Bidirectional text - ArchWiki

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From Wikipedia:Bidirectional text, is text that contains two text directionalities, right-to-left (RTL) and left-to-right (LTR).

## Concepts

Text direction
  in text editing, setting text direction changes how the program interacts with typed text including changes in text navigation, text selection, and text insertion.
Text alignment
  text alignment only changes how text is displayed and styled.
Fake Bidi
  a fake locale displaying completely reversed English sentences to mimic a RTL context. This helps developers who do not speak a RTL language to deal with RTL issues. For example:

      This English sentence contains SDROW CIBARA EMOS and ends with English words.

Poor man's bidi mode
  automatic visual text order right-to-left input in normal terminal.
Logical navigation
  words are traversed as they are read.
Visual navigation
  words are traversed as they are displayed. This GIF demonstrates the difference between the two.

Logical navigation is the correct way of navigation that programs should implement to fully support Bidi. Despite that, it would be preferable to have a switch between the two.

Unicode support
  there are three main Unicode control characters: Wikipedia:RLM, Wikipedia:LRM, Wikipedia:ALM.

Bidirectional Algorithm
  is the set of rules applied to display text in the correct order.

fribidi-gitAUR is an open source implementations of Bidi Algorithm. python-bidiAUR is a python library for related functions.

## Support

In order for a program to fully support Bidi text, it must have:

Letter rendering (RTL)
  able to correctly apply letter shaping and ligatures. See Complete Text Layout. This is often referred to shortly as RTL support.
Switch text alignment (Bidi)
  E.g: Firefox `Ctrl+Shift+X` shortcut.
Logical navigation
  in a RTL text, with RTL text alignment, arrow keys should not cause reversed navigation.

Tag | App | Date | RTL | Bidi | Nav | Notes
--- | --- | --- | --- | --- | --- | ---
browser | chromium | 2022-08-28 | Yes | No | Yes | Chromium is the engine of ElectronJS. Fixing this should resolve Electron Apps too.
browser | firefox | 2022-09-01 | Yes | No | No |
browser | qtwebbrowser | 2022-11-01 | Yes | No |  |
browser | webkit | 2022-11-01 | Yes | No |  |
editor | AbiWord | 2007-12-06 | Yes |  |  |
editor | emacs | 2019-06-31 | Yes | No |  | With extension
editor | kate | 2016-06-20 | Yes | No |  |
editor | LibreOffice |  | Yes | Yes | Yes | fully supported. Enabled using Complex Text Layout from settings.
editor | neovim | 2014-04-17 | No | No |  | see :set arabic
editor | texworks | 2009-03-01 | Yes | No |  |
editor | vim | 2015-08-19 | No | No |  | see :set arabic
other | groff | 2005-12-02 | No | No | – |
other | Wikipedia:HTML |  | Yes | Yes | Yes |
other | latex |  | Yes | Yes | – | Using LuaTeX or XeLaTeX with polyglossia
other | wine | 2002-04-21 | Yes | No |  |
terminal | alacritty | 2017-07-15 |  | No |  |
terminal | dvtm | 2019-10-12 |  | No |  |
terminal | gedit |  | Yes | No |  | For Gedit <= 2.1, workaround by extension.
terminal | irssi | 2019-10-12 |  | No |  |
terminal | kitty | 2019-11-01 |  | No |  |
terminal | konsole |  | Yes | No |  |
terminal | libvte |  | Yes | No |  | including libvte-based like Gnome, sakura, xfce4...
terminal | mltermAUR |  | Yes | No |  |
terminal | neatvi-gitAUR | 2019-07-04 |  | No |  |
terminal | pymux | 2019-10-12 |  | No |  |
terminal | qterminal |  | Yes | No |  |
terminal | radare2 | 2015-02-03 |  | No |  |
terminal | tmux | 2019-10-12 |  | No |  | won't fix
terminal | wezterm | 2021-05-11 |  | No |  |
terminal | xstAUR | 2018-10-26 |  | No |  |

## Troubleshooting

Verify UTF-8 Encoding is properly configured first. Make sure you install the fonts corresponding to your language: Arabic, Persian, Hebrew. For some terminal, (bicon-gitAUR) is required to properly display Arabic and Hebrew text.

### Temporary workarounds

- Sublime text.

## See also

### Internal links

- Locale
- Localization

### External links

- freedesktop specification for Bidi support: terminal.
- Comprehensive guide of RTL styling in HTML

Category:

- Input methods