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++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include <QtCore/QTimer>
++ #include <QtGui/QPainter>
++ #include <QtStateMachine/QFinalState>
++ #include <QtStateMachine/QStateMachine>
++ #include <QtWidgets/QApplication>
++ #include <QtWidgets/QVBoxLayout>
++ #include <QtWidgets/QWidget>
++
++ //! [0]
++ class LightWidget : public QWidget
++ {
++ Q_OBJECT
++ Q_PROPERTY(bool on READ isOn WRITE setOn)
++ public:
++ explicit LightWidget(const QColor &color, QWidget *parent = nullptr)
++ : QWidget(parent), m_color(color)
++ {
++ }
++
++ bool isOn() const { return m_on; }
++
++ void setOn(bool on)
++ {
++ if (on == m_on)
++ return;
++ m_on = on;
++ update();
++ }
++
++ public slots:
++ void turnOff() { setOn(false); }
++ void turnOn() { setOn(true); }
++
++ protected:
++ void paintEvent(QPaintEvent *) override
++ {
++ if (!m_on)
++ return;
++ QPainter painter(this);
++ painter.setRenderHint(QPainter::Antialiasing);
++ painter.setBrush(m_color);
++ painter.drawEllipse(rect());
++ }
++
++ private:
++ QColor m_color;
++ bool m_on = false;
++ };
++ //! [0]
++
++ //! [1]
++ class TrafficLightWidget : public QWidget
++ {
++ Q_OBJECT
++ public:
++ explicit TrafficLightWidget(QWidget *parent = nullptr) : QWidget(parent)
++ {
++ auto vbox = new QVBoxLayout(this);
++ m_red = new LightWidget(Qt::red);
++ vbox->addWidget(m_red);
++ m_yellow = new LightWidget(Qt::yellow);
++ vbox->addWidget(m_yellow);
++ m_green = new LightWidget(Qt::green);
++ vbox->addWidget(m_green);
++ auto pal = palette();
++ pal.setColor(QPalette::Window, Qt::black);
++ setPalette(pal);
++ setAutoFillBackground(true);
++ }
++
++ LightWidget *redLight() const { return m_red; }
++ LightWidget *yellowLight() const { return m_yellow; }
++ LightWidget *greenLight() const { return m_green; }
++
++ private:
++ LightWidget *m_red;
++ LightWidget *m_yellow;
++ LightWidget *m_green;
++ };
++ //! [1]
++
++ //! [2]
++ QState *createLightState(LightWidget *light, int duration, QState *parent = nullptr)
++ {
++ auto lightState = new QState(parent);
++ auto timer = new QTimer(lightState);
++ timer->setInterval(duration);
++ timer->setSingleShot(true);
++ auto timing = new QState(lightState);
++ QObject::connect(timing, &QAbstractState::entered, light, &LightWidget::turnOn);
++ QObject::connect(timing, &QAbstractState::entered, timer, QOverload<>::of(&QTimer::start));
++ QObject::connect(timing, &QAbstractState::exited, light, &LightWidget::turnOff);
++ auto done = new QFinalState(lightState);
++ timing->addTransition(timer, &QTimer::timeout, done);
++ lightState->setInitialState(timing);
++ return lightState;
++ }
++ //! [2]
++
++ //! [3]
++ class TrafficLight : public QWidget
++ {
++ Q_OBJECT
++ public:
++ explicit TrafficLight(QWidget *parent = nullptr) : QWidget(parent)
++ {
++ auto vbox = new QVBoxLayout(this);
++ auto widget = new TrafficLightWidget;
++ vbox->addWidget(widget);
++ vbox->setContentsMargins(QMargins());
++
++ auto machine = new QStateMachine(this);
++ auto redGoingYellow = createLightState(widget->redLight(), 3000);
++ redGoingYellow->setObjectName("redGoingYellow");
++ auto yellowGoingGreen = createLightState(widget->yellowLight(), 1000);
++ yellowGoingGreen->setObjectName("yellowGoingGreen");
++ redGoingYellow->addTransition(redGoingYellow, &QState::finished, yellowGoingGreen);
++ auto greenGoingYellow = createLightState(widget->greenLight(), 3000);
++ greenGoingYellow->setObjectName("greenGoingYellow");
++ yellowGoingGreen->addTransition(yellowGoingGreen, &QState::finished, greenGoingYellow);
++ auto yellowGoingRed = createLightState(widget->yellowLight(), 1000);
++ yellowGoingRed->setObjectName("yellowGoingRed");
++ greenGoingYellow->addTransition(greenGoingYellow, &QState::finished, yellowGoingRed);
++ yellowGoingRed->addTransition(yellowGoingRed, &QState::finished, redGoingYellow);
++
++ machine->addState(redGoingYellow);
++ machine->addState(yellowGoingGreen);
++ machine->addState(greenGoingYellow);
++ machine->addState(yellowGoingRed);
++ machine->setInitialState(redGoingYellow);
++ machine->start();
++ }
++ };
++ //! [3]
++
++ //! [4]
++ int main(int argc, char **argv)
++ {
++ QApplication app(argc, argv);
++
++ TrafficLight widget;
++ widget.resize(110, 300);
++ widget.show();
++
++ return app.exec();
++ }
++ //! [4]
++
++ #include "main.moc"