getTextPositionAbove method

@override TextPosition getTextPositionAbove(TextPosition position)

Returns the TextPosition above the given offset into the text.

If the offset is already on the first line, the offset of the first character will be returned.

Implementation

@override
TextPosition getTextPositionAbove(TextPosition position) {
  final child = childAtPosition(position);
  final localPosition =
      TextPosition(offset: position.offset - child.container.documentOffset);

  var newPosition = child.getPositionAbove(localPosition);

  if (newPosition == null) {
    // There was no text above in the current child, check the direct
    // sibling.
    final sibling = childBefore(child);
    if (sibling == null) {
      // reached beginning of the document, move to the
      // first character
      newPosition = const TextPosition(offset: 0);
    } else {
      final caretOffset = child.getOffsetForCaret(localPosition);
      final testPosition = TextPosition(offset: sibling.container.length - 1);
      final testOffset = sibling.getOffsetForCaret(testPosition);
      final finalOffset = Offset(caretOffset.dx, testOffset.dy);
      final siblingPosition = sibling.getPositionForOffset(finalOffset);
      newPosition = TextPosition(
          offset: sibling.container.documentOffset + siblingPosition.offset);
    }
  } else {
    newPosition = TextPosition(
        offset: child.container.documentOffset + newPosition.offset);
  }
  return newPosition;
}