In this example, we will learn how to use coordinate transformation and a timer to create a real-time clock display.
To create our first graphical clock display, let's follow these steps:
First, create a new Qt Widgets Application project. Then, open up
mainwindow.uiand remove the menu bar, tool bar, and status bar.After that, open up
mainwindow.hand include the following headers:#include <QTime> #include <QTimer> #include <QPainter>
Then, declare the
paintEvent()function, like so:public: explicit MainWindow(QWidget *parent = 0); ~MainWindow(); virtual void paintEvent(QPaintEvent *event);In
mainwindow.cpp, create three arrays to store the shapes of the hour hand, minute hand, and second hand, where each of the arrays contains three sets of coordinates:void MainWindow::paintEvent(QPaintEvent *event) { static const QPoint hourHand[3] = { QPoint(4, 4), QPoint(-4, 4), QPoint(0, -40) }; static const QPoint minuteHand...