qgraphicssceneevent.cpp

奇趣公司比较新的qt/emd版本

/****************************************************************************
**
** Copyright (C) 1992-2007 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at [e-mail].
**
** In addition, as a special exception, Trolltech gives you certain
** additional rights. These rights are described in the Trolltech GPL
** Exception version 1.0, which can be found at
** http://www.trolltech.com/products/qt/gplexception/ and in the file
** GPL_EXCEPTION.txt in this package.
**
** In addition, as a special exception, Trolltech, as the sole copyright
** holder for Qt Designer, grants users of the Qt/Eclipse Integration
** plug-in the right for the Qt/Eclipse Integration to link to
** functionality provided by Qt Designer and its related libraries.
**
** Trolltech reserves all rights not expressly granted herein.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
****************************************************************************/

/*!
    \class QGraphicsSceneEvent
    \brief The QGraphicsSceneEvent class provides a base class for all
    graphics view related events.
    \since 4.2
    \ingroup multimedia

    When a QGraphicsView receives Qt mouse, keyboard, and drag and
    drop events (QMouseEvent, QKeyEvent, QDragEvent, etc.), it
    translates them into instances of QGraphicsSceneEvent subclasses
    and forwards them to the QGraphicsScene it displays. The scene
    then forwards the events to the relevant items.

    For example, when a QGraphicsView receives a QMouseEvent of type
    MousePress as a response to a user click, the view sends a
    QGraphicsSceneMouseEvent of type GraphicsSceneMousePress to the
    underlying QGraphicsScene through its
    \l{QGraphicsScene::}{mousePressEvent()} function. The default
    QGraphicsScene::mousePressEvent() implementation determines which
    item was clicked and forwards the event to
    QGraphicsItem::mousePressEvent().

    \omit ### Beskrive widget() \endomit

    Subclasses such as QGraphicsSceneMouseEvent and
    QGraphicsSceneContextMenuEvent provide the coordinates from the
    original QEvent in screen, scene, and item coordinates (see
    \l{QGraphicsSceneMouseEvent::}{screenPos()},
    \l{QGraphicsSceneMouseEvent::}{scenePos()}, and
    \l{QGraphicsSceneMouseEvent::}{pos()}). The item coordinates are
    set by the QGraphicsScene before it forwards the event to the
    event to a QGraphicsItem. The mouse events also add the
    possibility to retrieve the coordinates from the last event
    received by the view (see
    \l{QGraphicsSceneMouseEvent::}{lastScreenPos()},
    \l{QGraphicsSceneMouseEvent::}{lastScenePos()}, and
    \l{QGraphicsSceneMouseEvent::}{lastPos()}). 

    \sa QEvent
*/

/*!
    \class QGraphicsSceneMouseEvent
    \brief The QGraphicsSceneMouseEvent class provides mouse events 
	   in the graphics view framework.
    \since 4.2
    \ingroup multimedia

    When a QGraphicsView receives a QMouseEvent, it translates it to
    a QGraphicsSceneMouseEvent. The event is then forwarded to the
    QGraphicsScene associated with the view.

    In addition to containing the item, scene, and screen coordinates
    of the event (as pos(), scenePos(), and screenPos()), mouse
    events also contain the coordinates of the previous mouse
    event received by the view. These can be retrieved with
    lastPos(), lastScreenPos(), and lastScenePos().

    \sa QGraphicsSceneContextMenuEvent,
	QGraphicsSceneHoverEvent, QGraphicsSceneWheelEvent,
	QMouseEvent
*/

/*!
    \class QGraphicsSceneWheelEvent
    \brief The QGraphicsSceneWheelEvent class provides wheel events 
	   in the graphics view framework.
    \brief The QGraphicsSceneWheelEvent class provides wheel events in the
    graphics view framework.
    \since 4.2
    \ingroup multimedia

    \l{QWheelEvent}{QWheelEvent}s received by a QGraphicsView are translated
    into QGraphicsSceneWheelEvents; it translates the QWheelEvent::globalPos()
    into item, scene, and screen coordinates (pos(), scenePos(), and
    screenPos()).

    \sa QGraphicsSceneMouseEvent, QGraphicsSceneContextMenuEvent,
    QGraphicsSceneHoverEvent, QWheelEvent
*/

/*!
    \class QGraphicsSceneContextMenuEvent
    \brief The QGraphicsSceneContextMenuEvent class provides context
	   menu events in the graphics view framework.
    \since 4.2
    \ingroup multimedia

    A QContextMenuEvent received by a QGraphicsView is translated
    into a QGraphicsSceneContextMenuEvent. The
    QWheelEvent::globalPos() is translated into item, scene, and
    screen coordinates (pos(), scenePos(), and screenPos()).

    \sa QGraphicsSceneMouseEvent, QGraphicsSceneWheelEvent,
    QContextMenuEvent
*/

/*!
    \enum QGraphicsSceneContextMenuEvent::Reason

    This enum describes the reason why the context event was sent.

    \value Mouse The mouse caused the event to be sent. On most
    platforms, this means the right mouse button was clicked.

    \value Keyboard The keyboard caused this event to be sent. On
    Windows and Mac OS X, this means the menu button was pressed.

    \value Other The event was sent by some other means (i.e. not
    by the mouse or keyboard).
*/

/*!
    \class QGraphicsSceneHoverEvent
    \brief The QGraphicsSceneHoverEvent class provides hover events 
	   in the graphics view framework.
    \since 4.2
    \ingroup multimedia

    When a QGraphicsView receives a QHoverEvent event, it translates
    it into QGraphicsSceneHoverEvent. The event is then forwarded to
    the QGraphicsScene associated with the view.

    \sa QGraphicsSceneMouseEvent, QGraphicsSceneContextMenuEvent,
        QGraphicsSceneWheelEvent, QHoverEvent
*/

/*!
    \class QGraphicsSceneHelpEvent
    \brief The QGraphicsSceneHelpEvent class provides events when a 
	   tooltip is requested.
    \since 4.2
    \ingroup multimedia

    When a QGraphicsView receives a QEvent of type
    QEvent::ToolTip, it creates a QGraphicsSceneHelpEvent, which is
    forwarded to the scene. You can set a tooltip on a QGraphicsItem
    with \l{QGraphicsItem::}{setToolTip()}; by default QGraphicsScene
    displays the tooltip of the QGraphicsItem with the highest
    z-value (i.e, the top-most item) under the mouse position.
    
    QGraphicsView does not forward events when
    \l{QWhatsThis}{"What's This"} and \l{QStatusTipEvent}{status tip}
    help is requested. If you need this, you can reimplement
    QGraphicsView::viewportEvent() and forward QStatusTipEvent
    events and \l{QEvent}{QEvents} of type QEvent::WhatsThis to the
    scene.

    \sa QEvent
*/

/*!
    \class QGraphicsSceneDragDropEvent
    \brief The QGraphicsSceneDragDropEvent class provides events for
	   drag and drop in the graphics view framework. 
    \since 4.2
    \ingroup multimedia

    QGraphicsView inherits the drag and drop functionality provided
    by QWidget. When it receives a drag and drop event, it translates
    it to a QGraphicsSceneDragDropEvent.

    QGraphicsSceneDragDropEvent stores events of type
    GraphicsSceneDragEnter, GraphicsSceneDragLeave,
    GraphicsSceneDragMove, or GraphicsSceneDrop.

    QGraphicsSceneDragDropEvent contains the position of the mouse
    cursor in both item, scene, and screen coordinates; this can be
    retrieved with pos(), scenePos(), and screenPos().

    The scene sends the event to the first QGraphicsItem under the
    mouse cursor that accepts drops; a graphics item is set to accept
    drops with \l{QGraphicsItem::}{setAcceptDrops()}.
*/

#include "qgraphicssceneevent.h"

#ifndef QT_NO_GRAPHICSVIEW

#ifndef QT_NO_DEBUG
#include <QtCore/qdebug.h>
#endif
#include <QtCore/qmap.h>
#include <QtCore/qstring.h>

class QGraphicsSceneEventPrivate
{
public:
    inline QGraphicsSceneEventPrivate()
        : widget(0),
          q_ptr(0)
    { }

    inline virtual ~QGraphicsSceneEventPrivate()
    { }

    QWidget *widget;
    QGraphicsSceneEvent *q_ptr;
};

/*!
    \internal

    Constructs a generic graphics scene event of the specified \a type.
*/
QGraphicsSceneEvent::QGraphicsSceneEvent(Type type)
    : QEvent(type), d_ptr(new QGraphicsSceneEventPrivate)
{
    d_ptr->q_ptr = this;
}

/*!
    \internal

    Constructs a generic graphics scene event.
*/
QGraphicsSceneEvent::QGraphicsSceneEvent(QGraphicsSceneEventPrivate &dd, Type type)
    : QEvent(type), d_ptr(&dd)
{
    d_ptr->q_ptr = this;
}

/*!
    Destroys the event.
*/
QGraphicsSceneEvent::~QGraphicsSceneEvent()
{
    delete d_ptr;
}

/*!
    Returns the widget where the event originated, or 0 if the event
    originates from another application.
*/
QWidget *QGraphicsSceneEvent::widget() const
{
    return d_ptr->widget;
}

/*!
    \internal

    Sets the \a widget related to this event.

    \sa widget()
*/
void QGraphicsSceneEvent::setWidget(QWidget *widget)
{
    d_ptr->widget = widget;
}

class QGraphicsSceneMouseEventPrivate : public QGraphicsSceneEventPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsSceneMouseEvent)
public:
    inline QGraphicsSceneMouseEventPrivate()
        : button(Qt::NoButton),
          buttons(0), modifiers(0)
    { }

    QPointF pos;
    QPointF scenePos;
    QPoint screenPos;
    QPointF lastPos;
    QPointF lastScenePos;
    QPoint lastScreenPos;
    QMap<Qt::MouseButton, QPointF> buttonDownPos;
    QMap<Qt::MouseButton, QPointF> buttonDownScenePos;
    QMap<Qt::MouseButton, QPoint> buttonDownScreenPos;
    Qt::MouseButton button;
    Qt::MouseButtons buttons;
    Qt::KeyboardModifiers modifiers;
};

/*!
    \internal

    Constructs a generic graphics scene mouse event of the specified \a type.
*/
QGraphicsSceneMouseEvent::QGraphicsSceneMouseEvent(Type type)
    : QGraphicsSceneEvent(*new QGraphicsSceneMouseEventPrivate, type)
{
}

/*!
    Destroys the event.
*/
QGraphicsSceneMouseEvent::~QGraphicsSceneMouseEvent()
{
}

/*!
    Returns the mouse cursor position in item coordinates.

    \sa scenePos(), screenPos(), lastPos()
*/
QPointF QGraphicsSceneMouseEvent::pos() const
{
    Q_D(const QGraphicsSceneMouseEvent);
    return d->pos;
}

/*!
    \internal
*/
void QGraphicsSceneMouseEvent::setPos(const QPointF &pos)
{
    Q_D(QGraphicsSceneMouseEvent);
    d->pos = pos;
}

/*!
    Returns the mouse cursor position in scene coordinates.

    \sa pos(), screenPos(), lastScenePos()
*/
QPointF QGraphicsSceneMouseEvent::scenePos() const
{
    Q_D(const QGraphicsSceneMouseEvent);
    return d->scenePos;
}

/*!
    \internal
*/
void QGraphicsSceneMouseEvent::setScenePos(const QPointF &pos)
{
    Q_D(QGraphicsSceneMouseEvent);
    d->scenePos = pos;
}

/*!
    Returns the mouse cursor position in screen coordinates.

    \sa pos(), scenePos(), lastScreenPos()
*/
QPoint QGraphicsSceneMouseEvent::screenPos() const
{
    Q_D(const QGraphicsSceneMouseEvent);
    return d->screenPos;
}

/*!
    \internal
*/
void QGraphicsSceneMouseEvent::setScreenPos(const QPoint &pos)
{
    Q_D(QGraphicsSceneMouseEvent);
    d->screenPos = pos;
}

/*!
    Returns the mouse cursor position in item coordinates where the specified
    \a button was clicked.

    \sa buttonDownScenePos(), buttonDownScreenPos(), pos()
*/
QPointF QGraphicsSceneMouseEvent::buttonDownPos(Qt::MouseButton button) const
{
    Q_D(const QGraphicsSceneMouseEvent);
    return d->buttonDownPos.value(button);
}

/*!
    \internal
*/
void QGraphicsSceneMouseEvent::setButtonDownPos(Qt::MouseButton button, const QPointF &pos)
{
    Q_D(QGraphicsSceneMouseEvent);
    d->buttonDownPos.insert(button, pos);
}

/*!
    Returns the mouse cursor position in scene coordinates where the
    specified \a button was clicked.

    \sa buttonDownPos(), buttonDownScreenPos(), scenePos()
*/
QPointF QGraphicsSceneMouseEvent::buttonDownScenePos(Qt::MouseButton button) const
{
    Q_D(const QGraphicsSceneMouseEvent);
    return d->buttonDownScenePos.value(button);
}

/*!
    \internal
*/
void QGraphicsSceneMouseEvent::setButtonDownScenePos(Qt::MouseButton button, const QPointF &pos)
{
    Q_D(QGraphicsSceneMouseEvent);
    d->buttonDownScenePos.insert(button, pos);
}

/*!
    Returns the mouse cursor position in screen coordinates where the
    specified \a button was clicked.

    \sa screenPos(), buttonDownPos(), buttonDownScenePos()
*/
QPoint QGraphicsSceneMouseEvent::buttonDownScreenPos(Qt::MouseButton button) const
{
    Q_D(const QGraphicsSceneMouseEvent);
    return d->buttonDownScreenPos.value(button);
}

/*!
    \internal
*/
void QGraphicsSceneMouseEvent::setButtonDownScreenPos(Qt::MouseButton button, const QPoint &pos)
{
    Q_D(QGraphicsSceneMouseEvent);
    d->buttonDownScreenPos.insert(button, pos);
}

/*!
    Returns the last recorded mouse cursor position in item
    coordinates.

    \sa lastScenePos(), lastScreenPos(), pos()
*/
QPointF QGraphicsSceneMouseEvent::lastPos() const
{
    Q_D(const QGraphicsSceneMouseEvent);
    return d->lastPos;
}

/*!
    \internal
*/
void QGraphicsSceneMouseEvent::setLastPos(const QPointF &pos)