Qt 5.6 | Qt GUI | Analog Clock Window Example | main.cpp Example File

Qt 5.6.3 Reference Documentation

# main.cpp Example File

analogclock/main.cpp

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      #include <QtGui>

      #include "rasterwindow.h"

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

      protected:
          void timerEvent(QTimerEvent *) Q_DECL_OVERRIDE;
          void render(QPainter *p) Q_DECL_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();
      }