Gets or sets the collection of nodes that are fixed and must not be moved.
The algorithm tries to preserve the mental map and, thus, non-fixed nodes cannot simply pass/jump over the fixed nodes (i.e. fixed nodes restrict the possible movement of non-fixed nodes).
Minimum distances for individual nodes can, for example, be defined using a delegate in the following way:Using a delegate to determine minimum node distances
// Scale the minimum distance around a node by the node size.// This ensures that larger nodes get more space.layoutData.minimumNodeDistances = (node) => Math.max(node.layout.width, node.layout.height)