windows-xp/Source/XPSP1/NT/multimedia/media/avi/drawdib.16/dcilib/lockbm.h

#define BM_NULL         0
#define BM_TYPE         0x0F        // type mask
#define BM_8BIT         0x01        // all SVGA, and other 256 color
#define BM_16555        0x02        // some HiDAC cards
#define BM_24BGR        0x03        // just like a DIB
#define BM_32BGR        0x04        // 32 bit BGR
#define BM_VGA          0x05        // VGA style bitmap.
#define BM_16565        0x06        // most HiDAC cards
#define BM_24RGB        0x07        // 24 bit RGB
#define BM_32RGB        0x08        // 32 bit RGB
#define BM_1BIT         0x09        // mono bitmap
#define BM_4BIT         0x0A        // 4 bit packed pixel.

//
//  this is a physical BITMAP in memory, this is just like a  BITMAP
//  structure, but with extra fields staring at bmWidthPlanes
//
typedef struct {
    short  bmType;
    short  bmWidth;
    short  bmHeight;
    short  bmWidthBytes;
    BYTE   bmPlanes;
    BYTE   bmBitsPixel;
    LPVOID bmBits;
    long   bmWidthPlanes;
    long   bmlpPDevice;
    short  bmSegmentIndex;
    short  bmScanSegment;
    short  bmFillBytes;
    short  reserved1;
    short  reserved2;
} IBITMAP;

LPVOID FAR GetPDevice(HDC hdc);
void   FAR TestSurfaceType(HDC hdc, int x, int y);
UINT   FAR GetSurfaceType(LPVOID lpBits);