CImageShowWidget::paintEvent - Image Drawing and Display in Qt

///'The paintEvent function is a member function of the CImageShowWidget class. It is called automatically when the widget needs to be repainted. //n//nIn this function, the paintEvent of the base class QWidget is called first to ensure that the base class paints its own content. Then, the function checks if the m_pixmap variable is null. If it is null, the ImageLab label is cleared and the function returns.//n//nIf the m_pixmap is not null, a concurrent task is started using the QtConcurrent::run function. This task performs the actual painting operations on a separate thread to avoid blocking the main thread. //n//nWithin the concurrent task, a scaled version of the m_pixmap is created to fit the size of the ImageLab label. A QPainter object is then created with the scaled pixmap as the paint device.//n//nVarious drawing operations are performed using the QPainter object to draw channel IDs, ROI rectangles, degree points, profile lines, line segments, and scale indicators. The results of the drawing operations are saved to the m_pix variable.//n//nFinally, the Signal_updateImage signal is emitted to update the displayed image in the ImageLab label.///