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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#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->points().count() == 2) {
const QEventPoint &touchPoint1 = touchEvent->points().first();
const QEventPoint &touchPoint2 = touchEvent->points().last();
QLineF line1(touchPoint1.sceneLastPosition(), touchPoint2.sceneLastPosition());
QLineF line2(touchPoint1.scenePosition(), touchPoint2.scenePosition());
setTransform(QTransform().rotate(line2.angleTo(line1)), true);
}
break;
}
default:
return QGraphicsItem::sceneEvent(event);
}
return true;
}
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