Remarks
m_ps is a public member variable of type PAINTSTRUCT. It is the PAINTSTRUCT that is passed to and filled out by CWnd::BeginPaint.
The PAINTSTRUCT contains information that the application uses to paint the client area of the window associated with a CPaintDC object.
Note that you can access the device-context handle through the PAINTSTRUCT. However, you can access the handle more directly through the m_hDC member variable that CPaintDC inherits from CDC.