IDirectDraw Interface Method Groups
Applications use the methods of the IDirectDraw interface to create DirectDraw objects and work with system-level variables. The methods can be organized into the following groups:
Allocating memory Compact
Creating objects CreateClipper
Device capabilities GetCaps
Display modes EnumDisplayModes
Display status GetScanLine
IUnknown AddRef
Miscellaneous GetAvailableVidMem
Setting behavior SetCooperativeLevel
Surfaces DuplicateSurface
All COM interfaces inherit the IUnknown interface methods, which are listed in the "IUnknown" group above. These three methods allow additional interfaces to be added to the DirectDraw object without affecting the functionality of the original interface.