exifcomment.cpp

Sample program showing how to set the Exif comment of an image.

// ***************************************************************** -*- C++ -*-
/*
  Abstract : Sample program showing how to set the Exif comment of an image,
             Exif.Photo.UserComment

  File:      exifcomment.cpp
  Author(s): Andreas Huggel (ahu) <ahuggel@gmx.net>
  History  : 10-May-04, ahu: created
             16-Jan-05, ahu: updated using CommentValue and operator trickery
 */
// *****************************************************************************
// included header files
#include <exiv2/exiv2.hpp>

#include <iostream>
#include <cassert>

// *****************************************************************************
// Main
int main(int argc, char* const argv[])
try {

    if (argc != 2) {
        std::cout << "Usage: " << argv[0] << " file\n";
        return 1;
    }

    Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(argv[1]);
    assert (image.get() != 0);
    image->readMetadata();
    Exiv2::ExifData &exifData = image->exifData();

    /*
      Exiv2 uses a CommentValue for Exif user comments. The format of the
      comment string includes an optional charset specification at the beginning:

      [charset=["]Ascii|Jis|Unicode|Undefined["] ]comment

      Undefined is used as a default if the comment doesn't start with a charset
      definition.

      Following are a few examples of valid comments. The last one is written to
      the file.
     */
    exifData["Exif.Photo.UserComment"]
        = "charset=\"Unicode\" An Unicode Exif comment added with Exiv2";
    exifData["Exif.Photo.UserComment"]
        = "charset=\"Undefined\" An undefined Exif comment added with Exiv2";
    exifData["Exif.Photo.UserComment"]
        = "Another undefined Exif comment added with Exiv2";
    exifData["Exif.Photo.UserComment"]
        = "charset=Ascii An ASCII Exif comment added with Exiv2";

    std::cout << "Writing user comment '"
              << exifData["Exif.Photo.UserComment"]
              << "' back to the image\n";

    image->writeMetadata();

    return 0;
}
catch (Exiv2::AnyError& e) {
    std::cout << "Caught Exiv2 exception '" << e << "'\n";
    return -1;
}