gimp/plug-ins/jpeg/gimpexif.c

155 lines
4.8 KiB
C

/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
* EXIF-handling code for the metadata library.
*/
#include "config.h"
#include <stdlib.h>
#include <libgimp/gimp.h>
#ifdef HAVE_EXIF
#include <libexif/exif-data.h>
#include <libexif/exif-content.h>
#include <libexif/exif-utils.h>
#include "gimpexif.h"
/*
* gimp_metadata_store_exif:
* @image_ID: the GIMP image to work on.
* @exif_data: the Exif data that is to be stored.
*
* This function is supposed to load the "gimp-metadata" parasite
* (which is in XMP format), parse it, add the exif information,
* reformat it into XMP, and store the result as the new parasite.
* The infrastructure to do this is not yet available, so for the
* moment it does something much simpler -- it calls upon libexif
* to serialize the exif data, and stores the result in a parasite
* called "exif-data".
*/
void gimp_metadata_store_exif (gint32 image_ID,
ExifData *exif_data)
{
GimpParasite *parasite = NULL;
guchar *exif_buf = NULL;
guint exif_buf_len = 0;
exif_data_save_data (exif_data, &exif_buf, &exif_buf_len);
if (exif_buf_len > EXIF_HEADER_SIZE)
{
parasite = gimp_parasite_new ("exif-data",
GIMP_PARASITE_PERSISTENT,
exif_buf_len, exif_buf);
gimp_image_parasite_attach (image_ID, parasite);
gimp_parasite_free (parasite);
}
free (exif_buf);
}
/*
* gimp_metadata_generate_exif:
* @image_ID: the ID of the GIMP image to work on.
*
* This function is supposed to load the "gimp-metadata" parasite
* (which is a block of XMP info), parse it, extract the exif
* values, and build an ExifData structure from them.
* The infrastructure to do this is not yet available, so for the
* moment it does something much simpler -- it loads the "exif-data"
* parasite (which is a serialized representation of the exif data),
* and calls upon libexif to parse it into an ExifData struct.
*
* returns: The reconstructed exif data, or NULL if none exists.
*/
ExifData *
gimp_metadata_generate_exif (gint32 image_ID)
{
ExifData *exif_data;
GimpParasite *parasite = gimp_image_parasite_find (image_ID,
"exif-data");
if (parasite)
{
exif_data = exif_data_new_from_data (gimp_parasite_data (parasite),
gimp_parasite_data_size (parasite));
gimp_parasite_free (parasite);
return exif_data;
}
return NULL;
}
/*
* gimp_exif_content_get_value:
* @content: ExifContent block from which to get value
* @tag: Tag whose value to get
* @value: Place to put the result
* @maxlen: Maximum size of returned string
*
* This function is a wrapper around the libexif function
* exif_content_get_value(), necessary to deal with an incompatible
* API change. It looks up the value of the specifed tag,
* returning the result as a human-readable string. Note that
* @value must be pre-allocated.
*/
const gchar *
gimp_exif_content_get_value (ExifContent *content,
ExifTag tag,
gchar *value,
gint maxlen)
{
ExifEntry *entry = exif_content_get_entry (content, tag);
if (entry)
return exif_entry_get_value (entry, value, maxlen);
else
return NULL;
}
/*
* gimp_exif_data_remove_entry:
* @data: ExifData pointer
* @ifd: Index of the ifd holding the entry to be removed
* @tag: Tag of the entry to be removed
*
* This is a convenience function for removing a specified
* entry from an exif data structure. If no such entry
* exists, the function returns without doing anything.
*/
void
gimp_exif_data_remove_entry (ExifData *exif_data,
ExifIfd ifd,
ExifTag tag)
{
ExifEntry *entry = exif_content_get_entry (exif_data->ifd[ifd],
tag);
if (entry)
exif_content_remove_entry (exif_data->ifd[ifd], entry);
}
#endif /* HAVE_EXIF */