------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.
http://bugs.kde.org/show_bug.cgi?id=114211
------- Additional Comments From caulier.gilles free fr 2006-04-25 14:39 -------
Marcel,
To clarify how Comments are embedded into JPEG files, i will describe this feature. There is 3 ways to embedded a comment in JPEG :
1/ the first is the JFIF COM section.
Important : this section is outside EXIF/IPTC/XMP section. Unlike konqueror file properties said, the comments don't come from Exif but JFIF in this dialog !!! (Perhaps this problem have been fixed in KDE 3.5.x).
There is no size limitation know but i don't know if UTF8 is supported here. This way have always been used by digikam since 0.7.x release to store comments in JPEG file.
2/ The second is the Exif UserComments tag. Like Exiv2 documentation said, this field support UTF8. In trunk, the DMetadata class implementation need to be fixed following this example.
//-------------------------------------------------------------
00029 Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(argv[1]);
00030 assert (image.get() != 0);
00031 image->readMetadata();
00032 Exiv2::ExifData &exifData = image->exifData();
00033
00034 /*
00035 Exiv2 uses a CommentValue for Exif user comments. The format of the
00036 comment string includes an optional charset specification at the beginning:
00037
00038 [charset=["]Ascii|Jis|Unicode|Undefined["] ]comment
00039
00040 Undefined is used as a default if the comment doesn't start with a charset
00041 definition.
00042
00043 Following are a few examples of valid comments. The last one is written to
00044 the file.
00045 */
00046 exifData["Exif.Photo.UserComment"]
00047 = "charset=\"Unicode\" An Unicode Exif comment added with Exiv2";
00048 exifData["Exif.Photo.UserComment"]
00049 = "charset=\"Undefined\" An undefined Exif comment added with Exiv2";
00050 exifData["Exif.Photo.UserComment"]
00051 = "Another undefined Exif comment added with Exiv2";
00052 exifData["Exif.Photo.UserComment"]
00053 = "charset=Ascii An ASCII Exif comment added with Exiv2";
00054
00055 std::cout << "Writing user comment '"
00056 << exifData["Exif.Photo.UserComment"]
00057 << "' back to the image\n";
00058
00059 image->writeMetadata();
//-------------------------------------------------------------
3/ The last is IPTC caption tag : do not support UTF8 (only ascii latin1) and limited to 2000 charactors.
In fact, to solve definitivly UTF8 problem with metadata in the future, we need to support XMP metadata. Exiv2 will support XMP in the future:
http://dev.robotbattle.com/bugs/view_all_bug_page.php (select Exiv2 project to the top-right of the page)
We need to be patient (:=)))...
Some URL :
http://park2.wakwak.com/~tsuruzoh/Computer/Digicams/exif-e.htmlhttp://www.iptc.org/IIM/4.1/specification/IIMV4.1.pdfhttp://www.adobe.com/products/xmp/main.htmlGilles Caulier
_______________________________________________
Digikam-devel mailing list
[hidden email]
https://mail.kde.org/mailman/listinfo/digikam-devel
Locked
