source: trunk/src/gui/kernel/qgesture.cpp@ 624

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#include "qgesture.h"
#include "private/qgesture_p.h"

QT_BEGIN_NAMESPACE

 /*!
    \class QGesture
    \since 4.6
    \ingroup gestures

    \brief The QGesture class represents a gesture, containing properties that
    describe the corresponding user input.

    Gesture objects are not constructed directly by developers. They are created by
    the QGestureRecognizer object that is registered with the application; see
    QGestureRecognizer::registerRecognizer().

    \section1 Gesture Properties

    The class has a list of properties that can be queried by the user to get
    some gesture-specific arguments. For example, the pinch gesture has a scale
    factor that is exposed as a property.

    Developers of custom gesture recognizers can add additional properties in
    order to provide additional information about a gesture. This can be done
    by adding new dynamic properties to a QGesture object, or by subclassing
    the QGesture class (or one of its subclasses).

    \section1 Lifecycle of a Gesture Object

    A QGesture instance is implicitly created when needed and is owned by Qt.
    Developers should never destroy them or store them for later use as Qt may
    destroy particular instances of them and create new ones to replace them.

    The registered gesture recognizer monitors the input events for the target
    object via its \l{QGestureRecognizer::}{recognize()} function, updating the
    properties of the gesture object as required.

    The gesture object may be delivered to the target object in a QGestureEvent if
    the corresponding gesture is active or has just been canceled. Each event that
    is delivered contains a list of gesture objects, since support for more than
    one gesture may be enabled for the target object. Due to the way events are
    handled in Qt, gesture events may be filtered by other objects.

    \sa QGestureEvent, QGestureRecognizer
*/

/*!
    Constructs a new gesture object with the given \a parent.

    QGesture objects are created by gesture recognizers in the
    QGestureRecognizer::create() function.
*/
QGesture::QGesture(QObject *parent)
    : QObject(*new QGesturePrivate, parent)
{
    d_func()->gestureType = Qt::CustomGesture;
}

/*!
    \internal
*/
QGesture::QGesture(QGesturePrivate &dd, QObject *parent)
    : QObject(dd, parent)
{
}

/*!
    Destroys the gesture object.
*/
QGesture::~QGesture()
{
}

/*!
    \property QGesture::state
    \brief the current state of the gesture
*/

/*!
    \property QGesture::gestureType
    \brief the type of the gesture
*/

/*!
    \property QGesture::hotSpot

    \brief The point that is used to find the receiver for the gesture event.

    The hot-spot is a point in the global coordinate system, use
    QWidget::mapFromGlobal() or QGestureEvent::mapToGraphicsScene() to get a
    local hot-spot.

    The hot-spot should be set by the gesture recognizer to allow gesture event
    delivery to a QGraphicsObject.
*/

/*!
    \property QGesture::hasHotSpot
    \brief whether the gesture has a hot-spot
*/

Qt::GestureType QGesture::gestureType() const
{
    return d_func()->gestureType;
}

Qt::GestureState QGesture::state() const
{
    return d_func()->state;
}

QPointF QGesture::hotSpot() const
{
    return d_func()->hotSpot;
}

void QGesture::setHotSpot(const QPointF &value)
{
    Q_D(QGesture);
    d->hotSpot = value;
    d->isHotSpotSet = true;
}

bool QGesture::hasHotSpot() const
{
    return d_func()->isHotSpotSet;
}

void QGesture::unsetHotSpot()
{
    d_func()->isHotSpotSet = false;
}

/*!
    \property QGesture::gestureCancelPolicy
    \brief the policy for deciding what happens on accepting a gesture

    On accepting one gesture Qt can automatically cancel other gestures
    that belong to other targets. The policy is normally set to not cancel
    any other gestures and can be set to cancel all active gestures in the
    context. For example for all child widgets.
*/

/*!
    \enum QGesture::GestureCancelPolicy

    This enum describes how accepting a gesture can cancel other gestures
    automatically.

    \value CancelNone On accepting this gesture no other gestures will be affected.

    \value CancelAllInContext On accepting this gesture all gestures that are
    active in the context (respecting the Qt::GestureFlag that were specified
    when subscribed to the gesture) will be cancelled.
*/

void QGesture::setGestureCancelPolicy(GestureCancelPolicy policy)
{
    Q_D(QGesture);
    d->gestureCancelPolicy = static_cast<uint>(policy);
}

QGesture::GestureCancelPolicy QGesture::gestureCancelPolicy() const
{
    Q_D(const QGesture);
    return static_cast<GestureCancelPolicy>(d->gestureCancelPolicy);
}

/*!
    \class QPanGesture
    \since 4.6
    \brief The QPanGesture class describes a panning gesture made by the user.
    \ingroup gestures

    \image pangesture.png

    \sa {Gestures Programming}, QPinchGesture, QSwipeGesture
*/

/*!
    \property QPanGesture::lastOffset
    \brief the last offset recorded for this gesture

    The last offset contains the change in position of the user's input as
    reported in the \l offset property when a previous gesture event was
    delivered for this gesture.

    If no previous event was delivered with information about this gesture
    (i.e., this gesture object contains information about the first movement
    in the gesture) then this property contains a zero size.
*/

/*!
    \property QPanGesture::offset
    \brief the total offset from the first input position to the current input
    position

    The offset measures the total change in position of the user's input
    covered by the gesture on the input device.
*/

/*!
    \property QPanGesture::delta
    \brief the offset from the previous input position to the current input

    This is essentially the same as the difference between offset() and
    lastOffset().
*/

/*!
    \property QPanGesture::acceleration
*/

/*!
    \internal
*/
QPanGesture::QPanGesture(QObject *parent)
    : QGesture(*new QPanGesturePrivate, parent)
{
    d_func()->gestureType = Qt::PanGesture;
}


QPointF QPanGesture::lastOffset() const
{
    return d_func()->lastOffset;
}

QPointF QPanGesture::offset() const
{
    return d_func()->offset;
}

QPointF QPanGesture::delta() const
{
    Q_D(const QPanGesture);
    return d->offset - d->lastOffset;
}

qreal QPanGesture::acceleration() const
{
    return d_func()->acceleration;
}

void QPanGesture::setLastOffset(const QPointF &value)
{
    d_func()->lastOffset = value;
}

void QPanGesture::setOffset(const QPointF &value)
{
    d_func()->offset = value;
}

void QPanGesture::setAcceleration(qreal value)
{
    d_func()->acceleration = value;
}

/*!
    \class QPinchGesture
    \since 4.6
    \brief The QPinchGesture class describes a pinch gesture made my the user.
    \ingroup multitouch
    \ingroup gestures

    A pinch gesture is a form of multitouch user input in which the user typically
    touches two points on the input device with a thumb and finger, before moving
    them closer together or further apart to change the scale factor, zoom, or level
    of detail of the user interface.

    \image pinchgesture.png

    Instead of repeatedly applying the same pinching gesture, the user may
    continue to touch the input device in one place, and apply a second touch
    to a new point, continuing the gesture. When this occurs, gesture events
    will continue to be delivered to the target object, containing an instance
    of QPinchGesture in the Qt::GestureUpdated state.

    \sa {Gestures Programming}, QPanGesture, QSwipeGesture
*/

/*!
    \enum QPinchGesture::ChangeFlag
    
    This enum describes the changes that can occur to the properties of
    the gesture object.

    \value ScaleFactorChanged The scale factor held by scaleFactor changed.
    \value RotationAngleChanged The rotation angle held by rotationAngle changed.
    \value CenterPointChanged The center point held by centerPoint changed.

    \sa changeFlags, totalChangeFlags
*/

/*!
    \property QPinchGesture::totalChangeFlags
    \brief the property of the gesture that has change

    This property indicates which of the other properties has changed since the
    gesture has started. You can use this information to determine which aspect
    of your user interface needs to be updated.

    \sa changeFlags, scaleFactor, rotationAngle, centerPoint
*/

/*!
    \property QPinchGesture::changeFlags
    \brief the property of the gesture that has changed in the current step

    This property indicates which of the other properties has changed since
    the previous gesture event included information about this gesture. You
    can use this information to determine which aspect of your user interface
    needs to be updated.

    \sa totalChangeFlags, scaleFactor, rotationAngle, centerPoint
*/

/*!
    \property QPinchGesture::totalScaleFactor
    \brief the total scale factor

    The total scale factor measures the total change in scale factor from the
    original value to the current scale factor.

    \sa scaleFactor, lastScaleFactor
*/
/*!
    \property QPinchGesture::lastScaleFactor
    \brief the last scale factor recorded for this gesture

    The last scale factor contains the scale factor reported in the
    \l scaleFactor property when a previous gesture event included
    information about this gesture.

    If no previous event was delivered with information about this gesture
    (i.e., this gesture object contains information about the first movement
    in the gesture) then this property contains zero.

    \sa scaleFactor, totalScaleFactor
*/
/*!
    \property QPinchGesture::scaleFactor
    \brief the current scale factor

    The scale factor measures the scale factor associated with the distance
    between two of the user's inputs on a multitouch device.