ref: 528fa0acfa3532dee4a50fca1ae49d147403edfc
dir: /sys/src/cmd/jpg/bmp.h/
#define BMP_RGB 0
#define BMP_RLE8 1
#define BMP_RLE4 2
#define BMP_BITFIELDS 3
typedef struct {
uchar red;
uchar green;
uchar blue;
uchar alpha;
} Rgb;
#define Filehdrsz 14
typedef struct {
short type;
long size; /* file size, not structure size */
short reserved1;
short reserved2;
long offbits;
} Filehdr;
typedef struct {
long size; /* Size of the Bitmap-file */
long lReserved; /* Reserved */
long dataoff; /* Picture data location */
long hsize; /* Header-Size */
long width; /* Picture width (pixels) */
long height; /* Picture height (pixels) */
short planes; /* Planes (must be 1) */
short bpp; /* Bits per pixel (1, 4, 8 or 24) */
long compression; /* Compression mode */
long imagesize; /* Image size (bytes) */
long hres; /* Horizontal Resolution (pels/meter) */
long vres; /* Vertical Resolution (pels/meter) */
long colours; /* Used Colours (Col-Table index) */
long impcolours; /* Important colours (Col-Table index) */
} Infohdr;