The paintEvent() function is a virtual function defined in the QWidget class and is responsible for painting the widget on the screen. In this case, the function is being overridden in the PM_ImageTransmissionTitle class to provide custom painting for the widget.
The function takes a QPaintEvent pointer as its argument, which represents the area of the widget that needs to be painted. However, in this implementation, the argument is not used.
First, a QStyleOption object is initialized with the current widget’s style using the init() function. This object holds various options and settings related to the widget’s appearance and behavior, such as the background color, font, and layout.
Next, a QPainter object is created, which is used to perform painting operations on the widget. The QPainter draws various graphical elements, such as lines, shapes, and text, onto the widget’s surface.
Finally, the style() function draws the widget’s primitive element using the drawPrimitive() function. The QStyle::PE_Widget parameter specifies the type of primitive element to be drawn, which in this case is a generic widget. The QStyleOption object and QPainter object are passed as arguments to the drawPrimitive() function to customize the appearance of the primitive element.
