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// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
#include <QtWidgets>
class TouchableItem : public QGraphicsRectItem
{
public:
TouchableItem() : QGraphicsRectItem(50, 50, 400, 400)
{
setBrush(Qt::yellow);
setAcceptTouchEvents(true);
}
protected:
bool sceneEvent(QEvent *e)
{
const bool ret = QGraphicsRectItem::sceneEvent(e);
switch (e->type()) {
case QEvent::TouchBegin:
case QEvent::TouchUpdate:
case QEvent::TouchEnd:
{
QTouchEvent *te = static_cast<QTouchEvent *>(e);
for (const QEventPoint &tp : te->touchPoints()) {
QGraphicsEllipseItem *diameterItem = nullptr;
QSizeF ellipse = tp.ellipseDiameters();
if (ellipse.isNull()) {
ellipse = QSizeF(5, 5);
} else {
diameterItem = new QGraphicsEllipseItem(QRectF(tp.pos().x() - ellipse.width() / 2, tp.pos().y() - ellipse.height() / 2,
ellipse.width(), ellipse.height()), this);
diameterItem->setPen(QPen(Qt::red));
diameterItem->setBrush(QBrush(Qt::red));
if (ellipse.width() > qreal(2) && ellipse.height() > qreal(2))
ellipse.scale(ellipse.width() - 2, ellipse.height() - 2, Qt::IgnoreAspectRatio);
}
QGraphicsItem *parent = diameterItem ? static_cast<QGraphicsItem *>(diameterItem) : static_cast<QGraphicsItem *>(this);
QGraphicsEllipseItem *ellipseItem = new QGraphicsEllipseItem(QRectF(tp.pos().x() - ellipse.width() / 2,
tp.pos().y() - ellipse.height() / 2,
ellipse.width(), ellipse.height()), parent);
ellipseItem->setPen(QPen(Qt::blue));
ellipseItem->setBrush(QBrush(Qt::blue));
}
te->accept();
return true;
}
default:
break;
}
return ret;
}
};
int main(int argc, char **argv)
{
QApplication a(argc, argv);
QMainWindow mw;
QWidget *w = new QWidget;
QVBoxLayout *vbox = new QVBoxLayout;
vbox->addWidget(new QLabel("The blue ellipses should indicate touch point contact patches"));
qDebug() << "Touch devices:";
for (const QPointingDevice *device : QPointingDevice::devices()) {
QString result;
QTextStream str(&result);
str << (device->type() == QInputDevice::DeviceType::TouchScreen ? "TouchScreen" : "TouchPad")
<< " \"" << device->name() << "\", max " << device->maximumTouchPoints()
<< " touch points, capabilities:";
const QPointingDevice::Capabilities capabilities = device->capabilities();
if (capabilities & QPointingDevice::Capability::Position)
str << " Position";
if (capabilities & QPointingDevice::Capability::Area)
str << " Area";
if (capabilities & QPointingDevice::Capability::Pressure)
str << " Pressure";
if (capabilities & QPointingDevice::Velocity)
str << " Velocity";
if (capabilities & QPointingDevice::Capability::NormalizedPosition)
str << " NormalizedPosition";
if (capabilities & QInputDevice::DeviceType::MouseEmulation)
str << " MouseEmulation";
vbox->addWidget(new QLabel(result));
qDebug() << " " << result;
}
QGraphicsView *view = new QGraphicsView;
view->viewport()->setAttribute(Qt::WA_AcceptTouchEvents);
QGraphicsScene *scene = new QGraphicsScene(0, 0, 500, 500);
TouchableItem *touchableItem = new TouchableItem;
scene->addItem(touchableItem);
view->setScene(scene);
vbox->addWidget(view);
w->setLayout(vbox);
mw.setCentralWidget(w);
QMenu *menu = mw.menuBar()->addMenu("Menu");
QAction *clear = new QAction("Clear");
QObject::connect(clear, &QAction::triggered, [=]() {
qDeleteAll(touchableItem->childItems());
});
menu->addAction(clear);
QAction *ignoreTransform = new QAction("Ignore transformations");
QObject::connect(ignoreTransform, &QAction::triggered, [=]() {
view->scale(1.5, 1.5);
touchableItem->setFlag(QGraphicsItem::ItemIgnoresTransformations);
});
menu->addAction(ignoreTransform);
QAction *quit = new QAction("Quit");
quit->setShortcut(QKeySequence::Quit);
QObject::connect(quit, &QAction::triggered, &QApplication::quit);
menu->addAction(quit);
mw.show();
return a.exec();
}
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