feat(arabic): add tashkeel support and shadda+vowel ligatures#343
Merged
oneplus1000 merged 2 commits intosignintech:masterfrom Feb 8, 2026
Merged
feat(arabic): add tashkeel support and shadda+vowel ligatures#343oneplus1000 merged 2 commits intosignintech:masterfrom
oneplus1000 merged 2 commits intosignintech:masterfrom
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- Add tashkeel (diacritical marks) constants: FATHA, DAMMA, KASRA, SUKUN, SHADDA, TANWEEN_*, and Quranic marks - Add Shadda+Vowel ligature constants (Arabic Presentation Forms-B) - Add GetShaddaLigature() function for vowel-to-ligature lookup - Add IsTashkeel() function to detect Arabic diacritical marks - Add Allah ligature (U+FDF2) automatic conversion - Implement reverseWithTashkeel() to keep tashkeel attached during RTL reversal - Update ToArabic() to handle tashkeel-aware character shaping - Add comprehensive tests for tashkeel handling and ligatures - Update Arabic example with Surah Al-Fatiha and Adobe-Arabic font
Contributor
Author
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@oneplus1000 please review |
Collaborator
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Okay, I'll do it during the weekend. :-) |
Collaborator
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Everything looks good overall. My only concern is that the Adobe TTF font should be replaced with an open-source font to avoid licensing issues. |
Contributor
Author
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done, I replaced it with Amiri-regular. |
Collaborator
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thank you |
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Summary
This PR enhances Arabic text support with proper handling of tashkeel (diacritical marks) and automatic ligature generation for better PDF rendering.
New Features
Tashkeel Constants: FATHA, DAMMA, KASRA, SUKUN, SHADDA, TANWEEN_*, and Quranic marks (SUPERSCRIPT_ALEF, MADDAH_ABOVE, etc.)
Shadda+Vowel Ligatures: Automatic combination using Arabic Presentation Forms-B (U+FC5E-U+FC63)
Allah Ligature: Automatic conversion of the word "الله" (Alef + Lam + Lam + Heh) to the special Allah ligature character U+FDF2 (ﷲ). This ensures the word is rendered correctly as a single beautiful ligature in PDF output, which is the proper typographic representation used in Arabic typography.
IsTashkeel(r rune) bool: Public function to detect Arabic diacritical marksGetShaddaLigature(vowel rune) rune: Get combined shadda+vowel formImprovements
Test plan
IsTashkeel(),GetShaddaLigature(), and tashkeel handling