calculateFixedChildSizes method

Size calculateFixedChildSizes(ChildLayouter layoutChild)

Implementation

Size calculateFixedChildSizes(ChildLayouter layoutChild) {
  var allocatedWidth = 0.0;
  var allocatedHeight = 0.0;

  double maxChildExtent = _direction == Axis.horizontal
      ? constraints.maxWidth
      : constraints.maxHeight;

  RenderBox? child = firstChild;

  // iterate through children
  while (child != null) {

    var data = getParentData(child.parentData);
    var model = data?.model;

    // perform layout
    if (data != null && model != null) {

      // assign flex value
      _setChildFlex(data, model);

      // layout child
      if (data.flex == null) {
        // get layout constraints
        var childConstraints =
        _getChildLayoutConstraints(child, model, maxChildExtent);

        // calculate the child's size by performing
        // a dry layout. We use LocalBoxConstraints in order to
        // override isTight, which is used in Layout() to determine if a
        // child size change forces a parent to resize.
        doLayout(child, childConstraints, layoutChild);

        // set width
        allocatedWidth = _direction == Axis.horizontal
            ? (allocatedWidth + (child.size.width))
            : max(allocatedWidth, (child.size.width));

        // set height
        allocatedHeight = _direction == Axis.horizontal
            ? max(allocatedHeight, (child.size.height))
            : allocatedHeight + (child.size.height);
      }
    }

    else {

      // calculate the child's size by performing
      // a dry layout. We use LocalBoxConstraints in order to
      // override isTight, which is used in Layout() to determine if a
      // child size change forces a parent to resize.
      doLayout(child, constraints, layoutChild);

      // set width
      allocatedWidth = _direction == Axis.horizontal
          ? (allocatedWidth + (child.size.width))
          : max(allocatedWidth, (child.size.width));

      // set height
      allocatedHeight = _direction == Axis.horizontal
          ? max(allocatedHeight, (child.size.height))
          : allocatedHeight + (child.size.height);
    }

    // get next child
    child = childAfter(child);
  }
  return Size(allocatedWidth, allocatedHeight);
}