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VMRALPHABITMAP structure

The VMRALPHABITMAP structure is used in the VMR-7 filter's IVMRMixerBitmap methods when the application is providing a static alpha-blended bitmap to be displayed on the composited video frame.

Syntax


typedef struct _VMRALPHABITMAP {
  DWORD                dwFlags;
  HDC                  hdc;
  LPDIRECTDRAWSURFACE7 pDDS;
  RECT                 rSrc;
  NORMALIZEDRECT       rDest;
  FLOAT                fAlpha;
  COLORREF             clrSrcKey;
} VMRALPHABITMAP, *PVMRALPHABITMAP;

Members

dwFlags

Flags that instruct the mixer where to find the bitmap. The following values are defined.

ValueMeaning
VMRBITMAP_DISABLE
0x00000001

Disable the bitmap. This flag cannot be combined with other flags.

VMRBITMAP_HDC
0x00000002

Obtain the bitmap from the HDC. If this flag is set, the hdc member must specify a valid handle to a device context, and the pDDS member must be NULL.

If this flag is absent, the pDDS member must point to a valid DirectDraw surface, and the hdc member must be NULL.

VMRBITMAP_ENTIREDDS
0x00000004

Take the entire DirectDraw surface. When this flag is specified, rSrc is ignored. This flag cannot be combined with the VMRBITMAP_HDC flag.

VMRBITMAP_SRCCOLORKEY
0x00000008

The clrSrcKey value is valid and should be used when blending.

VMRBITMAP_SRCRECT
0x00000010

Indicates that the rSrc rectangle is valid and specifies a sub-rectangle of the original app image to be blended.

This flag is only valid for the IVMRMixerBitmap::UpdateAlphaBitmapParameters method. For the IVMRMixerBitmap::SetAlphaBitmap method, the rSrc member must refer to the entire bitmap.

 

hdc

The handle to the device context for the bitmap. Specify NULL if the bitmap is located in a DirectDraw surface.

pDDS

Pointer to a DirectDraw surface that contains the bitmap. Specify NULL if the bitmap is to be obtained from a GDI device context. If a DirectDraw surface is specified, the pixel format must be ARGB-32 or RGB-32. If the surface contains per-pixel alpha, do not set the VMRBITMAP_SRCCOLORKEY flag in dwFlags.

rSrc

Specifies the source rectangle in either the GDI device context or the DirectDraw surface.

rDest

Specifies the destination rectangle in composition space.

fAlpha

Specifies the alpha blending value; must be a value from 0.0 to 1.0 (inclusive).

clrSrcKey

Specifies the source color key.

Requirements

Minimum supported client

Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

Strmif.h (include Dshow.h)

See also

DirectShow Structures

 

 

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