bfSize Specifies the size, in bytes, of the bitmap file.
bfReserved1 Reserved; must be zero.
bfReserved2 Reserved; must be zero.
bfOffBits Specifies the offset, in bytes, from the BITMAPFILEHEADER structure to the bitmap bits.
位图信息头： typedef struct tagBITMAPINFOHEADER{ // bmih DWORD biSize; LONG biWidth; LONG biHeight; WORD biPlanes; WORD biBitCount DWORD biCompression; DWORD biSizeImage; LONG biXPelsPerMeter; LONG biYPelsPerMeter; DWORD biClrUsed; DWORD biClrImportant; } BITMAPINFOHEADER;
Members
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 biHeight is positive, the bitmap is a bottom-up DIB and its origin is the lower left corner. If biHeight is 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. This value must be 1, 4, 8, 16, 24, or 32.
biCompression
Specifies the type of compression for a compressed bottom-up bitmap (top-down DIBs cannot be compressed). It can be one of the following values:
Value Description BI_RGB An uncompressed format. BI_RLE8 A run-length encoded (RLE) format for bitmaps with 8 bits per pixel. The compression format is a two-byte format consisting of a count byte followed by a byte containing a color index. For more information, see the following Remarks section. BI_RLE4 An RLE format for bitmaps with 4 bits per pixel. The compression format is a two-byte format consisting of a count byte followed by two word-length color indices. For more information, see the following Remarks section. BI_BITFIELDS Specifies that the bitmap is not compressed and that the color table consists of three doubleword color masks that specify the red, green, and blue components, respectively, of each pixel. This is valid when used with 16- and 32-bits-per-pixel bitmaps.
biSizeImage
Specifies the size, in bytes, of the image. This may be set to 0 for BI_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 biBitCount member for the compression mode specified by biCompression. If biClrUsed is nonzero and the biBitCount member is less than 16, the biClrUsed member specifies the actual number of colors the graphics engine or device driver accesses. If biBitCount is 16 or greater, then biClrUsed member specifies the size of the color table used to optimize performance of Windows color palettes. If biBitCount equals 16 or 32, the optimal color palette starts immediately following the three doubleword masks.
If the bitmap is a packed bitmap (a bitmap in which the bitmap array immediately follows the BITMAPINFO header and which is referenced by a single pointer), the biClrUsed member must be either 0 or the actual size of the color table.
biClrImportant
Specifies the number of color indices that are considered important for displaying the bitmap. If this value is zero, all colors are important.
