58 lines
1.9 KiB
Groff
58 lines
1.9 KiB
Groff
|
.TH IM_HEADER 3 "7 May 2002"
|
||
|
|
.SH NAME
|
||
|
|
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
|
||
|
|
.SH SYNOPSIS
|
||
|
|
#include <vips/vips.h>
|
||
|
|
|
||
|
|
int im_header_int( IMAGE *image, const char *field, int *out )
|
||
|
|
.br
|
||
|
|
int im_header_double( IMAGE *image, const char *field, double *out )
|
||
|
|
.br
|
||
|
|
int im_header_string( IMAGE *image, const char *field, char **out )
|
||
|
|
.br
|
||
|
|
GType im_header_get_type( IMAGE *im, const char *field );
|
||
|
|
.br
|
||
|
|
int im_header_get( IMAGE *im, const char *field, GValue *value_copy );
|
||
|
|
.br
|
||
|
|
typedef void *(*im_header_map_fn)( IMAGE *,
|
||
|
|
const char *, GValue *, void *, void * );
|
||
|
|
.br
|
||
|
|
void *im_header_map( IMAGE *im,
|
||
|
|
im_header_map_fn fn, void *a, void *b );
|
||
|
|
|
||
|
|
.SH DESCRIPTION
|
||
|
|
.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.
|
||
|
|
|
||
|
|
.B im_header_double(3)
|
||
|
|
reads the value of the integer header fields. These are
|
||
|
|
"Xres", and "Yres", or any double meta field.
|
||
|
|
|
||
|
|
.B im_header_string(3)
|
||
|
|
reads the value of the integer header fields. These are
|
||
|
|
"Hist", and "filename" or any string meta field.
|
||
|
|
|
||
|
|
.B 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
|
||
|
|
.B im_error(3),
|
||
|
|
so it's useful for test for a field's existence.
|
||
|
|
|
||
|
|
.B 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.
|
||
|
|
|
||
|
|
.B 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.
|
||
|
|
|
||
|
|
.SH RETURN VALUE
|
||
|
|
All functions returns 0 on success and -1 on error.
|
||
|
|
.SH SEE ALSO
|
||
|
|
im_close(3), im_open(3).
|