CDC::SetBkColor
Visual Studio 2012
Sets the current background color to the specified color.
virtual COLORREF SetBkColor( COLORREF crColor );
If the background mode is OPAQUE, the system uses the background color to fill the gaps in styled lines, the gaps between hatched lines in brushes, and the background in character cells. The system also uses the background color when converting bitmaps between color and monochrome device contexts.
If the device cannot display the specified color, the system sets the background color to the nearest physical color.