🌍 Add RTL Text Support for Canvas and SDF Font Renderers (Arabic, Hebrew, etc.)

[wouterlucas]

🌟 Feature Request: RTL Text Support in Font Engines

🚀 Goal

Support for Right-to-Left (RTL) text rendering is essential to accommodate languages like Arabic, Hebrew, and others 🌍. Currently, RTL rendering is not natively supported in the following font engines:

• 🖌️ Canvas Text Renderer
• ✍️ SDF Font Renderer

This feature will enable proper text alignment, glyph shaping, and directionality for RTL languages.

🔧 Suggested Implementation

• Add RTL text layout logic to both renderers.
• Integrate glyph shaping for languages with complex scripts (e.g., Arabic ligatures).
• Provide an API for switching between LTR and RTL modes on CoreTextNode.

🛠️ Resources

• Lightning 2 original PR for RTL support feature: TextTexture handle right to left text direction rdkcentral/Lightning#526

[elsassph]

It is important to note that the Lightning 2 PR is NOT a good reference:

• It has poor Chrome compatibility (77+)
• It doesn't support bidirectional text wrapping (mixed English and Arabic)

https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/direction#browser_compatibility

[wouterlucas]

That's good to know, we'll have to come up with a SDF one anyway, might see if we can port some of that processing over to the way canvas text is constructed (if possible).

Thanks for sharing!