IDirectDrawSurface5::UpdateOverlay

Article
06/30/2006

This method repositions or modifies the visual attributes of an overlay surface. These surfaces must have the DDSCAPS_OVERLAY flag set.

HRESULT UpdateOverlay(
  LPRECT lpSrcRect, 
  LPDIRECTDRAWSURFACE4 lpDDDestSurface, 
  LPRECT lpDestRect, 
  DWORD dwFlags, 
  LPDDOVERLAYFX lpDDOverlayFx
);

Parameters

lpSrcRect
Address of a RECT structure that defines the x, y, width, and height of the region on the source surface being used as the overlay. This parameter can be NULL when hiding an overlay, or to indicate that the entire overlay surface is to be used and that the overlay surface conforms to any boundary and size alignment restrictions imposed by the device driver.
lpDDDestSurface
Address of the IDirectDrawSurface5 interface for the surface that is being overlaid.
lpDestRect
Address of a RECT structure that defines the x, y, width, and height of the region on the destination surface that the overlay should be moved to. This parameter can be NULL when hiding the overlay.

dwFlags
The following table shows the possible flags.

Flag	Description
DDOVER_ADDDIRTYRECT	Adds a dirty rectangle to an emulated overlay surface.
DDOVER_ALPHADEST	Uses either the alpha information in pixel format or the alpha channel surface attached to the destination surface as the alpha channel for this overlay.
DDOVER_ALPHADESTCONSTOVERRIDE	Uses the dwAlphaDestConst member of the DDOVERLAYFX structure as the destination alpha channel for this overlay.
DDOVER_ALPHADESTNEG	Indicates that the destination surface becomes more transparent as the alpha value increases (zero equals opaque).
DDOVER_ALPHADESTSURFACEOVERRIDE	Uses the lpDDSAlphaDest member of the DDOVERLAYFX structure as the alpha channel destination for this overlay.
DDOVER_ALPHAEDGEBLEND	Uses the dwAlphaEdgeBlend member of the DDOVERLAYFX structure as the alpha channel for the edges of the image that border the color key colors.
DDOVER_ALPHASRC	Uses either the alpha information in pixel format or the alpha channel surface attached to the source surface as the source alpha channel for this overlay.
DDOVER_ALPHASRCCONSTOVERRIDE	Uses the dwAlphaSrcConst member of the DDOVERLAYFX structure as the source alpha channel for this overlay.
DDOVER_ALPHASRCNEG	Indicates that the source surface becomes more transparent as the alpha value increases (zero is opaque).
DDOVER_ALPHASRCSURFACEOVERRIDE	Uses the lpDDSAlphaSrc member of the DDOVERLAYFX structure as the alpha channel source for this overlay.
DDOVER_AUTOFLIP	Automatically flip to the next surface in the flip chain each time a video port VSYNC occurs.
DDOVER_BOB	Display each field individually of the interlaced video stream without causing any artifacts.
DDOVER_BOBHARDWARE	Indicates that bob operations will be performed using hardware rather than software or emulated. This flag must be used with the DDOVER_BOB flag.
DDOVER_DDFX	Uses the overlay FX flags in the lpDDOverlayFx parameter to define special overlay effects.
DDOVER_HIDE	Turns off this overlay.
DDOVER_KEYDEST	Uses the color key associated with the destination surface.
DDOVER_KEYDESTOVERRIDE	Uses the dckDestColorkey member of the DDOVERLAYFX structure as the color key for the destination surface.
DDOVER_KEYSRC	Uses the color key associated with the source surface.
DDOVER_KEYSRCOVERRIDE	Uses the dckSrcColorkey member of the DDOVERLAYFX structure as the color key for the source surface.
DDOVER_OVERRIDEBOBWEAVE	Indicates that bob and weave decisions should not be overridden by other interfaces.
DDOVER_INTERLEAVED	Indicates that the surface memory is composed of interleaved fields.
DDOVER_SHOW	Turns on this overlay.

lpDDOverlayFx
Address of a DDOVERLAYFX structure that describes the effects to be used. This parameter can be NULL if the DDOVER_DDFX flag is not specified.