Man Linux: Main Page and Category List


       im_header_int,   im_header_double,   im_header_string,   im_header_get,
       im_header_get_type, im_header_map - read fields from the image header


       #include <vips/vips.h>

       int im_header_int( IMAGE *image, const char *field, int *out )
       int im_header_double( IMAGE *image, const char *field, double *out )
       int im_header_string( IMAGE *image, const char *field, char **out )
       GType im_header_get_type( IMAGE *im, const char *field );
       int im_header_get( IMAGE *im, const char *field, GValue *value_copy );
       typedef void *(*im_header_map_fn)( IMAGE *,
         const char *, GValue *, void *, void * );
       void *im_header_map( IMAGE *im,
         im_header_map_fn fn, void *a, void *b );


       im_header_int(3) reads the value of an integer header field. These  are
       "Xsize", "Ysize", "Bands", "Bbits", "BandFmt", "Coding", and "Type", or
       any integer meta field.

       im_header_double(3) reads the value of the integer header fields. These
       are "Xres", and "Yres", or any double meta field.

       im_header_string(3) reads the value of the integer header fields. These
       are "Hist", and "filename" or any string meta field.

       im_header_get_type(3) returns the GType (eg. G_TYPE_INT) for  a  field.
       It  returns  zero  if  the  field  does  not  exist.  It  does  not set
       im_error(3), so it’s useful for test for a field’s existence.

       im_header_get(3) fills the GValue with a copy of the  field  value,  if
       the   field   exists.   The   value  should  be  zeroed  but  otherwise
       uninitialised. The value should be unset once  the  user  has  finished
       with it.

       im_header_map(3) maps a function over all header fields, presenting the
       value of each field as a GValue. Return non-NULL from the map  function
       to  stop  iteration  early. It maps over the builtin fields first, then
       any meta fields.


       All functions returns 0 on success and -1 on error.


       im_close(3), im_open(3).

                                  7 May 2002