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#include "knob.h"

#include <QBrush>
#include <QGraphicsSceneTouchEvent>

Knob::Knob()
    : QGraphicsEllipseItem(-50, -50, 100, 100)
{
    setAcceptTouchEvents(true);
    setBrush(Qt::lightGray);

    QGraphicsEllipseItem *leftItem = new QGraphicsEllipseItem(0, 0, 10, 10, this);
    leftItem->setPos(-45, -5);
    leftItem->setBrush(Qt::darkGreen);

    QGraphicsEllipseItem *rightItem = new QGraphicsEllipseItem(0, 0, 10, 10, this);
    rightItem->setPos(35, -5);
    rightItem->setBrush(Qt::darkRed);
}

bool Knob::sceneEvent(QEvent *event)
{
    switch (event->type()) {
    case QEvent::GraphicsSceneTouchBegin:
        event->accept();
        break;

    case QEvent::GraphicsSceneTouchUpdate:
    case QEvent::GraphicsSceneTouchEnd:
    {
        QGraphicsSceneTouchEvent *touchEvent = static_cast<QGraphicsSceneTouchEvent *>(event);

        if (touchEvent->touchPoints().count() == 2) {
            QGraphicsSceneTouchEvent::TouchPoint *touchPoint1 = touchEvent->touchPoints().first();
            QGraphicsSceneTouchEvent::TouchPoint *touchPoint2 = touchEvent->touchPoints().last();

            QLineF line1(touchPoint1->lastScenePos(), touchPoint2->lastScenePos());
            QLineF line2(touchPoint1->scenePos(), touchPoint2->scenePos());

            rotate(line2.angleTo(line1));
        }

        touchEvent->accept();
        break;
    }

    default:
        return QGraphicsItem::sceneEvent(event);
    }

    return true;
}