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#include "knob.h"

#include <QBrush>

#include <QTouchEvent>

Knob::Knob()

    : QGraphicsEllipseItem(-50, -50, 100, 100)

{

    setAcceptTouchEvents(true);

    setBrush(Qt::lightGray);

    QGraphicsEllipseItem *leftItem = new QGraphicsEllipseItem(0, 0, 20, 20, this);

    leftItem->setPos(-40, -10);

    leftItem->setBrush(Qt::darkGreen);

    QGraphicsEllipseItem *rightItem = new QGraphicsEllipseItem(0, 0, 20, 20, this);

    rightItem->setPos(20, -10);

    rightItem->setBrush(Qt::darkRed);

}

bool Knob::sceneEvent(QEvent *event)

{

    switch (event->type()) {

    case QEvent::TouchBegin:

    case QEvent::TouchUpdate:

    case QEvent::TouchEnd:

    {

        QTouchEvent *touchEvent = static_cast<QTouchEvent *>(event);

        if (touchEvent->touchPoints().count() == 2) {

            const QTouchEvent::TouchPoint &touchPoint1 = touchEvent->touchPoints().first();

            const QTouchEvent::TouchPoint &touchPoint2 = touchEvent->touchPoints().last();

            QLineF line1(touchPoint1.lastScenePos(), touchPoint2.lastScenePos());

            QLineF line2(touchPoint1.scenePos(), touchPoint2.scenePos());

            rotate(line2.angleTo(line1));

        }

        break;

    }

    default:

        return QGraphicsItem::sceneEvent(event);

    }

    return true;

}