wrapWithUnicode method

String wrapWithUnicode (String text, { bool isHtml: false, bool resetDir: true, TextDirection direction })

Format text of a known (if specified) or estimated direction for use in plain-text output of the context directionality, so an opposite-directionality text is neither garbled nor garbles what follows it. Unlike wrapWithSpan, this makes use of unicode BiDi formatting characters instead of spans for wrapping. The returned string would be RLE+text+PDF for RTL text, or LRE+text+PDF for LTR text.

If resetDir is true, and if the overall directionality or the exit directionality of text are opposite to the context directionality, a trailing unicode BiDi mark matching the context directionality is appended (LRM or RLM).

In HTML, the only valid use of this function is inside of elements that do not allow markup, e.g. an 'option' tag. This function does not do HTML-escaping regardless of the value of isHtml. isHtml is used to designate if the text contains HTML (escaped or unescaped).

Implementation 

String wrapWithUnicode(String text,
    {bool isHtml: false, bool resetDir: true, TextDirection direction}) {
  if (direction == null) direction = estimateDirection(text, isHtml: isHtml);
  var result = text;
  if (contextDirection.isDirectionChange(direction)) {
    var marker = direction == TextDirection.RTL ? Bidi.RLE : Bidi.LRE;
    result = "${marker}$text${Bidi.PDF}";
  }
  return result + (resetDir ? _resetDir(text, direction, isHtml) : '');
}