qdeclarativepincharea.cpp

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#include "qdeclarativepincharea_p.h"
#include "qdeclarativepincharea_p_p.h"

#include <QApplication>
#include <QGraphicsScene>

#include <float.h>
#include <math.h>

QT_BEGIN_NAMESPACE


QDeclarativePinch::QDeclarativePinch()
    : m_target(0), m_minScale(1.0), m_maxScale(1.0)
    , m_minRotation(0.0), m_maxRotation(0.0)
    , m_axis(NoDrag), m_xmin(-FLT_MAX), m_xmax(FLT_MAX)
    , m_ymin(-FLT_MAX), m_ymax(FLT_MAX), m_active(false)
{
}

QDeclarativePinchAreaPrivate::~QDeclarativePinchAreaPrivate()
{
    delete pinch;
}

QDeclarativePinchArea::QDeclarativePinchArea(QDeclarativeItem *parent)
  : QDeclarativeItem(*(new QDeclarativePinchAreaPrivate), parent)
{
    Q_D(QDeclarativePinchArea);
    d->init();
}

QDeclarativePinchArea::~QDeclarativePinchArea()
{
}

bool QDeclarativePinchArea::isEnabled() const
{
    Q_D(const QDeclarativePinchArea);
    return d->absorb;
}

void QDeclarativePinchArea::setEnabled(bool a)
{
    Q_D(QDeclarativePinchArea);
    if (a != d->absorb) {
        d->absorb = a;
        emit enabledChanged();
    }
}

bool QDeclarativePinchArea::event(QEvent *event)
{
    Q_D(QDeclarativePinchArea);
    if (!d->absorb || !isVisible())
        return QDeclarativeItem::event(event);
    switch (event->type()) {
    case QEvent::TouchBegin:
        d->touchEventsActive = true;
        // No break, continue to next case.
    case QEvent::TouchUpdate:
        if (d->touchEventsActive) {
            QTouchEvent *touch = static_cast<QTouchEvent*>(event);
            d->touchPoints.clear();
            for (int i = 0; i < touch->touchPoints().count(); ++i) {
                if (!(touch->touchPoints().at(i).state() & Qt::TouchPointReleased)) {
                    d->touchPoints << touch->touchPoints().at(i);
                }
            }
            updatePinch();
            return true;
        }
        break;
    case QEvent::WindowDeactivate:
        // No break, continue to next case.
    case QEvent::TouchEnd:
        d->touchEventsActive = false;
        d->touchPoints.clear();
        updatePinch();
        break;
    default:
        return QDeclarativeItem::event(event);
    }

    return QDeclarativeItem::event(event);
}

void QDeclarativePinchArea::updatePinch()
{
    Q_D(QDeclarativePinchArea);
    if (d->touchPoints.count() == 0) {
        if (d->inPinch) {
            d->stealMouse = false;
            setKeepMouseGrab(false);
            d->inPinch = false;
            QPointF pinchCenter = mapFromScene(d->sceneLastCenter);
            QDeclarativePinchEvent pe(pinchCenter, d->pinchLastScale, d->pinchLastAngle, d->pinchRotation);
            pe.setStartCenter(d->pinchStartCenter);
            pe.setPreviousCenter(pinchCenter);
            pe.setPreviousAngle(d->pinchLastAngle);
            pe.setPreviousScale(d->pinchLastScale);
            pe.setStartPoint1(mapFromScene(d->sceneStartPoint1));
            pe.setStartPoint2(mapFromScene(d->sceneStartPoint2));
            pe.setPoint1(mapFromScene(d->lastPoint1));
            pe.setPoint2(mapFromScene(d->lastPoint2));
            emit pinchFinished(&pe);
            d->pinchStartDist = 0;
            d->pinchActivated = false;
            if (d->pinch && d->pinch->target())
                d->pinch->setActive(false);
        }
        return;
    }
    QTouchEvent::TouchPoint touchPoint1 = d->touchPoints.at(0);
    QTouchEvent::TouchPoint touchPoint2 = d->touchPoints.at(d->touchPoints. count() >= 2 ? 1 : 0);
    if (d->touchPoints.count() == 2
        && (touchPoint1.state() & Qt::TouchPointPressed || touchPoint2.state() & Qt::TouchPointPressed)) {
        d->id1 = touchPoint1.id();
        d->sceneStartPoint1 = touchPoint1.scenePos();
        d->sceneStartPoint2 = touchPoint2.scenePos();
        d->inPinch = false;
        d->pinchRejected = false;
        d->pinchActivated = true;
    } else if (d->pinchActivated && !d->pinchRejected) {
        const int dragThreshold = QApplication::startDragDistance();
        QPointF p1 = touchPoint1.scenePos();
        QPointF p2 = touchPoint2.scenePos();
        qreal dx = p1.x() - p2.x();
        qreal dy = p1.y() - p2.y();
        qreal dist = sqrt(dx*dx + dy*dy);
        QPointF sceneCenter = (p1 + p2)/2;
        qreal angle = QLineF(p1, p2).angle();
        if (d->touchPoints.count() == 1) {
            // If we only have one point then just move the center
            if (d->id1 == touchPoint1.id())
                sceneCenter = d->sceneLastCenter + touchPoint1.scenePos() - d->lastPoint1;
            else
                sceneCenter = d->sceneLastCenter + touchPoint2.scenePos() - d->lastPoint2;
            angle = d->pinchLastAngle;
        }
        d->id1 = touchPoint1.id();
        if (angle > 180)
            angle -= 360;
        if (!d->inPinch) {
            if (d->touchPoints.count() >= 2
                    && (qAbs(p1.x()-d->sceneStartPoint1.x()) > dragThreshold
                    || qAbs(p1.y()-d->sceneStartPoint1.y()) > dragThreshold
                    || qAbs(p2.x()-d->sceneStartPoint2.x()) > dragThreshold
                    || qAbs(p2.y()-d->sceneStartPoint2.y()) > dragThreshold)) {
                d->sceneStartCenter = sceneCenter;
                d->sceneLastCenter = sceneCenter;
                d->pinchStartCenter = mapFromScene(sceneCenter);
                d->pinchStartDist = dist;
                d->pinchStartAngle = angle;
                d->pinchLastScale = 1.0;
                d->pinchLastAngle = angle;
                d->pinchRotation = 0.0;
                d->lastPoint1 = p1;
                d->lastPoint2 = p2;
                QDeclarativePinchEvent pe(d->pinchStartCenter, 1.0, angle, 0.0);
                pe.setStartCenter(d->pinchStartCenter);
                pe.setPreviousCenter(d->pinchStartCenter);
                pe.setPreviousAngle(d->pinchLastAngle);
                pe.setPreviousScale(d->pinchLastScale);
                pe.setStartPoint1(mapFromScene(d->sceneStartPoint1));
                pe.setStartPoint2(mapFromScene(d->sceneStartPoint2));
                pe.setPoint1(mapFromScene(d->lastPoint1));
                pe.setPoint2(mapFromScene(d->lastPoint2));
                pe.setPointCount(d->touchPoints.count());
                emit pinchStarted(&pe);
                if (pe.accepted()) {
                    d->inPinch = true;
                    d->stealMouse = true;
                    QGraphicsScene *s = scene();
                    if (s && s->mouseGrabberItem() != this)
                        grabMouse();
                    setKeepMouseGrab(true);
                    if (d->pinch && d->pinch->target()) {
                        d->pinchStartPos = pinch()->target()->pos();
                        d->pinchStartScale = d->pinch->target()->scale();
                        d->pinchStartRotation = d->pinch->target()->rotation();
                        d->pinch->setActive(true);
                    }
                } else {
                    d->pinchRejected = true;
                }
            }
        } else if (d->pinchStartDist > 0) {
            qreal scale = dist ? dist / d->pinchStartDist : d->pinchLastScale;
            qreal da = d->pinchLastAngle - angle;
            if (da > 180)
                da -= 360;
            else if (da < -180)
                da += 360;
            d->pinchRotation += da;
            QPointF pinchCenter = mapFromScene(sceneCenter);
            QDeclarativePinchEvent pe(pinchCenter, scale, angle, d->pinchRotation);
            pe.setStartCenter(d->pinchStartCenter);
            pe.setPreviousCenter(mapFromScene(d->sceneLastCenter));
            pe.setPreviousAngle(d->pinchLastAngle);
            pe.setPreviousScale(d->pinchLastScale);
            pe.setStartPoint1(mapFromScene(d->sceneStartPoint1));
            pe.setStartPoint2(mapFromScene(d->sceneStartPoint2));
            pe.setPoint1(touchPoint1.pos());
            pe.setPoint2(touchPoint2.pos());
            pe.setPointCount(d->touchPoints.count());
            d->pinchLastScale = scale;
            d->sceneLastCenter = sceneCenter;
            d->pinchLastAngle = angle;
            d->lastPoint1 = touchPoint1.scenePos();
            d->lastPoint2 = touchPoint2.scenePos();
            emit pinchUpdated(&pe);
            if (d->pinch && d->pinch->target()) {
                qreal s = d->pinchStartScale * scale;
                s = qMin(qMax(pinch()->minimumScale(),s), pinch()->maximumScale());
                pinch()->target()->setScale(s);
                QPointF pos = sceneCenter - d->sceneStartCenter + d->pinchStartPos;
                if (pinch()->axis() & QDeclarativePinch::XAxis) {
                    qreal x = pos.x();
                    if (x < pinch()->xmin())
                        x = pinch()->xmin();
                    else if (x > pinch()->xmax())
                        x = pinch()->xmax();
                    pinch()->target()->setX(x);
                }
                if (pinch()->axis() & QDeclarativePinch::YAxis) {
                    qreal y = pos.y();
                    if (y < pinch()->ymin())
                        y = pinch()->ymin();
                    else if (y > pinch()->ymax())
                        y = pinch()->ymax();
                    pinch()->target()->setY(y);
                }
                if (d->pinchStartRotation >= pinch()->minimumRotation()
                        && d->pinchStartRotation <= pinch()->maximumRotation()) {
                    qreal r = d->pinchRotation + d->pinchStartRotation;
                    r = qMin(qMax(pinch()->minimumRotation(),r), pinch()->maximumRotation());
                    pinch()->target()->setRotation(r);
                }
            }
        }
    }
}

void QDeclarativePinchArea::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    Q_D(QDeclarativePinchArea);
    d->stealMouse = false;
    if (!d->absorb)
        QDeclarativeItem::mousePressEvent(event);
    else {
        setKeepMouseGrab(false);
        event->setAccepted(true);
    }
}

void QDeclarativePinchArea::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    Q_D(QDeclarativePinchArea);
    if (!d->absorb) {
        QDeclarativeItem::mouseMoveEvent(event);
        return;
    }
}

void QDeclarativePinchArea::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    Q_D(QDeclarativePinchArea);
    d->stealMouse = false;
    if (!d->absorb) {
        QDeclarativeItem::mouseReleaseEvent(event);
    } else {
        QGraphicsScene *s = scene();
        if (s && s->mouseGrabberItem() == this)
            ungrabMouse();
        setKeepMouseGrab(false);
    }
}

bool QDeclarativePinchArea::sceneEvent(QEvent *event)
{
    bool rv = QDeclarativeItem::sceneEvent(event);
    if (event->type() == QEvent::UngrabMouse) {
        setKeepMouseGrab(false);
    }
    return rv;
}

bool QDeclarativePinchArea::sendMouseEvent(QGraphicsSceneMouseEvent *event)
{
    Q_D(QDeclarativePinchArea);
    QGraphicsSceneMouseEvent mouseEvent(event->type());
    QRectF myRect = mapToScene(QRectF(0, 0, width(), height())).boundingRect();

    QGraphicsScene *s = scene();
    QDeclarativeItem *grabber = s ? qobject_cast<QDeclarativeItem*>(s->mouseGrabberItem()) : 0;
    bool stealThisEvent = d->stealMouse;
    if ((stealThisEvent || myRect.contains(event->scenePos().toPoint())) && (!grabber || !grabber->keepMouseGrab())) {
        mouseEvent.setAccepted(false);
        for (int i = 0x1; i <= 0x10; i <<= 1) {
            if (event->buttons() & i) {
                Qt::MouseButton button = Qt::MouseButton(i);
                mouseEvent.setButtonDownPos(button, mapFromScene(event->buttonDownPos(button)));
            }
        }
        mouseEvent.setScenePos(event->scenePos());
        mouseEvent.setLastScenePos(event->lastScenePos());
        mouseEvent.setPos(mapFromScene(event->scenePos()));
        mouseEvent.setLastPos(mapFromScene(event->lastScenePos()));

        switch(mouseEvent.type()) {
        case QEvent::GraphicsSceneMouseMove:
            mouseMoveEvent(&mouseEvent);
            break;
        case QEvent::GraphicsSceneMousePress:
            mousePressEvent(&mouseEvent);
            break;
        case QEvent::GraphicsSceneMouseRelease:
            mouseReleaseEvent(&mouseEvent);
            break;
        default:
            break;
        }
        grabber = qobject_cast<QDeclarativeItem*>(s->mouseGrabberItem());
        if (grabber && stealThisEvent && !grabber->keepMouseGrab() && grabber != this)
            grabMouse();

        return stealThisEvent;
    }
    if (mouseEvent.type() == QEvent::GraphicsSceneMouseRelease) {
        d->stealMouse = false;
        if (s && s->mouseGrabberItem() == this)
            ungrabMouse();
        setKeepMouseGrab(false);
    }
    return false;
}

bool QDeclarativePinchArea::sceneEventFilter(QGraphicsItem *i, QEvent *e)
{
    Q_D(QDeclarativePinchArea);
    if (!d->absorb || !isVisible())
        return QDeclarativeItem::sceneEventFilter(i, e);
    switch (e->type()) {
    case QEvent::GraphicsSceneMousePress:
    case QEvent::GraphicsSceneMouseMove:
    case QEvent::GraphicsSceneMouseRelease:
        return sendMouseEvent(static_cast<QGraphicsSceneMouseEvent *>(e));
        break;
    case QEvent::TouchBegin:
    case QEvent::TouchUpdate: {
            QTouchEvent *touch = static_cast<QTouchEvent*>(e);
            d->touchPoints.clear();
            for (int i = 0; i < touch->touchPoints().count(); ++i)
                if (!(touch->touchPoints().at(i).state() & Qt::TouchPointReleased))
                    d->touchPoints << touch->touchPoints().at(i);
            updatePinch();
        }
        return d->inPinch;
    case QEvent::TouchEnd:
        d->touchPoints.clear();
        updatePinch();
        break;
    default:
        break;
    }

    return QDeclarativeItem::sceneEventFilter(i, e);
}

void QDeclarativePinchArea::geometryChanged(const QRectF &newGeometry,
                                            const QRectF &oldGeometry)
{
    QDeclarativeItem::geometryChanged(newGeometry, oldGeometry);
}

QVariant QDeclarativePinchArea::itemChange(GraphicsItemChange change,
                                       const QVariant &value)
{
    return QDeclarativeItem::itemChange(change, value);
}

QDeclarativePinch *QDeclarativePinchArea::pinch()
{
    Q_D(QDeclarativePinchArea);
    if (!d->pinch)
        d->pinch = new QDeclarativePinch;
    return d->pinch;
}


QT_END_NAMESPACE