This is GNU FriBidi The Free Implementation of the Unicode Bidirectional Algorithm. Background ========== One of the missing links stopping the penetration of free software in Middle East is the lack of support for the Arabic and Hebrew alphabets. In order to have proper Arabic and Hebrew support, the BiDi algorithm should have been implemented. It is our hope that this library will stimulate more free software in the Middle Eastern countries. Audience ======== It is our hope that this library will stimulate the implementation of Hebrew and Arabic in lots of free software. Here is a small list of projects that would benefit from the use of the GNU FriBidi library, but of course there are many more: Wine, Mozilla, Qt, KDE, lynx, OpenOffice. GNU FriBidi is already being used in projects like Pango (resulting in GTK+ and GNOME using GNU FriBidi), AbiWord, MLTerm, MPlayer, and BiCon. Dependencies ============ Currently GNU FriBidi does not depend on any other library, but uses Glib if available. It uses GNU Build System for build and installation on POSIX systems. Downloading =========== The latest version of GNU FriBidi may be found at: http://fribidi.org/ Building ======== See INSTALL for a description of how to build and install GNU FriBidi. License ========= GNU FriBidi is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. GNU FriBidi 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with GNU FriBidi, in a file named COPYING; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA For licensing issues, contact <license@farsiweb.info>. Implementation ============== The library implements the algorithm described in the "Unicode Standard Annex #9, The Bidirectional Algorithm", available at http://www.unicode.org/unicode/reports/tr9/. GNU Fribidi has been tested exhaustively against the Unicode Reference Code, and to the best of our knowledge, it completely conforms to the specification, always producing the same result as the Reference Code. The library uses Unicode (UTF32) entirely. The character properties are automatically extracted from the Unicode data files, available from: http://www.unicode.org/Public/UNIDATA/ This means that every Unicode character is treated in strict accordance with the Unicode specification. There is a limited support for character set conversion from/to the UTF32 encoding. Data in these character sets must be converted into UTF32 before the library may be used. iconv(3) can always do a better job on that, so you may find that the character sets conversion code is typically turned off on POSIX machines. The reordering of characters is typically done through the function: fribidi_boolean fribidi_log2vis(/* input */ FriBidiChar *str, FriBidiStrIndex len, FriBidiCharType *pbase_dir, /* output */ FriBidiChar *visual_str, FriBidiStrIndex *position_L_to_V_list, FriBidiStrIndex *position_V_to_L_list, FriBidiLevel *embedding_level_list ) where str is the Unicode input string len is the length of the unicode string pbase_dir is the input and output base direction. If base == FRIBIDI_TYPE_ON then fribidi_log2vis calculates the base direction on its own according to the BiDi algorithm. visual_str The reordered output unicode string. position_L_to_V_list Maps the positions in the logical string to positions in the visual string. position_V_to_L_list Maps the positions in the visual string to the positions in the logical string. embedding_level_list Returns the classification of each character. Even levels indicate LTR characters, and odd levels indicate RTL characters. The main use of this list is in interactive applications when the embedding e.g. level determines cursor display. In any of the output pointers == NULL, then that information is not calculated. How it looks like ================= Have a look at tests directory, to see some input and outputs, which CapRTL charset means that CAPITAL letters are right to left, and digits 6, 7, 8, 9 are Arabic digits, try 'fribidi --charsetdesc CapRTL' for the full description. Executable ========== There is also a command-line utilitity called fribidi that loops over the text of a file and performs the BiDi algorithm on each line, also used for testing the algorithm. Run fribidi with the --help option to learn about usage. The command-line utility is known to have problems with line-breaking and ltov/vtol lists. Bugs and comments ================= Report GNU FriBidi bugs at: http://fribidi.org/bug And send your comments to: fribidi@freedesktop.org Behdad Esfahbod behdad@gnu.org
