Content and Label on a Node - Cytoscape

Question

I'm trying to display nodes that have a font icon in the center of the node using 'content' and a text label underneath.

My styling is currently:

{
  'selector': 'node[icon]',
  'style': {
    'content': 'data(icon)',
    'font-family': 'Material Icons',
    'text-valign': 'center',
    'text-halign': 'center'
  }
},
{
  'selector': 'node[label]',
  'style': {
    'label': 'data(label)',
    'text-valign': 'bottom',
    'text-halign': 'center'
  }
}

However, this doesn't work as i assume both of the styles is used on one element (the node).

There are a few solutions I've considered, such as:

• Putting the label on a parent node
• Use Popper.js or similar to show the label
• Use a multi-lined label

The first 2 seem 'hacky', and the third could cause a lot of alignment problems. Is there a better solution to this?

Answer 1

I've found a solution using the extension: https://github.com/kaluginserg/cytoscape-node-html-label.

You can create custom HTML labels for nodes which do not interfere with the base Cytoscape labels. An example of using the Material Icons:

// Initialise the HTML Label
this.cy.nodeHtmlLabel([{
  query: '.nodeIcon',
  halign: 'center',
  valign: 'center',
  halignBox: 'center',
  valignBox: 'center',
  tpl: (data) => {
    return '<i class="material-icons">' + data.icon + '</i>';
  }
}]);

// Add the HTML Label to the node:
const node =  {
  group: 'nodes',
  data: {
    id: data.id,
    label: data.label,
    icon: data.icon
  },
  classes: 'nodeIcon' // <---- Add the HTML Label class here
};

With the method you can dynamically create nodes with font icons without the need to download a load of images.

You can even add CSS styling to change the colour of the icon:

Answer 2

If you want an icon as the nodes body, you can use it as the background image and define the label like you do:

var cy = window.cy = cytoscape({
  container: document.getElementById('cy'),

  boxSelectionEnabled: false,
  autounselectify: true,

  style: [{
      selector: 'node',
      css: {
        'label': 'data(id)',
        'text-valign': 'bottom',
        'text-halign': 'center',
        'height': '60px',
        'width': '60px',
        'border-color': 'black',
        'border-opacity': '1',
        'background-image': 'https://farm8.staticflickr.com/7272/7633179468_3e19e45a0c_b.jpg',
        "text-background-opacity": 1,
        "text-background-color": "lightgray"
      }
    },
    {
      selector: ':selected',
      css: {
        'background-color': 'black',
        'line-color': 'black',
        'target-arrow-color': 'black',
        'source-arrow-color': 'black'
      }
    }
  ],

  elements: {
    nodes: [{
        data: {
          id: 'n0'
        }
      },
      {
        data: {
          id: 'n1'
        }
      },
      {
        data: {
          id: 'n2'
        }
      },
      {
        data: {
          id: 'n3'
        }
      },
      {
        data: {
          id: 'n4'
        }
      },
      {
        data: {
          id: 'n5'
        }
      },
      {
        data: {
          id: 'n6'
        }
      },
      {
        data: {
          id: 'n7'
        }
      },
      {
        data: {
          id: 'n8'
        }
      },
      {
        data: {
          id: 'n9'
        }
      },
      {
        data: {
          id: 'n10'
        }
      },
      {
        data: {
          id: 'n11'
        }
      },
      {
        data: {
          id: 'n12'
        }
      },
      {
        data: {
          id: 'n13'
        }
      },
      {
        data: {
          id: 'n14'
        }
      },
      {
        data: {
          id: 'n15'
        }
      },
      {
        data: {
          id: 'n16'
        }
      }
    ],
    edges: [{
        data: {
          source: 'n0',
          target: 'n1'
        }
      },
      {
        data: {
          source: 'n1',
          target: 'n2'
        }
      },
      {
        data: {
          source: 'n1',
          target: 'n3'
        }
      },
      {
        data: {
          source: 'n2',
          target: 'n7'
        }
      },
      {
        data: {
          source: 'n2',
          target: 'n11'
        }
      },
      {
        data: {
          source: 'n2',
          target: 'n16'
        }
      },
      {
        data: {
          source: 'n3',
          target: 'n4'
        }
      },
      {
        data: {
          source: 'n3',
          target: 'n16'
        }
      },
      {
        data: {
          source: 'n4',
          target: 'n5'
        }
      },
      {
        data: {
          source: 'n4',
          target: 'n6'
        }
      },
      {
        data: {
          source: 'n6',
          target: 'n8'
        }
      },
      {
        data: {
          source: 'n8',
          target: 'n9'
        }
      },
      {
        data: {
          source: 'n8',
          target: 'n10'
        }
      },
      {
        data: {
          source: 'n11',
          target: 'n12'
        }
      },
      {
        data: {
          source: 'n12',
          target: 'n13'
        }
      },
      {
        data: {
          source: 'n13',
          target: 'n14'
        }
      },
      {
        data: {
          source: 'n13',
          target: 'n15'
        }
      },
    ]
  },

  layout: {
    name: 'dagre',
    padding: 5
  }
});

body {
  font: 14px helvetica neue, helvetica, arial, sans-serif;
}

#cy {
  height: 100%;
  width: 75%;
  position: absolute;
  left: 0;
  top: 0;
  float: left;
}

<html>

<head>
  <meta charset=utf-8 />
  <meta name="viewport" content="user-scalable=no, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, minimal-ui">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/cytoscape/3.2.17/cytoscape.min.js"></script>
  <script src="https://unpkg.com/[email protected]/dist/jquery.js"></script>
  <script src="https://unpkg.com/[email protected]/dist/dagre.js"></script>
  <script src="https://cdn.rawgit.com/cytoscape/cytoscape.js-dagre/1.5.0/cytoscape-dagre.js"></script>
</head>

<body>
  <div id="cy"></div>
</body>

</html>