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The BITMAPINFOHEADERstructure contains information for the video stream of an AVI RIFF file. This structure has the following members.
typedef struct tagBITMAPINFOHEADER {
DWORD
biSize
;
LONG
biWidth
;
LONG
biHeight
;
WORD
biPlanes
;
WORD
biBitCount
;
DWORD
biCompression
;
DWORD
biSizeImage
;
LONG
biXPelsPerMeter
;
LONG
biYPelsPerMeter
;
DWORD
biClrUsed
;
DWORD
biClrImportant
;
} BITMAPINFOHEADER;
- biSize
- Specifies the number of bytes required by the structure.
- biWidth
- Specifies the width of the bitmap, in pixels.
- biHeight
- Specifies the height of the bitmap, in pixels. If biHeightis positive, the bitmap is a bottom-up DIB (device-independent bitmap) and its origin is the lower left corner. If biHeightis negative, the bitmap is a top-down DIB and its origin is the upper left corner.
- biPlanes
- Specifies the number of planes for the target device. This value must be set to 1.
- biBitCount
- Specifies the number of bits per pixel. Some compression formats need this information to properly decode the colors in the pixel.
- biCompression
- Specifies the type of compression used or requested. Both existing and new compression formats use this member.
- biSizeImage
- Specifies the size, in bytes, of the image. This can be set to 0 for uncompressed RGB bitmaps.
- biXPelsPerMeter
- Specifies the horizontal resolution, in pixels per meter, of the target device for the bitmap. An application can use this value to select a bitmap from a resource group that best matches the characteristics of the current device.
- biYPelsPerMeter
- Specifies the vertical resolution, in pixels per meter, of the target device for the bitmap.
- biClrUsed
- Specifies the number of color indices in the color table that are actually used by the bitmap. If this value is zero, the bitmap uses the maximum number of colors corresponding to the value of the biBitCountmember for the compression mode specified by biCompression.
- biClrImportant
- Specifies the number of color indices that are considered
important for displaying the bitmap. If this value is zero, all
colors are important.
When the value in the biBitCountmember is set to greater than eight, video drivers can assume bitmaps are true color and they do not use a color table.
When the value in the biBitCountmember is set to less than or equal to eight, video drivers can assume the bitmap uses a palette or color table defined in the BITMAPINFOdata structure. This data structure has the following members:
typedef struct tagBITMAPINFO { BITMAPINFOHEADER bmiHeader ; RGBQUAD bmiColors [1]; } BITMAPINFO;The BITMAPINFO bmiheadermember specifies a BITMAPINFOHEADERstructure. The BITMAPINFO bmiColorsmember specifies an array of RGBQUADdata types that define the colors in the bitmap.
Last updated on Tuesday, May 18, 2004