isFullWidthCharacter method

bool isFullWidthCharacter()

Checks if a single character is a full-width character (occupies 2 columns). Authoritative standard: Unicode East Asian Width (EAW)

Implementation

bool isFullWidthCharacter() {
  if (isEmpty) return false;
  // Only handle single visual characters (avoid combining characters/corrupted text)
  if (characters.length != 1) return false;

  final code = runes.first;

  // 1. CJK Unified Ideographs (all Chinese characters)
  if (code >= 0x4E00 && code <= 0x9FFF) return true;
  // 2. Japanese Hiragana and Katakana
  if (code >= 0x3040 && code <= 0x30FF) return true;
  // 3. Korean Hangul Syllables
  if (code >= 0xAC00 && code <= 0xD7AF) return true;
  // 4. Full-width punctuation marks
  if (code >= 0x3000 && code <= 0x303F) return true;
  // 5. Full-width letters/digits/symbols (Ａ Ｂ Ｃ １２３！＠＃)
  if (code >= 0xFF00 && code <= 0xFFEF) return true;
  // 6. Emoji & special symbols (occupy 2 columns in terminal)
  if (code >= 0x1F600 && code <= 0x1F64F) return true; // Emoticons
  if (code >= 0x1F300 && code <= 0x1F5FF) return true; // Icons
  // 7. Full-width space (especially important)
  if (code == 0x3000) return true;

  return false;
}