DeleteDC()
Deletes all resources associated with a device context.
Comments
In general, do not call this function; the destructor will do it for you.
An application should not call DeleteDC if objects have been selected into the device context. Objects must
first be selected out of the device context before it it is deleted.
An application must not delete a device
context whose handle was obtained by calling CWnd::GetDC. Instead, it must call CWnd::ReleaseDC to free the
device context.
The DeleteDC function is generally used to delete device contexts created with CreateDC,
CreateIC, or CreateCompatibleDC.