- Qt 5.5
- Qt Designer Manual
- Custom Widget Plugin Example
- analogclock.cpp Example File
- Qt 5.5.1 Reference Documentation

# analogclock.cpp Example File

customwidgetplugin/analogclock.cpp

    /****************************************************************************
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    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
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    ** This file is part of the examples of the Qt Toolkit.
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    ** $QT_BEGIN_LICENSE:BSD$
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    #include "analogclock.h"

    #include <QMouseEvent>
    #include <QPainter>
    #include <QTime>
    #include <QTimer>

    AnalogClock::AnalogClock(QWidget *parent)
        : QWidget(parent)
    {
        typedef void (QWidget::*WidgetUpdateSlot)();

        QTimer *timer = new QTimer(this);
        connect(timer, &QTimer::timeout, this, static_cast<WidgetUpdateSlot>(&QWidget::update));
        timer->start(1000);

        setWindowTitle(tr("Analog Clock"));
        resize(200, 200);
    }

    void AnalogClock::paintEvent(QPaintEvent *)
    {
        static const QPoint hourHand[3] = {
            QPoint(7, 8),
            QPoint(-7, 8),
            QPoint(0, -40)
        };
        static const QPoint minuteHand[3] = {
            QPoint(7, 8),
            QPoint(-7, 8),
            QPoint(0, -70)
        };

        QColor hourColor(127, 0, 127);
        QColor minuteColor(0, 127, 127, 191);

        int side = qMin(width(), height());
        QTime time = QTime::currentTime();

        QPainter painter(this);
        painter.setRenderHint(QPainter::Antialiasing);
        painter.translate(width() / 2, height() / 2);
        painter.scale(side / 200.0, side / 200.0);

        painter.setPen(Qt::NoPen);
        painter.setBrush(hourColor);

        painter.save();
        painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
        painter.drawConvexPolygon(hourHand, 3);
        painter.restore();

        painter.setPen(hourColor);

        for (int i = 0; i < 12; ++i) {
            painter.drawLine(88, 0, 96, 0);
            painter.rotate(30.0);
        }

        painter.setPen(Qt::NoPen);
        painter.setBrush(minuteColor);

        painter.save();
        painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
        painter.drawConvexPolygon(minuteHand, 3);
        painter.restore();

        painter.setPen(minuteColor);

        for (int j = 0; j < 60; ++j) {
            if ((j % 5) != 0)
                painter.drawLine(92, 0, 96, 0);
            painter.rotate(6.0);
        }
    }