javascript - vis.js - Place node manually

Question

How do I set a node's position in vis.js?

I want to initially position at least one node manually.

I know that a node has the options x and y. I set both, and also tried variations of layout options (randomSeed, improvedLayout, hierarchical), the node was never placed where I set it.

Here's the simple network I defined:

  nodes = new vis.DataSet([
    {id: 1,  shape: 'circularImage', image: DIR + '1_circle', label:"1", x: 200, y: 100},
    {id: 2,  shape: 'circularImage', image: DIR + '2_circle', label:"2"},
    {id: 3,  shape: 'circularImage', image: DIR + '3_circle', label:"3"},
  ]);

  edges = [
    {id: "01-03", from: 1, to: 3, length: 300, label: '1 - 3'},
    {id: "02-03", from: 2, to: 3},
  ];

  var container = document.getElementById('graphcontainer');
  var data = {
    nodes: nodes,
    edges: edges
  };
  var options = {
    nodes: {
      borderWidth: 4,
      size: 30,
      color: {
        border: '#222222',
        background: '#666666'
      },
      font:{
        color:'#000000'
      }
    },
    edges: {
      color: 'lightgray'
    },
    //layout: {randomSeed:0}
    //layout: {hierarchical: true}
    layout: {
      randomSeed: undefined,
      improvedLayout:true,
      hierarchical: {
        enabled:false,
        levelSeparation: 150,
        direction: 'UD',   // UD, DU, LR, RL
        sortMethod: 'hubsize' // hubsize, directed
      }
    }
  };
  network = new vis.Network(container, data, options);

The node is placed, but not at the point I set (200,100), but at another position.

I haven't found an example for explicitly setting a node's position on the vis.js page. Could someone please provide one? Thanks!

Answer 1

You can indeed set a fixed position for a node by setting its x and y properties, and yes, this feature works and is not broken.

The x and y position of a node does not mean a position in pixels on the screen, but is a fixed position in the Networks coordinate system. When you move and zoom in the Network, the fixed items will move and zoom too, but they will always keep the same position relative to each other. It's like your home town has a fixed location (long, lat) on earth, but you can still zoom and move your town in Google Maps.

EDIT: To achieve what you want, you can fix zooming and moving, and adjust the viewport such that it matches the pixels of the HTML canvas, here is a demo:

// create an array with nodes
var nodes = new vis.DataSet([
    {id: 1, label: 'x=200, y=200', x: 200, y: 200},
    {id: 2, label: 'node 2', x: 0, y: 0},
    {id: 3, label: 'node 3', x: 0, y: 400},
    {id: 4, label: 'node 4', x: 400, y: 400},
    {id: 5, label: 'node 5', x: 400, y: 0}
]);

// create an array with edges
var edges = new vis.DataSet([
    {from: 1, to: 2, label: 'to x=0, y=0'},
    {from: 1, to: 3, label: 'to x=0, y=400'},
    {from: 1, to: 4, label: 'to x=400, y=400'},
    {from: 1, to: 5, label: 'to x=400, y=0'}
]);

// create a network
var container = document.getElementById('mynetwork');
var data = {
    nodes: nodes,
    edges: edges
};
var width = 400;
var height = 400;
var options = {
    width: width + 'px',
    height: height + 'px',
    nodes: {
        shape: 'dot'
    },
    edges: {
        smooth: false
    },
    physics: false,
    interaction: {
        dragNodes: false,// do not allow dragging nodes
        zoomView: false, // do not allow zooming
        dragView: false  // do not allow dragging
    }
};
var network = new vis.Network(container, data, options);
  
// Set the coordinate system of Network such that it exactly
// matches the actual pixels of the HTML canvas on screen
// this must correspond with the width and height set for
// the networks container element.
network.moveTo({
    position: {x: 0, y: 0},
    offset: {x: -width/2, y: -height/2},
    scale: 1,
})

#mynetwork {
    border: 1px solid black;
    background: white;
    display: inline-block;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/vis/4.9.0/vis.min.js"></script>
<link href="https://cdnjs.cloudflare.com/ajax/libs/vis/4.9.0/vis.min.css" rel="stylesheet" type="text/css" />

<p>The following network has a fixed scale and position, such that the networks viewport exactly matches the pixels of the HTML canvas.</p>
<div id="mynetwork"></div>