main.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
 ** BSD License Usage
 ** Alternatively, you may use this file under the terms of the BSD license
 ** as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of The Qt Company Ltd nor the names of its
 **     contributors may be used to endorse or promote products derived
 **     from this software without specific prior written permission.
 **
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QtGui>

 #include "rasterwindow.h"

 class AnalogClockWindow : public RasterWindow
 {
 public:
     AnalogClockWindow();

 protected:
     void timerEvent(QTimerEvent *) override;
     void render(QPainter *p) override;

 private:
     int m_timerId;
 };

 AnalogClockWindow::AnalogClockWindow()
 {
     setTitle("Analog Clock");
     resize(200, 200);

     m_timerId = startTimer(1000);
 }

 void AnalogClockWindow::timerEvent(QTimerEvent *event)
 {
     if (event->timerId() == m_timerId)
         renderLater();
 }

 void AnalogClockWindow::render(QPainter *p)
 {
     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);

     p->setRenderHint(QPainter::Antialiasing);
     p->translate(width() / 2, height() / 2);

     int side = qMin(width(), height());
     p->scale(side / 200.0, side / 200.0);

     p->setPen(Qt::NoPen);
     p->setBrush(hourColor);

     QTime time = QTime::currentTime();

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

     p->setPen(hourColor);

     for (int i = 0; i < 12; ++i) {
         p->drawLine(88, 0, 96, 0);
         p->rotate(30.0);
     }
     p->setPen(Qt::NoPen);
     p->setBrush(minuteColor);

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

     p->setPen(minuteColor);

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

 int main(int argc, char **argv)
 {
     QGuiApplication app(argc, argv);

     AnalogClockWindow clock;
     clock.show();

     return app.exec();
 }