How to draw line between two nodes placed in different Panes / Regions

Question

I am tryin to draw a genealogy tree. In my tree, I store information about ex partners. So the Panel (Region) for person shoud looking like this

Z * * * Z * * * Z * * * X --- Y

Where Z represent exPartner, X represent Persion and Y represent current Wife / Husband

And now I would like to draw line to connect current relation with children. And ec relations with children. (graphicaly there will be a line beetwen Z and *)

But when the person is in the other region LayoutX and LayoutX property return relative value. How Can I do that, and how dynamicaly resize this Panel ? I would like that Z should be allways at middle of line Horizontal line connecting children.

Answer 1

Given any node, you can get its bounds in the coordinate system of any other node in the same scene graph with:

Node nodeOfInterest = ... ;
Node anotherNode = ... ;

// ...

Bounds boundsInScene = nodeOfInterest.localToScene(nodeOfInterest.getBoundsInLocal());
Bounds boundRelativeToAnotherNode = anotherNode.sceneToLocal(boundsInScene);

So assuming you have some kind of pane which is a common ancestor to two nodes you want to connect, you can do this:

Pane commonAncestor = ... ;
Node n1 = ... ;
Node n2 = ... ;

Bounds n1InCommonAncestor = getRelativeBounds(n1, commonAncestor);
Bounds n2InCommonAncestor = getRelativeBounds(n2, commonAncestor);
Point2D n1Center = getCenter(n1InCommonAncestor);
Point2D n2Center = getCenter(n2InCommonAncestor);

Line connector = new Line(n1Center.getX(), n1Center.getY(), n2Center.getX(), n2Center.getY());
commonAncestor.getChildren().add(connector);

// ...

private Bounds getRelativeBounds(Node node, Node relativeTo) {
    Bounds nodeBoundsInScene = node.localToScene(node.getBoundsInLocal());
    return relativeTo.sceneToLocal(nodeBoundsInScene);
}

private Point2D getCenter(Bounds b) {
    return new Point2D(b.getMinX() + b.getWidth() / 2, b.getMinY() + b.getHeight() / 2);
}