IDirectDrawSurface3::UpdateOverlay

The IDirectDrawSurface3::UpdateOverlay method repositions or modifies the visual attributes of an overlay surface. These surfaces must have the DDSCAPS_OVERLAY value set.

HRESULT UpdateOverlay(

LPRECT lpSrcRect,

LPDIRECTDRAWSURFACE3 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 DirectDraw 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

DDOVER_ADDDIRTYRECT
	Adds a dirty rectangle to an emulated overlaid 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 (0 is 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 (0 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_DDFX
	Uses the overlay FX flags in the lpDDOverlayFx parameter to define special overlay effects.
DDOVER_HIDE
	Turns this overlay off.
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/weave decisions should not be overridden by other interfaces.
DDOVER_INTERLEAVED
	Indicates that the surface memory is composed of interleaved fields.
DDOVER_SHOW
	Turns this overlay on.

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.

Return Values

If the method succeeds, the return value is DD_OK.

If the method fails, the return value may be one of the following error values:

DDERR_DEVICEDOESNTOWNSURFACE

DDERR_INVALIDSURFACETYPE

DDERR_NOSTRETCHHW

DDERR_NOTAOVERLAYSURFACE