Joining Type - Join Causing

Join Causing is a value assigned to certain Arabic and Syriac script characters, indicating that they actively connect to adjacent letters on both sides, thereby causing cursive joining behavior in text rendering. Unlike characters with a neutral or transparent joining type, those marked as Join Causing form a visible ligature or connection with the preceding and following characters, even if they are not themselves inherently joining. This affects how words are shaped in scripts like Arabic, ensuring that a character like a medial form or a special connector (e.g., tatweel) promotes seamless horizontal linkage. Consequently, this value is crucial for proper shaping and bidirectional text display, as it overrides the default non-joining tendency of certain base forms.