Creating a custom widget

It is time to actually get something onto the screen by painting on a widget. A widget is repainted as a result of receiving a paint event, which is handled by reimplementing the paintEvent() virtual method. This method accepts a pointer to the event object of the QPaintEventtype that contains various bits of information about the repaint request. Remember that you can only paint on the widget from within that widget's paintEvent() call.

Time for action – Custom-painted widgets

Let's immediately put our new skills in to practice! Start by creating a new Qt Widgets Application in Qt Creator, choosing QWidget as the base class, and ensuring that the Generate Form box is unchecked. The name of our widget class will be Widget.

Switch to the header file for the newly created class, add a protected section to the class, and type void paintEvent in that section. Then, press Ctrl + Space on your keyboard and Creator will suggest the parameters for the method. You should end...