calculateBoundedFloatingCursorOffset method

Offset calculateBoundedFloatingCursorOffset(Offset rawCursorOffset, double preferredLineHeight)

Returns the position within the editor closest to the raw cursor offset.

Implementation

Offset calculateBoundedFloatingCursorOffset(
    Offset rawCursorOffset, double preferredLineHeight) {
  var deltaPosition = Offset.zero;
  final topBound = _kFloatingCursorAddedMargin.top;
  final bottomBound =
      size.height - preferredLineHeight + _kFloatingCursorAddedMargin.bottom;
  final leftBound = _kFloatingCursorAddedMargin.left;
  final rightBound = size.width - _kFloatingCursorAddedMargin.right;

  if (_previousOffset != null) {
    deltaPosition = rawCursorOffset - _previousOffset!;
  }

  // If the raw cursor offset has gone off an edge,
  // we want to reset the relative origin of
  // the dragging when the user drags back into the field.
  if (_resetOriginOnLeft && deltaPosition.dx > 0) {
    _relativeOrigin =
        Offset(rawCursorOffset.dx - leftBound, _relativeOrigin.dy);
    _resetOriginOnLeft = false;
  } else if (_resetOriginOnRight && deltaPosition.dx < 0) {
    _relativeOrigin =
        Offset(rawCursorOffset.dx - rightBound, _relativeOrigin.dy);
    _resetOriginOnRight = false;
  }
  if (_resetOriginOnTop && deltaPosition.dy > 0) {
    _relativeOrigin =
        Offset(_relativeOrigin.dx, rawCursorOffset.dy - topBound);
    _resetOriginOnTop = false;
  } else if (_resetOriginOnBottom && deltaPosition.dy < 0) {
    _relativeOrigin =
        Offset(_relativeOrigin.dx, rawCursorOffset.dy - bottomBound);
    _resetOriginOnBottom = false;
  }

  final currentX = rawCursorOffset.dx - _relativeOrigin.dx;
  final currentY = rawCursorOffset.dy - _relativeOrigin.dy;
  final double adjustedX =
      math.min(math.max(currentX, leftBound), rightBound);
  final double adjustedY =
      math.min(math.max(currentY, topBound), bottomBound);
  final adjustedOffset = Offset(adjustedX, adjustedY);

  if (currentX < leftBound && deltaPosition.dx < 0) {
    _resetOriginOnLeft = true;
  } else if (currentX > rightBound && deltaPosition.dx > 0) {
    _resetOriginOnRight = true;
  }
  if (currentY < topBound && deltaPosition.dy < 0) {
    _resetOriginOnTop = true;
  } else if (currentY > bottomBound && deltaPosition.dy > 0) {
    _resetOriginOnBottom = true;
  }

  _previousOffset = rawCursorOffset;

  return adjustedOffset;
}