When a FITS header is scanned in memory or read from a file several image values are retrieved from the header and stored in s FITSImage structure. This structure may be accesed with the following macros:
#define ft_hasbscale(fits) ( fits->image->has_bscale )
#define ft_bscale(fits) ( fits->image->bscale )
#define ft_hasbzero(fits) ( fits->image->has_bzero )
#define ft_bzero(fits) ( fits->image->bzero )
#define ft_hasblank(fits) ( fits->image->has_blank )
#define ft_blank(fits) ( fits->image->blank )
typedef struct FITSImage {
int has_bscale;
int bscale;
int has_bzero;
int bzero;
int has_blank;
int blank;
} *FITSImage;