doLayout method

Implementation

@override
void doLayout(Context context, TreeLayoutNode root, num width, num height) {
  if (root.childCount <= 1) {
    CompactLayout l = CompactLayout(
      levelAlign: Align2.start,
      direction: Direction2.ltr,
      gapFun: gapFun,
      levelGapFun: levelGapFun,
      sizeFun: sizeFun,
    );
    l.doLayout(context, root, width, height);
    return;
  }

  TreeLayoutNode leftRoot = TreeLayoutNode(null, root.data);
  TreeLayoutNode rightRoot = TreeLayoutNode(null, root.data);
  int rightTreeSize = (root.childCount / 2).round();
  int i = 0;
  for (var node in root.children) {
    if (i < rightTreeSize) {
      leftRoot.add(node);
    } else {
      rightRoot.add(node);
    }
    i++;
  }

  CompactLayout leftLayout = CompactLayout(
    levelAlign: Align2.start,
    direction: Direction2.rtl,
    gapFun: gapFun,
    levelGapFun: levelGapFun,
    sizeFun: sizeFun,
  );
  leftLayout.doLayout(context, leftRoot, width, height);

  CompactLayout rightLayout = CompactLayout(
    levelAlign: Align2.start,
    direction: Direction2.ltr,
    gapFun: gapFun,
    levelGapFun: levelGapFun,
    sizeFun: sizeFun,
  );
  rightLayout.doLayout(context, rightRoot, width, height);

  root.children.clear();
  for (var element in leftRoot.children) {
    root.add(element);
  }
  for (var element in rightRoot.children) {
    root.add(element);
  }

  num tx = leftRoot.x - rightRoot.x;
  num ty = leftRoot.y - rightRoot.y;
  rightRoot.each((node, index, startNode) {
    node.x += tx;
    node.y += ty;
    return false;
  });
  root.x = leftRoot.x;
  root.y = leftRoot.y;
}