executeHandleInsertText function

void executeHandleInsertText(String text, FluentDocument document)

Inserts text by iterating through grapheme clusters instead of UTF-16 code units. This ensures emoji and other multi-code-unit characters are inserted as single units.

Implementation

void executeHandleInsertText(String text, FluentDocument document) {
  if (text.isEmpty) return;

  // Iterate through the text by UTF-16 code units, but preserve surrogate pairs
  // by checking if we're in the middle of a surrogate pair
  int i = 0;
  while (i < text.length) {
    int charCode = text.codeUnitAt(i);

    // Check if this is a high surrogate (start of emoji)
    if (charCode >= 0xD800 && charCode <= 0xDBFF && i + 1 < text.length) {
      int nextCharCode = text.codeUnitAt(i + 1);
      // Check if next is a low surrogate
      if (nextCharCode >= 0xDC00 && nextCharCode <= 0xDFFF) {
        // This is a complete surrogate pair (emoji), insert as one character
        final emoji = text.substring(i, i + 2);
        executeHandleInsertCharacter(emoji, document);
        i += 2;
        continue;
      }
    }

    // Regular single code unit character
    executeHandleInsertCharacter(text[i], document);
    i++;
  }
}