true;
            if (isWidget && !focusItem->isWindow()) {
                do {
                    if (focusItem == q_ptr) {
                        clear = !static_cast<QGraphicsWidget *>(q_ptr)->focusNextPrevChild(true);
                        break;
                    }
                } while ((focusItem = focusItem->parentWidget()) && !focusItem->isWindow());
            }
            if (clear)
                q_ptr->clearFocus();
        }
        if (q_ptr->isSelected())
            q_ptr->setSelected(false);
    } else {
        if (isWidget && scene) {
            QGraphicsWidget *widget = static_cast<QGraphicsWidget *>(q_ptr);
            if (widget->windowType() == Qt::Popup)
                scene->d_func()->addPopup(widget);
        }
    }

    // Update children with explicitly = false.
    const bool updateChildren = update && !(flags & QGraphicsItem::ItemClipsChildrenToShape);
    foreach (QGraphicsItem *child, children) {
        if (!newVisible || !child->d_ptr->explicitlyHidden)
            child->d_ptr->setVisibleHelper(newVisible, false, updateChildren);
    }

    // Enable subfocus
    if (newVisible && isWidget) {
        QGraphicsWidget *widget = static_cast<QGraphicsWidget *>(q_ptr);
        QGraphicsWidget *fw = widget->focusWidget();
        if (fw && fw != scene->focusItem())
            scene->setFocusItem(fw);
    }

    // Deliver post-change notification.
    q_ptr->itemChange(QGraphicsItem::ItemVisibleHasChanged, newVisibleVariant);
}

/*!
    If \a visible is true, the item is made visible. Otherwise, the item is
    made invisible. Invisible items are not painted, nor do they receive any
    events. In particular, mouse events pass right through invisible items,
    and are delivered to any item that may be behind. Invisible items are also
    unselectable, they cannot take input focus, and are not detected by
    QGraphicsScene's item location functions.

    If an item becomes invisible while grabbing the mouse, (i.e., while it is
    receiving mouse events,) it will automatically lose the mouse grab, and
    the grab is not regained by making the item visible again; it must receive
    a new mouse press to regain the mouse grab.

    Similarly, an invisible item cannot have focus, so if the item has focus
    when it becomes invisible, it will lose focus, and the focus is not
    regained by simply making the item visible again.

    If you hide a parent item, all its children will also be hidden. If you
    show a parent item, all children will be shown, unless they have been
    explicitly hidden (i.e., if you call setVisible(false) on a child, it will
    not be reshown even if its parent is hidden, and then shown again).

    Items are visible by default; it is unnecessary to call
    setVisible() on a new item.

    \sa isVisible(), show(), hide()
*/
void QGraphicsItem::setVisible(bool visible)
{
    d_ptr->setVisibleHelper(visible, /* explicit = */ true);
}

/*!
    \fn void QGraphicsItem::hide()

    Hides the item. (Items are visible by default.)

    This convenience function is equivalent to calling \c setVisible(false).

    \sa show(), setVisible()
*/

/*!
    \fn void QGraphicsItem::show()

    Shows the item. (Items are visible by default.)

    This convenience function is equivalent to calling \c setVisible(true).

    \sa hide(), setVisible()
*/

/*!
    Returns true if the item is enabled; otherwise, false is returned.

    \sa setEnabled()
*/
bool QGraphicsItem::isEnabled() const
{
    return d_ptr->enabled;
}

/*!
    \internal

    Sets this item's visibility to \a newEnabled. If \a explicitly is true,
    this item will be "explicitly" \a newEnabled; otherwise, it.. will not be.
*/
void QGraphicsItemPrivate::setEnabledHelper(bool newEnabled, bool explicitly, bool update)
{
    // Update explicit bit.
    if (explicitly)
        explicitlyDisabled = newEnabled ? 0 : 1;

    // Check if there's nothing to do.
    if (enabled == quint32(newEnabled))
        return;

    // Certain properties are dropped when an item is disabled.
    if (!newEnabled) {
        if (scene && scene->mouseGrabberItem() == q_ptr)
            q_ptr->ungrabMouse();
        if (q_ptr->hasFocus()) {
            // Disabling the closest non-window ancestor of the focus item
            // causes focus to pop to the next item, otherwise it's cleared.
            QGraphicsItem *focusItem = scene->focusItem();
            bool clear = true;
            if (isWidget && !focusItem->isWindow() && q_ptr->isAncestorOf(focusItem)) {
                do {
                    if (focusItem == q_ptr) {
                        clear = !static_cast<QGraphicsWidget *>(q_ptr)->focusNextPrevChild(true);
                        break;
                    }
                } while ((focusItem = focusItem->parentWidget()) && !focusItem->isWindow());
            }
            if (clear)
                q_ptr->clearFocus();
        }
        if (q_ptr->isSelected())
            q_ptr->setSelected(false);
    }

    // Modify the property.
    const QVariant newEnabledVariant(q_ptr->itemChange(QGraphicsItem::ItemEnabledChange,
                                                       quint32(newEnabled)));
    enabled = newEnabledVariant.toBool();

    // Schedule redraw.
    if (update)
        updateHelper();

    foreach (QGraphicsItem *child, children) {
        if (!newEnabled || !child->d_ptr->explicitlyDisabled)
            child->d_ptr->setEnabledHelper(newEnabled, /* explicitly = */ false);
    }

    // Deliver post-change notification.
    q_ptr->itemChange(QGraphicsItem::ItemEnabledHasChanged, newEnabledVariant);
}

/*!
    If \a enabled is true, the item is enabled; otherwise, it is disabled.

    Disabled items are visible, but they do not receive any events, and cannot
    take focus nor be selected. Mouse events are discarded; they are not
    propagated unless the item is also invisible, or if it does not accept
    mouse events (see acceptedMouseButtons()). A disabled item cannot become the
    mouse grabber, and as a result of this, an item loses the grab if it
    becomes disabled when grabbing the mouse, just like it loses focus if it
    had focus when it was disabled.

    Disabled items are traditionally drawn using grayed-out colors (see \l
    QPalette::Disabled).

    If you disable a parent item, all its children will also be disabled. If
    you enable a parent item, all children will be enabled, unless they have
    been explicitly disabled (i.e., if you call setEnabled(false) on a child,
    it will not be reenabled if its parent is disabled, and then enabled
    again).

    Items are enabled by default.

    \note If you install an event filter, you can still intercept events
    before they are delivered to items; this mechanism disregards the item's
    enabled state.

    \sa isEnabled()
*/
void QGraphicsItem::setEnabled(bool enabled)
{
    d_ptr->setEnabledHelper(enabled, /* explicitly = */ true);
}

/*!
    Returns true if this item is selected; otherwise, false is returned.

    Items that are in a group inherit the group's selected state.

    Items are not selected by default.

    \sa setSelected(), QGraphicsScene::setSelectionArea()
*/
bool QGraphicsItem::isSelected() const
{
    if (QGraphicsItemGroup *group = this->group())
        return group->isSelected();
    return d_ptr->selected;
}

/*!
    If \a selected is true and this item is selectable, this item is selected;
    otherwise, it is unselected.

    If the item is in a group, the whole group's selected state is toggled by
    this function. If the group is selected, all items in the group are also
    selected, and if the group is not selected, no item in the group is
    selected.

    Only visible, enabled, selectable items can be selected.  If \a selected
    is true and this item is either invisible or disabled or unselectable,
    this function does nothing.

    By default, items cannot be selected. To enable selection, set the
    ItemIsSelectable flag.

    This function is provided for convenience, allowing individual toggling of
    the selected state of an item. However, a more common way of selecting
    items is to call QGraphicsScene::setSelectionArea(), which will call this
    function for all visible, enabled, and selectable items within a specified
    area on the scene.

    \sa isSelected(), QGraphicsScene::selectedItems()
*/
void QGraphicsItem::setSelected(bool selected)
{
    if (QGraphicsItemGroup *group = this->group()) {
        group->setSelected(selected);
        return;
    }

    if (!(d_ptr->flags & ItemIsSelectable) || !d_ptr->enabled || !d_ptr->visible)
        selected = false;
    if (d_ptr->selected == selected)
        return;
    const QVariant newSelectedVariant(itemChange(ItemSelectedChange, quint32(selected)));
    bool newSelected = newSelectedVariant.toBool();
    if (d_ptr->selected == newSelected)
        return;
    d_ptr->selected = newSelected;

    d_ptr->updateHelper();

    if (d_ptr->scene) {
        QGraphicsScenePrivate *sceneD = d_ptr->scene->d_func();
        if (selected) {
            sceneD->selectedItems << this;
        } else {
            // QGraphicsScene::selectedItems() lazily pulls out all items that are
            // no longer selected.
        }
        if (!sceneD->selectionChanging)
            emit d_ptr->scene->selectionChanged();
    }

    // Deliver post-change notification.
    itemChange(QGraphicsItem::ItemSelectedHasChanged, newSelectedVariant);
}

/*!
    \since 4.5

    Returns this item's local opacity, which is between 0.0 (transparent) and
    1.0 (opaque). This value is combined with parent and ancestor values into
    the effectiveOpacity(). The effective opacity decides how the item is
    rendered.

    The opacity property decides the state of the painter passed to the
    paint() function. If the item is cached, i.e., ItemCoordinateCache or
    DeviceCoordinateCache, the effective property will be applied to the item's
    cache as it is rendered.

    The default opacity is 1.0; fully opaque.

    \sa setOpacity(), paint(), ItemIgnoresParentOpacity,
    ItemDoesntPropagateOpacityToChildren
*/
qreal QGraphicsItem::opacity() const
{
    if (d_ptr->hasOpacity) {
        QVariant o = d_ptr->extra(QGraphicsItemPrivate::ExtraOpacity);
        if (!o.isNull())
            return o.toDouble();
    }
    return qreal(1.0);
}

/*!
    \since 4.5

    Returns this item's \e effective opacity, which is between 0.0
    (transparent) and 1.0 (opaque). This value is a combination of this item's
    local opacity, and its parent and ancestors' opacities. The effective
    opacity decides how the item is rendered.

    \sa opacity(), setOpacity(), paint(), ItemIgnoresParentOpacity,
    ItemDoesntPropagateOpacityToChildren
*/
qreal QGraphicsItem::effectiveOpacity() const
{
    if (!d_ptr->hasEffectiveOpacity)
        return qreal(1.0);

    QVariant effectiveOpacity = d_ptr->extra(QGraphicsItemPrivate::ExtraEffectiveOpacity);
    return effectiveOpacity.isNull() ? qreal(1.0) : qreal(effectiveOpacity.toDouble());
}

/*!
    \since 4.5

    Sets this item's local \a opacity, between 0.0 (transparent) and 1.0
    (opaque). The item's local opacity is combined with parent and ancestor
    opacities into the effectiveOpacity().

    By default, opacity propagates from parent to child, so if a parent's
    opacity is 0.5 and the child is also 0.5, the child's effective opacity
    will be 0.25.

    The opacity property decides the state of the painter passed to the
    paint() function. If the item is cached, i.e., ItemCoordinateCache or
    DeviceCoordinateCache, the effective property will be applied to the
    item's cache as it is rendered.

    There are two item flags that affect how the item's opacity is combined
    with the parent: ItemIgnoresParentOpacity and
    ItemDoesntPropagateOpacityToChildren.

    \sa opacity(), effectiveOpacity()
*/
void QGraphicsItem::setOpacity(qreal opacity)
{
    // Notify change.
    const QVariant newOpacityVariant(itemChange(ItemOpacityChange, double(opacity)));
    qreal newOpacity = newOpacityVariant.toDouble();

    // Normalize.
    newOpacity = qBound<qreal>(0.0, newOpacity, 1.0);

    // No change? Done.
    if (qFuzzyIsNull(newOpacity - this->opacity()))
        return;

    // Assign local opacity.
    if (qFuzzyIsNull(newOpacity - 1)) {
        // Opaque, unset opacity.
        d_ptr->hasOpacity = 0;
        d_ptr->unsetExtra(QGraphicsItemPrivate::ExtraOpacity);
    } else {
        d_ptr->hasOpacity = 1;
        d_ptr->setExtra(QGraphicsItemPrivate::ExtraOpacity, double(newOpacity));
    }

    // Resolve effective opacity.
    if (QGraphicsItem *p = d_ptr->parent)
        d_ptr->resolveEffectiveOpacity(p->effectiveOpacity());
    else
        d_ptr->resolveEffectiveOpacity(1.0);

    // Notify change.
    itemChange(ItemOpacityHasChanged, newOpacity);

    // Update.
    d_ptr->fullUpdateHelper(/*childrenOnly=*/false, /*maybeDirtyClipPath=*/false, /*ignoreOpacity=*/true);
}

/*!
   Returns true if this item can accept drag and drop events; otherwise,
   returns false. By default, items do not accept drag and drop events; items
   are transparent to drag and drop.

   \sa setAcceptDrops()
*/
bool QGraphicsItem::acceptDrops() const
{
    return d_ptr->acceptDrops;
}

/*!
    If \a on is true, this item will accept drag and drop events; otherwise,
    it is transparent for drag and drop events. By default, items do not
    accept drag and drop events.

    \sa acceptDrops()
*/
void QGraphicsItem::setAcceptDrops(bool on)
{
    d_ptr->acceptDrops = on;
}

/*!
    Returns the mouse buttons that this item accepts mouse events for.  By
    default, all mouse buttons are accepted.

    If an item accepts a mouse button, it will become the mouse
    grabber item when a mouse press event is delivered for that mouse
    button. However, if the item does not accept the button,
    QGraphicsScene will forward the mouse events to the first item
    beneath it that does.

    \sa setAcceptedMouseButtons(), mousePressEvent()
*/
Qt::MouseButtons QGraphicsItem::acceptedMouseButtons() const
{
    return Qt::MouseButtons(d_ptr->acceptedMouseButtons);
}

/*!
    Sets the mouse \a buttons that this item accepts mouse events for.

    By default, all mouse buttons are accepted. If an item accepts a
    mouse button, it will become the mouse grabber item when a mouse
    press event is delivered for that button. However, if the item
    does not accept the mouse button, QGraphicsScene will forward the
    mouse events to the first item beneath it that does.

    To disable mouse events for an item (i.e., make it transparent for mouse
    events), call setAcceptedMouseButtons(0).

    \sa acceptedMouseButtons(), mousePressEvent()
*/
void QGraphicsItem::setAcceptedMouseButtons(Qt::MouseButtons buttons)
{
    if (Qt::MouseButtons(d_ptr->acceptedMouseButtons) != buttons) {
        if (buttons == 0 && d_ptr->scene && d_ptr->scene->mouseGrabberItem() == this
            && d_ptr->scene->d_func()->lastMouseGrabberItemHasImplicitMouseGrab) {
            ungrabMouse();
        }
        d_ptr->acceptedMouseButtons = quint32(buttons);
    }
}

/*!
    \since 4.4

    Returns true if an item accepts hover events
    (QGraphicsSceneHoverEvent); otherwise, returns false. By default,
    items do not accept hover events.

    \sa setAcceptedMouseButtons()
*/
bool QGraphicsItem::acceptHoverEvents() const
{
    return d_ptr->acceptsHover;
}

/*!
    \obsolete

    Call acceptHoverEvents() instead.
*/
bool QGraphicsItem::acceptsHoverEvents() const
{
    return d_ptr->acceptsHover;
}

/*!
    \since 4.4

    If \a enabled is true, this item will accept hover events;
    otherwise, it will ignore them. By default, items do not accept
    hover events.

    Hover events are delivered when there is no current mouse grabber
    item.  They are sent when the mouse cursor enters an item, when it
    moves around inside the item, and when the cursor leaves an
    item. Hover events are commonly used to highlight an item when
    it's entered, and for tracking the mouse cursor as it hovers over
    the item (equivalent to QWidget::mouseTracking).

    Parent items receive hover enter events before their children, and
    leave events after their children. The parent does not receive a
    hover leave event if the cursor enters a child, though; the parent
    stays "hovered" until the cursor leaves its area, including its
    children's areas.

    If a parent item handles child events (setHandlesChildEvents()), it will
    receive hover move, drag move, and drop events as the cursor passes
    through its children, but it does not receive hover enter and hover leave,
    nor drag enter and drag leave events on behalf of its children.

    A QGraphicsWidget with window decorations will accept hover events
    regardless of the value of acceptHoverEvents().

    \sa acceptHoverEvents(), hoverEnterEvent(), hoverMoveEvent(),
    hoverLeaveEvent()
*/
void QGraphicsItem::setAcceptHoverEvents(bool enabled)
{
    if (d_ptr->acceptsHover == quint32(enabled))
        return;
    d_ptr->acceptsHover = quint32(enabled);
    if (d_ptr->acceptsHover && d_ptr->scene && d_ptr->scene->d_func()->allItemsIgnoreHoverEvents) {
        d_ptr->scene->d_func()->allItemsIgnoreHoverEvents = false;
        d_ptr->scene->d_func()->enableMouseTrackingOnViews();
    }
}

/*!
    \obsolete

    Use setAcceptHoverEvents(\a enabled) instead.
*/
void QGraphicsItem::setAcceptsHoverEvents(bool enabled)
{
    setAcceptHoverEvents(enabled);
}

/*! \since 4.6

    Returns true if an item accepts touch events
    (QGraphicsSceneTouchEvent); otherwise, returns false. By default,
    items do not accept touch events.

    \sa setAcceptTouchEvents()
*/
bool QGraphicsItem::acceptTouchEvents() const
{
    return d_ptr->acceptTouchEvents;
}

/*!
    \since 4.6

    If \a enabled is true, this item will accept touch events;
    otherwise, it will ignore them. By default, items do not accept
    touch events.
*/
void QGraphicsItem::setAcceptTouchEvents(bool enabled)
{
    d_ptr->acceptTouchEvents = quint32(enabled);
}

/*!
    Returns true if this item handles child events (i.e., all events
    intended for any of its children are instead sent to this item);
    otherwise, false is returned.

    This property is useful for item groups; it allows one item to
    handle events on behalf of its children, as opposed to its
    children handling their events individually.

    The default is to return false; children handle their own events.
    The exception for this is if the item is a QGraphicsItemGroup, then
    it defaults to return true.

    \sa setHandlesChildEvents()
*/
bool QGraphicsItem::handlesChildEvents() const
{
    return d_ptr->handlesChildEvents;
}

/*!
    If \a enabled is true, this item is set to handle all events for
    all its children (i.e., all events intented for any of its
    children are instead sent to this item); otherwise, if \a enabled
    is false, this item will only handle its own events. The default
    value is false.

    This property is useful for item groups; it allows one item to
    handle events on behalf of its children, as opposed to its
    children handling their events individually.

    If a child item accepts hover events, its parent will receive
    hover move events as the cursor passes through the child, but it
    does not receive hover enter and hover leave events on behalf of
    its child.

    \sa handlesChildEvents()
*/
void QGraphicsItem::setHandlesChildEvents(bool enabled)
{
    if (d_ptr->handlesChildEvents == enabled)
        return;

    d_ptr->handlesChildEvents = enabled;
    d_ptr->updateAncestorFlag(QGraphicsItem::GraphicsItemFlag(-1));
}

/*!
    Returns true if this item has keyboard input focus; otherwise, returns
    false.

    \sa QGraphicsScene::focusItem(), setFocus(), QGraphicsScene::setFocusItem()
*/
bool QGraphicsItem::hasFocus() const
{
    return (d_ptr->scene && d_ptr->scene->focusItem() == this);
}

/*!
    Gives keyboard input focus to this item. The \a focusReason argument will
    be passed into any focus event generated by this function; it is used to
    give an explanation of what caused the item to get focus.

    Only items that set the ItemIsFocusable flag can accept keyboard focus.

    If this item is not visible (i.e., isVisible() returns false), not
    enabled, not associated with a scene, or if it already has input focus,
    this function will do nothing.

    As a result of calling this function, this item will receive a focus in
    event with \a focusReason. If another item already has focus, that item
    will first receive a focus out event indicating that it has lost input
    focus.

    \sa clearFocus(), hasFocus()
*/
void QGraphicsItem::setFocus(Qt::FocusReason focusReason)
{
    if (!d_ptr->scene || !isEnabled() || hasFocus() || !(d_ptr->flags & ItemIsFocusable))
        return;
    if (isVisible()) {
        // Visible items immediately gain focus from scene.
        d_ptr->scene->setFocusItem(this, focusReason);
    } else if (d_ptr->isWidget) {
        // Just set up subfocus.
        static_cast<QGraphicsWidget *>(this)->d_func()->setFocusWidget();
    }
}

/*!
    Takes keyboard input focus from the item.

    If it has focus, a focus out event is sent to this item to tell it that it
    is about to lose the focus.

    Only items that set the ItemIsFocusable flag, or widgets that set an
    appropriate focus policy, can accept keyboard focus.

    \sa setFocus(), QGraphicsWidget::focusPolicy
*/
void QGraphicsItem::clearFocus()
{
    if (!d_ptr->scene)
        return;
    if (d_ptr->isWidget) {
        // Invisible widget items with focus must explicitly clear subfocus.
        static_cast<QGraphicsWidget *>(this)->d_func()->clearFocusWidget();
    }
    if (d_ptr->scene->focusItem() == this) {
        // If this item has the scene's input focus, clear it.
        d_ptr->scene->setFocusItem(0);
    }
}

/*!
    \since 4.4
    Grabs the mouse input.

    This item will receive all mouse events for the scene until any of the
    following events occurs:

    \list
    \o The item becomes invisible
    \o The item is removed from the scene
    \o The item is deleted
    \o The item call ungrabMouse()
    \o Another item calls grabMouse(); the item will regain the mouse grab
    when the other item calls ungrabMouse().
    \endlist

    When an item gains the mouse grab, it receives a QEvent::GrabMouse
    event. When it loses the mouse grab, it receives a QEvent::UngrabMouse
    event. These events can be used to detect when your item gains or loses
    the mouse grab through other means than receiving mouse button events.

    It is almost never necessary to explicitly grab the mouse in Qt, as Qt
    grabs and releases it sensibly. In particular, Qt grabs the mouse when you
    press a mouse button, and keeps the mouse grabbed until you release the
    last mouse button. Also, Qt::Popup widgets implicitly call grabMouse()
    when shown, and ungrabMouse() when hidden.

    Note that only visible items can grab mouse input. Calling grabMouse() on
    an invisible item has no effect.

    Keyboard events are not affected.

    \sa QGraphicsScene::mouseGrabberItem(), ungrabMouse(), grabKeyboard()
*/
void QGraphicsItem::grabMouse()
{
    if (!d_ptr->scene) {
        qWarning("QGraphicsItem::grabMouse: cannot grab mouse without scene");
        return;
    }
    if (!d_ptr->visible) {
        qWarning("QGraphicsItem::grabMouse: cannot grab mouse while invisible");
        return;
    }
    d_ptr->scene->d_func()->grabMouse(this);
}

/*!
    \since 4.4
    Releases the mouse grab.

    \sa grabMouse(), ungrabKeyboard()
*/
void QGraphicsItem::ungrabMouse()
{
    if (!d_ptr->scene) {
        qWarning("QGraphicsItem::ungrabMouse: cannot ungrab mouse without scene");
        return;
    }
    d_ptr->scene->d_func()->ungrabMouse(this);
}

/*!
    \since 4.4
    Grabs the keyboard input.

    The item will receive all keyboard input to the scene until one of the
    following events occur:

    \list
    \o The item becomes invisible
    \o The item is removed from the scene
    \o The item is deleted
    \o The item calls ungrabKeyboard()
    \o Another item calls grabKeyboard(); the item will regain the keyboard grab
    when the other item calls ungrabKeyboard().
    \endlist

    When an item gains the keyboard grab, it receives a QEvent::GrabKeyboard
    event. When it loses the keyboard grab, it receives a
    QEvent::UngrabKeyboard event. These events can be used to detect when your
    item gains or loses the keyboard grab through other means than gaining
    input focus.

    It is almost never necessary to explicitly grab the keyboard in Qt, as Qt
    grabs and releases it sensibly. In particular, Qt grabs the keyboard when
    your item gains input focus, and releases it when your item loses input
    focus, or when the item is hidden.

    Note that only visible items can grab keyboard input. Calling
    grabKeyboard() on an invisible item has no effect.

    Keyboard events are not affected.

    \sa ungrabKeyboard(), grabMouse(), setFocus()
*/
void QGraphicsItem::grabKeyboard()
{
    if (!d_ptr->scene) {
        qWarning("QGraphicsItem::grabKeyboard: cannot grab keyboard without scene");
        return;
    }
    if (!d_ptr->visible) {
        qWarning("QGraphicsItem::grabKeyboard: cannot grab keyboard while invisible");
        return;
    }
    d_ptr->scene->d_func()->grabKeyboard(this);
}

/*!
    \since 4.4
    Releases the keyboard grab.

    \sa grabKeyboard(), ungrabMouse()
*/
void QGraphicsItem::ungrabKeyboard()
{
    if (!d_ptr->scene) {
        qWarning("QGraphicsItem::ungrabKeyboard: cannot ungrab keyboard without scene");
        return;
    }
    d_ptr->scene->d_func()->ungrabKeyboard(this);
}

/*!
    Returns the position of the item in parent coordinates. If the item has no
    parent, its position is given in scene coordinates.

    The position of the item describes its origin (local coordinate
    (0, 0)) in parent coordinates; this function returns the same as
    mapToParent(0, 0).

    For convenience, you can also call scenePos() to determine the
    item's position in scene coordinates, regardless of its parent.

    \sa x(), y(), setPos(), matrix(), {The Graphics View Coordinate System}
*/
QPointF QGraphicsItem::pos() const
{
    return d_ptr->pos;
}

/*!
    \fn QGraphicsItem::x() const

    This convenience function is equivalent to calling pos().x().

    \sa y()
*/

/*!
    \fn QGraphicsItem::y() const

    This convenience function is equivalent to calling pos().y().

    \sa x()
*/

/*!
    Returns the item's position in scene coordinates. This is
    equivalent to calling \c mapToScene(0, 0).

    \sa pos(), sceneTransform(), {The Graphics View Coordinate System}
*/
QPointF QGraphicsItem::scenePos() const
{
    return mapToScene(0, 0);
}

/*!
    \internal

    Sets the position \a pos and notifies the change. If \a update is true,
    the item is also updated; otherwise it is not updated before and after the
    change.
*/
void QGraphicsItemPrivate::setPosHelper(const QPointF &pos)
{
    Q_Q(QGraphicsItem);
    if (this->pos == pos)
        return;

    // Notify the item that the position is changing.
    const QVariant newPosVariant(q->itemChange(QGraphicsItem::ItemPositionChange, pos));
    QPointF newPos = newPosVariant.toPointF();
    if (newPos == this->pos)
        return;

    // Update and repositition.
    inSetPosHelper = 1;
    updateCachedClipPathFromSetPosHelper(newPos);
    if (scene) {
        fullUpdateHelper(true);
        q->prepareGeometryChange();
    }
    this->pos = newPos;
    invalidateSceneTransformCache();

    // Send post-notification.
    q->itemChange(QGraphicsItem::ItemPositionHasChanged, newPosVariant);
    inSetPosHelper = 0;
}

/*!
    Sets the position of the item to \a pos, which is in parent
    coordinates.  For items with no parent, \a pos is in scene
    coordinates.

    The position of the item describes its origin (local coordinate
    (0, 0)) in parent coordinates.

    \sa pos(), scenePos(), {The Graphics View Coordinate System}
*/
void QGraphicsItem::setPos(const QPointF &pos)
{
    d_ptr->setPosHelper(pos);
}

/*!
    \fn void QGraphicsItem::setPos(qreal x, qreal y)
    \overload

    This convenience function is equivalent to calling setPos(QPointF(\a x, \a
    y)).
*/

/*!
    \fn void QGraphicsItem::moveBy(qreal dx, qreal dy)

    Moves the item by \a dx points horizontally, and \a dy point
    vertically. This function is equivalent to calling setPos(pos() +
    QPointF(\a dx, \a dy)).
*/

/*!
    If this item is part of a scene that is viewed by a QGraphicsView, this
    convenience function will attempt to scroll the view to ensure that \a
    rect is visible inside the view's viewport. If \a rect is a null rect (the
    default), QGraphicsItem will default to the item's bounding rect. \a xmargin
    and \a ymargin are the number of pixels the view should use for margins.

    If the specified rect cannot be reached, the contents are scrolled to the
    nearest valid position.

    If this item is not viewed by a QGraphicsView, this function does nothing.

    \sa QGraphicsView::ensureVisible()
*/
void QGraphicsItem::ensureVisible(const QRectF &rect, int xmargin, int ymargin)
{
    if (d_ptr->scene) {
        QRectF sceneRect;
        if (!rect.isNull())
            sceneRect = sceneTransform().mapRect(rect);
        else
            sceneRect = sceneBoundingRect();
        foreach (QGraphicsView *view, d_ptr->scene->d_func()->views)
            view->ensureVisible(sceneRect, xmargin, ymargin);
    }
}

/*!
    \fn void QGraphicsItem::ensureVisible(qreal x, qreal y, qreal w, qreal h,
    int xmargin = 50, int ymargin = 50)

    This convenience function is equivalent to calling
    ensureVisible(QRectF(\a x, \a y, \a w, \a h), \a xmargin, \a ymargin):
*/

/*!
    \obsolete

    Returns the item's affine transformation matrix. This is a subset or the
    item's full transformation matrix, and might not represent the item's full
    transformation.

    Use transform() instead.

    \sa setTransform(), sceneTransform()
*/
QMatrix QGraphicsItem::matrix() const
{
    return transform().toAffine();
}

/*!
    \since 4.3

    Returns this item's transformation matrix. If no matrix has been set, the
    identity matrix is returned.

    \sa setTransform(), sceneTransform()
*/
QTransform QGraphicsItem::transform() const
{
    if (!d_ptr->hasTransform)
        return QTransform();
    return qVariantValue<QTransform>(d_ptr->extra(QGraphicsItemPrivate::ExtraTransform));
}

/*!
    \obsolete

    Use sceneTransform() instead.

    \sa transform(), setTransform(), scenePos(), {The Graphics View Coordinate System}
*/
QMatrix QGraphicsItem::sceneMatrix() const
{
    return sceneTransform().toAffine();
}


/*!
    \since 4.3

    Returns this item's scene transformation matrix. This matrix can be used
    to map coordinates and geometrical shapes from this item's local
    coordinate system to the scene's coordinate system. To map coordinates
    from the scene, you must first invert the returned matrix.

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 4

    Unlike transform(), which returns only an item's local transformation, this
    function includes the item's (and any parents') position.

    \sa transform(), setTransform(), scenePos(), {The Graphics View Coordinate System}
*/
QTransform QGraphicsItem::sceneTransform() const
{
    // Check if there's any entry in the transform cache.
    QGraphicsScenePrivate *sd = d_ptr->scene ? d_ptr->scene->d_func() : 0;
    int index = d_ptr->sceneTransformIndex;
    if (sd && index != -1 && sd->validTransforms.testBit(index))
        return sd->sceneTransformCache[index];

    // Calculate local transform.
    QTransform m;
    if (d_ptr->hasTransform) {
        m = transform();
        if (!d_ptr->pos.isNull())
            m *= QTransform::fromTranslate(d_ptr->pos.x(), d_ptr->pos.y());
    } else if (!d_ptr->pos.isNull()) {
        m = QTransform::fromTranslate(d_ptr->pos.x(), d_ptr->pos.y());
    }

    // Combine with parent and add to cache.
    if (d_ptr->parent) {
        m *= d_ptr->parent->sceneTransform();
        // Don't cache toplevels
        if (sd) {
            if (index == -1) {
                if (!sd->freeSceneTransformSlots.isEmpty()) {
                    index = sd->freeSceneTransformSlots.last();
                    sd->freeSceneTransformSlots.pop_back();
                } else {
                    index = sd->sceneTransformCache.size();
                }
                d_ptr->sceneTransformIndex = index;
                if (index >= sd->validTransforms.size()) {
                    sd->validTransforms.resize(index + 1);
                    sd->sceneTransformCache.resize(index + 1);
                }
            }
            sd->validTransforms.setBit(index, 1);
            sd->sceneTransformCache[index] = m;
        }
    }
    return m;
}

/*!
    \since 4.3

    Returns this item's device transformation matrix, using \a
    viewportTransform to map from scene to device coordinates. This matrix can
    be used to map coordinates and geometrical shapes from this item's local
    coordinate system to the viewport's (or any device's) coordinate
    system. To map coordinates from the viewport, you must first invert the
    returned matrix.

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 5

    This function is the same as combining this item's scene transform with
    the view's viewport transform, but it also understands the
    ItemIgnoresTransformations flag. The device transform can be used to do
    accurate coordinate mapping (and collision detection) for untransformable
    items.

    \sa transform(), setTransform(), scenePos(), {The Graphics View Coordinate
    System}, itemTransform()
*/
QTransform QGraphicsItem::deviceTransform(const QTransform &viewportTransform) const
{
    // Find the topmost item that ignores view transformations.
    const QGraphicsItem *untransformedAncestor = this;
    QList<const QGraphicsItem *> parents;
    while (untransformedAncestor && ((untransformedAncestor->d_ptr->ancestorFlags
                                     & QGraphicsItemPrivate::AncestorIgnoresTransformations))) {
        parents.prepend(untransformedAncestor);
        untransformedAncestor = untransformedAncestor->parentItem();
    }

    if (!untransformedAncestor) {
        // Assert in debug mode, continue in release.
        Q_ASSERT_X(untransformedAncestor, "QGraphicsItem::deviceTransform",
                   "Invalid object structure!");
        return QTransform();
    }

    // First translate the base untransformable item.
    QPointF mappedPoint = (untransformedAncestor->sceneTransform() * viewportTransform).map(QPointF(0, 0));
    QTransform matrix;
    matrix.translate(mappedPoint.x(), mappedPoint.y());
    matrix = untransformedAncestor->transform() * matrix;

    // Then transform and translate all children.
    for (int i = 0; i < parents.size(); ++i) {
        const QGraphicsItem *parent = parents.at(i);
        QPointF pos = parent->pos();
        QTransform moveMatrix;
        moveMatrix.translate(pos.x(), pos.y());
        matrix = (parent->transform() * moveMatrix) * matrix;
    }

    return matrix;
}

/*!
    \since 4.5

    Returns a QTransform that maps coordinates from this item to \a other. If
    \a ok is not null, and if there is no such transform, the boolean pointed
    to by \a ok will be set to false; otherwise it will be set to true.

    This transform provides an alternative to the mapToItem() or mapFromItem()
    functions, by returning the appropriate transform so that you can map
    shapes and coordinates yourself. It also helps you write more efficient
    code when repeatedly mapping between the same two items.

    \note In rare circumstances, there is no transform that maps between two
    items.

    \sa mapToItem(), mapFromItem(), deviceTransform()
*/
QTransform QGraphicsItem::itemTransform(const QGraphicsItem *other, bool *ok) const
{
    // Catch simple cases first.
    if (other == 0) {
        qWarning("QGraphicsItem::itemTransform: null pointer passed");
        return QTransform();
    }
    if (other == this) {
        if (ok)
            *ok = true;
        return QTransform();
    }

    QGraphicsItem *parent = d_ptr->parent;
    const QGraphicsItem *otherParent = other->d_ptr->parent;

    // This is other's child
    if (parent == other) {
        if (ok)
            *ok = true;
        const QPointF &itemPos = d_ptr->pos;
        if (itemPos.isNull())
            return d_ptr->hasTransform ? transform() : QTransform();
        if (d_ptr->hasTransform)
            return transform() * QTransform::fromTranslate(itemPos.x(), itemPos.y());
        return QTransform::fromTranslate(itemPos.x(), itemPos.y());
    }

    // This is other's parent
    if (otherParent == this) {
        const QPointF &otherPos = other->d_ptr->pos;
        if (other->d_ptr->hasTransform) {
            QTransform otherToParent = other->transform();
            if (!otherPos.isNull())
                otherToParent *= QTransform::fromTranslate(otherPos.x(), otherPos.y());
            return otherToParent.inverted(ok);
        } else {
            if (ok)
                *ok = true;
            return QTransform::fromTranslate(-otherPos.x(), -otherPos.y());
        }
    }

    // Siblings
    if (parent == otherParent) {
        bool hasTr = d_ptr->hasTransform;
        bool otherHasTr = other->d_ptr->hasTransform;
        const QPointF &itemPos = d_ptr->pos;
        const QPointF &otherPos = other->d_ptr->pos;

        if (!hasTr && !otherHasTr) {
            QPointF delta = itemPos - otherPos;
            if (ok)
                *ok = true;
            return QTransform::fromTranslate(delta.x(), delta.y());
        }

        QTransform itemToParent = QTransform::fromTranslate(itemPos.x(), itemPos.y());
        if (hasTr)
            itemToParent = itemPos.isNull() ? transform() : transform() * itemToParent;

        QTransform otherToParent = QTransform::fromTranslate(otherPos.x(), otherPos.y());
        if (otherHasTr)
            otherToParent = otherPos.isNull() ? other->transform() : other->transform() * otherToParent;

        return itemToParent * otherToParent.inverted(ok);
    }

    // Find the closest common ancestor. If the two items don't share an
    // ancestor, then the only way is to combine their scene transforms.
    const QGraphicsItem *commonAncestor = commonAncestorItem(other);
    if (!commonAncestor)
        return sceneTransform() * other->sceneTransform().inverted(ok);

    // If the two items are cousins (in sibling branches), map both to the
    // common ancestor, and combine the two transforms.
    bool cousins = other != commonAncestor && this != commonAncestor;
    if (cousins) {
        bool good = false;
        QTransform thisToScene;
        QTransform otherToScene;
        thisToScene = itemTransform(commonAncestor, &good);
        if (good)
            otherToScene = other->itemTransform(commonAncestor, &good);
        if (!good) {
            if (ok)
                *ok = false;
            return QTransform();
        }
        return thisToScene * otherToScene.inverted(ok);
    }

    // One is an ancestor of the other; walk the chain.
    bool parentOfOther = isAncestorOf(other);
    const QGraphicsItem *child = parentOfOther ? other : this;
    const QGraphicsItem *root = parentOfOther ? this : other;

    QTransform x;
    const QGraphicsItem *p = child;
    do {
        const QGraphicsItemPrivate *pd = p->d_ptr;
        if (pd->hasTransform)
            x *= p->transform();
        if (!pd->pos.isNull())
            x *= QTransform::fromTranslate(pd->pos.x(), pd->pos.y());
    } while ((p = p->d_ptr->parent) && p != root);
    if (parentOfOther)
        return x.inverted(ok);
    if (ok)
        *ok = true;
    return x;
}

/*!
    \obsolete

    Sets the item's affine transformation matrix. This is a subset or the
    item's full transformation matrix, and might not represent the item's full
    transformation.

    Use setTransform() instead.

    \sa transform(), rotate(), scale(), shear(), translate(), {The Graphics View Coordinate System}
*/
void QGraphicsItem::setMatrix(const QMatrix &matrix, bool combine)
{
    QTransform oldTransform = this->transform();
    QTransform newTransform;
    if (!combine)
        newTransform = QTransform(matrix);
    else
        newTransform = QTransform(matrix) * oldTransform;
    if (oldTransform == newTransform)
        return;

    // Notify the item that the matrix is changing.
    QVariant newTransformVariant(itemChange(ItemMatrixChange,
                                            qVariantFromValue<QMatrix>(newTransform.toAffine())));
    newTransform = QTransform(qVariantValue<QMatrix>(newTransformVariant));
    if (oldTransform == newTransform)
        return;

    // Update and set the new transformation.
    d_ptr->fullUpdateHelper(true, true);
    prepareGeometryChange();
    d_ptr->hasTransform = !newTransform.isIdentity();
    d_ptr->setExtra(QGraphicsItemPrivate::ExtraTransform, newTransform);
    d_ptr->invalidateSceneTransformCache();

    // Send post-notification.
    // NB! We have to change the value from QMatrix to QTransform.
    qVariantSetValue<QTransform>(newTransformVariant, newTransform);
    itemChange(ItemTransformHasChanged, newTransformVariant);
}

/*!
    \since 4.3

    Sets the item's current transformation matrix to \a matrix.

    If \a combine is true, then \a matrix is combined with the current matrix;
    otherwise, \a matrix \e replaces the current matrix. \a combine is false
    by default.

    To simplify interation with items using a transformed view, QGraphicsItem
    provides mapTo... and mapFrom... functions that can translate between
    items' and the scene's coordinates. For example, you can call mapToScene()
    to map an item coordiate to a scene coordinate, or mapFromScene() to map
    from scene coordinates to item coordinates.

    \sa transform(), rotate(), scale(), shear(), translate(), {The Graphics View Coordinate System}
*/
void QGraphicsItem::setTransform(const QTransform &matrix, bool combine)
{
    QTransform oldTransform = this->transform();
    QTransform newTransform;
    if (!combine)
        newTransform = matrix;
    else
        newTransform = matrix * oldTransform;
    if (oldTransform == newTransform)
        return;

    // Notify the item that the transformation matrix is changing.
    const QVariant newTransformVariant(itemChange(ItemTransformChange,
                                                  qVariantFromValue<QTransform>(newTransform)));
    newTransform = qVariantValue<QTransform>(newTransformVariant);
    if (oldTransform == newTransform)
        return;

    // Update and set the new transformation.
    d_ptr->fullUpdateHelper(true, true);
    prepareGeometryChange();
    d_ptr->hasTransform = !newTransform.isIdentity();
    d_ptr->setExtra(QGraphicsItemPrivate::ExtraTransform, newTransform);
    d_ptr->invalidateSceneTransformCache();

    // Send post-notification.
    itemChange(ItemTransformHasChanged, newTransformVariant);
}

/*!
    \obsolete

    Use resetTransform() instead.
*/
void QGraphicsItem::resetMatrix()
{
    resetTransform();
}

/*!
    \since 4.3

    Resets this item's transformation matrix to the identity matrix. This is
    equivalent to calling \c setTransform(QTransform()).

    \sa setTransform(), transform()
*/
void QGraphicsItem::resetTransform()
{
    setTransform(QTransform(), false);
}

/*!
    Rotates the current item transformation \a angle degrees clockwise around
    its origin. To translate around an arbitrary point (x, y), you need to
    combine translation and rotation with setTransform().

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 6

    \sa setTransform(), transform(), scale(), shear(), translate()
*/
void QGraphicsItem::rotate(qreal angle)
{
    setTransform(QTransform().rotate(angle), true);
}

/*!
    Scales the current item transformation by (\a sx, \a sy) around its
    origin. To scale from an arbitrary point (x, y), you need to combine
    translation and scaling with setTransform().

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 7

    \sa setTransform(), transform(), rotate(), shear(), translate()
*/
void QGraphicsItem::scale(qreal sx, qreal sy)
{
    setTransform(QTransform::fromScale(sx, sy), true);
}

/*!
    Shears the current item transformation by (\a sh, \a sv).

    \sa setTransform(), transform(), rotate(), scale(), translate()
*/
void QGraphicsItem::shear(qreal sh, qreal sv)
{
    setTransform(QTransform().shear(sh, sv), true);
}

/*!
    Translates the current item transformation by (\a dx, \a dy).

    If all you want is to move an item, you should call moveBy() or
    setPos() instead; this function changes the item's translation,
    which is conceptually separate from its position.

    \sa setTransform(), transform(), rotate(), scale(), shear()
*/
void QGraphicsItem::translate(qreal dx, qreal dy)
{
    setTransform(QTransform::fromTranslate(dx, dy), true);
}

/*!
    This virtual function is called twice for all items by the
    QGraphicsScene::advance() slot. In the first phase, all items are called
    with \a phase == 0, indicating that items on the scene are about to
    advance, and then all items are called with \a phase == 1. Reimplement
    this function to update your item if you need simple scene-controlled
    animation.

    The default implementation does nothing.

    For individual item animation, an alternative to this function is to
    either use QGraphicsItemAnimation, or to multiple-inherit from QObject and
    QGraphicsItem, and animate your item using QObject::startTimer() and
    QObject::timerEvent().

    \sa QGraphicsItemAnimation, QTimeLine
*/
void QGraphicsItem::advance(int phase)
{
    Q_UNUSED(phase);
}

/*!
    Returns the Z-value, or the elevation, of the item. The Z-value decides
    the stacking order of sibling (neighboring) items.

    The default Z-value is 0.

    \sa setZValue()
*/
qreal QGraphicsItem::zValue() const
{
    return d_ptr->z;
}

/*!
    Sets the Z-value, or the elevation, of the item, to \a z. The elevation
    decides the stacking order of sibling (neighboring) items. An item of high
    Z-value will be drawn on top of an item with a lower Z-value if they share
    the same parent item. In addition, children of an item will always be
    drawn on top of the parent, regardless of the child's Z-value. Sibling
    items that share the same Z-value will be drawn in order of insertion; the
    last inserted child is stacked above previous children.

    \img graphicsview-zorder.png

    Children of different parents are stacked according to the Z-value of
    each item's ancestor item which is an immediate child of the two
    items' closest common ancestor. For example, a robot item might
    define a torso item as the parent of a head item, two arm items,
    and two upper-leg items. The upper-leg items would each be parents
    of one lower-leg item, and each lower-leg item would be parents of
    one foot item.  The stacking order of the feet is the same as the
    stacking order of each foot's ancestor that is an immediate child
    of the two feet's common ancestor (i.e., the torso item); so the
    feet are stacked in the same order as the upper-leg items,
    regardless of each foot's Z-value.

    The Z-value does not affect the item's size in any way.

    The default Z-value is 0.

    \sa zValue()
*/
void QGraphicsItem::setZValue(qreal z)
{
    const QVariant newZVariant(itemChange(ItemZValueChange, double(z)));
    qreal newZ = qreal(newZVariant.toDouble());
    if (newZ == d_ptr->z)
        return;
    d_ptr->z = newZ;
    d_ptr->fullUpdateHelper();

    if (d_ptr->scene) {
        // Invalidate any sort caching; arrival of a new item means we need to
        // resort.
        d_ptr->scene->d_func()->invalidateSortCache();
    }

    itemChange(ItemZValueHasChanged, newZVariant);
}

/*!
    Returns the bounding rect of this item's descendants (i.e., its
    children, their children, etc.) in local coordinates. The
    rectangle will contain all descendants after they have been mapped
    to local coordinates. If the item has no children, this function
    returns an empty QRectF.

    This does not include this item's own bounding rect; it only returns
    its descendants' accumulated bounding rect. If you need to include this
    item's bounding rect, you can add boundingRect() to childrenBoundingRect()
    using QRectF::operator|().

    This function is linear in complexity; it determines the size of the
    returned bounding rect by iterating through all descendants.

    \sa boundingRect(), sceneBoundingRect()
*/
QRectF QGraphicsItem::childrenBoundingRect() const
{
    QRectF childRect;
    QTransform x;
    d_ptr->childrenBoundingRectHelper(&x, &childRect);
    return childRect;
}

/*!
    \fn virtual QRectF QGraphicsItem::boundingRect() const = 0

    This pure virtual function defines the outer bounds of the item as
    a rectangle; all painting must be restricted to inside an item's
    bounding rect. QGraphicsView uses this to determine whether the
    item requires redrawing.

    Although the item's shape can be arbitrary, the bounding rect is
    always rectangular, and it is unaffected by the items'
    transformation (scale(), rotate(), etc.).

    If you want to change the item's bounding rectangle, you must first call
    prepareGeometryChange(). This notifies the scene of the imminent change,
    so that its can update its item geometry index; otherwise, the scene will
    be unaware of the item's new geometry, and the results are undefined
    (typically, rendering artifacts are left around in the view).

    Reimplement this function to let QGraphicsView determine what
    parts of the widget, if any, need to be redrawn.

    Note: For shapes that paint an outline / stroke, it is important
    to include half the pen width in the bounding rect. It is not
    necessary to compensate for antialiasing, though.

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 8

    \sa boundingRegion(), shape(), contains(), {The Graphics View Coordinate
    System}, prepareGeometryChange()
*/

/*!
    Returns the bounding rect of this item in scene coordinates, by combining
    sceneTransform() with boundingRect().

    \sa boundingRect(), {The Graphics View Coordinate System}
*/
QRectF QGraphicsItem::sceneBoundingRect() const
{
    // Find translate-only offset
    QPointF offset;
    const QGraphicsItem *parentItem = this;
    const QGraphicsItemPrivate *itemd;
    do {
        itemd = parentItem->d_ptr;
        if (itemd->hasTransform)
            break;
        offset += itemd->pos;
    } while ((parentItem = itemd->parent));

    QRectF br = boundingRect();
    br.translate(offset);
    return !parentItem ? br : parentItem->sceneTransform().mapRect(br);
}

/*!
    Returns the shape of this item as a QPainterPath in local
    coordinates. The shape is used for many things, including collision
    detection, hit tests, and for the QGraphicsScene::items() functions.

    The default implementation calls boundingRect() to return a simple
    rectangular shape, but subclasses can reimplement this function to return
    a more accurate shape for non-rectangular items. For example, a round item
    may choose to return an elliptic shape for better collision detection. For
    example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 9

    The outline of a shape can vary depending on the width and style of the
    pen used when drawing. If you want to include this outline in the item's
    shape, you can create a shape from the stroke using QPainterPathStroker.

    This function is called by the default implementations of contains() and
    collidesWithPath().

    \sa boundingRect(), contains(), prepareGeometryChange(), QPainterPathStroker
*/
QPainterPath QGraphicsItem::shape() const
{
    QPainterPath path;
    path.addRect(boundingRect());
    return path;
}

/*!
    Returns true if this item is clipped. An item is clipped if it has either
    set the \l ItemClipsToShape flag, or if it or any of its ancestors has set
    the \l ItemClipsChildrenToShape flag.

    Clipping affects the item's appearance (i.e., painting), as well as mouse
    and hover event delivery.

    \sa clipPath(), shape(), setFlags()
*/
bool QGraphicsItem::isClipped() const
{
    Q_D(const QGraphicsItem);
    return (d->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren)
        || (d->flags & QGraphicsItem::ItemClipsToShape);
}

/*!
    \since 4.5

    Returns this item's clip path, or an empty QPainterPath if this item is
    not clipped. The clip path constrains the item's appearance and
    interaction (i.e., restricts the area the item can draw, and it also
    restricts the area that the item receives events).

    You can enable clipping by setting the ItemClipsToShape or
    ItemClipsChildrenToShape flags. The item's clip path is calculated by
    intersecting all clipping ancestors' shapes. If the item sets
    ItemClipsToShape, the final clip is intersected with the item's own shape.

    \note Clipping introduces a performance penalty for all items involved;
    you should generally avoid using clipping if you can (e.g., if your items
    always draw inside boundingRect() or shape() boundaries, clipping is not
    necessary).

    \sa isClipped(), shape(), setFlags()
*/
QPainterPath QGraphicsItem::clipPath() const
{
    Q_D(const QGraphicsItem);
    if (!d->dirtyClipPath)
        return d->emptyClipPath ? QPainterPath() : d->cachedClipPath;

    if (!isClipped()) {
        d_ptr->setCachedClipPath(QPainterPath());
        return d->cachedClipPath;
    }

    const QRectF thisBoundingRect(boundingRect());
    if (thisBoundingRect.isEmpty()) {
        if (d_ptr->flags & ItemClipsChildrenToShape)
            d_ptr->setEmptyCachedClipPathRecursively();
        else
            d_ptr->setEmptyCachedClipPath();
        return QPainterPath();
    }

    QPainterPath clip;
    // Start with the item's bounding rect.
    clip.addRect(thisBoundingRect);

    if (d->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren) {
        const QGraphicsItem *parent = this;
        const QGraphicsItem *lastParent = this;

        // Intersect any in-between clips starting at the top and moving downwards.
        bool foundValidClipPath = false;
        while ((parent = parent->d_ptr->parent)) {
            if (parent->d_ptr->flags & ItemClipsChildrenToShape) {
                // Map clip to the current parent and intersect with its shape/clipPath
                clip = lastParent->itemTransform(parent).map(clip);
                if ((foundValidClipPath = !parent->d_ptr->dirtyClipPath && parent->isClipped())) {
                    if (parent->d_ptr->emptyClipPath) {
                        if (d_ptr->flags & ItemClipsChildrenToShape)
                            d_ptr->setEmptyCachedClipPathRecursively();
                        else
                            d_ptr->setEmptyCachedClipPath();
                        return QPainterPath();
                    }
                    clip = clip.intersected(parent->d_ptr->cachedClipPath);
                    if (!(parent->d_ptr->flags & ItemClipsToShape))
                        clip = clip.intersected(parent->shape());
                } else {
                    clip = clip.intersected(parent->shape());
                }

                if (clip.isEmpty()) {
                    if (d_ptr->flags & ItemClipsChildrenToShape)
                        d_ptr->setEmptyCachedClipPathRecursively();
                    else
                        d_ptr->setEmptyCachedClipPath();
                    return clip;
                }
                lastParent = parent;
            }

            if (!(parent->d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren)
                || foundValidClipPath) {
                break;
            }
        }

        if (lastParent != this) {
            // Map clip back to the item's transform.
            // ### what if itemtransform fails
            clip = lastParent->itemTransform(this).map(clip);
        }
    }

    if (d->flags & ItemClipsToShape)
        clip = clip.intersected(shape());

    d_ptr->setCachedClipPath(clip);
    return clip;
}

/*!
    Returns true if this item contains \a point, which is in local
    coordinates; otherwise, false is returned. It is most often called from
    QGraphicsView to determine what item is under the cursor, and for that
    reason, the implementation of this function should be as light-weight as
    possible.

    By default, this function calls shape(), but you can reimplement it in a
    subclass to provide a (perhaps more efficient) implementation.

    \sa shape(), boundingRect(), collidesWithPath()
*/
bool QGraphicsItem::contains(const QPointF &point) const
{
    return isClipped() ? clipPath().contains(point) : shape().contains(point);
}

/*!

    Returns true if this item collides with \a other; otherwise
    returns false.

    The \a mode is applied to \a other, and the resulting shape or
    bounding rectangle is then compared to this item's shape. The
    default value for \a mode is Qt::IntersectsItemShape; \a other
    collides with this item if it either intersects, contains, or is
    contained by this item's shape (see Qt::ItemSelectionMode for
    details).

    The default implementation is based on shape intersection, and it calls
    shape() on both items. Because the complexity of arbitrary shape-shape
    intersection grows with an order of magnitude when the shapes are complex,
    this operation can be noticably time consuming. You have the option of
    reimplementing this function in a subclass of QGraphicsItem to provide a
    custom algorithm. This allows you to make use of natural constraints in
    the shapes of your own items, in order to improve the performance of the
    collision detection. For instance, two untransformed perfectly circular
    items' collision can be determined very efficiently by comparing their
    positions and radii.

    Keep in mind that when reimplementing this function and calling shape() or
    boundingRect() on \a other, the returned coordinates must be mapped to
    this item's coordinate system before any intersection can take place.

    \sa contains(), shape()
*/
bool QGraphicsItem::collidesWithItem(const QGraphicsItem *other, Qt::ItemSelectionMode mode) const
{
    if (other == this)
        return true;
    if (!other)
        return false;
    // The items share the same clip if their closest clipper is the same, or
    // if one clips the other.
    bool clips = (d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren);
    bool otherClips = (other->d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren);
    if (clips || otherClips) {
        const QGraphicsItem *closestClipper = isAncestorOf(other) ? this : parentItem();
        while (closestClipper && !(closestClipper->flags() & ItemClipsChildrenToShape))
            closestClipper = closestClipper->parentItem();
        const QGraphicsItem *otherClosestClipper = other->isAncestorOf(this) ? other : other->parentItem();
        while (otherClosestClipper && !(otherClosestClipper->flags() & ItemClipsChildrenToShape))
            otherClosestClipper = otherClosestClipper->parentItem();
        if (closestClipper == otherClosestClipper) {
            d_ptr->localCollisionHack = 1;
            bool res = collidesWithPath(mapFromItem(other, other->shape()), mode);
            d_ptr->localCollisionHack = 0;
            return res;
        }
    }

    QPainterPath otherShape = other->isClipped() ? other->clipPath() : other->shape();
    return collidesWithPath(mapFromItem(other, otherShape), mode);
}

/*!
    Returns true if this item collides with \a path.

    The collision is determined by \a mode. The default value for \a mode is
    Qt::IntersectsItemShape; \a path collides with this item if it either
    intersects, contains, or is contained by this item's shape.

    Note that this function checks whether the item's shape or
    bounding rectangle (depending on \a mode) is contained within \a
    path, and not whether \a path is contained within the items shape
    or bounding rectangle. 

    \sa collidesWithItem(), contains(), shape()
*/
bool QGraphicsItem::collidesWithPath(const QPainterPath &path, Qt::ItemSelectionMode mode) const
{
    if (path.isEmpty()) {
        // No collision with empty paths.
        return false;
    }

    QRectF rectA(boundingRect());
    _q_adjustRect(&rectA);
    QRectF rectB(path.controlPointRect());
    _q_adjustRect(&rectB);
    if (!rectA.intersects(rectB)) {
        // This we can determine efficiently. If the two rects neither
        // intersect nor contain eachother, then the two items do not collide.
        return false;
    }

    // For further testing, we need this item's shape or bounding rect.
    QPainterPath thisShape;
    if (mode == Qt::IntersectsItemShape || mode == Qt::ContainsItemShape)
        thisShape = (isClipped() && !d_ptr->localCollisionHack) ? clipPath() : shape();
    else
        thisShape.addRect(rectA);

    if (thisShape == QPainterPath()) {
        // Empty shape? No collision.
        return false;
    }

    // Use QPainterPath boolean operations to determine the collision, O(N*logN).
    if (mode == Qt::IntersectsItemShape || mode == Qt::IntersectsItemBoundingRect)
        return path.intersects(thisShape);
    return path.contains(thisShape);
}

/*!
    Returns a list of all items that collide with this item.

    The way collisions are detected is determined by applying \a mode
    to items that are compared to this item, i.e., each item's shape
    or bounding rectangle is checked against this item's shape. The
    default value for \a mode is Qt::IntersectsItemShape.

    \sa collidesWithItem()
*/
QList<QGraphicsItem *> QGraphicsItem::collidingItems(Qt::ItemSelectionMode mode) const
{
    if (d_ptr->scene)
        return d_ptr->scene->collidingItems(this, mode);
    return QList<QGraphicsItem *>();
}

/*!
    Returns true if this item's bounding rect is completely obscured by the
    opaque shape of any of colliding items above it (i.e., with a higher Z
    value than this item).

    Its implementation is based on calling isObscuredBy(), which you can
    reimplement to provide a custom obscurity algorithm.

  \sa opaqueArea()
*/
bool QGraphicsItem::isObscured() const
{
    return isObscured(QRectF());
}

/*!
    \internal

    Item obscurity helper function.

    Returns true if the subrect \a rect of \a item's bounding rect is obscured
    by \a other (i.e., \a other's opaque area covers \a item's \a rect
    completely. \a other is assumed to already be "on top of" \a item
    wrt. stacking order.
*/
static bool qt_QGraphicsItem_isObscured(const QGraphicsItem *item,
                                        const QGraphicsItem *other,
                                        const QRectF &rect)
{
    return other->mapToItem(item, other->opaqueArea()).contains(rect);
}

/*!
    \overload
    \since 4.3

    Returns true if \a rect is completely obscured by the opaque shape of any
    of colliding items above it (i.e., with a higher Z value than this item).

    Unlike the default isObscured() function, this function does not call
    isObscuredBy().

    \sa opaqueArea()
*/
bool QGraphicsItem::isObscured(const QRectF &rect) const
{
    Q_D(const QGraphicsItem);
    if (!d->scene)
        return false;

    QRectF br = boundingRect();
    QRectF testRect = rect.isNull() ? br : rect;

    foreach (QGraphicsItem *item, d->scene->items(mapToScene(br), Qt::IntersectsItemBoundingRect)) {
        if (item == this)
            break;
        if (qt_QGraphicsItem_isObscured(this, item, testRect))
            return true;
    }
    return false;
}

/*!
    \fn bool QGraphicsItem::isObscured(qreal x, qreal y, qreal w, qreal h) const
    \since 4.3

    This convenience function is equivalent to calling isObscured(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Returns true if this item's bounding rect is completely obscured by the
    opaque shape of \a item.

    The base implementation maps \a item's opaqueArea() to this item's
    coordinate system, and then checks if this item's boundingRect() is fully
    contained within the mapped shape.

    You can reimplement this function to provide a custom algorithm for
    determining whether this item is obscured by \a item.

    \sa opaqueArea(), isObscured()
*/
bool QGraphicsItem::isObscuredBy(const QGraphicsItem *item) const
{
    if (!item)
        return false;
    return QGraphicsScenePrivate::closestItemFirst_withoutCache(item, this)
        && qt_QGraphicsItem_isObscured(this, item, boundingRect());
}

/*!
    This virtual function returns a shape representing the area where this
    item is opaque. An area is opaque if it is filled using an opaque brush or
    color (i.e., not transparent).

    This function is used by isObscuredBy(), which is called by underlying
    items to determine if they are obscured by this item.

    The default implementation returns an empty QPainterPath, indicating that
    this item is completely transparent and does not obscure any other items.

    \sa isObscuredBy(), isObscured(), shape()
*/
QPainterPath QGraphicsItem::opaqueArea() const
{
    return QPainterPath();
}

/*!
    \since 4.4

    Returns the bounding region for this item. The coordinate space of the
    returned region depends on \a itemToDeviceTransform. If you pass an
    identity QTransform as a parameter, this function will return a local
    coordinate region.

    The bounding region describes a coarse outline of the item's visual
    contents. Although it's expensive to calculate, it's also more precise
    than boundingRect(), and it can help to avoid unnecessary repainting when
    an item is updated. This is particularily efficient for thin items (e.g.,
    lines or simple polygons). You can tune the granularity for the bounding
    region by calling setBoundingRegionGranularity(). The default granularity
    is 0; in which the item's bounding region is the same as its bounding
    rect.

    \a itemToDeviceTransform is the transformation from item coordinates to
    device coordinates. If you want this function to return a QRegion in scene
    coordinates, you can pass sceneTransform() as an argument.

    \sa boundingRegionGranularity()
*/
QRegion QGraphicsItem::boundingRegion(const QTransform &itemToDeviceTransform) const
{
    // ### Ideally we would have a better way to generate this region,
    // preferably something in the lines of QPainterPath::toRegion(QTransform)
    // coupled with a way to generate a painter path from a set of painter
    // operations (e.g., QPicture::toPainterPath() or so). The current
    // approach generates a bitmap with the size of the item's bounding rect
    // in device coordinates, scaled by b.r.granularity, then paints the item
    // into the bitmap, converts the result to a QRegion and scales the region
    // back to device space with inverse granularity.
    qreal granularity = boundingRegionGranularity();
    QRect deviceRect = itemToDeviceTransform.mapRect(boundingRect()).toRect();
    _q_adjustRect(&deviceRect);
    if (granularity == 0.0)
        return QRegion(deviceRect);

    int pad = 1;
    QSize bitmapSize(qMax(1, int(deviceRect.width() * granularity) + pad * 2),
                     qMax(1, int(deviceRect.height() * granularity) + pad * 2));
    QImage mask(bitmapSize, QImage::Format_ARGB32_Premultiplied);
    mask.fill(0);
    QPainter p(&mask);
    p.setRenderHints(QPainter::Antialiasing);

    // Transform painter (### this code is from QGraphicsScene::drawItemHelper
    // and doesn't work properly with perspective transformations).
    QPointF viewOrigo = itemToDeviceTransform.map(QPointF(0,  0));
    QPointF offset = viewOrigo - deviceRect.topLeft();
    p.scale(granularity, granularity);
    p.translate(offset);
    p.translate(pad, pad);
    p.setWorldTransform(itemToDeviceTransform, true);
    p.translate(itemToDeviceTransform.inverted().map(QPointF(0, 0)));

    // Render
    QStyleOptionGraphicsItem option;
    const_cast<QGraphicsItem *>(this)->paint(&p, &option, 0);
    p.end();

    // Transform QRegion back to device space
    QTransform unscale;
    unscale.scale(1 / granularity, 1 / granularity);
    QRegion r;
    QBitmap colorMask = QBitmap::fromImage(mask.createMaskFromColor(0));
    foreach (const QRect &rect, QRegion( colorMask ).rects()) {
        QRect xrect = unscale.mapRect(rect).translated(deviceRect.topLeft() - QPoint(pad, pad));
        r += xrect.adjusted(-1, -1, 1, 1) & deviceRect;
    }
    return r;
}

/*!
    \since 4.4

    Returns the item's bounding region granularity; a value between and
    including 0 and 1. The default value is 0 (i.e., the lowest granularity,
    where the bounding region corresponds to the item's bounding rectangle).

\omit
### NOTE
\endomit

    \sa setBoundingRegionGranularity()
*/
qreal QGraphicsItem::boundingRegionGranularity() const
{
    return d_ptr->hasBoundingRegionGranularity
        ? qVariantValue<qreal>(d_ptr->extra(QGraphicsItemPrivate::ExtraBoundingRegionGranularity))
        : 0;
}

/*!
    \since 4.4
    Sets the bounding region granularity to \a granularity; a value between
    and including 0 and 1. The default value is 0 (i.e., the lowest
    granularity, where the bounding region corresponds to the item's bounding
    rectangle).

    The granularity is used by boundingRegion() to calculate how fine the
    bounding region of the item should be. The highest achievable granularity
    is 1, where boundingRegion() will return the finest outline possible for
    the respective device (e.g., for a QGraphicsView viewport, this gives you
    a pixel-perfect bounding region). The lowest possible granularity is
    0. The value of \a granularity describes the ratio between device
    resolution and the resolution of the bounding region (e.g., a value of
    0.25 will provide a region where each chunk corresponds to 4x4 device
    units / pixels).

    \sa boundingRegionGranularity()
*/
void QGraphicsItem::setBoundingRegionGranularity(qreal granularity)
{
    if (granularity < 0.0 || granularity > 1.0) {
        qWarning("QGraphicsItem::setBoundingRegionGranularity: invalid granularity %g", granularity);
        return;
    }
    if (granularity == 0.0) {
        d_ptr->unsetExtra(QGraphicsItemPrivate::ExtraBoundingRegionGranularity);
        d_ptr->hasBoundingRegionGranularity = 0;
        return;
    }
    d_ptr->hasBoundingRegionGranularity = 1;
    d_ptr->setExtra(QGraphicsItemPrivate::ExtraBoundingRegionGranularity,
                    qVariantFromValue<qreal>(granularity));
}

/*!
    \fn virtual void QGraphicsItem::paint(QPainter *painter, const
    QStyleOptionGraphicsItem *option, QWidget *widget = 0) = 0

    This function, which is usually called by QGraphicsView, paints the
    contents of an item in local coordinates.

    Reimplement this function in a QGraphicsItem subclass to provide the
    item's painting implementation, using \a painter. The \a option parameter
    provides style options for the item, such as its state, exposed area and
    its level-of-detail hints. The \a widget argument is optional. If
    provided, it points to the widget that is being painted on; otherwise, it
    is 0. For cached painting, \a widget is always 0.

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 10

    The painter's pen is 0-width by default, and its pen is initialized to the
    QPalette::Text brush from the paint device's palette. The brush is
    initialized to QPalette::Window.

    Make sure to constrain all painting inside the boundaries of
    boundingRect() to avoid rendering artifacts (as QGraphicsView does not
    clip the painter for you). In particular, when QPainter renders the
    outline of a shape using an assigned QPen, half of the outline will be
    drawn outside, and half inside, the shape you're rendering (e.g., with a
    pen width of 2 units, you must draw outlines 1 unit inside
    boundingRect()). QGraphicsItem does not support use of cosmetic pens with
    a non-zero width.

    All painting is done in local coordinates.

    \sa setCacheMode(), QPen::width(), {Item Coordinates}
*/

/*!
    \internal
    Returns true if we can discard an update request; otherwise false.
*/
bool QGraphicsItemPrivate::discardUpdateRequest(bool ignoreClipping, bool ignoreVisibleBit,
                                                bool ignoreDirtyBit, bool ignoreOpacity) const
{
    // No scene, or if the scene is updating everything, means we have nothing
    // to do. The only exception is if the scene tracks the growing scene rect.
    return (!visible && !ignoreVisibleBit)
           || (dirty && !ignoreDirtyBit)
           || !scene
           || (scene->d_func()->updateAll && scene->d_func()->hasSceneRect)
           || (!ignoreClipping && (childrenClippedToShape() && isClippedAway()))
           || (!ignoreOpacity && childrenCombineOpacity() && isFullyTransparent());
}

/*!
    \internal

    Asks the scene to mark this item's scene rect as dirty, requesting a
    redraw.  This does not invalidate any cache.

    The \a force argument is for the update call in setVisible(), which is the
    only case where the item's background should be marked as dirty even when
    the item isn't visible.
*/
void QGraphicsItemPrivate::updateHelper(const QRectF &rect, bool force, bool maybeDirtyClipPath)
{
    // No scene, or if the scene is updating everything, means we have nothing
    // to do. The only exception is if the scene tracks the growing scene rect.
    if (discardUpdateRequest(/*ignoreClipping=*/maybeDirtyClipPath, /*ignoreVisibleBit=*/force))
        return;

    if (rect.isNull())
        dirty = 1;
    scene->itemUpdated(q_ptr, rect);
}

/*!
    \internal

    Propagates updates to \a item and all its children.
*/
void QGraphicsItemPrivate::fullUpdateHelper(bool childrenOnly, bool maybeDirtyClipPath, bool ignoreOpacity)
{
    if (discardUpdateRequest(/*ignoreClipping=*/maybeDirtyClipPath, /*ignoreVisibleBit=*/false,
                             /*ignoreDirtyBit=*/true, ignoreOpacity)) {
        return;
    }

    if (!childrenOnly && !dirty) {
        // Effectively the same as updateHelper(QRectF(), false, maybeDirtyClipPath).
        dirty = 1;
        scene->itemUpdated(q_ptr, QRectF());
    }

    if (dirtyChildren || childrenClippedToShape()) {
        // Unnecessary to update children as well.
        return;
    }

    if (ancestorFlags & AncestorClipsChildren) {
        Q_Q(QGraphicsItem);
        // Check if we can avoid updating all children.
        QGraphicsItem *p = parent;
        QRectF br = q->boundingRect();
        while (p) {
            if (p->d_ptr->flags & QGraphicsItem::ItemClipsChildrenToShape) {
                bool ok;
                QTransform x = q->itemTransform(p, &ok);
                if (!ok)
                    break;
                if (x.mapRect(br).contains(p->boundingRect()))
                    return;
            }
            p = p->d_ptr->parent;
            if (!p || !(p->d_ptr->ancestorFlags & AncestorClipsChildren))
                break;
            // ### check one level only
            break;
        }
    }
    foreach (QGraphicsItem *child, children)
        child->d_ptr->fullUpdateHelper(false, maybeDirtyClipPath);
    dirtyChildren = 1;
}

static inline bool allChildrenCombineOpacityHelper(QGraphicsItem *parent)
{
    Q_ASSERT(parent);
    if (parent->flags() & QGraphicsItem::ItemDoesntPropagateOpacityToChildren)
        return false;

    const QList<QGraphicsItem *> children(parent->childItems());
    for (int i = 0; i < children.size(); ++i) {
        if (children.at(i)->flags() & QGraphicsItem::ItemIgnoresParentOpacity)
            return false;
    }
    return true;
}

void QGraphicsItemPrivate::updateEffectiveOpacity()
{
    Q_Q(QGraphicsItem);
    if (parent) {
        resolveEffectiveOpacity(parent->effectiveOpacity());
        parent->d_ptr->allChildrenCombineOpacity = allChildrenCombineOpacityHelper(parent);
    } else {
        resolveEffectiveOpacity(1.0);
    }
    allChildrenCombineOpacity = allChildrenCombineOpacityHelper(q);
}

/*!
    \internal

    Resolves and propagates this item's effective opacity to its children.
*/
void QGraphicsItemPrivate::resolveEffectiveOpacity(qreal parentEffectiveOpacity)
{
    Q_Q(QGraphicsItem);
    QGraphicsItem::GraphicsItemFlags myFlags = q->flags();
    QGraphicsItem::GraphicsItemFlags parentFlags = parent ? parent->flags() : QGraphicsItem::GraphicsItemFlags(0);

    // My local opacity is always part of my effective opacity.
    qreal myEffectiveOpacity = q->opacity();

    // If I have a parent, and I don't ignore my parent's opacity, and my
    // parent propagates to me, then combine my local opacity with my parent's
    // effective opacity into my effective opacity.
    if (parent
        && !(myFlags & QGraphicsItem::ItemIgnoresParentOpacity)
        && !(parentFlags & QGraphicsItem::ItemDoesntPropagateOpacityToChildren)) {
        myEffectiveOpacity *= parentEffectiveOpacity;
    }

    // Set this item's resolved opacity.
    if (qFuzzyIsNull(myEffectiveOpacity - 1)) {
        // Opaque, unset effective opacity.
        hasEffectiveOpacity = 0;
        unsetExtra(ExtraEffectiveOpacity);
    } else {
        hasEffectiveOpacity = 1;
        setExtra(ExtraEffectiveOpacity, myEffectiveOpacity);
    }

    // Resolve children always.
    for (int i = 0; i < children.size(); ++i)
        children.at(i)->d_ptr->resolveEffectiveOpacity(myEffectiveOpacity);
}

/*!
    \internal

    Resolves the stacking depth of this object and all its children.
*/
void QGraphicsItemPrivate::resolveDepth(int parentDepth)
{
    depth = parentDepth + 1;
    for (int i = 0; i < children.size(); ++i)
        children.at(i)->d_ptr->resolveDepth(depth);
}

/*!
    \internal
*/
void QGraphicsItemPrivate::invalidateSceneTransformCache()
{
    if (!scene || (parent && sceneTransformIndex == -1))
        return;
    if (sceneTransformIndex != -1)
        scene->d_func()->validTransforms.setBit(sceneTransformIndex, 0);
    for (int i = 0; i < children.size(); ++i)
        children.at(i)->d_ptr->invalidateSceneTransformCache();
}

/*!
    \internal
*/
void QGraphicsItemPrivate::addChild(QGraphicsItem *child)
{
    child->d_ptr->siblingIndex = children.size();
    children.append(child);
}

/*!
    \internal
*/
void QGraphicsItemPrivate::removeChild(QGraphicsItem *child)
{
    int idx = child->d_ptr->siblingIndex;
    int size = children.size();
    for (int i = idx; i < size - 1; ++i) {
        QGraphicsItem *p = children[i + 1];
        children[i] = p;
        p->d_ptr->siblingIndex = i;
    }
    children.removeLast();
}

/*!
    \internal
*/
QGraphicsItemCache *QGraphicsItemPrivate::maybeExtraItemCache() const
{
    return (QGraphicsItemCache *)qVariantValue<void *>(extra(ExtraCacheData));
}

/*!
    \internal
*/
QGraphicsItemCache *QGraphicsItemPrivate::extraItemCache() const
{
    QGraphicsItemCache *c = (QGraphicsItemCache *)qVariantValue<void *>(extra(ExtraCacheData));
    if (!c) {
        QGraphicsItemPrivate *that = const_cast<QGraphicsItemPrivate *>(this);
        c = new QGraphicsItemCache;
        that->setExtra(ExtraCacheData, qVariantFromValue<void *>(c));
    }
    return c;
}

/*!
    \internal
*/
void QGraphicsItemPrivate::removeExtraItemCache()
{
    QGraphicsItemCache *c = (QGraphicsItemCache *)qVariantValue<void *>(extra(ExtraCacheData));
    if (c) {
        c->purge();
        delete c;
    }
    unsetExtra(ExtraCacheData);
}

void QGraphicsItemPrivate::setEmptyCachedClipPathRecursively(const QRectF &emptyIfOutsideThisRect)
{
    setEmptyCachedClipPath();

    const bool checkRect = !emptyIfOutsideThisRect.isNull()
                           && !(flags & QGraphicsItem::ItemClipsChildrenToShape);
    for (int i = 0; i < children.size(); ++i) {
        if (!checkRect) {
            children.at(i)->d_ptr->setEmptyCachedClipPathRecursively();
            continue;
        }

        QGraphicsItem *child = children.at(i);
        const QRectF rect = child->mapRectFromParent(emptyIfOutsideThisRect);
        if (rect.intersects(child->boundingRect()))
            child->d_ptr->invalidateCachedClipPathRecursively(false, rect);
        else
            child->d_ptr->setEmptyCachedClipPathRecursively(rect);
    }
}

void QGraphicsItemPrivate::invalidateCachedClipPathRecursively(bool childrenOnly, const QRectF &emptyIfOutsideThisRect)
{
    if (!childrenOnly)
        invalidateCachedClipPath();

    const bool checkRect = !emptyIfOutsideThisRect.isNull();
    for (int i = 0; i < children.size(); ++i) {
        if (!checkRect) {
            children.at(i)->d_ptr->invalidateCachedClipPathRecursively(false);
            continue;
        }

        QGraphicsItem *child = children.at(i);
        const QRectF rect = child->mapRectFromParent(emptyIfOutsideThisRect);
        if (rect.intersects(child->boundingRect()))
            child->d_ptr->invalidateCachedClipPathRecursively(false, rect);
        else
            child->d_ptr->setEmptyCachedClipPathRecursively(rect);
    }
}

void QGraphicsItemPrivate::updateCachedClipPathFromSetPosHelper(const QPointF &newPos)
{
    Q_ASSERT(inSetPosHelper);

    if (!(ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren))
        return; // Not clipped by any ancestor.

    // Find closest clip ancestor and transform.
    Q_Q(QGraphicsItem);
    QTransform thisToParentTransform = hasTransform
                                       ? q->transform() * QTransform::fromTranslate(newPos.x(), newPos.y())
                                       : QTransform::fromTranslate(newPos.x(), newPos.y());
    QGraphicsItem *clipParent = parent;
    while (clipParent && !(clipParent->d_ptr->flags & QGraphicsItem::ItemClipsChildrenToShape)) {
        if (clipParent->d_ptr->hasTransform)
            thisToParentTransform *= clipParent->transform();
        if (!clipParent->d_ptr->pos.isNull()) {
            thisToParentTransform *= QTransform::fromTranslate(clipParent->d_ptr->pos.x(),
                                                               clipParent->d_ptr->pos.y());
        }
        clipParent = clipParent->d_ptr->parent;
    }

    // thisToParentTransform is now the same as q->itemTransform(clipParent), except
    // that the new position (which is not yet set on the item) is taken into account.
    Q_ASSERT(clipParent);
    Q_ASSERT(clipParent->d_ptr->flags & QGraphicsItem::ItemClipsChildrenToShape);

    // From here everything is calculated in clip parent's coordinates.
    const QRectF parentBoundingRect(clipParent->boundingRect());
    const QRectF thisBoundingRect(thisToParentTransform.mapRect(q->boundingRect()));

    if (!parentBoundingRect.intersects(thisBoundingRect)) {
        // Item is moved outside the clip parent's bounding rect,
        // i.e. it is fully clipped and the clip path is empty.
        if (flags & QGraphicsItem::ItemClipsChildrenToShape)
            setEmptyCachedClipPathRecursively();
        else
            setEmptyCachedClipPathRecursively(thisToParentTransform.inverted().mapRect(parentBoundingRect));
        return;
    }

    const QPainterPath parentClip(clipParent->isClipped() ? clipParent->clipPath() : clipParent->shape());
    if (parentClip.contains(thisBoundingRect))
        return; // Item is inside the clip parent's shape. No update required.

    const QRectF parentClipRect(parentClip.controlPointRect());
    if (!parentClipRect.intersects(thisBoundingRect)) {
        // Item is moved outside the clip parent's shape,
        // i.e. it is fully clipped and the clip path is empty.
        if (flags & QGraphicsItem::ItemClipsChildrenToShape)
            setEmptyCachedClipPathRecursively();
        else
            setEmptyCachedClipPathRecursively(thisToParentTransform.inverted().mapRect(parentClipRect));
    } else {
        // Item is partially inside the clip parent's shape,
        // i.e. the cached clip path must be invalidated.
        invalidateCachedClipPathRecursively(false, thisToParentTransform.inverted().mapRect(parentClipRect));
    }
}

/*!
    \internal

    Tells us if it is a proxy widget
*/
bool QGraphicsItemPrivate::isProxyWidget() const
{
    return false;
}

/*!
    Schedules a redraw of the area covered by \a rect in this item. You can
    call this function whenever your item needs to be redrawn, such as if it
    changes appearance or size.

    This function does not cause an immediate paint; instead it schedules a
    paint request that is processed by QGraphicsView after control reaches the
    event loop. The item will only be redrawn if it is visible in any
    associated view.

    As a side effect of the item being repainted, other items that overlap the
    area \a rect may also be repainted.

    If the item is invisible (i.e., isVisible() returns false), this function
    does nothing.

    \sa paint(), boundingRect()
*/
void QGraphicsItem::update(const QRectF &rect)
{
    if (rect.isEmpty() && !rect.isNull())
        return;

    if (CacheMode(d_ptr->cacheMode) != NoCache) {
        QGraphicsItemCache *cache = d_ptr->extraItemCache();
        if (d_ptr->discardUpdateRequest(/* ignoreVisibleBit = */ false,
                                        /* ignoreClipping = */ false,
                                        /* ignoreDirtyBit = */ true)) {
            return;
        }

        // Invalidate cache.
        if (!cache->allExposed) {
            if (rect.isNull()) {
                cache->allExposed = true;
                cache->exposed.clear();
            } else {
                cache->exposed.append(rect);
            }
        }
        // Only invalidate cache; item is already dirty.
        if (d_ptr->dirty)
            return;
    } else if (d_ptr->discardUpdateRequest()) {
        return;
    }

    // Effectively the same as updateHelper(rect);
    if (rect.isNull())
        d_ptr->dirty = 1;
    d_ptr->scene->itemUpdated(this, rect);
}

/*!
    \internal

    Scrolls \a rect in \a pix by \a dx, \a dy.

    ### This can be done much more efficiently by using XCopyArea on X11 with
    the same dst and src, and through moving pixels in the raster engine. It
    can probably also be done much better on the other paint engines.
*/
void _q_scrollPixmap(QPixmap *pix, const QRect &rect, int dx, int dy)
{
#if 0
    QPainter painter(pix);
    painter.setClipRect(rect);
    painter.drawPixmap(rect.translated(dx, dy), *pix, rect);
    painter.end();
#elif defined Q_WS_X11
    GC gc = XCreateGC(X11->display, pix->handle(), 0, 0);

    XRectangle xrect;
    xrect.x = rect.x();
    xrect.y = rect.y();
    xrect.width = rect.width();
    xrect.height = rect.height();
    XSetClipRectangles(X11->display, gc, 0, 0, &xrect, 1, YXBanded);

    XCopyArea(X11->display, pix->handle(), pix->handle(), gc,
              rect.x(), rect.y(), rect.width(), rect.height(),
              rect.x()+dx, rect.y()+dy);
    XFreeGC(X11->display, gc);
#else
    QPixmap newPix = *pix;
    QPainter painter(&newPix);
    painter.setClipRect(rect);
    painter.drawPixmap(rect.translated(dx, dy), *pix, rect);
    painter.end();
    *pix = newPix;
#endif
}

/*!
    \since 4.4
    Scrolls the contents of \a rect by \a dx, \a dy. If \a rect is a null rect
    (the default), the item's bounding rect is scrolled.

    Scrolling provides a fast alternative to simply redrawing when the
    contents of the item (or parts of the item) are shifted vertically or
    horizontally. Depending on the current transformation and the capabilities
    of the paint device (i.e., the viewport), this operation may consist of
    simply moving pixels from one location to another using memmove(). In most
    cases this is faster than rerendering the entire area.

    After scrolling, the item will issue an update for the newly exposed
    areas. If scrolling is not supported (e.g., you are rendering to an OpenGL
    viewport, which does not benefit from scroll optimizations), this function
    is equivalent to calling update(\a rect).

    \sa boundingRect()
*/
void QGraphicsItem::scroll(qreal dx, qreal dy, const QRectF &rect)
{
    Q_D(QGraphicsItem);
    if (dx == 0.0 && dy == 0.0)
        return;
    if (!d->scene)
        return;
    if (d->cacheMode != NoCache) {
        QGraphicsItemCache *c;
        bool scrollCache = qFuzzyIsNull(dx - int(dx)) && qFuzzyIsNull(dy - int(dy))
                           && (c = (QGraphicsItemCache *)qVariantValue<void *>(d_ptr->extra(QGraphicsItemPrivate::ExtraCacheData)))
                           && (d->cacheMode == ItemCoordinateCache && !c->fixedSize.isValid());
        if (scrollCache) {
            QPixmap pix;
            if (QPixmapCache::find(c->key, pix)) {
                // Adjust with 2 pixel margin. Notice the loss of precision
                // when converting to QRect.
                int adjust = 2;
                QRectF br = boundingRect().adjusted(-adjust, -adjust, adjust, adjust);
                QRect irect = rect.toRect().translated(-br.x(), -br.y());

                _q_scrollPixmap(&pix, irect, dx, dy);

                QPixmapCache::insert(c->key, pix);

                // Translate the existing expose.
                foreach (QRectF exposedRect, c->exposed)
                    c->exposed += exposedRect.translated(dx, dy) & rect;

                // Calculate exposure.
                QRegion exposed;
                QRect r = rect.toRect();
                exposed += r;
                exposed -= r.translated(dx, dy);
                foreach (QRect rect, exposed.rects())
                    update(rect);
                d_ptr->updateHelper();
            } else {
                update(rect);
            }
        } else {
            // ### This is very slow, and can be done much better. If the cache is
            // local and matches the below criteria for rotation and scaling, we
            // can easily scroll. And if the cache is in device coordinates, we
            // can scroll both the viewport and the cache.
            update(rect);
        }
        return;
    }

    QRectF scrollRect = !rect.isNull() ? rect : boundingRect();
    int couldntScroll = d->scene->views().size();
    foreach (QGraphicsView *view, d->scene->views()) {
        if (view->viewport()->inherits("QGLWidget")) {
            // ### Please replace with a widget attribute; any widget that
            // doesn't support partial updates / doesn't support scrolling
            // should be skipped in this code. Qt::WA_NoPartialUpdates or so.
            continue;
        }

        static const QLineF up(0, 0, 0, -1);
        static const QLineF down(0, 0, 0, 1);
        static const QLineF left(0, 0, -1, 0);
        static const QLineF right(0, 0, 1, 0);

        QTransform deviceTr;
        if (d->itemIsUntransformable()) {
            deviceTr = deviceTransform(view->viewportTransform());
        } else {
            deviceTr = sceneTransform() * view->viewportTransform();
        }

        QRect deviceScrollRect = deviceTr.mapRect(scrollRect).toRect();
        QLineF v1 = deviceTr.map(right);
        QLineF v2 = deviceTr.map(down);
        QLineF u1 = v1.unitVector(); u1.translate(-v1.p1());
        QLineF u2 = v2.unitVector(); u2.translate(-v2.p1());
        bool noScroll = false;

        // Check if the delta resolves to ints in device space.
        QPointF deviceDelta = deviceTr.map(QPointF(dx, dy));
        if ((deviceDelta.x() - int(deviceDelta.x()))
            || (deviceDelta.y() - int(deviceDelta.y()))) {
            noScroll = true;
        } else {
            // Check if the unit vectors have no fraction in device space.
            qreal v1l = v1.length();
            if (v1l - int(v1l)) {
                noScroll = true;
            } else {
                dx *= v1.length();
            }
            qreal v2l = v2.length();
            if (v2l - int(v2l)) {
                noScroll = true;
            } else {
                dy *= v2.length();
            }
        }

        if (!noScroll) {
            if (u1 == right) {
                if (u2 == up) {
                    // flipped
                    dy = -dy;
                } else if (u2 == down) {
                    // normal
                } else {
                    noScroll = true;
                }
            } else if (u1 == left) {
                if (u2 == up) {
                    // mirrored & flipped / rotated 180 degrees
                    dx = -dx;
                    dy = -dy;
                } else if (u2 == down) {
                    // mirrored
                    dx = -dx;
                } else {
                    noScroll = true;
                }
            } else if (u1 == up) {
                if (u2 == left) {
                    // rotated -90 & mirrored
                    qreal tmp = dy;
                    dy = -dx;
                    dx = -tmp;
                } else if (u2 == right) {
                    // rotated -90
                    qreal tmp = dy;
                    dy = -dx;
                    dx = tmp;
                } else {
                    noScroll = true;
                }
            } else if (u1 == down) {
                if (u2 == left) {
                    // rotated 90
                    qreal tmp = dy;
                    dy = dx;
                    dx = -tmp;
                } else if (u2 == right) {
                    // rotated 90 & mirrored
                    qreal tmp = dy;
                    dy = dx;
                    dx = tmp;
                } else {
                    noScroll = true;
                }
            }
        }

        if (!noScroll) {
            view->viewport()->scroll(int(dx), int(dy), deviceScrollRect);
            --couldntScroll;
        }
    }
    if (couldntScroll)
        update(rect);
}

/*!
    \fn void QGraphicsItem::update(qreal x, qreal y, qreal width, qreal height)
    \overload

    This convenience function is equivalent to calling update(QRectF(\a x, \a
    y, \a width, \a height)).
*/

/*!
    Maps the point \a point, which is in this item's coordinate system, to \a
    item's coordinate system, and returns the mapped coordinate.

    If \a item is 0, this function returns the same as mapToScene().

    \sa itemTransform(), mapToParent(), mapToScene(), transform(), mapFromItem(), {The Graphics
    View Coordinate System}
*/
QPointF QGraphicsItem::mapToItem(const QGraphicsItem *item, const QPointF &point) const
{
    if (item)
        return itemTransform(item).map(point);
    return mapToScene(point);
}

/*!
    \fn QPointF QGraphicsItem::mapToItem(const QGraphicsItem *item, qreal x, qreal y) const
    \overload

    This convenience function is equivalent to calling mapToItem(\a item,
    QPointF(\a x, \a y)).
*/

/*!
    Maps the point \a point, which is in this item's coordinate system, to its
    parent's coordinate system, and returns the mapped coordinate. If the item
    has no parent, \a point will be mapped to the scene's coordinate system.

    \sa mapToItem(), mapToScene(), transform(), mapFromParent(), {The Graphics
    View Coordinate System}
*/
QPointF QGraphicsItem::mapToParent(const QPointF &point) const
{
    if (!d_ptr->hasTransform)
        return point + d_ptr->pos;
    return transform().map(point) + d_ptr->pos;
}

/*!
    \fn QPointF QGraphicsItem::mapToParent(qreal x, qreal y) const
    \overload

    This convenience function is equivalent to calling mapToParent(QPointF(\a
    x, \a y)).
*/

/*!
    Maps the point \a point, which is in this item's coordinate system, to the
    scene's coordinate system, and returns the mapped coordinate.

    \sa mapToItem(), mapToParent(), transform(), mapFromScene(), {The Graphics
    View Coordinate System}
*/
QPointF QGraphicsItem::mapToScene(const QPointF &point) const
{
    return sceneTransform().map(point);
}

/*!
    \fn QPointF QGraphicsItem::mapToScene(qreal x, qreal y) const
    \overload

    This convenience function is equivalent to calling mapToScene(QPointF(\a
    x, \a y)).
*/

/*!
    Maps the rectangle \a rect, which is in this item's coordinate system, to
    \a item's coordinate system, and returns the mapped rectangle as a polygon.

    If \a item is 0, this function returns the same as mapToScene().

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QPolygonF QGraphicsItem::mapToItem(const QGraphicsItem *item, const QRectF &rect) const
{
    if (item)
        return itemTransform(item).map(rect);
    return mapToScene(rect);
}

/*!
    \fn QPolygonF QGraphicsItem::mapToItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
    \since 4.3

    This convenience function is equivalent to calling mapToItem(item, QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Maps the rectangle \a rect, which is in this item's coordinate system, to
    its parent's coordinate system, and returns the mapped rectangle as a
    polygon. If the item has no parent, \a rect will be mapped to the scene's
    coordinate system.

    \sa mapToScene(), mapToItem(), mapFromParent(), {The Graphics View
    Coordinate System}
*/
QPolygonF QGraphicsItem::mapToParent(const QRectF &rect) const
{
    if (!d_ptr->hasTransform)
        return rect.translated(d_ptr->pos);
    return transform().map(rect).translated(d_ptr->pos);
}

/*!
    \fn QPolygonF QGraphicsItem::mapToParent(qreal x, qreal y, qreal w, qreal h) const
    \since 4.3

    This convenience function is equivalent to calling mapToParent(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Maps the rectangle \a rect, which is in this item's coordinate system, to
    the scene's coordinate system, and returns the mapped rectangle as a polygon.

    \sa mapToParent(), mapToItem(), mapFromScene(), {The Graphics View
    Coordinate System}
*/
QPolygonF QGraphicsItem::mapToScene(const QRectF &rect) const
{
    return sceneTransform().map(rect);
}

/*!
    \fn QPolygonF QGraphicsItem::mapToScene(qreal x, qreal y, qreal w, qreal h) const
    \since 4.3

    This convenience function is equivalent to calling mapToScene(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    \since 4.5

    Maps the rectangle \a rect, which is in this item's coordinate system, to
    \a item's coordinate system, and returns the mapped rectangle as a new
    rectangle (i.e., the bounding rectangle of the resulting polygon).

    If \a item is 0, this function returns the same as mapRectToScene().

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QRectF QGraphicsItem::mapRectToItem(const QGraphicsItem *item, const QRectF &rect) const
{
    if (item)
        return itemTransform(item).mapRect(rect);
    return mapRectToScene(rect);
}

/*!
    \fn QRectF QGraphicsItem::mapRectToItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
    \since 4.5

    This convenience function is equivalent to calling mapRectToItem(item, QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    \since 4.5

    Maps the rectangle \a rect, which is in this item's coordinate system, to
    its parent's coordinate system, and returns the mapped rectangle as a new
    rectangle (i.e., the bounding rectangle of the resulting polygon).

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QRectF QGraphicsItem::mapRectToParent(const QRectF &rect) const
{
    QRectF r = !d_ptr->hasTransform ? rect : transform().mapRect(rect);
    return r.translated(d_ptr->pos);
}

/*!
    \fn QRectF QGraphicsItem::mapRectToParent(qreal x, qreal y, qreal w, qreal h) const
    \since 4.5

    This convenience function is equivalent to calling mapRectToParent(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    \since 4.5

    Maps the rectangle \a rect, which is in this item's coordinate system, to
    the scene coordinate system, and returns the mapped rectangle as a new
    rectangle (i.e., the bounding rectangle of the resulting polygon).

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QRectF QGraphicsItem::mapRectToScene(const QRectF &rect) const
{
    return sceneTransform().mapRect(rect);
}

/*!
    \fn QRectF QGraphicsItem::mapRectToScene(qreal x, qreal y, qreal w, qreal h) const
    \since 4.5

    This convenience function is equivalent to calling mapRectToScene(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    \since 4.5

    Maps the rectangle \a rect, which is in \a item's coordinate system, to
    this item's coordinate system, and returns the mapped rectangle as a new
    rectangle (i.e., the bounding rectangle of the resulting polygon).

    If \a item is 0, this function returns the same as mapRectFromScene().

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QRectF QGraphicsItem::mapRectFromItem(const QGraphicsItem *item, const QRectF &rect) const
{
    if (item)
        return item->itemTransform(this).mapRect(rect);
    return mapRectFromScene(rect);
}

/*!
    \fn QRectF QGraphicsItem::mapRectFromItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
    \since 4.5

    This convenience function is equivalent to calling mapRectFromItem(item, QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    \since 4.5

    Maps the rectangle \a rect, which is in this item's parent's coordinate
    system, to this item's coordinate system, and returns the mapped rectangle
    as a new rectangle (i.e., the bounding rectangle of the resulting
    polygon).

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QRectF QGraphicsItem::mapRectFromParent(const QRectF &rect) const
{
    QRectF r = rect.translated(-d_ptr->pos);
    return d_ptr->hasTransform ? transform().inverted().mapRect(r) : r;
}

/*!
    \fn QRectF QGraphicsItem::mapRectFromParent(qreal x, qreal y, qreal w, qreal h) const
    \since 4.5

    This convenience function is equivalent to calling mapRectFromParent(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    \since 4.5

    Maps the rectangle \a rect, which is in scene coordinates, to this item's
    coordinate system, and returns the mapped rectangle as a new rectangle
    (i.e., the bounding rectangle of the resulting polygon).

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QRectF QGraphicsItem::mapRectFromScene(const QRectF &rect) const
{
    return sceneTransform().inverted().mapRect(rect);
}

/*!
    \fn QRectF QGraphicsItem::mapRectFromScene(qreal x, qreal y, qreal w, qreal h) const
    \since 4.5

    This convenience function is equivalent to calling mapRectFromScene(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Maps the polygon \a polygon, which is in this item's coordinate system, to
    \a item's coordinate system, and returns the mapped polygon.

    If \a item is 0, this function returns the same as mapToScene().

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QPolygonF QGraphicsItem::mapToItem(const QGraphicsItem *item, const QPolygonF &polygon) const
{
    if (item)
        return itemTransform(item).map(polygon);
    return mapToScene(polygon);
}

/*!
    Maps the polygon \a polygon, which is in this item's coordinate system, to
    its parent's coordinate system, and returns the mapped polygon. If the
    item has no parent, \a polygon will be mapped to the scene's coordinate
    system.

    \sa mapToScene(), mapToItem(), mapFromParent(), {The Graphics View
    Coordinate System}
*/
QPolygonF QGraphicsItem::mapToParent(const QPolygonF &polygon) const
{
    if (!d_ptr->hasTransform)
        return polygon.translated(d_ptr->pos);
    return transform().map(polygon).translated(d_ptr->pos);
}

/*!
    Maps the polygon \a polygon, which is in this item's coordinate system, to
    the scene's coordinate system, and returns the mapped polygon.

    \sa mapToParent(), mapToItem(), mapFromScene(), {The Graphics View
    Coordinate System}
*/
QPolygonF QGraphicsItem::mapToScene(const QPolygonF &polygon) const
{
    return sceneTransform().map(polygon);
}

/*!
    Maps the path \a path, which is in this item's coordinate system, to
    \a item's coordinate system, and returns the mapped path.

    If \a item is 0, this function returns the same as mapToScene().

    \sa itemTransform(), mapToParent(), mapToScene(), mapFromItem(), {The
    Graphics View Coordinate System}
*/
QPainterPath QGraphicsItem::mapToItem(const QGraphicsItem *item, const QPainterPath &path) const
{
    if (item)
        return itemTransform(item).map(path);
    return mapToScene(path);
}

/*!
    Maps the path \a path, which is in this item's coordinate system, to
    its parent's coordinate system, and returns the mapped path. If the
    item has no parent, \a path will be mapped to the scene's coordinate
    system.

    \sa mapToScene(), mapToItem(), mapFromParent(), {The Graphics View
    Coordinate System}
*/
QPainterPath QGraphicsItem::mapToParent(const QPainterPath &path) const
{
    if (!d_ptr->hasTransform)
        return path.translated(d_ptr->pos);
    return transform().map(path).translated(d_ptr->pos);
}

/*!
    Maps the path \a path, which is in this item's coordinate system, to
    the scene's coordinate system, and returns the mapped path.

    \sa mapToParent(), mapToItem(), mapFromScene(), {The Graphics View
    Coordinate System}
*/
QPainterPath QGraphicsItem::mapToScene(const QPainterPath &path) const
{
    return sceneTransform().map(path);
}

/*!
    Maps the point \a point, which is in \a item's coordinate system, to this
    item's coordinate system, and returns the mapped coordinate.

    If \a item is 0, this function returns the same as mapFromScene().

    \sa itemTransform(), mapFromParent(), mapFromScene(), transform(), mapToItem(), {The Graphics
    View Coordinate System}
*/
QPointF QGraphicsItem::mapFromItem(const QGraphicsItem *item, const QPointF &point) const
{
    if (item)
        return item->itemTransform(this).map(point);
    return mapFromScene(point);
}

/*!
    \fn QPointF QGraphicsItem::mapFromItem(const QGraphicsItem *item, qreal x, qreal y) const
    \overload

    This convenience function is equivalent to calling mapFromItem(\a item,
    QPointF(\a x, \a y)).
*/

/*!
    Maps the point \a point, which is in this item's parent's coordinate
    system, to this item's coordinate system, and returns the mapped
    coordinate.

    \sa mapFromItem(), mapFromScene(), transform(), mapToParent(), {The Graphics
    View Coordinate System}
*/
QPointF QGraphicsItem::mapFromParent(const QPointF &point) const
{
    if (d_ptr->hasTransform)
        return transform().inverted().map(point - d_ptr->pos);
    return point - d_ptr->pos;
}

/*!
    \fn QPointF QGraphicsItem::mapFromParent(qreal x, qreal y) const
    \overload

    This convenience function is equivalent to calling
    mapFromParent(QPointF(\a x, \a y)).
*/

/*!
    Maps the point \a point, which is in this item's scene's coordinate
    system, to this item's coordinate system, and returns the mapped
    coordinate.

    \sa mapFromItem(), mapFromParent(), transform(), mapToScene(), {The Graphics
    View Coordinate System}
*/
QPointF QGraphicsItem::mapFromScene(const QPointF &point) const
{
    return sceneTransform().inverted().map(point);
}

/*!
    \fn QPointF QGraphicsItem::mapFromScene(qreal x, qreal y) const
    \overload

    This convenience function is equivalent to calling mapFromScene(QPointF(\a
    x, \a y)).
*/

/*!
    Maps the rectangle \a rect, which is in \a item's coordinate system, to
    this item's coordinate system, and returns the mapped rectangle as a
    polygon.

    If \a item is 0, this function returns the same as mapFromScene()

    \sa itemTransform(), mapToItem(), mapFromParent(), transform(), {The Graphics View Coordinate
    System}
*/
QPolygonF QGraphicsItem::mapFromItem(const QGraphicsItem *item, const QRectF &rect) const
{
    if (item)
        return item->itemTransform(this).map(rect);
    return mapFromScene(rect);
}

/*!
    \fn QPolygonF QGraphicsItem::mapFromItem(const QGraphicsItem *item, qreal x, qreal y, qreal w, qreal h) const
    \since 4.3

    This convenience function is equivalent to calling mapFromItem(item, QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Maps the rectangle \a rect, which is in this item's parent's coordinate
    system, to this item's coordinate system, and returns the mapped rectangle
    as a polygon.

    \sa mapToParent(), mapFromItem(), transform(), {The Graphics View Coordinate
    System}
*/
QPolygonF QGraphicsItem::mapFromParent(const QRectF &rect) const
{
    QRectF r = rect.translated(-d_ptr->pos);
    return d_ptr->hasTransform ? transform().inverted().map(r) : r;
}

/*!
    \fn QPolygonF QGraphicsItem::mapFromParent(qreal x, qreal y, qreal w, qreal h) const
    \since 4.3

    This convenience function is equivalent to calling mapFromItem(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Maps the rectangle \a rect, which is in this item's scene's coordinate
    system, to this item's coordinate system, and returns the mapped rectangle
    as a polygon.

    \sa mapToScene(), mapFromItem(), transform(), {The Graphics View Coordinate
    System}
*/
QPolygonF QGraphicsItem::mapFromScene(const QRectF &rect) const
{
    return sceneTransform().inverted().map(rect);
}

/*!
    \fn QPolygonF QGraphicsItem::mapFromScene(qreal x, qreal y, qreal w, qreal h) const
    \since 4.3

    This convenience function is equivalent to calling mapFromScene(QRectF(\a x, \a y, \a w, \a h)).
*/

/*!
    Maps the polygon \a polygon, which is in \a item's coordinate system, to
    this item's coordinate system, and returns the mapped polygon.

    If \a item is 0, this function returns the same as mapFromScene().

    \sa itemTransform(), mapToItem(), mapFromParent(), transform(), {The
    Graphics View Coordinate System}
*/
QPolygonF QGraphicsItem::mapFromItem(const QGraphicsItem *item, const QPolygonF &polygon) const
{
    if (item)
        return item->itemTransform(this).map(polygon);
    return mapFromScene(polygon);
}

/*!
    Maps the polygon \a polygon, which is in this item's parent's coordinate
    system, to this item's coordinate system, and returns the mapped polygon.

    \sa mapToParent(), mapToItem(), transform(), {The Graphics View Coordinate
    System}
*/
QPolygonF QGraphicsItem::mapFromParent(const QPolygonF &polygon) const
{
    QPolygonF p = polygon;
    p.translate(-d_ptr->pos);
    return d_ptr->hasTransform ? transform().inverted().map(p) : p;
}

/*!
    Maps the polygon \a polygon, which is in this item's scene's coordinate
    system, to this item's coordinate system, and returns the mapped polygon.

    \sa mapToScene(), mapFromParent(), transform(), {The Graphics View Coordinate
    System}
*/
QPolygonF QGraphicsItem::mapFromScene(const QPolygonF &polygon) const
{
    return sceneTransform().inverted().map(polygon);
}

/*!
    Maps the path \a path, which is in \a item's coordinate system, to
    this item's coordinate system, and returns the mapped path.

    If \a item is 0, this function returns the same as mapFromScene().

    \sa itemTransform(), mapFromParent(), mapFromScene(), mapToItem(), {The
    Graphics View Coordinate System}
*/
QPainterPath QGraphicsItem::mapFromItem(const QGraphicsItem *item, const QPainterPath &path) const
{
    if (item)
        return item->itemTransform(this).map(path);
    return mapFromScene(path);
}

/*!
    Maps the path \a path, which is in this item's parent's coordinate
    system, to this item's coordinate system, and returns the mapped path.

    \sa mapFromScene(), mapFromItem(), mapToParent(), {The Graphics View
    Coordinate System}
*/
QPainterPath QGraphicsItem::mapFromParent(const QPainterPath &path) const
{
    QPainterPath p(path);
    p.translate(-d_ptr->pos);
    return d_ptr->hasTransform ? transform().inverted().map(p) : p;
}

/*!
    Maps the path \a path, which is in this item's scene's coordinate
    system, to this item's coordinate system, and returns the mapped path.

    \sa mapFromParent(), mapFromItem(), mapToScene(), {The Graphics View
    Coordinate System}
*/
QPainterPath QGraphicsItem::mapFromScene(const QPainterPath &path) const
{
    return sceneTransform().inverted().map(path);
}

/*!
    Returns true if this item is an ancestor of \a child (i.e., if this item
    is \a child's parent, or one of \a child's parent's ancestors).

    \sa parentItem()
*/
bool QGraphicsItem::isAncestorOf(const QGraphicsItem *child) const
{
    if (!child || child == this)
        return false;
    const QGraphicsItem *ancestor = child;
    while ((ancestor = ancestor->d_ptr->parent)) {
        if (ancestor == this)
            return true;
    }
    return false;
}

/*!
    \since 4.4

    Returns the closest common ancestor item of this item and \a other, or 0
    if either \a other is 0, or there is no common ancestor.

    \sa isAncestorOf()
*/
QGraphicsItem *QGraphicsItem::commonAncestorItem(const QGraphicsItem *other) const
{
    if (!other)
        return 0;
    if (other == this)
        return const_cast<QGraphicsItem *>(this);
    const QGraphicsItem *thisw = this;
    const QGraphicsItem *otherw = other;
    int thisDepth = d_ptr->depth;
    int otherDepth = other->d_ptr->depth;
    while (thisDepth > otherDepth) {
        thisw = thisw->d_ptr->parent;
        --thisDepth;
    }
    while (otherDepth > thisDepth) {
        otherw = otherw->d_ptr->parent;
        --otherDepth;
    }
    while (thisw && thisw != otherw) {
        thisw = thisw->d_ptr->parent;
        otherw = otherw->d_ptr->parent;
    }
    return const_cast<QGraphicsItem *>(thisw);
}

/*!
    \since 4,4
    Returns true if this item is currently under the mouse cursor in one of
    the views; otherwise, false is returned.

    \sa QGraphicsScene::views(), QCursor::pos()
*/
bool QGraphicsItem::isUnderMouse() const
{
    Q_D(const QGraphicsItem);
    if (!d->scene)
        return false;

    QPoint cursorPos = QCursor::pos();
    foreach (QGraphicsView *view, d->scene->views()) {
        if (contains(mapFromScene(view->mapToScene(view->mapFromGlobal(cursorPos)))))
            return true;
    }
    return false;
}

/*!
    Returns this item's custom data for the key \a key as a QVariant.

    Custom item data is useful for storing arbitrary properties in any
    item. Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 11

    Qt does not use this feature for storing data; it is provided solely
    for the convenience of the user.

    \sa setData()
*/
QVariant QGraphicsItem::data(int key) const
{
    QGraphicsItemCustomDataStore *store = qt_dataStore();
    if (!store->data.contains(this))
        return QVariant();
    return store->data.value(this).value(key);
}

/*!
    Sets this item's custom data for the key \a key to \a value.

    Custom item data is useful for storing arbitrary properties for any
    item. Qt does not use this feature for storing data; it is provided solely
    for the convenience of the user.

    \sa data()
*/
void QGraphicsItem::setData(int key, const QVariant &value)
{
    qt_dataStore()->data[this][key] = value;
}

/*!
    \fn T qgraphicsitem_cast(QGraphicsItem *item)
    \relates QGraphicsItem
    \since 4.2

    Returns the given \a item cast to type T if \a item is of type T;
    otherwise, 0 is returned.

    \note To make this function work correctly with custom items, reimplement
    the \l{QGraphicsItem::}{type()} function for each custom QGraphicsItem
    subclass.

    \sa QGraphicsItem::type(), QGraphicsItem::UserType
*/

/*!
    Returns the type of an item as an int. All standard graphicsitem classes
    are associated with a unique value; see QGraphicsItem::Type. This type
    information is used by qgraphicsitem_cast() to distinguish between types.

    The default implementation (in QGraphicsItem) returns UserType.

    To enable use of qgraphicsitem_cast() with a custom item, reimplement this
    function and declare a Type enum value equal to your custom item's type.
    Custom items must return a value larger than or equal to UserType (65536).

    For example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp QGraphicsItem type

    \sa UserType
*/
int QGraphicsItem::type() const
{
    return (int)UserType;
}

/*!
    Installs an event filter for this item on \a filterItem, causing
    all events for this item to first pass through \a filterItem's
    sceneEventFilter() function.

    To filter another item's events, install this item as an event filter
    for the other item. Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 12

    An item can only filter events for other items in the same
    scene. Also, an item cannot filter its own events; instead, you
    can reimplement sceneEvent() directly.

    Items must belong to a scene for scene event filters to be installed and
    used.

    \sa removeSceneEventFilter(), sceneEventFilter(), sceneEvent()
*/
void QGraphicsItem::installSceneEventFilter(QGraphicsItem *filterItem)
{
    if (!d_ptr->scene) {
        qWarning("QGraphicsItem::installSceneEventFilter: event filters can only be installed"
                 " on items in a scene.");
        return;
    }
    if (d_ptr->scene != filterItem->scene()) {
        qWarning("QGraphicsItem::installSceneEventFilter: event filters can only be installed"
                 " on items in the same scene.");
        return;
    }
    d_ptr->scene->d_func()->installSceneEventFilter(this, filterItem);
}

/*!
    Removes an event filter on this item from \a filterItem.

    \sa installSceneEventFilter()
*/
void QGraphicsItem::removeSceneEventFilter(QGraphicsItem *filterItem)
{
    if (!d_ptr->scene || d_ptr->scene != filterItem->scene())
        return;
    d_ptr->scene->d_func()->removeSceneEventFilter(this, filterItem);
}

/*!
    Filters events for the item \a watched. \a event is the filtered
    event.

    Reimplementing this function in a subclass makes it possible
    for the item to be used as an event filter for other items,
    intercepting all the events send to those items before they are
    able to respond.

    Reimplementations must return true to prevent further processing of
    a given event, ensuring that it will not be delivered to the watched
    item, or return false to indicate that the event should be propagated
    further by the event system.

    \sa installSceneEventFilter()
*/
bool QGraphicsItem::sceneEventFilter(QGraphicsItem *watched, QEvent *event)
{
    Q_UNUSED(watched);
    Q_UNUSED(event);
    return false;
}

/*!
    This virtual function receives events to this item. Reimplement
    this function to intercept events before they are dispatched to
    the specialized event handlers contextMenuEvent(), focusInEvent(),
    focusOutEvent(), hoverEnterEvent(), hoverMoveEvent(),
    hoverLeaveEvent(), keyPressEvent(), keyReleaseEvent(),
    mousePressEvent(), mouseReleaseEvent(), mouseMoveEvent(), and
    mouseDoubleClickEvent().

    Returns true if the event was recognized and handled; otherwise, (e.g., if
    the event type was not recognized,) false is returned.

    \a event is the intercepted event.
*/
bool QGraphicsItem::sceneEvent(QEvent *event)
{
    if (d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorHandlesChildEvents) {
        if (event->type() == QEvent::HoverEnter || event->type() == QEvent::HoverLeave
            || event->type() == QEvent::DragEnter || event->type() == QEvent::DragLeave) {
            // Hover enter and hover leave events for children are ignored;
            // hover move events are forwarded.
            return true;
        }

        QGraphicsItem *handler = this;
        do {
            handler = handler->d_ptr->parent;
            Q_ASSERT(handler);
        } while (handler->d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorHandlesChildEvents);
        // Forward the event to the closest parent that handles child
        // events, mapping existing item-local coordinates to its
        // coordinate system.
        d_ptr->remapItemPos(event, handler);
        handler->sceneEvent(event);
        return true;
    }

    if (!d_ptr->visible) {
        // Eaten
        return true;
    }

    switch (event->type()) {
    case QEvent::FocusIn:
        focusInEvent(static_cast<QFocusEvent *>(event));
        break;
    case QEvent::FocusOut:
        focusOutEvent(static_cast<QFocusEvent *>(event));
        break;
    case QEvent::GraphicsSceneContextMenu:
        contextMenuEvent(static_cast<QGraphicsSceneContextMenuEvent *>(event));
        break;
    case QEvent::GraphicsSceneDragEnter:
        dragEnterEvent(static_cast<QGraphicsSceneDragDropEvent *>(event));
        break;
    case QEvent::GraphicsSceneDragMove:
        dragMoveEvent(static_cast<QGraphicsSceneDragDropEvent *>(event));
        break;
    case QEvent::GraphicsSceneDragLeave:
        dragLeaveEvent(static_cast<QGraphicsSceneDragDropEvent *>(event));
        break;
    case QEvent::GraphicsSceneDrop:
        dropEvent(static_cast<QGraphicsSceneDragDropEvent *>(event));
        break;
    case QEvent::GraphicsSceneHoverEnter:
        hoverEnterEvent(static_cast<QGraphicsSceneHoverEvent *>(event));
        break;
    case QEvent::GraphicsSceneHoverMove:
        hoverMoveEvent(static_cast<QGraphicsSceneHoverEvent *>(event));
        break;
    case QEvent::GraphicsSceneHoverLeave:
        hoverLeaveEvent(static_cast<QGraphicsSceneHoverEvent *>(event));
        break;
    case QEvent::GraphicsSceneMouseMove:
        mouseMoveEvent(static_cast<QGraphicsSceneMouseEvent *>(event));
        break;
    case QEvent::GraphicsSceneMousePress:
        mousePressEvent(static_cast<QGraphicsSceneMouseEvent *>(event));
        break;
    case QEvent::GraphicsSceneMouseRelease:
        mouseReleaseEvent(static_cast<QGraphicsSceneMouseEvent *>(event));
        break;
    case QEvent::GraphicsSceneMouseDoubleClick:
        mouseDoubleClickEvent(static_cast<QGraphicsSceneMouseEvent *>(event));
        break;
    case QEvent::GraphicsSceneWheel:
        wheelEvent(static_cast<QGraphicsSceneWheelEvent *>(event));
        break;
    case QEvent::KeyPress: {
        QKeyEvent *k = static_cast<QKeyEvent *>(event);
        if (k->key() == Qt::Key_Tab || k->key() == Qt::Key_Backtab) {
            if (!(k->modifiers() & (Qt::ControlModifier | Qt::AltModifier))) {  //### Add MetaModifier?
                bool res = false;
                if (k->key() == Qt::Key_Backtab
                    || (k->key() == Qt::Key_Tab && (k->modifiers() & Qt::ShiftModifier))) {
                    if (d_ptr->isWidget) {
                        res = static_cast<QGraphicsWidget *>(this)->focusNextPrevChild(false);
                    } else if (d_ptr->scene) {
                        res = d_ptr->scene->focusNextPrevChild(false);
                    }
                } else if (k->key() == Qt::Key_Tab) {
                    if (d_ptr->isWidget) {
                        res = static_cast<QGraphicsWidget *>(this)->focusNextPrevChild(true);
                    } else if (d_ptr->scene) {
                        res = d_ptr->scene->focusNextPrevChild(true);
                    }
                }
                if (!res)
                    event->ignore();
                return true;
            }
        }
        keyPressEvent(static_cast<QKeyEvent *>(event));
        break;
    }
    case QEvent::KeyRelease:
        keyReleaseEvent(static_cast<QKeyEvent *>(event));
        break;
    case QEvent::InputMethod:
        inputMethodEvent(static_cast<QInputMethodEvent *>(event));
        break;
    default:
        return false;
    }

    return true;
}

/*!
    This event handler can be reimplemented in a subclass to process context
    menu events. The \a event parameter contains details about the event to
    be handled.

    If you ignore the event, (i.e., by calling QEvent::ignore(),) \a event
    will propagate to any item beneath this item. If no items accept the
    event, it will be ignored by the scene, and propagate to the view.

    It's common to open a QMenu in response to receiving a context menu
    event. Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 13

    The default implementation ignores the event.

    \sa sceneEvent()
*/
void QGraphicsItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
{
    event->ignore();
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    drag enter events for this item. Drag enter events are generated as the
    cursor enters the item's area.

    By accepting the event, (i.e., by calling QEvent::accept(),) the item will
    accept drop events, in addition to receiving drag move and drag
    leave. Otherwise, the event will be ignored and propagate to the item
    beneath. If the event is accepted, the item will receive a drag move event
    before control goes back to the event loop.

    A common implementation of dragEnterEvent accepts or ignores \a event
    depending on the associated mime data in \a event. Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 14

    Items do not receive drag and drop events by default; to enable this
    feature, call \c setAcceptDrops(true).

    The default implementation does nothing.

    \sa dropEvent(), dragMoveEvent(), dragLeaveEvent()
*/
void QGraphicsItem::dragEnterEvent(QGraphicsSceneDragDropEvent *event)
{
    Q_D(QGraphicsItem);
    // binary compatibility workaround between 4.4 and 4.5
    if (d->isProxyWidget())
        static_cast<QGraphicsProxyWidget*>(this)->dragEnterEvent(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    drag leave events for this item. Drag leave events are generated as the
    cursor leaves the item's area. Most often you will not need to reimplement
    this function, but it can be useful for resetting state in your item
    (e.g., highlighting).

    Calling QEvent::ignore() or QEvent::accept() on \a event has no effect.

    Items do not receive drag and drop events by default; to enable this
    feature, call \c setAcceptDrops(true).

    The default implementation does nothing.

    \sa dragEnterEvent(), dropEvent(), dragMoveEvent()
*/
void QGraphicsItem::dragLeaveEvent(QGraphicsSceneDragDropEvent *event)
{
    Q_D(QGraphicsItem);
    // binary compatibility workaround between 4.4 and 4.5
    if (d->isProxyWidget())
        static_cast<QGraphicsProxyWidget*>(this)->dragLeaveEvent(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    drag move events for this item. Drag move events are generated as the
    cursor moves around inside the item's area. Most often you will not need
    to reimplement this function; it is used to indicate that only parts of
    the item can accept drops.

    Calling QEvent::ignore() or QEvent::accept() on \a event toggles whether
    or not the item will accept drops at the position from the event. By
    default, \a event is accepted, indicating that the item allows drops at
    the specified position.

    Items do not receive drag and drop events by default; to enable this
    feature, call \c setAcceptDrops(true).

    The default implementation does nothing.

    \sa dropEvent(), dragEnterEvent(), dragLeaveEvent()
*/
void QGraphicsItem::dragMoveEvent(QGraphicsSceneDragDropEvent *event)
{
    Q_D(QGraphicsItem);
    // binary compatibility workaround between 4.4 and 4.5
    if (d->isProxyWidget())
        static_cast<QGraphicsProxyWidget*>(this)->dragMoveEvent(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    drop events for this item. Items can only receive drop events if the last
    drag move event was accepted.

    Calling QEvent::ignore() or QEvent::accept() on \a event has no effect.

    Items do not receive drag and drop events by default; to enable this
    feature, call \c setAcceptDrops(true).

    The default implementation does nothing.

    \sa dragEnterEvent(), dragMoveEvent(), dragLeaveEvent()
*/
void QGraphicsItem::dropEvent(QGraphicsSceneDragDropEvent *event)
{
    Q_D(QGraphicsItem);
    // binary compatibility workaround between 4.4 and 4.5
    if (d->isProxyWidget())
        static_cast<QGraphicsProxyWidget*>(this)->dropEvent(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    focus in events for this item. The default implementation calls
    ensureVisible().

    \sa focusOutEvent(), sceneEvent()
*/
void QGraphicsItem::focusInEvent(QFocusEvent *event)
{
    Q_UNUSED(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    focus out events for this item. The default implementation does nothing.

    \sa focusInEvent(), sceneEvent()
*/
void QGraphicsItem::focusOutEvent(QFocusEvent *event)
{
    Q_UNUSED(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    hover enter events for this item. The default implementation calls
    update(); otherwise it does nothing.

    Calling QEvent::ignore() or QEvent::accept() on \a event has no effect.

    \sa hoverMoveEvent(), hoverLeaveEvent(), sceneEvent(), setAcceptHoverEvents()
*/
void QGraphicsItem::hoverEnterEvent(QGraphicsSceneHoverEvent *event)
{
    Q_UNUSED(event);
    d_ptr->updateHelper();
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    hover move events for this item. The default implementation does nothing.

    Calling QEvent::ignore() or QEvent::accept() on \a event has no effect.

    \sa hoverEnterEvent(), hoverLeaveEvent(), sceneEvent(), setAcceptHoverEvents()
*/
void QGraphicsItem::hoverMoveEvent(QGraphicsSceneHoverEvent *event)
{
    Q_UNUSED(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    hover leave events for this item. The default implementation calls
    update(); otherwise it does nothing.

    Calling QEvent::ignore() or QEvent::accept() on \a event has no effect.

    \sa hoverEnterEvent(), hoverMoveEvent(), sceneEvent(), setAcceptHoverEvents()
*/
void QGraphicsItem::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
{
    Q_UNUSED(event);
    d_ptr->updateHelper();
}

/*!
    This event handler, for event \a event, can be reimplemented to
    receive key press events for this item. The default implementation
    ignores the event. If you reimplement this handler, the event will by
    default be accepted.

    Note that key events are only received for items that set the
    ItemIsFocusable flag, and that have keyboard input focus.

    \sa keyReleaseEvent(), setFocus(), QGraphicsScene::setFocusItem(),
    sceneEvent()
*/
void QGraphicsItem::keyPressEvent(QKeyEvent *event)
{
    event->ignore();
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    key release events for this item. The default implementation
    ignores the event. If you reimplement this handler, the event will by
    default be accepted.

    Note that key events are only received for items that set the
    ItemIsFocusable flag, and that have keyboard input focus.

    \sa keyPressEvent(), setFocus(), QGraphicsScene::setFocusItem(),
    sceneEvent()
*/
void QGraphicsItem::keyReleaseEvent(QKeyEvent *event)
{
    event->ignore();
}

/*!
    This event handler, for event \a event, can be reimplemented to
    receive mouse press events for this item. Mouse press events are
    only delivered to items that accept the mouse button that is
    pressed. By default, an item accepts all mouse buttons, but you
    can change this by calling setAcceptedMouseButtons().

    The mouse press event decides which item should become the mouse
    grabber (see QGraphicsScene::mouseGrabberItem()). If you do not
    reimplement this function, the press event will propagate to any
    topmost item beneath this item, and no other mouse events will be
    delivered to this item.

    If you do reimplement this function, \a event will by default be
    accepted (see QEvent::accept()), and this item is then the mouse
    grabber. This allows the item to receive future move, release and
    doubleclick events. If you call QEvent::ignore() on \a event, this
    item will lose the mouse grab, and \a event will propagate to any
    topmost item beneath. No further mouse events will be delivered to
    this item unless a new mouse press event is received.

    The default implementation handles basic item interaction, such as
    selection and moving. If you want to keep the base implementation
    when reimplementing this function, call
    QGraphicsItem::mousePressEvent() in your reimplementation.

    The event is \l{QEvent::ignore()}d for items that are neither
    \l{QGraphicsItem::ItemIsMovable}{movable} nor
    \l{QGraphicsItem::ItemIsSelectable}{selectable}.

    \sa mouseMoveEvent(), mouseReleaseEvent(),
    mouseDoubleClickEvent(), sceneEvent()
*/
void QGraphicsItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if (event->button() == Qt::LeftButton && (flags() & ItemIsSelectable)) {
        bool multiSelect = (event->modifiers() & Qt::ControlModifier) != 0;
        if (!multiSelect) {
            if (!d_ptr->selected) {
                if (QGraphicsScene *scene = d_ptr->scene) {
                    ++scene->d_func()->selectionChanging;
                    scene->clearSelection();
                    --scene->d_func()->selectionChanging;
                }
                setSelected(true);
            }
        }
    } else if (!(flags() & ItemIsMovable)) {
        event->ignore();
    }
    if (d_ptr->isWidget) {
        // Qt::Popup closes when you click outside.
        QGraphicsWidget *w = static_cast<QGraphicsWidget *>(this);
        if (w->windowFlags() & Qt::Popup) {
            event->accept();
            if (!w->rect().contains(event->pos()))
                w->close();
        }
    }
}

/*!
    obsolete
*/
bool _qt_movableAncestorIsSelected(const QGraphicsItem *item)
{
    const QGraphicsItem *parent = item->parentItem();
    return parent && (((parent->flags() & QGraphicsItem::ItemIsMovable) && parent->isSelected()) || _qt_movableAncestorIsSelected(parent));
}

bool QGraphicsItemPrivate::movableAncestorIsSelected(const QGraphicsItem *item)
{
    const QGraphicsItem *parent = item->d_ptr->parent;
    return parent && (((parent->flags() & QGraphicsItem::ItemIsMovable) && parent->isSelected()) || _qt_movableAncestorIsSelected(parent));
}

/*!
    This event handler, for event \a event, can be reimplemented to
    receive mouse move events for this item. If you do receive this
    event, you can be certain that this item also received a mouse
    press event, and that this item is the current mouse grabber.

    Calling QEvent::ignore() or QEvent::accept() on \a event has no
    effect.

    The default implementation handles basic item interaction, such as
    selection and moving. If you want to keep the base implementation
    when reimplementing this function, call
    QGraphicsItem::mouseMoveEvent() in your reimplementation.

    Please note that mousePressEvent() decides which graphics item it
    is that receives mouse events. See the mousePressEvent()
    description for details.

    \sa mousePressEvent(), mouseReleaseEvent(),
    mouseDoubleClickEvent(), sceneEvent()
*/
void QGraphicsItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    if ((event->buttons() & Qt::LeftButton) && (flags() & ItemIsMovable)) {
        // Determine the list of items that need to be moved.
        QList<QGraphicsItem *> selectedItems;
        QMap<QGraphicsItem *, QPointF> initialPositions;
        if (d_ptr->scene) {
            selectedItems = d_ptr->scene->selectedItems();
            initialPositions = d_ptr->scene->d_func()->movingItemsInitialPositions;
            if (initialPositions.isEmpty()) {
                foreach (QGraphicsItem *item, selectedItems)
                    initialPositions[item] = item->pos();
                initialPositions[this] = pos();
            }
            d_ptr->scene->d_func()->movingItemsInitialPositions = initialPositions;
        }

        // Find the active view.
        QGraphicsView *view = 0;
        if (event->widget())
            view = qobject_cast<QGraphicsView *>(event->widget()->parentWidget());

        // Move all selected items
        int i = 0;
        bool movedMe = false;
        while (i <= selectedItems.size()) {
            QGraphicsItem *item = 0;
            if (i < selectedItems.size())
                item = selectedItems.at(i);
            else
                item = this;
            if (item == this) {
                // Slightly clumsy-looking way to ensure that "this" is part
                // of the list of items to move, this is to avoid allocations
                // (appending this item to the list of selected items causes a
                // detach).
                if (movedMe)
                    break;
                movedMe = true;
            }

            if ((item->flags() & ItemIsMovable) && !QGraphicsItemPrivate::movableAncestorIsSelected(item)) {
                QPointF currentParentPos;
                QPointF buttonDownParentPos;
                if (item->d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorIgnoresTransformations) {
                    // Items whose ancestors ignore transformations need to
                    // map screen coordinates to local coordinates, then map
                    // those to the parent.
                    QTransform viewToItemTransform = (item->deviceTransform(view->viewportTransform())).inverted();
                    currentParentPos = mapToParent(viewToItemTransform.map(QPointF(view->mapFromGlobal(event->screenPos()))));
                    buttonDownParentPos = mapToParent(viewToItemTransform.map(QPointF(view->mapFromGlobal(event->buttonDownScreenPos(Qt::LeftButton)))));
                } else if (item->flags() & ItemIgnoresTransformations) {
                    // Root items that ignore transformations need to
                    // calculate their diff by mapping viewport coordinates
                    // directly to parent coordinates.
                    QTransform viewToParentTransform = (item->transform().translate(item->d_ptr->pos.x(), item->d_ptr->pos.y()))
                                                       * (item->sceneTransform() * view->viewportTransform()).inverted();
                    currentParentPos = viewToParentTransform.map(QPointF(view->mapFromGlobal(event->screenPos())));
                    buttonDownParentPos = viewToParentTransform.map(QPointF(view->mapFromGlobal(event->buttonDownScreenPos(Qt::LeftButton))));
                } else {
                    // All other items simply map from the scene.
                    currentParentPos = item->mapToParent(item->mapFromScene(event->scenePos()));
                    buttonDownParentPos = item->mapToParent(item->mapFromScene(event->buttonDownScenePos(Qt::LeftButton)));
                }

                item->setPos(initialPositions.value(item) + currentParentPos - buttonDownParentPos);

                if (item->flags() & ItemIsSelectable)
                    item->setSelected(true);
            }
            ++i;
        }

    } else {
        event->ignore();
    }
}

/*!
    This event handler, for event \a event, can be reimplemented to
    receive mouse release events for this item.

    Calling QEvent::ignore() or QEvent::accept() on \a event has no
    effect.

    The default implementation handles basic item interaction, such as
    selection and moving. If you want to keep the base implementation
    when reimplementing this function, call
    QGraphicsItem::mouseReleaseEvent() in your reimplementation.

    Please note that mousePressEvent() decides which graphics item it
    is that receives mouse events. See the mousePressEvent()
    description for details.

    \sa mousePressEvent(), mouseMoveEvent(), mouseDoubleClickEvent(),
    sceneEvent()
*/
void QGraphicsItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    if (flags() & ItemIsSelectable) {
        bool multiSelect = (event->modifiers() & Qt::ControlModifier) != 0;
        if (event->scenePos() == event->buttonDownScenePos(Qt::LeftButton)) {
            // The item didn't move
            if (multiSelect) {
                setSelected(!isSelected());
            } else {
                bool selectionChanged = false;
                if (QGraphicsScene *scene = d_ptr->scene) {
                    ++scene->d_func()->selectionChanging;
                    // Clear everything but this item. Bypass
                    // QGraphicsScene::clearSelection()'s default behavior by
                    // temporarily removing this item from the selection list.
                    if (d_ptr->selected) {
                        scene->d_func()->selectedItems.remove(this);
                        foreach (QGraphicsItem *item, scene->d_func()->selectedItems) {
                            if (item->isSelected()) {
                                selectionChanged = true;
                                break;
                            }
                        }
                    }
                    scene->clearSelection();
                    if (d_ptr->selected)
                        scene->d_func()->selectedItems.insert(this);
                    --scene->d_func()->selectionChanging;
                    if (selectionChanged)
                        emit d_ptr->scene->selectionChanged();
                }
                setSelected(true);
            }
        }
    }
    if (d_ptr->scene && !event->buttons())
        d_ptr->scene->d_func()->movingItemsInitialPositions.clear();
}

/*!
    This event handler, for event \a event, can be reimplemented to
    receive mouse doubleclick events for this item.

    When doubleclicking an item, the item will first receive a mouse
    press event, followed by a release event (i.e., a click), then a
    doubleclick event, and finally a release event.

    Calling QEvent::ignore() or QEvent::accept() on \a event has no
    effect.

    The default implementation calls mousePressEvent(). If you want to
    keep the base implementation when reimplementing this function,
    call QGraphicsItem::mouseDoubleClickEvent() in your
    reimplementation.

    Note that an item will not receive double click events if it is
    neither \l {QGraphicsItem::ItemIsSelectable}{selectable} nor
    \l{QGraphicsItem::ItemIsMovable}{movable} (single mouse clicks are
    ignored in this case, and that stops the generation of double
    clicks).

    \sa mousePressEvent(), mouseMoveEvent(), mouseReleaseEvent(), sceneEvent()
*/
void QGraphicsItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
{
    mousePressEvent(event);
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    wheel events for this item. If you reimplement this function, \a event
    will be accepted by default.

    If you ignore the event, (i.e., by calling QEvent::ignore(),) it will
    propagate to any item beneath this item. If no items accept the event, it
    will be ignored by the scene, and propagate to the view (e.g., the view's
    vertical scroll bar).

    The default implementation ignores the event.

    \sa sceneEvent()
*/
void QGraphicsItem::wheelEvent(QGraphicsSceneWheelEvent *event)
{
    event->ignore();
}

/*!
    This event handler, for event \a event, can be reimplemented to receive
    input method events for this item. The default implementation ignores the
    event.

    \sa inputMethodQuery(), sceneEvent()
*/
void QGraphicsItem::inputMethodEvent(QInputMethodEvent *event)
{
    event->ignore();
}

/*!
    This method is only relevant for input items. It is used by the
    input method to query a set of properties of the item to be able
    to support complex input method operations, such as support for
    surrounding text and reconversions. \a query specifies which
    property is queried.

    \sa inputMethodEvent()
*/
QVariant QGraphicsItem::inputMethodQuery(Qt::InputMethodQuery query) const
{
    if (isWidget()) {
        // ### Qt 5: Remove. The reimplementation in
        // QGraphicsProxyWidget solves this problem (but requires a
        // recompile to take effect).
        return d_ptr->inputMethodQueryHelper(query);
    }

    Q_UNUSED(query);
    return QVariant();
}

/*!
    \since 4.6

    Subscribes the graphics item to the specified \a gesture type.

    Returns the id of the gesture.

    \sa releaseGesture(), setGestureEnabled()
*/
int QGraphicsItem::grabGesture(Qt::GestureType gesture)
{
    return grabGesture(qt_getStandardGestureTypeName(gesture));
}

/*!
    \since 4.6

    Subscribes the graphics item to the specified \a gesture type.

    Returns the id of the gesture.

    \sa releaseGesture(), setGestureEnabled()
*/
int QGraphicsItem::grabGesture(const QString &gesture)
{
    int id = QGestureManager::instance()->makeGestureId(gesture);
    d_ptr->gestures << id;
    if (d_ptr->scene)
        d_ptr->scene->d_func()->grabGesture(this, id);
    return id;
}

/*!
    \since 4.6

    Unsubscribes the graphics item from a gesture, which is specified
    by the \a gestureId.

    \sa grabGesture(), setGestureEnabled()
*/
void QGraphicsItem::releaseGesture(int gestureId)
{
    if (d_ptr->scene)
        d_ptr->scene->d_func()->releaseGesture(this, gestureId);
    QGestureManager::instance()->releaseGestureId(gestureId);
    d_ptr->gestures.remove(gestureId);
}

/*!
    \since 4.6

    If \a enable is true, the gesture with the given \a gestureId is
    enabled; otherwise the gesture is disabled.

    The id of the gesture is returned by the grabGesture().

    \sa grabGesture(), releaseGesture()
*/
void QGraphicsItem::setGestureEnabled(int gestureId, bool enable)
{
    //###
}

/*!
    This virtual function is called by QGraphicsItem to notify custom items
    that some part of the item's state changes. By reimplementing this
    function, your can react to a change, and in some cases, (depending on \a
    change,) adjustments can be made.

    \a change is the parameter of the item that is changing. \a value is the
    new value; the type of the value depends on \a change.

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 15

    The default implementation does nothing, and returns \a value.

    Note: Certain QGraphicsItem functions cannot be called in a
    reimplementation of this function; see the GraphicsItemChange
    documentation for details.

    \sa GraphicsItemChange
*/
QVariant QGraphicsItem::itemChange(GraphicsItemChange change, const QVariant &value)
{
    Q_UNUSED(change);
    if (change == QGraphicsItem::ItemSceneChange) {
        if (!qVariantValue<QGraphicsScene*>(value)) {
            // the item has been removed from a scene, unsubscribe gestures.
            Q_ASSERT(d_ptr->scene);
            foreach(int id, d_ptr->gestures)
                d_ptr->scene->d_func()->releaseGesture(this, id);
        }
    } else if (change == QGraphicsItem::ItemSceneHasChanged) {
        if (QGraphicsScene *scene = qVariantValue<QGraphicsScene*>(value)) {
            // item has been added to the scene
            foreach(int id, d_ptr->gestures)
                scene->d_func()->grabGesture(this, id);
        }
    }
    return value;
}

/*!
    \internal

    Note: This is provided as a hook to avoid future problems related
    to adding virtual functions.
*/
bool QGraphicsItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal

    Note: This is provided as a hook to avoid future problems related
    to adding virtual functions.
*/
void QGraphicsItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal

    Note: This is provided as a hook to avoid future problems related
    to adding virtual functions.
*/
QVariant QGraphicsItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \internal

    Adds this item to the scene's index. Called in conjunction with
    removeFromIndex() to ensure the index bookkeeping is correct when
    the item's position, transformation or shape changes.
*/
void QGraphicsItem::addToIndex()
{
    if (d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren) {
        // ### add to child index only if applicable
        return;
    }
    if (d_ptr->scene)
        d_ptr->scene->d_func()->addToIndex(this);
    d_ptr->updateHelper();
}

/*!
    \internal

    Removes this item from the scene's index. Called in conjunction
    with addToIndex() to ensure the index bookkeeping is correct when
    the item's position, transformation or shape changes.
*/
void QGraphicsItem::removeFromIndex()
{
    if (d_ptr->ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren) {
        // ### remove from child index only if applicable
        return;
    }
    d_ptr->updateHelper();
    if (d_ptr->scene)
        d_ptr->scene->d_func()->removeFromIndex(this);
}

/*!
    Prepares the item for a geometry change. Call this function before
    changing the bounding rect of an item to keep QGraphicsScene's index up to
    date.

    prepareGeometryChange() will call update() if this is necessary.

    Example:

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 16

    \sa boundingRect()
*/
void QGraphicsItem::prepareGeometryChange()
{
    if (d_ptr->scene) {
        d_ptr->updateHelper(QRectF(), false, /*maybeDirtyClipPath=*/!d_ptr->inSetPosHelper);
        QGraphicsScenePrivate *scenePrivate = d_ptr->scene->d_func();
        scenePrivate->removeFromIndex(this);
    }

    if (d_ptr->inSetPosHelper)
        return;

    if (d_ptr->flags & ItemClipsChildrenToShape)
        d_ptr->invalidateCachedClipPathRecursively();
    else
        d_ptr->invalidateCachedClipPath();
}

/*!
    \internal

    Highlights \a item as selected.

    NOTE: This function is a duplicate of qt_graphicsItem_highlightSelected() in
          qgraphicssvgitem.cpp!
*/
static void qt_graphicsItem_highlightSelected(
    QGraphicsItem *item, QPainter *painter, const QStyleOptionGraphicsItem *option)
{
    const QRectF murect = painter->transform().mapRect(QRectF(0, 0, 1, 1));
    if (qFuzzyIsNull(qMax(murect.width(), murect.height())))
        return;

    const QRectF mbrect = painter->transform().mapRect(item->boundingRect());
    if (qMin(mbrect.width(), mbrect.height()) < qreal(1.0))
        return;

    qreal itemPenWidth;
    switch (item->type()) {
        case QGraphicsEllipseItem::Type:
            itemPenWidth = static_cast<QGraphicsEllipseItem *>(item)->pen().widthF();
            break;
        case QGraphicsPathItem::Type:
            itemPenWidth = static_cast<QGraphicsPathItem *>(item)->pen().widthF();
            break;
        case QGraphicsPolygonItem::Type:
            itemPenWidth = static_cast<QGraphicsPolygonItem *>(item)->pen().widthF();
            break;
        case QGraphicsRectItem::Type:
            itemPenWidth = static_cast<QGraphicsRectItem *>(item)->pen().widthF();
            break;
        case QGraphicsSimpleTextItem::Type:
            itemPenWidth = static_cast<QGraphicsSimpleTextItem *>(item)->pen().widthF();
            break;
        case QGraphicsLineItem::Type:
            itemPenWidth = static_cast<QGraphicsLineItem *>(item)->pen().widthF();
            break;
        default:
            itemPenWidth = 1.0;
    }
    const qreal pad = itemPenWidth / 2;

    const qreal penWidth = 0; // cosmetic pen

    const QColor fgcolor = option->palette.windowText().color();
    const QColor bgcolor( // ensure good contrast against fgcolor
        fgcolor.red()   > 127 ? 0 : 255,
        fgcolor.green() > 127 ? 0 : 255,
        fgcolor.blue()  > 127 ? 0 : 255);

    painter->setPen(QPen(bgcolor, penWidth, Qt::SolidLine));
    painter->setBrush(Qt::NoBrush);
    painter->drawRect(item->boundingRect().adjusted(pad, pad, -pad, -pad));

    painter->setPen(QPen(option->palette.windowText(), 0, Qt::DashLine));
    painter->setBrush(Qt::NoBrush);
    painter->drawRect(item->boundingRect().adjusted(pad, pad, -pad, -pad));
}

/*!
    \class QAbstractGraphicsShapeItem
    \brief The QAbstractGraphicsShapeItem class provides a common base for
    all path items.
    \since 4.2
    \ingroup multimedia

    This class does not fully implement an item by itself; in particular, it
    does not implement boundingRect() and paint(), which are inherited by
    QGraphicsItem.

    You can subclass this item to provide a simple base implementation of
    accessors for the item's pen and brush.

    \sa QGraphicsRectItem, QGraphicsEllipseItem, QGraphicsPathItem,
    QGraphicsPolygonItem, QGraphicsTextItem, QGraphicsLineItem,
    QGraphicsPixmapItem, {The Graphics View Framework}
*/

class QAbstractGraphicsShapeItemPrivate : public QGraphicsItemPrivate
{
    Q_DECLARE_PUBLIC(QAbstractGraphicsShapeItem)
public:

    QBrush brush;
    QPen pen;

    // Cached bounding rectangle
    mutable QRectF boundingRect;
};

/*!
    Constructs a QAbstractGraphicsShapeItem. \a parent is passed to
    QGraphicsItem's constructor.
*/
QAbstractGraphicsShapeItem::QAbstractGraphicsShapeItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                                       // obsolete argument
                                                       , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(*new QAbstractGraphicsShapeItemPrivate, parent, scene)
{
}

/*!
    \internal
*/
QAbstractGraphicsShapeItem::QAbstractGraphicsShapeItem(QAbstractGraphicsShapeItemPrivate &dd,
                                                     QGraphicsItem *parent,
                                                     QGraphicsScene *scene)
    : QGraphicsItem(dd, parent, scene)
{
}

/*!
    Destroys a QAbstractGraphicsShapeItem.
*/
QAbstractGraphicsShapeItem::~QAbstractGraphicsShapeItem()
{
}

/*!
    Returns the item's pen. If no pen has been set, this function returns
    QPen(), a default black solid line pen with 0 width.
*/
QPen QAbstractGraphicsShapeItem::pen() const
{
    Q_D(const QAbstractGraphicsShapeItem);
    return d->pen;
}

/*!
    Sets the pen for this item to \a pen.

    The pen is used to draw the item's outline.

    \sa pen()
*/
void QAbstractGraphicsShapeItem::setPen(const QPen &pen)
{
    Q_D(QAbstractGraphicsShapeItem);
    prepareGeometryChange();
    d->pen = pen;
    d->boundingRect = QRectF();
    update();
}

/*!
    Returns the item's brush, or an empty brush if no brush has been set.

    \sa setBrush()
*/
QBrush QAbstractGraphicsShapeItem::brush() const
{
    Q_D(const QAbstractGraphicsShapeItem);
    return d->brush;
}

/*!
    Sets the item's brush to \a brush.

    The item's brush is used to fill the item.

    If you use a brush with a QGradient, the gradient
    is relative to the item's coordinate system.

    \sa brush()
*/
void QAbstractGraphicsShapeItem::setBrush(const QBrush &brush)
{
    Q_D(QAbstractGraphicsShapeItem);
    d->brush = brush;
    update();
}

/*!
    \reimp
*/
bool QAbstractGraphicsShapeItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QGraphicsItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QAbstractGraphicsShapeItem::opaqueArea() const
{
    Q_D(const QAbstractGraphicsShapeItem);
    if (d->brush.isOpaque())
        return isClipped() ? clipPath() : shape();
    return QGraphicsItem::opaqueArea();
}

/*!
    \class QGraphicsPathItem
    \brief The QGraphicsPathItem class provides a path item that you
    can add to a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    To set the item's path, pass a QPainterPath to QGraphicsPathItem's
    constructor, or call the setPath() function. The path() function
    returns the current path.

    \image graphicsview-pathitem.png

    QGraphicsPathItem uses the path to provide a reasonable
    implementation of boundingRect(), shape(), and contains(). The
    paint() function draws the path using the item's associated pen
    and brush, which you can set by calling the setPen() and
    setBrush() functions.

    \sa QGraphicsRectItem, QGraphicsEllipseItem, QGraphicsPolygonItem,
    QGraphicsTextItem, QGraphicsLineItem, QGraphicsPixmapItem, {The Graphics
    View Framework}
*/

class QGraphicsPathItemPrivate : public QAbstractGraphicsShapeItemPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsPathItem)
public:
    QPainterPath path;
};

/*!
    Constructs a QGraphicsPath item using \a path as the default path. \a
    parent is passed to QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsPathItem::QGraphicsPathItem(const QPainterPath &path,
                                     QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsPathItemPrivate, parent, scene)
{
    if (!path.isEmpty())
        setPath(path);
}

/*!
    Constructs a QGraphicsPath. \a parent is passed to
    QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsPathItem::QGraphicsPathItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsPathItemPrivate, parent, scene)
{
}

/*!
    Destroys the QGraphicsPathItem.
*/
QGraphicsPathItem::~QGraphicsPathItem()
{
}

/*!
    Returns the item's path as a QPainterPath. If no item has been set, an
    empty QPainterPath is returned.

    \sa setPath()
*/
QPainterPath QGraphicsPathItem::path() const
{
    Q_D(const QGraphicsPathItem);
    return d->path;
}

/*!
    Sets the item's path to be the given \a path.

    \sa path()
*/
void QGraphicsPathItem::setPath(const QPainterPath &path)
{
    Q_D(QGraphicsPathItem);
    if (d->path == path)
        return;
    prepareGeometryChange();
    d->path = path;
    d->boundingRect = QRectF();
    update();
}

/*!
    \reimp
*/
QRectF QGraphicsPathItem::boundingRect() const
{
    Q_D(const QGraphicsPathItem);
    if (d->boundingRect.isNull()) {
        qreal pw = pen().widthF();
        if (pw == 0.0)
            d->boundingRect = d->path.controlPointRect();
        else {
            d->boundingRect = shape().controlPointRect();
        }
    }
    return d->boundingRect;
}

/*!
    \reimp
*/
QPainterPath QGraphicsPathItem::shape() const
{
    Q_D(const QGraphicsPathItem);
    return qt_graphicsItem_shapeFromPath(d->path, d->pen);
}

/*!
    \reimp
*/
bool QGraphicsPathItem::contains(const QPointF &point) const
{
    return QAbstractGraphicsShapeItem::contains(point);
}

/*!
    \reimp
*/
void QGraphicsPathItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                              QWidget *widget)
{
    Q_D(QGraphicsPathItem);
    Q_UNUSED(widget);
    painter->setPen(d->pen);
    painter->setBrush(d->brush);
    painter->drawPath(d->path);

    if (option->state & QStyle::State_Selected)
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsPathItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QAbstractGraphicsShapeItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsPathItem::opaqueArea() const
{
    return QAbstractGraphicsShapeItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsPathItem::type() const
{
    return Type;
}

/*!
    \internal
*/
bool QGraphicsPathItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsPathItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsPathItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \class QGraphicsRectItem
    \brief The QGraphicsRectItem class provides a rectangle item that you
    can add to a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    To set the item's rectangle, pass a QRectF to QGraphicsRectItem's
    constructor, or call the setRect() function. The rect() function
    returns the current rectangle.

    \image graphicsview-rectitem.png

    QGraphicsRectItem uses the rectangle and the pen width to provide
    a reasonable implementation of boundingRect(), shape(), and
    contains(). The paint() function draws the rectangle using the
    item's associated pen and brush, which you can set by calling the
    setPen() and setBrush() functions.

    \note The rendering of invalid rectangles, such as those with negative
    widths or heights, is undefined. If you cannot be sure that you are
    using valid rectangles (for example, if you are creating
    rectangles using data from an unreliable source) then you should
    use QRectF::normalized() to create normalized rectangles, and use
    those instead.

    \sa QGraphicsPathItem, QGraphicsEllipseItem, QGraphicsPolygonItem,
    QGraphicsTextItem, QGraphicsLineItem, QGraphicsPixmapItem, {The Graphics
    View Framework}
*/

class QGraphicsRectItemPrivate : public QAbstractGraphicsShapeItemPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsRectItem)
public:
    QRectF rect;
};

/*!
    Constructs a QGraphicsRectItem, using \a rect as the default rectangle.
    \a parent is passed to QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsRectItem::QGraphicsRectItem(const QRectF &rect, QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsRectItemPrivate, parent, scene)
{
    setRect(rect);
}

/*!
    \fn QGraphicsRectItem::QGraphicsRectItem(qreal x, qreal y, qreal width, qreal height,
                                     QGraphicsItem *parent)

    Constructs a QGraphicsRectItem with a default rectangle defined
    by (\a x, \a y) and the given \a width and \a height.

    \a parent is passed to QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsRectItem::QGraphicsRectItem(qreal x, qreal y, qreal w, qreal h,
                                     QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsRectItemPrivate, parent, scene)
{
    setRect(QRectF(x, y, w, h));
}

/*!
    Constructs a QGraphicsRectItem. \a parent is passed to
    QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsRectItem::QGraphicsRectItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsRectItemPrivate, parent, scene)
{
}

/*!
    Destroys the QGraphicsRectItem.
*/
QGraphicsRectItem::~QGraphicsRectItem()
{
}

/*!
    Returns the item's rectangle.

    \sa setRect()
*/
QRectF QGraphicsRectItem::rect() const
{
    Q_D(const QGraphicsRectItem);
    return d->rect;
}

/*!
    \fn void QGraphicsRectItem::setRect(const QRectF &rectangle)

    Sets the item's rectangle to be the given \a rectangle.

    \sa rect()
*/
void QGraphicsRectItem::setRect(const QRectF &rect)
{
    Q_D(QGraphicsRectItem);
    if (d->rect == rect)
        return;
    prepareGeometryChange();
    d->rect = rect;
    d->boundingRect = QRectF();
    update();
}

/*!
    \fn void QGraphicsRectItem::setRect(qreal x, qreal y, qreal width, qreal height)
    \fn void QGraphicsEllipseItem::setRect(qreal x, qreal y, qreal width, qreal height)

    Sets the item's rectangle to the rectangle defined by (\a x, \a y)
    and the given \a width and \a height.

    This convenience function is equivalent to calling \c
    {setRect(QRectF(x, y, width, height))}

    \sa rect()
*/

/*!
    \reimp
*/
QRectF QGraphicsRectItem::boundingRect() const
{
    Q_D(const QGraphicsRectItem);
    if (d->boundingRect.isNull()) {
        qreal halfpw = pen().widthF() / 2;
        d->boundingRect = d->rect;
        if (halfpw > 0.0)
            d->boundingRect.adjust(-halfpw, -halfpw, halfpw, halfpw);
    }
    return d->boundingRect;
}

/*!
    \reimp
*/
QPainterPath QGraphicsRectItem::shape() const
{
    Q_D(const QGraphicsRectItem);
    QPainterPath path;
    path.addRect(d->rect);
    return qt_graphicsItem_shapeFromPath(path, d->pen);
}

/*!
    \reimp
*/
bool QGraphicsRectItem::contains(const QPointF &point) const
{
    return QAbstractGraphicsShapeItem::contains(point);
}

/*!
    \reimp
*/
void QGraphicsRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                              QWidget *widget)
{
    Q_D(QGraphicsRectItem);
    Q_UNUSED(widget);
    painter->setPen(d->pen);
    painter->setBrush(d->brush);
    painter->drawRect(d->rect);

    if (option->state & QStyle::State_Selected)
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsRectItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QAbstractGraphicsShapeItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsRectItem::opaqueArea() const
{
    return QAbstractGraphicsShapeItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsRectItem::type() const
{
    return Type;
}

/*!
    \internal
*/
bool QGraphicsRectItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsRectItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsRectItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \class QGraphicsEllipseItem
    \brief The QGraphicsEllipseItem class provides an ellipse item that you
    can add to a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    QGraphicsEllipseItem respresents an ellipse with a fill and an outline,
    and you can also use it for ellipse segments (see startAngle(),
    spanAngle()).

    \table
        \row
            \o \inlineimage graphicsview-ellipseitem.png
            \o \inlineimage graphicsview-ellipseitem-pie.png
    \endtable

    To set the item's ellipse, pass a QRectF to QGraphicsEllipseItem's
    constructor, or call setRect(). The rect() function returns the
    current ellipse geometry.

    QGraphicsEllipseItem uses the rect and the pen width to provide a
    reasonable implementation of boundingRect(), shape(), and contains(). The
    paint() function draws the ellipse using the item's associated pen and
    brush, which you can set by calling setPen() and setBrush().

    \sa QGraphicsPathItem, QGraphicsRectItem, QGraphicsPolygonItem,
    QGraphicsTextItem, QGraphicsLineItem, QGraphicsPixmapItem, {The Graphics
    View Framework}
*/

class QGraphicsEllipseItemPrivate : public QAbstractGraphicsShapeItemPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsEllipseItem)
public:
    inline QGraphicsEllipseItemPrivate()
        : startAngle(0), spanAngle(360 * 16)
    { }

    QRectF rect;
    int startAngle;
    int spanAngle;
};

/*!
    Constructs a QGraphicsEllipseItem using \a rect as the default rectangle.
    \a parent is passed to QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsEllipseItem::QGraphicsEllipseItem(const QRectF &rect, QGraphicsItem *parent
#ifndef Q_QDOC
                                           // obsolete argument
                                           , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsEllipseItemPrivate, parent, scene)
{
    setRect(rect);
}

/*!
    \fn QGraphicsEllipseItem::QGraphicsEllipseItem(qreal x, qreal y, qreal width, qreal height, QGraphicsItem *parent)
    \since 4.3

    Constructs a QGraphicsEllipseItem using the rectangle defined by (\a x, \a
    y) and the given \a width and \a height, as the default rectangle. \a
    parent is passed to QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsEllipseItem::QGraphicsEllipseItem(qreal x, qreal y, qreal w, qreal h,
                                           QGraphicsItem *parent
#ifndef Q_QDOC
                                           // obsolete argument
                                           , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsEllipseItemPrivate, parent, scene)
{
    setRect(x,y,w,h);
}



/*!
    Constructs a QGraphicsEllipseItem. \a parent is passed to
    QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsEllipseItem::QGraphicsEllipseItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                           // obsolete argument
                                           , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsEllipseItemPrivate, parent, scene)
{
}

/*!
    Destroys the QGraphicsEllipseItem.
*/
QGraphicsEllipseItem::~QGraphicsEllipseItem()
{
}

/*!
    Returns the item's ellipse geometry as a QRectF.

    \sa setRect(), QPainter::drawEllipse()
*/
QRectF QGraphicsEllipseItem::rect() const
{
    Q_D(const QGraphicsEllipseItem);
    return d->rect;
}

/*!
    Sets the item's ellipse geometry to \a rect. The rectangle's left edge
    defines the left edge of the ellipse, and the rectangle's top edge
    describes the top of the ellipse. The height and width of the rectangle
    describe the height and width of the ellipse.

    \sa rect(), QPainter::drawEllipse()
*/
void QGraphicsEllipseItem::setRect(const QRectF &rect)
{
    Q_D(QGraphicsEllipseItem);
    if (d->rect == rect)
        return;
    prepareGeometryChange();
    d->rect = rect;
    d->boundingRect = QRectF();
    update();
}

/*!
    Returns the start angle for an ellipse segment in 16ths of a degree. This
    angle is used together with spanAngle() for representing an ellipse
    segment (a pie). By default, the start angle is 0.

    \sa setStartAngle(), spanAngle()
*/
int QGraphicsEllipseItem::startAngle() const
{
    Q_D(const QGraphicsEllipseItem);
    return d->startAngle;
}

/*!
    Sets the start angle for an ellipse segment to \a angle, which is in 16ths
    of a degree. This angle is used together with spanAngle() for representing
    an ellipse segment (a pie). By default, the start angle is 0.

    \sa startAngle(), setSpanAngle(), QPainter::drawPie()
*/
void QGraphicsEllipseItem::setStartAngle(int angle)
{
    Q_D(QGraphicsEllipseItem);
    if (angle != d->startAngle) {
        prepareGeometryChange();
        d->boundingRect = QRectF();
        d->startAngle = angle;
        update();
    }
}

/*!
    Returns the span angle of an ellipse segment in 16ths of a degree. This
    angle is used together with startAngle() for representing an ellipse
    segment (a pie). By default, this function returns 5760 (360 * 16, a full
    ellipse).

    \sa setSpanAngle(), startAngle()
*/
int QGraphicsEllipseItem::spanAngle() const
{
    Q_D(const QGraphicsEllipseItem);
    return d->spanAngle;
}

/*!
    Sets the span angle for an ellipse segment to \a angle, which is in 16ths
    of a degree. This angle is used together with startAngle() to represent an
    ellipse segment (a pie). By default, the span angle is 5760 (360 * 16, a
    full ellipse).

    \sa spanAngle(), setStartAngle(), QPainter::drawPie()
*/
void QGraphicsEllipseItem::setSpanAngle(int angle)
{
    Q_D(QGraphicsEllipseItem);
    if (angle != d->spanAngle) {
        prepareGeometryChange();
        d->boundingRect = QRectF();
        d->spanAngle = angle;
        update();
    }
}

/*!
    \reimp
*/
QRectF QGraphicsEllipseItem::boundingRect() const
{
    Q_D(const QGraphicsEllipseItem);
    if (d->boundingRect.isNull()) {
        qreal pw = pen().widthF();
        if (pw == 0.0 && d->spanAngle == 360 * 16)
            d->boundingRect = d->rect;
        else
            d->boundingRect = shape().controlPointRect();
    }
    return d->boundingRect;
}

/*!
    \reimp
*/
QPainterPath QGraphicsEllipseItem::shape() const
{
    Q_D(const QGraphicsEllipseItem);
    QPainterPath path;
    if (d->rect.isNull())
        return path;
    if (d->spanAngle != 360 * 16) {
        path.moveTo(d->rect.center());
        path.arcTo(d->rect, d->startAngle / 16.0, d->spanAngle / 16.0);
    } else {
        path.addEllipse(d->rect);
    }

    return qt_graphicsItem_shapeFromPath(path, d->pen);
}

/*!
    \reimp
*/
bool QGraphicsEllipseItem::contains(const QPointF &point) const
{
    return QAbstractGraphicsShapeItem::contains(point);
}

/*!
    \reimp
*/
void QGraphicsEllipseItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                                 QWidget *widget)
{
    Q_D(QGraphicsEllipseItem);
    Q_UNUSED(widget);
    painter->setPen(d->pen);
    painter->setBrush(d->brush);
    if ((d->spanAngle != 0) && (qAbs(d->spanAngle) % (360 * 16) == 0))
        painter->drawEllipse(d->rect);
    else
        painter->drawPie(d->rect, d->startAngle, d->spanAngle);

    if (option->state & QStyle::State_Selected)
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsEllipseItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QAbstractGraphicsShapeItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsEllipseItem::opaqueArea() const
{
    return QAbstractGraphicsShapeItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsEllipseItem::type() const
{
    return Type;
}


/*!
    \internal
*/
bool QGraphicsEllipseItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsEllipseItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsEllipseItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \class QGraphicsPolygonItem
    \brief The QGraphicsPolygonItem class provides a polygon item that you
    can add to a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    To set the item's polygon, pass a QPolygonF to
    QGraphicsPolygonItem's constructor, or call the setPolygon()
    function. The polygon() function returns the current polygon.

    \image graphicsview-polygonitem.png

    QGraphicsPolygonItem uses the polygon and the pen width to provide
    a reasonable implementation of boundingRect(), shape(), and
    contains(). The paint() function draws the polygon using the
    item's associated pen and brush, which you can set by calling the
    setPen() and setBrush() functions.

    \sa QGraphicsPathItem, QGraphicsRectItem, QGraphicsEllipseItem,
    QGraphicsTextItem, QGraphicsLineItem, QGraphicsPixmapItem, {The Graphics
    View Framework}
*/

class QGraphicsPolygonItemPrivate : public QAbstractGraphicsShapeItemPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsPolygonItem)
public:
    inline QGraphicsPolygonItemPrivate()
        : fillRule(Qt::OddEvenFill)
    { }

    QPolygonF polygon;
    Qt::FillRule fillRule;
};

/*!
    Constructs a QGraphicsPolygonItem with \a polygon as the default
    polygon. \a parent is passed to QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsPolygonItem::QGraphicsPolygonItem(const QPolygonF &polygon,
                                           QGraphicsItem *parent
#ifndef Q_QDOC
                                           // obsolete argument
                                           , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsPolygonItemPrivate, parent, scene)
{
    setPolygon(polygon);
}

/*!
    Constructs a QGraphicsPolygonItem. \a parent is passed to
    QAbstractGraphicsShapeItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsPolygonItem::QGraphicsPolygonItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                           // obsolete argument
                                           , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsPolygonItemPrivate, parent, scene)
{
}

/*!
    Destroys the QGraphicsPolygonItem.
*/
QGraphicsPolygonItem::~QGraphicsPolygonItem()
{
}

/*!
    Returns the item's polygon, or an empty polygon if no polygon
    has been set.

    \sa setPolygon()
*/
QPolygonF QGraphicsPolygonItem::polygon() const
{
    Q_D(const QGraphicsPolygonItem);
    return d->polygon;
}

/*!
    Sets the item's polygon to be the given \a polygon.

    \sa polygon()
*/
void QGraphicsPolygonItem::setPolygon(const QPolygonF &polygon)
{
    Q_D(QGraphicsPolygonItem);
    if (d->polygon == polygon)
        return;
    prepareGeometryChange();
    d->polygon = polygon;
    d->boundingRect = QRectF();
    update();
}

/*!
     Returns the fill rule of the polygon. The default fill rule is
     Qt::OddEvenFill.

     \sa setFillRule(), QPainterPath::fillRule(), QPainter::drawPolygon()
*/
Qt::FillRule QGraphicsPolygonItem::fillRule() const
{
     Q_D(const QGraphicsPolygonItem);
     return d->fillRule;
}

/*!
     Sets the fill rule of the polygon to \a rule. The default fill rule is
     Qt::OddEvenFill.

     \sa fillRule(), QPainterPath::fillRule(), QPainter::drawPolygon()
*/
void QGraphicsPolygonItem::setFillRule(Qt::FillRule rule)
{
     Q_D(QGraphicsPolygonItem);
     if (rule != d->fillRule) {
         d->fillRule = rule;
         update();
     }
}

/*!
    \reimp
*/
QRectF QGraphicsPolygonItem::boundingRect() const
{
    Q_D(const QGraphicsPolygonItem);
    if (d->boundingRect.isNull()) {
        qreal pw = pen().widthF();
        if (pw == 0.0)
            d->boundingRect = d->polygon.boundingRect();
        else
            d->boundingRect = shape().controlPointRect();
    }
    return d->boundingRect;
}

/*!
    \reimp
*/
QPainterPath QGraphicsPolygonItem::shape() const
{
    Q_D(const QGraphicsPolygonItem);
    QPainterPath path;
    path.addPolygon(d->polygon);
    return qt_graphicsItem_shapeFromPath(path, d->pen);
}

/*!
    \reimp
*/
bool QGraphicsPolygonItem::contains(const QPointF &point) const
{
    return QAbstractGraphicsShapeItem::contains(point);
}

/*!
    \reimp
*/
void QGraphicsPolygonItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_D(QGraphicsPolygonItem);
    Q_UNUSED(widget);
    painter->setPen(d->pen);
    painter->setBrush(d->brush);
    painter->drawPolygon(d->polygon, d->fillRule);

    if (option->state & QStyle::State_Selected)
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsPolygonItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QAbstractGraphicsShapeItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsPolygonItem::opaqueArea() const
{
    return QAbstractGraphicsShapeItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsPolygonItem::type() const
{
    return Type;
}

/*!
    \internal
*/
bool QGraphicsPolygonItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsPolygonItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsPolygonItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \class QGraphicsLineItem
    \brief The QGraphicsLineItem class provides a line item that you can add to a
    QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    To set the item's line, pass a QLineF to QGraphicsLineItem's
    constructor, or call the setLine() function. The line() function
    returns the current line. By default the line is black with a
    width of 0, but you can change this by calling setPen().

    \img graphicsview-lineitem.png

    QGraphicsLineItem uses the line and the pen width to provide a reasonable
    implementation of boundingRect(), shape(), and contains(). The paint()
    function draws the line using the item's associated pen.

    \sa QGraphicsPathItem, QGraphicsRectItem, QGraphicsEllipseItem,
    QGraphicsTextItem, QGraphicsPolygonItem, QGraphicsPixmapItem, {The
    Graphics View Framework}
*/

class QGraphicsLineItemPrivate : public QGraphicsItemPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsLineItem)
public:
    QLineF line;
    QPen pen;
};

/*!
    Constructs a QGraphicsLineItem, using \a line as the default line. \a
    parent is passed to QGraphicsItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsLineItem::QGraphicsLineItem(const QLineF &line, QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(*new QGraphicsLineItemPrivate, parent, scene)
{
    setLine(line);
}

/*!
    Constructs a QGraphicsLineItem, using the line between (\a x1, \a y1) and
    (\a x2, \a y2) as the default line.  \a parent is passed to
    QGraphicsItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsLineItem::QGraphicsLineItem(qreal x1, qreal y1, qreal x2, qreal y2, QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(*new QGraphicsLineItemPrivate, parent, scene)
{
    setLine(x1, y1, x2, y2);
}



/*!
    Constructs a QGraphicsLineItem. \a parent is passed to QGraphicsItem's
    constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsLineItem::QGraphicsLineItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(*new QGraphicsLineItemPrivate, parent, scene)
{
}

/*!
    Destroys the QGraphicsLineItem.
*/
QGraphicsLineItem::~QGraphicsLineItem()
{
}

/*!
    Returns the item's pen, or a black solid 0-width pen if no pen has
    been set.

    \sa setPen()
*/
QPen QGraphicsLineItem::pen() const
{
    Q_D(const QGraphicsLineItem);
    return d->pen;
}

/*!
    Sets the item's pen to \a pen. If no pen is set, the line will be painted
    using a black solid 0-width pen.

    \sa pen()
*/
void QGraphicsLineItem::setPen(const QPen &pen)
{
    Q_D(QGraphicsLineItem);
    prepareGeometryChange();
    d->pen = pen;
    update();
}

/*!
    Returns the item's line, or a null line if no line has been set.

    \sa setLine()
*/
QLineF QGraphicsLineItem::line() const
{
    Q_D(const QGraphicsLineItem);
    return d->line;
}

/*!
    Sets the item's line to be the given \a line.

    \sa line()
*/
void QGraphicsLineItem::setLine(const QLineF &line)
{
    Q_D(QGraphicsLineItem);
    if (d->line == line)
        return;
    prepareGeometryChange();
    d->line = line;
    update();
}

/*!
    \fn void QGraphicsLineItem::setLine(qreal x1, qreal y1, qreal x2, qreal y2)
    \overload

    Sets the item's line to be the line between (\a x1, \a y1) and (\a
    x2, \a y2).

    This is the same as calling \c {setLine(QLineF(x1, y1, x2, y2))}.
*/

/*!
    \reimp
*/
QRectF QGraphicsLineItem::boundingRect() const
{
    Q_D(const QGraphicsLineItem);
    if (d->pen.widthF() == 0.0) {
        const qreal x1 = d->line.p1().x();
        const qreal x2 = d->line.p2().x();
        const qreal y1 = d->line.p1().y();
        const qreal y2 = d->line.p2().y();
        qreal lx = qMin(x1, x2);
        qreal rx = qMax(x1, x2);
        qreal ty = qMin(y1, y2);
        qreal by = qMax(y1, y2);
        return QRectF(lx, ty, rx - lx, by - ty);
    }
    return shape().controlPointRect();
}

/*!
    \reimp
*/
QPainterPath QGraphicsLineItem::shape() const
{
    Q_D(const QGraphicsLineItem);
    QPainterPath path;
    if (d->line == QLineF())
        return path;

    path.moveTo(d->line.p1());
    path.lineTo(d->line.p2());
    return qt_graphicsItem_shapeFromPath(path, d->pen);
}

/*!
    \reimp
*/
bool QGraphicsLineItem::contains(const QPointF &point) const
{
    return QGraphicsItem::contains(point);
}

/*!
    \reimp
*/
void QGraphicsLineItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_D(QGraphicsLineItem);
    Q_UNUSED(widget);
    painter->setPen(d->pen);
    painter->drawLine(d->line);

    if (option->state & QStyle::State_Selected)
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsLineItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QGraphicsItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsLineItem::opaqueArea() const
{
    return QGraphicsItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsLineItem::type() const
{
    return Type;
}

/*!
    \internal
*/
bool QGraphicsLineItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsLineItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsLineItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \class QGraphicsPixmapItem
    \brief The QGraphicsPixmapItem class provides a pixmap item that you can add to
    a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    To set the item's pixmap, pass a QPixmap to QGraphicsPixmapItem's
    constructor, or call the setPixmap() function. The pixmap()
    function returns the current pixmap.

    QGraphicsPixmapItem uses pixmap's optional alpha mask to provide a
    reasonable implementation of boundingRect(), shape(), and contains().

    \image graphicsview-pixmapitem.png

    The pixmap is drawn at the item's (0, 0) coordinate, as returned by
    offset(). You can change the drawing offset by calling setOffset().

    You can set the pixmap's transformation mode by calling
    setTransformationMode(). By default, Qt::FastTransformation is used, which
    provides fast, non-smooth scaling. Qt::SmoothTransformation enables
    QPainter::SmoothPixmapTransform on the painter, and the quality depends on
    the platform and viewport. The result is usually not as good as calling
    QPixmap::scale() directly. Call transformationMode() to get the current
    transformation mode for the item.

    \sa QGraphicsPathItem, QGraphicsRectItem, QGraphicsEllipseItem,
    QGraphicsTextItem, QGraphicsPolygonItem, QGraphicsLineItem, {The
    Graphics View Framework}
*/

/*!
    \enum QGraphicsPixmapItem::ShapeMode

    This enum describes how QGraphicsPixmapItem calculates its shape and
    opaque area.

    The default value is MaskShape.

    \value MaskShape The shape is determined by calling QPixmap::mask().
    This shape includes only the opaque pixels of the pixmap.
    Because the shape is more complex, however, it can be slower than the other modes,
    and uses more memory.

    \value BoundingRectShape The shape is determined by tracing the outline of
    the pixmap. This is the fastest shape mode, but it does not take into account
    any transparent areas on the pixmap.

    \value HeuristicMaskShape The shape is determine by calling
    QPixmap::createHeuristicMask().  The performance and memory consumption
    is similar to MaskShape.
*/
extern QPainterPath qt_regionToPath(const QRegion &region);

class QGraphicsPixmapItemPrivate : public QGraphicsItemPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsPixmapItem)
public:
    QGraphicsPixmapItemPrivate()
        : transformationMode(Qt::FastTransformation),
        shapeMode(QGraphicsPixmapItem::MaskShape),
        hasShape(false)
    {}

    QPixmap pixmap;
    Qt::TransformationMode transformationMode;
    QPointF offset;
    QGraphicsPixmapItem::ShapeMode shapeMode;
    QPainterPath shape;
    bool hasShape;

    void updateShape()
    {
        shape = QPainterPath();
        switch (shapeMode) {
        case QGraphicsPixmapItem::MaskShape: {
            QBitmap mask = pixmap.mask();
            if (!mask.isNull()) {
                shape = qt_regionToPath(QRegion(mask).translated(offset.toPoint()));
                break;
            }
            // FALL THROUGH
        }
        case QGraphicsPixmapItem::BoundingRectShape:
            shape.addRect(QRectF(offset.x(), offset.y(), pixmap.width(), pixmap.height()));
            break;
        case QGraphicsPixmapItem::HeuristicMaskShape:
#ifndef QT_NO_IMAGE_HEURISTIC_MASK
            shape = qt_regionToPath(QRegion(pixmap.createHeuristicMask()).translated(offset.toPoint()));
#else
            shape.addRect(QRectF(offset.x(), offset.y(), pixmap.width(), pixmap.height()));
#endif
            break;
        }
    }
};

/*!
    Constructs a QGraphicsPixmapItem, using \a pixmap as the default pixmap.
    \a parent is passed to QGraphicsItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsPixmapItem::QGraphicsPixmapItem(const QPixmap &pixmap,
                                         QGraphicsItem *parent
#ifndef Q_QDOC
                                         // obsolete argument
                                         , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(*new QGraphicsPixmapItemPrivate, parent, scene)
{
    setPixmap(pixmap);
}

/*!
    Constructs a QGraphicsPixmapItem. \a parent is passed to QGraphicsItem's
    constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsPixmapItem::QGraphicsPixmapItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                         // obsolete argument
                                         , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(*new QGraphicsPixmapItemPrivate, parent, scene)
{
}

/*!
    Destroys the QGraphicsPixmapItem.
*/
QGraphicsPixmapItem::~QGraphicsPixmapItem()
{
}

/*!
    Sets the item's pixmap to \a pixmap.

    \sa pixmap()
*/
void QGraphicsPixmapItem::setPixmap(const QPixmap &pixmap)
{
    Q_D(QGraphicsPixmapItem);
    prepareGeometryChange();
    d->pixmap = pixmap;
    d->hasShape = false;
    update();
}

/*!
    Returns the item's pixmap, or an invalid QPixmap if no pixmap has been
    set.

    \sa setPixmap()
*/
QPixmap QGraphicsPixmapItem::pixmap() const
{
    Q_D(const QGraphicsPixmapItem);
    return d->pixmap;
}

/*!
    Returns the transformation mode of the pixmap. The default mode is
    Qt::FastTransformation, which provides quick transformation with no
    smoothing.

    \sa setTransformationMode()
*/
Qt::TransformationMode QGraphicsPixmapItem::transformationMode() const
{
    Q_D(const QGraphicsPixmapItem);
    return d->transformationMode;
}

/*!
    Sets the pixmap item's transformation mode to \a mode, and toggles an
    update of the item. The default mode is Qt::FastTransformation, which
    provides quick transformation with no smoothing.

    Qt::SmoothTransformation enables QPainter::SmoothPixmapTransform on the
    painter, and the quality depends on the platform and viewport. The result
    is usually not as good as calling QPixmap::scale() directly.

    \sa transformationMode()
*/
void QGraphicsPixmapItem::setTransformationMode(Qt::TransformationMode mode)
{
    Q_D(QGraphicsPixmapItem);
    if (mode != d->transformationMode) {
        d_ptr->updateHelper();
        d->transformationMode = mode;
        update();
    }
}

/*!
    Returns the pixmap item's \e offset, which defines the point of the
    top-left corner of the pixmap, in local coordinates.

    \sa setOffset()
*/
QPointF QGraphicsPixmapItem::offset() const
{
    Q_D(const QGraphicsPixmapItem);
    return d->offset;
}

/*!
    Sets the pixmap item's offset to \a offset. QGraphicsPixmapItem will draw
    its pixmap using \a offset for its top-left corner.

    \sa offset()
*/
void QGraphicsPixmapItem::setOffset(const QPointF &offset)
{
    Q_D(QGraphicsPixmapItem);
    if (d->offset == offset)
        return;
    prepareGeometryChange();
    d->offset = offset;
    d->hasShape = false;
    update();
}

/*!
    \fn void QGraphicsPixmapItem::setOffset(qreal x, qreal y)
    \since 4.3

    This convenience function is equivalent to calling setOffset(QPointF(\a x, \a y)).
*/

/*!
    \reimp
*/
QRectF QGraphicsPixmapItem::boundingRect() const
{
    Q_D(const QGraphicsPixmapItem);
    qreal pw = 1.0;
    if (d->pixmap.isNull())
        return QRectF();
    return QRectF(d->offset, d->pixmap.size()).adjusted(-pw/2, -pw/2, pw/2, pw/2);
}

/*!
    \reimp
*/
QPainterPath QGraphicsPixmapItem::shape() const
{
    Q_D(const QGraphicsPixmapItem);
    if (!d->hasShape) {
        QGraphicsPixmapItemPrivate *thatD = const_cast<QGraphicsPixmapItemPrivate *>(d);
        thatD->updateShape();
        thatD->hasShape = true;
    }
    return d_func()->shape;
}

/*!
    \reimp
*/
bool QGraphicsPixmapItem::contains(const QPointF &point) const
{
    return QGraphicsItem::contains(point);
}

/*!
    \reimp
*/
void QGraphicsPixmapItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                                QWidget *widget)
{
    Q_D(QGraphicsPixmapItem);
    Q_UNUSED(widget);

    painter->setRenderHint(QPainter::SmoothPixmapTransform,
                           (d->transformationMode == Qt::SmoothTransformation));

    QRectF exposed = option->exposedRect.adjusted(-1, -1, 1, 1);
    exposed &= QRectF(d->offset.x(), d->offset.y(), d->pixmap.width(), d->pixmap.height());
    painter->drawPixmap(exposed, d->pixmap, exposed.translated(-d->offset));

    if (option->state & QStyle::State_Selected)
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsPixmapItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QGraphicsItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsPixmapItem::opaqueArea() const
{
    return shape();
}

/*!
    \reimp
*/
int QGraphicsPixmapItem::type() const
{
    return Type;
}

/*!
    Returns the item's shape mode. The shape mode describes how
    QGraphicsPixmapItem calculates its shape. The default mode is MaskShape.

    \sa setShapeMode(), ShapeMode
*/
QGraphicsPixmapItem::ShapeMode QGraphicsPixmapItem::shapeMode() const
{
    return d_func()->shapeMode;
}

/*!
    Sets the item's shape mode to \a mode. The shape mode describes how
    QGraphicsPixmapItem calculates its shape. The default mode is MaskShape.

    \sa shapeMode(), ShapeMode
*/
void QGraphicsPixmapItem::setShapeMode(ShapeMode mode)
{
    Q_D(QGraphicsPixmapItem);
    if (d->shapeMode == mode)
        return;
    d->shapeMode = mode;
    d->hasShape = false;
}

/*!
    \internal
*/
bool QGraphicsPixmapItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsPixmapItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsPixmapItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \class QGraphicsTextItem
    \brief The QGraphicsTextItem class provides a text item that you can add to
    a QGraphicsScene to display formatted text.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    If you only need to show plain text in an item, consider using QGraphicsSimpleTextItem
    instead.

    To set the item's text, pass a QString to QGraphicsTextItem's
    constructor, or call setHtml()/setPlainText().

    QGraphicsTextItem uses the text's formatted size and the associated font
    to provide a reasonable implementation of boundingRect(), shape(),
    and contains(). You can set the font by calling setFont().

    It is possible to make the item editable by setting the Qt::TextEditorInteraction flag
    using setTextInteractionFlags().

    The item's preferred text width can be set using setTextWidth() and obtained
    using textWidth().

    \note In order to align HTML text in the center, the item's text width must be set.

    \img graphicsview-textitem.png

    \note QGraphicsTextItem accepts \l{QGraphicsItem::acceptHoverEvents()}{hover events}
          by default. You can change this with \l{QGraphicsItem::}{setAcceptHoverEvents()}.

    \sa QGraphicsSimpleTextItem, QGraphicsPathItem, QGraphicsRectItem,
        QGraphicsEllipseItem, QGraphicsPixmapItem, QGraphicsPolygonItem,
        QGraphicsLineItem, {The Graphics View Framework}
*/

class QGraphicsTextItemPrivate
{
public:
    QGraphicsTextItemPrivate()
        : control(0), pageNumber(0), useDefaultImpl(false), tabChangesFocus(false)
    { }

    mutable QTextControl *control;
    QTextControl *textControl() const;

    inline QPointF controlOffset() const
    { return QPointF(0., pageNumber * control->document()->pageSize().height()); }
    inline void sendControlEvent(QEvent *e)
    { if (control) control->processEvent(e, controlOffset()); }

    void _q_updateBoundingRect(const QSizeF &);
    void _q_update(QRectF);
    void _q_ensureVisible(QRectF);
    bool _q_mouseOnEdge(QGraphicsSceneMouseEvent *);

    QRectF boundingRect;
    int pageNumber;
    bool useDefaultImpl;
    bool tabChangesFocus;

    QGraphicsTextItem *qq;
};

/*!
    Constructs a QGraphicsTextItem, using \a text as the default plain
    text. \a parent is passed to QGraphicsItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsTextItem::QGraphicsTextItem(const QString &text, QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(parent, scene), dd(new QGraphicsTextItemPrivate)
{
    dd->qq = this;
    if (!text.isEmpty())
        setPlainText(text);
    setAcceptDrops(true);
    setAcceptHoverEvents(true);
}

/*!
    Constructs a QGraphicsTextItem. \a parent is passed to QGraphicsItem's
    constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsTextItem::QGraphicsTextItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                     // obsolete argument
                                     , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(parent, scene), dd(new QGraphicsTextItemPrivate)
{
    dd->qq = this;
    setAcceptDrops(true);
    setAcceptHoverEvents(true);
}

/*!
    Destroys the QGraphicsTextItem.
*/
QGraphicsTextItem::~QGraphicsTextItem()
{
    delete dd;
}

/*!
    Returns the item's text converted to HTML, or an empty QString if no text has been set.

    \sa setHtml()
*/
QString QGraphicsTextItem::toHtml() const
{
#ifndef QT_NO_TEXTHTMLPARSER
    if (dd->control)
        return dd->control->toHtml();
#endif
    return QString();
}

/*!
    Sets the item's text to \a text, assuming that text is HTML formatted. If
    the item has keyboard input focus, this function will also call
    ensureVisible() to ensure that the text is visible in all viewports.

    \sa toHtml(), hasFocus(), QGraphicsSimpleTextItem
*/
void QGraphicsTextItem::setHtml(const QString &text)
{
    dd->textControl()->setHtml(text);
}

/*!
    Returns the item's text converted to plain text, or an empty QString if no text has been set.

    \sa setPlainText()
*/
QString QGraphicsTextItem::toPlainText() const
{
    if (dd->control)
        return dd->control->toPlainText();
    return QString();
}

/*!
    Sets the item's text to \a text. If the item has keyboard input focus,
    this function will also call ensureVisible() to ensure that the text is
    visible in all viewports.

    \sa toHtml(), hasFocus()
*/
void QGraphicsTextItem::setPlainText(const QString &text)
{
    dd->textControl()->setPlainText(text);
}

/*!
    Returns the item's font, which is used to render the text.

    \sa setFont()
*/
QFont QGraphicsTextItem::font() const
{
    if (!dd->control)
        return QFont();
    return dd->control->document()->defaultFont();
}

/*!
    Sets the font used to render the text item to \a font.

    \sa font()
*/
void QGraphicsTextItem::setFont(const QFont &font)
{
    dd->textControl()->document()->setDefaultFont(font);
}

/*!
    Sets the color for unformatted text to \a col.
*/
void QGraphicsTextItem::setDefaultTextColor(const QColor &col)
{
    QTextControl *c = dd->textControl();
    QPalette pal = c->palette();
    pal.setColor(QPalette::Text, col);
    c->setPalette(pal);
}

/*!
    Returns the default text color that is used to for unformatted text.
*/
QColor QGraphicsTextItem::defaultTextColor() const
{
    return dd->textControl()->palette().color(QPalette::Text);
}

/*!
    \reimp
*/
QRectF QGraphicsTextItem::boundingRect() const
{
    return dd->boundingRect;
}

/*!
    \reimp
*/
QPainterPath QGraphicsTextItem::shape() const
{
    if (!dd->control)
        return QPainterPath();
    QPainterPath path;
    path.addRect(dd->boundingRect);
    return path;
}

/*!
    \reimp
*/
bool QGraphicsTextItem::contains(const QPointF &point) const
{
    return dd->boundingRect.contains(point);
}

/*!
    \reimp
*/
void QGraphicsTextItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                              QWidget *widget)
{
    Q_UNUSED(widget);
    if (dd->control) {
        painter->save();
        QRectF r = option->exposedRect;
        painter->translate(-dd->controlOffset());
        r.translate(dd->controlOffset());

        QTextDocument *doc = dd->control->document();
        QTextDocumentLayout *layout = qobject_cast<QTextDocumentLayout *>(doc->documentLayout());

        // the layout might need to expand the root frame to
        // the viewport if NoWrap is set
        if (layout)
            layout->setViewport(dd->boundingRect);

        dd->control->drawContents(painter, r);

        if (layout)
            layout->setViewport(QRect());

        painter->restore();
    }

    if (option->state & (QStyle::State_Selected | QStyle::State_HasFocus))
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsTextItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QGraphicsItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsTextItem::opaqueArea() const
{
    return QGraphicsItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsTextItem::type() const
{
    return Type;
}

/*!
    Sets the preferred width for the item's text. If the actual text
    is wider than the specified width then it will be broken into
    multiple lines.

    If \a width is set to -1 then the text will not be broken into
    multiple lines unless it is enforced through an explicit line
    break or a new paragraph.

    The default value is -1.

    Note that QGraphicsTextItem keeps a QTextDocument internally,
    which is used to calculate the text width.

    \sa textWidth(), QTextDocument::setTextWidth()
*/
void QGraphicsTextItem::setTextWidth(qreal width)
{
    dd->textControl()->setTextWidth(width);
}

/*!
    Returns the text width.

    The width is calculated with the QTextDocument that
    QGraphicsTextItem keeps internally.

    \sa setTextWidth(), QTextDocument::textWidth()
*/
qreal QGraphicsTextItem::textWidth() const
{
    if (!dd->control)
        return -1;
    return dd->control->textWidth();
}

/*!
    Adjusts the text item to a reasonable size.
*/
void QGraphicsTextItem::adjustSize()
{
    if (dd->control)
        dd->control->adjustSize();
}

/*!
    Sets the text document \a document on the item.
*/
void QGraphicsTextItem::setDocument(QTextDocument *document)
{
    dd->textControl()->setDocument(document);
    dd->_q_updateBoundingRect(dd->control->size());
}

/*!
    Returns the item's text document.
*/
QTextDocument *QGraphicsTextItem::document() const
{
    return dd->textControl()->document();
}

/*!
    \reimp
*/
bool QGraphicsTextItem::sceneEvent(QEvent *event)
{
    QEvent::Type t = event->type();
    if (!dd->tabChangesFocus && (t == QEvent::KeyPress || t == QEvent::KeyRelease)) {
        int k = ((QKeyEvent *)event)->key();
        if (k == Qt::Key_Tab || k == Qt::Key_Backtab) {
            dd->sendControlEvent(event);
            return true;
        }
    }
    return QGraphicsItem::sceneEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if ((QGraphicsItem::d_ptr->flags & (ItemIsSelectable | ItemIsMovable))
	&& (event->buttons() & Qt::LeftButton) && dd->_q_mouseOnEdge(event)) {
	// User left-pressed on edge of selectable/movable item, use
	// base impl.
	dd->useDefaultImpl = true;
    } else if (event->buttons() == event->button()
	       && dd->control->textInteractionFlags() == Qt::NoTextInteraction) {
	// User pressed first button on non-interactive item.
	dd->useDefaultImpl = true;
    }
    if (dd->useDefaultImpl) {
        QGraphicsItem::mousePressEvent(event);
	if (!event->isAccepted())
	    dd->useDefaultImpl = false;
        return;
    }
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    if (dd->useDefaultImpl) {
        QGraphicsItem::mouseMoveEvent(event);
        return;
    }
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    if (dd->useDefaultImpl) {
        QGraphicsItem::mouseReleaseEvent(event);
	if (dd->control->textInteractionFlags() == Qt::NoTextInteraction
	    && !event->buttons()) {
	    // User released last button on non-interactive item.
            dd->useDefaultImpl = false;
	} else  if ((event->buttons() & Qt::LeftButton) == 0) {
	    // User released the left button on an interactive item.
            dd->useDefaultImpl = false;
	}
        return;
    }
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
{
    if (dd->useDefaultImpl) {
        QGraphicsItem::mouseDoubleClickEvent(event);
        return;
    }

    if (!hasFocus()) {
        QGraphicsItem::mouseDoubleClickEvent(event);
        return;
    }

    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::keyPressEvent(QKeyEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::keyReleaseEvent(QKeyEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::focusInEvent(QFocusEvent *event)
{
    dd->sendControlEvent(event);
    update();
}

/*!
    \reimp
*/
void QGraphicsTextItem::focusOutEvent(QFocusEvent *event)
{
    dd->sendControlEvent(event);
    update();
}

/*!
    \reimp
*/
void QGraphicsTextItem::dragEnterEvent(QGraphicsSceneDragDropEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::dragLeaveEvent(QGraphicsSceneDragDropEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::dragMoveEvent(QGraphicsSceneDragDropEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::dropEvent(QGraphicsSceneDragDropEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::inputMethodEvent(QInputMethodEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::hoverEnterEvent(QGraphicsSceneHoverEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::hoverMoveEvent(QGraphicsSceneHoverEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
void QGraphicsTextItem::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
{
    dd->sendControlEvent(event);
}

/*!
    \reimp
*/
QVariant QGraphicsTextItem::inputMethodQuery(Qt::InputMethodQuery query) const
{
    QVariant v;
    if (dd->control)
        v = dd->control->inputMethodQuery(query);
    if (v.type() == QVariant::RectF)
        v = v.toRectF().translated(-dd->controlOffset());
    else if (v.type() == QVariant::PointF)
        v = v.toPointF() - dd->controlOffset();
    else if (v.type() == QVariant::Rect)
        v = v.toRect().translated(-dd->controlOffset().toPoint());
    else if (v.type() == QVariant::Point)
        v = v.toPoint() - dd->controlOffset().toPoint();
    return v;
}

/*!
    \internal
*/
bool QGraphicsTextItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsTextItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsTextItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \internal
*/
void QGraphicsTextItemPrivate::_q_update(QRectF rect)
{
    if (rect.isValid()) {
        rect.translate(-controlOffset());
    } else {
        rect = boundingRect;
    }
    if (rect.intersects(boundingRect))
        qq->update(rect);
}

/*!
    \internal
*/
void QGraphicsTextItemPrivate::_q_updateBoundingRect(const QSizeF &size)
{
    if (!control) return; // can't happen
    const QSizeF pageSize = control->document()->pageSize();
    // paged items have a constant (page) size
    if (size == boundingRect.size() || pageSize.height() != -1)
        return;
    qq->prepareGeometryChange();
    boundingRect.setSize(size);
    qq->update();
}

/*!
    \internal
*/
void QGraphicsTextItemPrivate::_q_ensureVisible(QRectF rect)
{
    if (qq->hasFocus()) {
        rect.translate(-controlOffset());
        qq->ensureVisible(rect, /*xmargin=*/0, /*ymargin=*/0);
    }
}

QTextControl *QGraphicsTextItemPrivate::textControl() const
{
    if (!control) {
        QGraphicsTextItem *that = const_cast<QGraphicsTextItem *>(qq);
        control = new QTextControl(that);
        control->setTextInteractionFlags(Qt::NoTextInteraction);

        QObject::connect(control, SIGNAL(updateRequest(QRectF)),
                         qq, SLOT(_q_update(QRectF)));
        QObject::connect(control, SIGNAL(documentSizeChanged(QSizeF)),
                         qq, SLOT(_q_updateBoundingRect(QSizeF)));
        QObject::connect(control, SIGNAL(visibilityRequest(QRectF)),
                         qq, SLOT(_q_ensureVisible(QRectF)));
        QObject::connect(control, SIGNAL(linkActivated(QString)),
                         qq, SIGNAL(linkActivated(QString)));
        QObject::connect(control, SIGNAL(linkHovered(QString)),
                         qq, SIGNAL(linkHovered(QString)));

        const QSizeF pgSize = control->document()->pageSize();
        if (pgSize.height() != -1) {
            qq->prepareGeometryChange();
            that->dd->boundingRect.setSize(pgSize);
            qq->update();
        } else {
            that->dd->_q_updateBoundingRect(control->size());
        }
    }
    return control;
}

/*!
    \internal
*/
bool QGraphicsTextItemPrivate::_q_mouseOnEdge(QGraphicsSceneMouseEvent *event)
{
    QPainterPath path;
    path.addRect(qq->boundingRect());

    QPainterPath docPath;
    const QTextFrameFormat format = control->document()->rootFrame()->frameFormat();
    docPath.addRect(
        qq->boundingRect().adjusted(
            format.leftMargin(),
            format.topMargin(),
            -format.rightMargin(),
            -format.bottomMargin()));

    return path.subtracted(docPath).contains(event->pos());
}

/*!
    \fn QGraphicsTextItem::linkActivated(const QString &link)

    This signal is emitted when the user clicks on a link on a text item
    that enables Qt::LinksAccessibleByMouse or Qt::LinksAccessibleByKeyboard.
    \a link is the link that was clicked.

    \sa setTextInteractionFlags()
*/

/*!
    \fn QGraphicsTextItem::linkHovered(const QString &link)

    This signal is emitted when the user hovers over a link on a text item
    that enables Qt::LinksAccessibleByMouse. \a link is
    the link that was hovered over.

    \sa setTextInteractionFlags()
*/

/*!
    Sets the flags \a flags to specify how the text item should react to user
    input.

    The default for a QGraphicsTextItem is Qt::NoTextInteraction. Setting a
    value different to Qt::NoTextInteraction will also set the ItemIsFocusable
    QGraphicsItem flag.

    By default, the text is read-only. To transform the item into an editor,
    set the Qt::TextEditable flag.
*/
void QGraphicsTextItem::setTextInteractionFlags(Qt::TextInteractionFlags flags)
{
    if (flags == Qt::NoTextInteraction)
        setFlags(this->flags() & ~QGraphicsItem::ItemIsFocusable);
    else
        setFlags(this->flags() | QGraphicsItem::ItemIsFocusable);
    dd->textControl()->setTextInteractionFlags(flags);
}

/*!
    Returns the current text interaction flags.

    \sa setTextInteractionFlags()
*/
Qt::TextInteractionFlags QGraphicsTextItem::textInteractionFlags() const
{
    if (!dd->control)
        return Qt::NoTextInteraction;
    return dd->control->textInteractionFlags();
}

/*!
    \since 4.5

    If \a b is true, the \gui Tab key will cause the widget to change focus;
    otherwise, the tab key will insert a tab into the document.

    In some occasions text edits should not allow the user to input tabulators
    or change indentation using the \gui Tab key, as this breaks the focus
    chain. The default is false.

    \sa tabChangesFocus(), ItemIsFocusable, textInteractionFlags()
*/
void QGraphicsTextItem::setTabChangesFocus(bool b)
{
    dd->tabChangesFocus = b;
}

/*!
    \since 4.5

    Returns true if the \gui Tab key will cause the widget to change focus;
    otherwise, false is returned.

    By default, this behavior is disabled, and this function will return false.

    \sa setTabChangesFocus()
*/
bool QGraphicsTextItem::tabChangesFocus() const
{
    return dd->tabChangesFocus;
}

/*!
    \property QGraphicsTextItem::openExternalLinks

    Specifies whether QGraphicsTextItem should automatically open links using
    QDesktopServices::openUrl() instead of emitting the
    linkActivated signal.

    The default value is false.
*/
void QGraphicsTextItem::setOpenExternalLinks(bool open)
{
    dd->textControl()->setOpenExternalLinks(open);
}

bool QGraphicsTextItem::openExternalLinks() const
{
    if (!dd->control)
        return false;
    return dd->control->openExternalLinks();
}

/*!
    \property QGraphicsTextItem::textCursor

    This property represents the visible text cursor in an editable
    text item.

    By default, if the item's text has not been set, this property
    contains a null text cursor; otherwise it contains a text cursor
    placed at the start of the item's document.
*/
void QGraphicsTextItem::setTextCursor(const QTextCursor &cursor)
{
    dd->textControl()->setTextCursor(cursor);
}

QTextCursor QGraphicsTextItem::textCursor() const
{
    if (!dd->control)
        return QTextCursor();
    return dd->control->textCursor();
}

class QGraphicsSimpleTextItemPrivate : public QAbstractGraphicsShapeItemPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsSimpleTextItem)
public:
    inline QGraphicsSimpleTextItemPrivate() {
        pen.setStyle(Qt::NoPen);
        brush.setStyle(Qt::SolidPattern);
    }
    QString text;
    QFont font;
    QRectF boundingRect;

    void updateBoundingRect();
};

static QRectF setupTextLayout(QTextLayout *layout)
{
    layout->setCacheEnabled(true);
    layout->beginLayout();
    while (layout->createLine().isValid())
        ;
    layout->endLayout();
    qreal maxWidth = 0;
    qreal y = 0;
    for (int i = 0; i < layout->lineCount(); ++i) {
        QTextLine line = layout->lineAt(i);
        maxWidth = qMax(maxWidth, line.naturalTextWidth());
        line.setPosition(QPointF(0, y));
        y += line.height();
    }
    return QRectF(0, 0, maxWidth, y);
}

void QGraphicsSimpleTextItemPrivate::updateBoundingRect()
{
    Q_Q(QGraphicsSimpleTextItem);
    QRectF br;
    if (text.isEmpty()) {
        br = QRectF();
    } else {
        QString tmp = text;
        tmp.replace(QLatin1Char('\n'), QChar::LineSeparator);
        QStackTextEngine engine(tmp, font);
        QTextLayout layout(&engine);
        br = setupTextLayout(&layout);
    }
    if (br != boundingRect) {
        q->prepareGeometryChange();
        boundingRect = br;
        q->update();
    }
}

/*!
    \class QGraphicsSimpleTextItem
    \brief The QGraphicsSimpleTextItem class provides a simple text path item
    that you can add to a QGraphicsScene.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    To set the item's text, you can either pass a QString to
    QGraphicsSimpleTextItem's constructor, or call setText() to change the
    text later. To set the text fill color, call setBrush().

    The simple text item can have both a fill and an outline; setBrush() will
    set the text fill (i.e., text color), and setPen() sets the pen that will
    be used to draw the text outline. (The latter can be slow, especially for
    complex pens, and items with long text content.) If all you want is to
    draw a simple line of text, you should call setBrush() only, and leave the
    pen unset; QGraphicsSimpleTextItem's pen is by default Qt::NoPen.

    QGraphicsSimpleTextItem uses the text's formatted size and the associated
    font to provide a reasonable implementation of boundingRect(), shape(),
    and contains(). You can set the font by calling setFont().

    QGraphicsSimpleText does not display rich text; instead, you can use
    QGraphicsTextItem, which provides full text control capabilities.

    \img graphicsview-simpletextitem.png

    \sa QGraphicsTextItem, QGraphicsPathItem, QGraphicsRectItem, QGraphicsEllipseItem,
    QGraphicsPixmapItem, QGraphicsPolygonItem, QGraphicsLineItem, {The
    Graphics View Framework}
*/

/*!
    Constructs a QGraphicsSimpleTextItem.

    \a parent is passed to QGraphicsItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsSimpleTextItem::QGraphicsSimpleTextItem(QGraphicsItem *parent
#ifndef Q_QDOC
                                                 // obsolete argument
                                                 , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsSimpleTextItemPrivate, parent, scene)
{
}

/*!
    Constructs a QGraphicsSimpleTextItem, using \a text as the default plain text.

    \a parent is passed to QGraphicsItem's constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsSimpleTextItem::QGraphicsSimpleTextItem(const QString &text, QGraphicsItem *parent
#ifndef Q_QDOC
                                                 // obsolete argument
                                                 , QGraphicsScene *scene
#endif
    )
    : QAbstractGraphicsShapeItem(*new QGraphicsSimpleTextItemPrivate, parent, scene)
{
    setText(text);
}

/*!
    Destroys the QGraphicsSimpleTextItem.
*/
QGraphicsSimpleTextItem::~QGraphicsSimpleTextItem()
{
}

/*!
    Sets the item's text to \a text. The text will be displayed as
    plain text. Newline characters ('\n') as well as characters of
    type QChar::LineSeparator will cause item to break the text into
    multiple lines.
*/
void QGraphicsSimpleTextItem::setText(const QString &text)
{
    Q_D(QGraphicsSimpleTextItem);
    if (d->text == text)
        return;
    d->text = text;
    d->updateBoundingRect();
    update();
}

/*!
    Returns the item's text.
*/
QString QGraphicsSimpleTextItem::text() const
{
    Q_D(const QGraphicsSimpleTextItem);
    return d->text;
}

/*!
    Sets the font that is used to draw the item's text to \a font.
*/
void QGraphicsSimpleTextItem::setFont(const QFont &font)
{
    Q_D(QGraphicsSimpleTextItem);
    d->font = font;
    d->updateBoundingRect();
}

/*!
    Returns the font that is used to draw the item's text.
*/
QFont QGraphicsSimpleTextItem::font() const
{
    Q_D(const QGraphicsSimpleTextItem);
    return d->font;
}

/*!
    \reimp
*/
QRectF QGraphicsSimpleTextItem::boundingRect() const
{
    Q_D(const QGraphicsSimpleTextItem);
    return d->boundingRect;
}

/*!
    \reimp
*/
QPainterPath QGraphicsSimpleTextItem::shape() const
{
    Q_D(const QGraphicsSimpleTextItem);
    QPainterPath path;
    path.addRect(d->boundingRect);
    return path;
}

/*!
    \reimp
*/
bool QGraphicsSimpleTextItem::contains(const QPointF &point) const
{
    Q_D(const QGraphicsSimpleTextItem);
    return d->boundingRect.contains(point);
}

/*!
    \reimp
*/
void QGraphicsSimpleTextItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_UNUSED(widget);
    Q_D(QGraphicsSimpleTextItem);

    painter->setFont(d->font);

    QString tmp = d->text;
    tmp.replace(QLatin1Char('\n'), QChar::LineSeparator);
    QStackTextEngine engine(tmp, d->font);
    QTextLayout layout(&engine);
    setupTextLayout(&layout);

    QPen p;
    p.setBrush(d->brush);
    painter->setPen(p);
    if (d->pen.style() == Qt::NoPen && d->brush.style() == Qt::SolidPattern) {
        painter->setBrush(Qt::NoBrush);
    } else {
        QTextLayout::FormatRange range;
        range.start = 0;
        range.length = layout.text().length();
        range.format.setTextOutline(d->pen);
        QList<QTextLayout::FormatRange> formats;
        formats.append(range);
        layout.setAdditionalFormats(formats);
    }

    layout.draw(painter, QPointF(0, 0));

    if (option->state & (QStyle::State_Selected | QStyle::State_HasFocus))
        qt_graphicsItem_highlightSelected(this, painter, option);
}

/*!
    \reimp
*/
bool QGraphicsSimpleTextItem::isObscuredBy(const QGraphicsItem *item) const
{
    return QAbstractGraphicsShapeItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsSimpleTextItem::opaqueArea() const
{
    return QAbstractGraphicsShapeItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsSimpleTextItem::type() const
{
    return Type;
}

/*!
    \internal
*/
bool QGraphicsSimpleTextItem::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

/*!
    \internal
*/
void QGraphicsSimpleTextItem::setExtension(Extension extension, const QVariant &variant)
{
    Q_UNUSED(extension);
    Q_UNUSED(variant);
}

/*!
    \internal
*/
QVariant QGraphicsSimpleTextItem::extension(const QVariant &variant) const
{
    Q_UNUSED(variant);
    return QVariant();
}

/*!
    \class QGraphicsItemGroup
    \brief The QGraphicsItemGroup class provides treating a group of items as
    one.
    \since 4.2
    \ingroup multimedia
    \ingroup graphicsview-api

    A QGraphicsItemGroup is a special type of compound item that
    treats itself and all its children as one item (i.e., all events
    and geometries for all children are merged together). It's common
    to use item groups in presentation tools, when the user wants to
    group several smaller items into one big item in order to simplify
    moving and copying of items.

    If all you want is to store items inside other items, you can use
    any QGraphicsItem directly by passing a suitable parent to
    setParentItem().

    The boundingRect() function of QGraphicsItemGroup returns the
    bounding rectangle of all items in the item group. In addition,
    item groups have handlesChildEvents() enabled by default, so all
    events sent to a member of the group go to the item group (i.e.,
    selecting one item in a group will select them all).
    QGraphicsItemGroup ignores the ItemIgnoresTransformations flag on its
    children (i.e., with respect to the geometry of the group item, the
    children are treated as if they were transformable).

    There are two ways to construct an item group. The easiest and
    most common approach is to pass a list of items (e.g., all
    selected items) to QGraphicsScene::createItemGroup(), which
    returns a new QGraphicsItemGroup item. The other approach is to
    manually construct a QGraphicsItemGroup item, add it to the scene
    calling QGraphicsScene::addItem(), and then add items to the group
    manually, one at a time by calling addToGroup(). To dismantle
    ("ungroup") an item group, you can either call
    QGraphicsScene::destroyItemGroup(), or you can manually remove all
    items from the group by calling removeFromGroup().

    \snippet doc/src/snippets/code/src_gui_graphicsview_qgraphicsitem.cpp 17

    The operation of adding and removing items preserves the items'
    scene-relative position and transformation, as opposed to calling
    setParentItem(), where only the child item's parent-relative
    position and transformation are kept.

    The addtoGroup() function reparents the target item to this item
    group, keeping the item's position and transformation intact
    relative to the scene. Visually, this means that items added via
    addToGroup() will remain completely unchanged as a result of this
    operation, regardless of the item or the group's current position
    or transformation; although the item's position and matrix are
    likely to change.

    The removeFromGroup() function has similar semantics to
    setParentItem(); it reparents the item to the parent item of the
    item group. As with addToGroup(), the item's scene-relative
    position and transformation remain intact.

    \sa QGraphicsItem, {The Graphics View Framework}
*/

class QGraphicsItemGroupPrivate : public QGraphicsItemPrivate
{
public:
    QRectF itemsBoundingRect;
};

/*!
    Constructs a QGraphicsItemGroup. \a parent is passed to QGraphicsItem's
    constructor.

    \sa QGraphicsScene::addItem()
*/
QGraphicsItemGroup::QGraphicsItemGroup(QGraphicsItem *parent
#ifndef Q_QDOC
                                       // obsolete argument
                                       , QGraphicsScene *scene
#endif
    )
    : QGraphicsItem(*new QGraphicsItemGroupPrivate, parent, scene)
{
    setHandlesChildEvents(true);
}

/*!
    Destroys the QGraphicsItemGroup.
*/
QGraphicsItemGroup::~QGraphicsItemGroup()
{
}

/*!
    Adds the given \a item to this item group. The item will be
    reparented to this group, but its position and transformation
    relative to the scene will stay intact.

    \sa removeFromGroup(), QGraphicsScene::createItemGroup()
*/
void QGraphicsItemGroup::addToGroup(QGraphicsItem *item)
{
    Q_D(QGraphicsItemGroup);
    if (!item) {
        qWarning("QGraphicsItemGroup::addToGroup: cannot add null item");
        return;
    }
    if (item == this) {
        qWarning("QGraphicsItemGroup::addToGroup: cannot add a group to itself");
        return;
    }

    QTransform oldSceneMatrix = item->sceneTransform();
    item->setPos(mapFromItem(item, 0, 0));
    item->setParentItem(this);
    QTransform newItemTransform(oldSceneMatrix);
    newItemTransform *= sceneTransform().inverted();
    if (!item->pos().isNull())
        newItemTransform *= QTransform::fromTranslate(-item->x(), -item->y());
    item->setTransform(newItemTransform);
    item->d_func()->setIsMemberOfGroup(true);
    prepareGeometryChange();
    QTransform itemTransform(item->transform());
    if (!item->pos().isNull())
        itemTransform *= QTransform::fromTranslate(item->x(), item->y());
    d->itemsBoundingRect |= itemTransform.mapRect(item->boundingRect() | item->childrenBoundingRect());
    update();
}

/*!
    Removes the specified \a item from this group. The item will be
    reparented to this group's parent item, or to 0 if this group has
    no parent.  Its position and transformation relative to the scene
    will stay intact.

    \sa addToGroup(), QGraphicsScene::destroyItemGroup()
*/
void QGraphicsItemGroup::removeFromGroup(QGraphicsItem *item)
{
    Q_D(QGraphicsItemGroup);
    if (!item) {
        qWarning("QGraphicsItemGroup::removeFromGroup: cannot remove null item");
        return;
    }

    QGraphicsItem *newParent = d_ptr->parent;
    QPointF oldPos = item->mapToItem(newParent, 0, 0);
    item->setParentItem(newParent);
    // ### This function should remap the item's matrix to keep the item's
    // transformation unchanged relative to the scene.
    item->setPos(oldPos);
    item->d_func()->setIsMemberOfGroup(item->group() != 0);

    // ### Quite expensive. But removeFromGroup() isn't called very often.
    prepareGeometryChange();
    d->itemsBoundingRect = childrenBoundingRect();
}

/*!
    \reimp

    Returns the bounding rect of this group item, and all its children.
*/
QRectF QGraphicsItemGroup::boundingRect() const
{
    Q_D(const QGraphicsItemGroup);
    return d->itemsBoundingRect;
}

/*!
    \reimp
*/
void QGraphicsItemGroup::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
                               QWidget *widget)
{
    Q_UNUSED(widget);
    if (option->state & QStyle::State_Selected) {
        Q_D(QGraphicsItemGroup);
        painter->setBrush(Qt::NoBrush);
        painter->drawRect(d->itemsBoundingRect);
    }
}

/*!
    \reimp
*/
bool QGraphicsItemGroup::isObscuredBy(const QGraphicsItem *item) const
{
    return QGraphicsItem::isObscuredBy(item);
}

/*!
    \reimp
*/
QPainterPath QGraphicsItemGroup::opaqueArea() const
{
    return QGraphicsItem::opaqueArea();
}

/*!
    \reimp
*/
int QGraphicsItemGroup::type() const
{
    return Type;
}

#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug debug, QGraphicsItem *item)
{
    if (!item) {
        debug << "QGraphicsItem(0)";
        return debug;
    }

    QStringList flags;
    if (item->isVisible()) flags << QLatin1String("isVisible");
    if (item->isEnabled()) flags << QLatin1String("isEnabled");
    if (item->isSelected()) flags << QLatin1String("isSelected");
    if (item->hasFocus()) flags << QLatin1String("HasFocus");

    debug << "QGraphicsItem(this =" << ((void*)item)
          << ", parent =" << ((void*)item->parentItem())
          << ", pos =" << item->pos()
          << ", z =" << item->zValue() << ", flags = {"
          << flags.join(QLatin1String("|")) << " })";
    return debug;
}

QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemChange change)
{
    const char *str = "UnknownChange";
    switch (change) {
    case QGraphicsItem::ItemChildAddedChange:
        str = "ItemChildAddedChange";
        break;
    case QGraphicsItem::ItemChildRemovedChange:
        str = "ItemChildRemovedChange";
        break;
    case QGraphicsItem::ItemCursorChange:
        str = "ItemCursorChange";
        break;
    case QGraphicsItem::ItemCursorHasChanged:
        str = "ItemCursorHasChanged";
        break;
    case QGraphicsItem::ItemEnabledChange:
        str = "ItemEnabledChange";
        break;
    case QGraphicsItem::ItemEnabledHasChanged:
        str = "ItemEnabledHasChanged";
        break;
    case QGraphicsItem::ItemFlagsChange:
        str = "ItemFlagsChange";
        break;
    case QGraphicsItem::ItemFlagsHaveChanged:
        str = "ItemFlagsHaveChanged";
        break;
    case QGraphicsItem::ItemMatrixChange:
        str = "ItemMatrixChange";
        break;
    case QGraphicsItem::ItemParentChange:
        str = "ItemParentChange";
        break;
    case QGraphicsItem::ItemParentHasChanged:
        str = "ItemParentHasChanged";
        break;
    case QGraphicsItem::ItemPositionChange:
        str = "ItemPositionChange";
        break;
    case QGraphicsItem::ItemPositionHasChanged:
        str = "ItemPositionHasChanged";
        break;
    case QGraphicsItem::ItemSceneChange:
        str = "ItemSceneChange";
        break;
    case QGraphicsItem::ItemSceneHasChanged:
        str = "ItemSceneHasChanged";
        break;
    case QGraphicsItem::ItemSelectedChange:
        str = "ItemSelectedChange";
        break;
    case QGraphicsItem::ItemSelectedHasChanged:
        str = "ItemSelectedHasChanged";
        break;
    case QGraphicsItem::ItemToolTipChange:
        str = "ItemToolTipChange";
        break;
    case QGraphicsItem::ItemToolTipHasChanged:
        str = "ItemToolTipHasChanged";
        break;
    case QGraphicsItem::ItemTransformChange:
        str = "ItemTransformChange";
        break;
    case QGraphicsItem::ItemTransformHasChanged:
        str = "ItemTransformHasChanged";
        break;
    case QGraphicsItem::ItemVisibleChange:
        str = "ItemVisibleChange";
        break;
    case QGraphicsItem::ItemVisibleHasChanged:
        str = "ItemVisibleHasChanged";
        break;
    case QGraphicsItem::ItemZValueChange:
        str = "ItemZValueChange";
        break;
    case QGraphicsItem::ItemZValueHasChanged:
        str = "ItemZValueHasChanged";
        break;
    case QGraphicsItem::ItemOpacityChange:
        str = "ItemOpacityChange";
        break;
    case QGraphicsItem::ItemOpacityHasChanged:
        str = "ItemOpacityHasChanged";
        break;
    }
    debug << str;
    return debug;
}

QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemFlag flag)
{
    const char *str = "UnknownFlag";
    switch (flag) {
    case QGraphicsItem::ItemIsMovable:
        str = "ItemIsMovable";
        break;
    case QGraphicsItem::ItemIsSelectable:
        str = "ItemIsSelectable";
        break;
    case QGraphicsItem::ItemIsFocusable:
        str = "ItemIsFocusable";
        break;
    case QGraphicsItem::ItemClipsToShape:
        str = "ItemClipsToShape";
        break;
    case QGraphicsItem::ItemClipsChildrenToShape:
        str = "ItemClipsChildrenToShape";
        break;
    case QGraphicsItem::ItemIgnoresTransformations:
        str = "ItemIgnoresTransformations";
        break;
    case QGraphicsItem::ItemIgnoresParentOpacity:
        str = "ItemIgnoresParentOpacity";
        break;
    case QGraphicsItem::ItemDoesntPropagateOpacityToChildren:
        str = "ItemDoesntPropagateOpacityToChildren";
        break;
    case QGraphicsItem::ItemStacksBehindParent:
        str = "ItemStacksBehindParent";
        break;
    }
    debug << str;
    return debug;
}

QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemFlags flags)
{
    debug << "(";
    bool f = false;
    for (int i = 0; i < 9; ++i) {
        if (flags & (1 << i)) {
            if (f)
                debug << "|";
            f = true;
            debug << QGraphicsItem::GraphicsItemFlag(int(flags & (1 << i)));
        }
    }
    debug << ")";
    return debug;
}

#endif

QT_END_NAMESPACE

#include "moc_qgraphicsitem.cpp"

#endif // QT_NO_GRAPHICSVIEW