qt5base-lts/examples/widgets/touch/knobs/knob.cpp
Paul Wicking a62bab95d3 Doc: Move touch examples around so they get included in docs
Task-number: QTBUG-59249
Change-Id: I71f1d2e28f0cadbad1d6bcf117198018eaf8e012
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>
2018-09-14 03:56:22 +00:00

99 lines
3.7 KiB
C++

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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());
setTransform(QTransform().rotate(line2.angleTo(line1)), true);
}
break;
}
default:
return QGraphicsItem::sceneEvent(event);
}
return true;
}