C++ QPanGesture::state方法代码示例

    void gestureEvent(QGestureEvent *event)
    {
        QPanGesture *pan = static_cast<QPanGesture *>(event->gesture(Qt::PanGesture));
        if (pan) {
            switch(pan->state()) {
            case Qt::GestureStarted: qDebug() << this << "Pan: started"; break;
            case Qt::GestureFinished: qDebug() << this << "Pan: finished"; break;
            case Qt::GestureCanceled: qDebug() << this << "Pan: canceled"; break;
            case Qt::GestureUpdated: break;
            default: qDebug() << this << "Pan: <unknown state>"; break;
            }

            if (pan->state() == Qt::GestureStarted)
                outside = false;
            event->ignore();
            event->ignore(pan);
            if (outside)
                return;

            const QPointF delta = pan->delta();
            const QPointF totalOffset = pan->offset();
            QScrollBar *vbar = verticalScrollBar();
            QScrollBar *hbar = horizontalScrollBar();

            if ((vbar->value() == vbar->minimum() && totalOffset.y() > 10) ||
                (vbar->value() == vbar->maximum() && totalOffset.y() < -10)) {
                outside = true;
                return;
            }
            if ((hbar->value() == hbar->minimum() && totalOffset.x() > 10) ||
                (hbar->value() == hbar->maximum() && totalOffset.x() < -10)) {
                outside = true;
                return;
            }
            vbar->setValue(vbar->value() - delta.y());
            hbar->setValue(hbar->value() - delta.x());
            event->accept(pan);
        }
    }

QGestureRecognizer::Result QPanGestureRecognizer::recognize(QGesture *state,
                                                            QObject *,
                                                            QEvent *event)
{
    QPanGesture *q = static_cast<QPanGesture *>(state);
    QPanGesturePrivate *d = q->d_func();

    QGestureRecognizer::Result result = QGestureRecognizer::Ignore;
    switch (event->type()) {
    case QEvent::TouchBegin: {
        const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);
        result = QGestureRecognizer::MayBeGesture;
        QTouchEvent::TouchPoint p = ev->touchPoints().at(0);
        d->lastOffset = d->offset = QPointF();
        d->pointCount = m_pointCount;
        break;
    }
    case QEvent::TouchEnd: {
        if (q->state() != Qt::NoGesture) {
            const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);
            if (ev->touchPoints().size() == d->pointCount) {
                d->lastOffset = d->offset;
                d->offset = panOffset(ev->touchPoints(), d->pointCount);
            }
            result = QGestureRecognizer::FinishGesture;
        } else {
            result = QGestureRecognizer::CancelGesture;
        }
        break;
    }
    case QEvent::TouchUpdate: {
        const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);
        if (ev->touchPoints().size() >= d->pointCount) {
            d->lastOffset = d->offset;
            d->offset = panOffset(ev->touchPoints(), d->pointCount);
            if (d->offset.x() > 10  || d->offset.y() > 10 ||
                d->offset.x() < -10 || d->offset.y() < -10) {
                q->setHotSpot(ev->touchPoints().first().startScreenPos());
                result = QGestureRecognizer::TriggerGesture;
            } else {
                result = QGestureRecognizer::MayBeGesture;
            }
        }
        break;
    }
    default:
        break;
    }
    return result;
}

QGestureRecognizer::Result QWinNativePanGestureRecognizer::recognize(QGesture *state,
                                                                     QObject *,
                                                                     QEvent *event)
{
    QPanGesture *q = static_cast<QPanGesture*>(state);
    QPanGesturePrivate *d = q->d_func();

    QGestureRecognizer::Result result = QGestureRecognizer::Ignore;
    if (event->type() == QEvent::NativeGesture) {
        QNativeGestureEvent *ev = static_cast<QNativeGestureEvent*>(event);
        switch(ev->gestureType) {
        case QNativeGestureEvent::GestureBegin:
            break;
        case QNativeGestureEvent::Pan:
            result = QGestureRecognizer::TriggerGesture;
            event->accept();
            break;
        case QNativeGestureEvent::GestureEnd:
            if (q->state() == Qt::NoGesture)
                return QGestureRecognizer::Ignore; // some other gesture has ended
            result = QGestureRecognizer::FinishGesture;
            break;
        default:
            return QGestureRecognizer::Ignore;
        }
        if (q->state() == Qt::NoGesture) {
            d->lastOffset = d->offset = QPointF();
            d->startPosition = ev->position;
        } else {
            d->lastOffset = d->offset;
            d->offset = QPointF(ev->position.x() - d->startPosition.x(),
                                ev->position.y() - d->startPosition.y());
        }
    }
    return result;
}

QGestureRecognizer::Result QPanGestureRecognizer::recognize(QGesture *state,
                                                            QObject *,
                                                            QEvent *event)
{
    QPanGesture *q = static_cast<QPanGesture *>(state);
    QPanGesturePrivate *d = q->d_func();

    const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);

    QGestureRecognizer::Result result;
    switch (event->type()) {
    case QEvent::TouchBegin: {
        result = QGestureRecognizer::MayBeGesture;
        QTouchEvent::TouchPoint p = ev->touchPoints().at(0);
        d->lastOffset = d->offset = QPointF();
        break;
    }
    case QEvent::TouchEnd: {
        if (q->state() != Qt::NoGesture) {
            if (ev->touchPoints().size() == 2) {
                QTouchEvent::TouchPoint p1 = ev->touchPoints().at(0);
                QTouchEvent::TouchPoint p2 = ev->touchPoints().at(1);
                d->lastOffset = d->offset;
                d->offset =
                        QPointF(p1.pos().x() - p1.startPos().x() + p2.pos().x() - p2.startPos().x(),
                              p1.pos().y() - p1.startPos().y() + p2.pos().y() - p2.startPos().y()) / 2;
            }
            result = QGestureRecognizer::FinishGesture;
        } else {
            result = QGestureRecognizer::CancelGesture;
        }
        break;
    }
    case QEvent::TouchUpdate: {
        if (ev->touchPoints().size() >= 2) {
            QTouchEvent::TouchPoint p1 = ev->touchPoints().at(0);
            QTouchEvent::TouchPoint p2 = ev->touchPoints().at(1);
            d->lastOffset = d->offset;
            d->offset =
                    QPointF(p1.pos().x() - p1.startPos().x() + p2.pos().x() - p2.startPos().x(),
                          p1.pos().y() - p1.startPos().y() + p2.pos().y() - p2.startPos().y()) / 2;
            if (d->offset.x() > 10  || d->offset.y() > 10 ||
                d->offset.x() < -10 || d->offset.y() < -10) {
                q->setHotSpot(p1.startScreenPos());
                result = QGestureRecognizer::TriggerGesture;
            } else {
                result = QGestureRecognizer::MayBeGesture;
            }
        }
        break;
    }
    case QEvent::MouseButtonPress:
    case QEvent::MouseMove:
    case QEvent::MouseButtonRelease:
        result = QGestureRecognizer::Ignore;
        break;
    default:
        result = QGestureRecognizer::Ignore;
        break;
    }
    return result;
}

//===============================================================
bool MousePanNZoomNavigator::eventFilter(QObject *widget, QEvent *e) {
// according to Qt's doc, this constant has been defined by wheel mouse vendors
// we need it to interpret the value of QWheelEvent->delta()
#define WHEEL_DELTA 120
  if (e->type() == QEvent::Wheel &&
      (((QWheelEvent *) e)->orientation() == Qt::Vertical)) {

    GlMainWidget *g = (GlMainWidget *) widget;

    if(((QWheelEvent *) e)->delta() < 0 && g->getScene()->getCamera().getZoomFactor() < 0.5f) {
      return true;
    }

    g->getScene()->zoomXY(((QWheelEvent *) e)->delta() / WHEEL_DELTA,
                          ((QWheelEvent *) e)->x(), ((QWheelEvent *) e)->y());
    g->draw(false);
    return true;
  }

  if(e->type() == QEvent::Gesture) {
    GlMainWidget *g = (GlMainWidget *) widget;
    QGestureEvent* gesture = (QGestureEvent*)e;
    QPointF center;
    //swipe events and pan events are never fired, known Qt bug
    /*if(gesture->gesture(Qt::SwipeGesture)) {
      QSwipeGesture* swipe = (QSwipeGesture*)gesture->gesture(Qt::SwipeGesture);
      int x = cos(swipe->swipeAngle()) * swipe->property("velocity").toFloat();
      int y = sin(swipe->swipeAngle()) * swipe->property("velocity").toFloat();
      g->getScene()->translateCamera(x, y, 0);
    }*/

    if(gesture->gesture(Qt::PinchGesture)) {
      QPinchGesture* pinch = (QPinchGesture*)gesture->gesture(Qt::PinchGesture);
      Camera& camera = g->getScene()->getCamera();

      //store the camera scale factor when starting the gesture
      if(pinch->state() == Qt::GestureStarted) {
        cameraScaleFactor = camera.getZoomFactor();
        isGesturing = true;
      }

      if(pinch->changeFlags() & QPinchGesture::ScaleFactorChanged) {
        //only set the zoom factor if two events in a row were in the same direction (zoom in or out) to smooth a bit the effect.
        if((pinch->lastScaleFactor() > 1 && pinch->scaleFactor() > 1) || (pinch->lastScaleFactor() <= 1 && pinch->scaleFactor() <= 1)) {
          camera.setZoomFactor(cameraScaleFactor * pinch->totalScaleFactor());
        }
      }

      if(pinch->changeFlags() & QPinchGesture::RotationAngleChanged) {
        /*//backup the current camera center
              Coord oldCenter = camera.getCenter();
              Coord oldEye = camera.getEyes();
        //sets the camera center to the center of the pich gesture
              Coord rotationCenter(g->mapFromGlobal(pinch->centerPoint().toPoint()).x(), g->mapFromGlobal(pinch->centerPoint().toPoint()).y(), oldCenter.getZ());
              Coord rotationEye=camera.getEyes()+(rotationCenter-oldCenter);
              camera.setCenter(rotationCenter);
              camera.setEyes(rotationEye);*/
        //rotates the camera
        camera.rotate((pinch->rotationAngle() - pinch->lastRotationAngle())/180*M_PI, 0, 0, 1);
        /*
        //restore old camera center and eyes
              camera.setCenter(oldCenter);
              camera.setEyes(oldEye); */
      }

      if(pinch->state() == Qt::GestureFinished) {
        isGesturing = false;
      }

      if(gesture->gesture(Qt::PanGesture)) {
        QPanGesture* pan = (QPanGesture*)gesture->gesture(Qt::PanGesture);

        if(pan->state() == Qt::GestureStarted) {
          isGesturing = true;
        }

        if(pan->state() == Qt::GestureFinished) {
          isGesturing = false;
        }

        center = pan->delta();
        g->getScene()->translateCamera(pan->delta().x(), -pan->delta().y(), 0);
      }
    }

    g->draw(false);
    return true;
  }

  return false;
}