layout method

@override void layout(Context context, BoxConstraints constraints, { bool parentUsesSize = false, })

First widget pass to calculate the children layout and bounding box

Implementation

@override
void layout(
  Context context,
  BoxConstraints constraints, {
  bool parentUsesSize = false,
}) {
  super.layout(context, constraints, parentUsesSize: parentUsesSize);

  final datasets = Chart.of(context).datasets;
  final size = constraints.biggest;

  // In simple conditions, this loop will run only 2 times.
  var count = 5;
  while (count-- > 0) {
    _xAxis.crossAxisPosition = _yAxis.axisPosition;
    _xAxis.axisPosition = math.max(
      _xAxis.axisPosition,
      _yAxis.crossAxisPosition,
    );
    _xAxis.layout(context, constraints);
    assert(_xAxis.box != null);
    _yAxis.crossAxisPosition = _xAxis.axisPosition;
    _yAxis.axisPosition = math.max(
      _yAxis.axisPosition,
      _xAxis.crossAxisPosition,
    );
    _yAxis.layout(context, constraints);
    assert(_yAxis.box != null);
    if (_yAxis.crossAxisPosition == _xAxis.axisPosition &&
        _xAxis.crossAxisPosition == _yAxis.axisPosition) {
      break;
    }
  }

  final width = _yAxis.axisPosition;
  final height = _xAxis.axisPosition;
  gridBox = PdfRect(width, height, size.x - width, size.y - height);

  for (final dataset in datasets) {
    dataset.layout(context, BoxConstraints.tight(gridBox.size));
    dataset.box = PdfRect.fromPoints(
      PdfPoint(width, height),
      dataset.box!.size,
    );
  }
}