calculateLine method

(int, int, int) calculateLine(int yoffset)

calculateLine taking soft wrapping into account, returns the total viewable lines and the real-line index for the given yoffset, as well as the virtual line offset.

Implementation

(int total, int ridx, int voffset) calculateLine(int yoffset) {
  if (!softWrap) {
    return (_lines.length, math.min(yoffset, _lines.length), 0);
  }

  final maxWidth = _maxWidth().toDouble();
  if (maxWidth <= 0) return (0, 0, 0);

  var total = 0;
  var ridx = 0;
  var voffset = 0;

  for (var i = 0; i < _lines.length; i++) {
    final line = _lines[i];
    final lineWidth = Style.visibleLength(line);
    final lineHeight = math.max(1, (lineWidth / maxWidth).ceil());

    if (yoffset >= total && yoffset < total + lineHeight) {
      ridx = i;
      voffset = yoffset - total;
    }
    total += lineHeight;
  }

  if (yoffset >= total) {
    ridx = _lines.length;
    voffset = 0;
  }

  return (total, ridx, voffset);
}