Feature Request: RTL/BiDi text support (direction CSS property, TextArea RTL editing)

[dotancohen]

I'm building a notes application that needs to support Right-to-Left (Hebrew and Arabic) text alongside English. The application displays a list of notes and allows editing in a TextArea widget. RTL languages require:

• Text direction - Characters flow right-to-left
• Text alignment - Content aligns to the right
• Bidirectional text - Mixed RTL/LTR content (e.g., Hebrew with embedded English words or numbers) renders correctly

What I've tried for displaying text (Static, Label, ListView):

• Unicode directional isolates (RLI \u2067 / PDI \u2069) around RTL text
• CSS text-align: right on widgets

What I've tried for editing text (TextArea):

• Applied CSS class with text-align: right - no effect
• Tried direction: rtl CSS - not a supported property (causes StylesheetParseError)

.rtl {
  text-align: right;  /* Works for Static/Label */
  direction: rtl;     /* Not supported - causes parse error */
}

• text-align: right works on Static and Label widgets
• text-align has no effect on TextArea
• direction CSS property is not supported
• TextArea has no RTL editing support

Requested Features:

1. CSS direction property - Support direction: rtl to set text direction on widgets. This is standard CSS and essential for RTL languages.
2. TextArea RTL support - Allow TextArea to respect text-align and direction CSS, or provide a direction parameter/property for RTL editing.
3. BiDi-aware text rendering - Framework-level support for the Unicode Bidirectional Algorithm would ensure consistent RTL display regardless of terminal capabilities.

I was testing with Textual 6.11.0 with Python: 3.12 on Kubuntu 24.04 and KDE's Konsole terminal. This terminal has excellent RTL support.