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G6

Render the Tutorial Demo

7 min read

In this chapter, we preliminary configure and render the Tutorial Demo. You will learn the common configurations of Graph.

Basic Rendering

Create a HTML Container

Create an HTML container for graph canvas, div tag in general. G6 will append a canvas tag to it and draw graph on the canvas.

<body>
  <div id="mountNode"></div>
  
  <!-- Import G6 -->
  <!-- ... -->
</body>

Data Preparation

The data for G6 should be JSON format, includes array properties nodes and edges:

<script>
  // console.log(G6.Global.version);
  const initData = {
    // The array of nodes
    nodes: [{
      id: 'node1',   // String, unique and required
      x: 100,        // Number, the x coordinate
      y: 200,        // Number, the y coordinate
      label: 'Source' // The label of the node
    },{
      id: 'node2',
      x: 300,
      y: 200,
      label: 'Target'
   }],
    // The array of edges
    edges: [
      // An edge links from node1 to node2
      {
        source: 'node1',  // String, required, the id of the source node
        target: 'node2',  // String, required, the id of the target node
        label: 'I am an edge'   // The label of the edge
      }
    ]
  };
</script>

⚠️Attention:

  • nodes is an array of nodes, the id is an unique and required property; the x and y are the coordinates of the node;
  • edges is an array of edges, source and target are required, represent the id of the source node and the id of the target node respectively.
  • The properties of node and edge are described in Built-in Nodes and Built-in Edges document.

Instantiate the Graph

The container, width, and height are required configurations when instantiating a Graph:

<script>
  // const initData = { ... }
  const graph = new G6.Graph({
    container: 'mountNode', // String | HTMLElement, required, the id of DOM element or an HTML node
    width: 800,              // Number, required, the width of the graph
    height: 500              // Number, required, the height of the graph
  });
</script>

Load the Data and Render

Load data and render are two separated steps.

<script>
  // const initData = { ... }
  //  const graph = ...
  graph.data(data);  // Load the data defined in Step 2
  graph.render();    // Render the graph
</script>

The Result

After calling graph.render() , G6 will render the graph according to the data with Canvas by default. To switch to SVG rendered, configure the renderer when instantiating the graph.

Load the Real Data

In the above demo, we render a graph with two nodes and one edge defined in the code directly. For real scenario, the data might be loaded remotely. We prepare the JSON data for Tutorial Demo with the address:
https://gw.alipayobjects.com/os/basement_prod/6cae02ab-4c29-44b2-b1fd-4005688febcb.json

Load the Remote Data

Modify index.html to load remote data asynchronously by fetch, and pass it to the instance of G6 Graph:

<script>
  //  const graph = ...
  const main = async () => {
    const response = await fetch('https://gw.alipayobjects.com/os/basement_prod/6cae02ab-4c29-44b2-b1fd-4005688febcb.json');
    const remoteData = await response.json();
    
    // ...
    graph.data(remoteData); // Load the remote data
    graph.render();         // Render the graph
  };
  main();
</script>

fetch allows us to fetch the remote data asynchronously, and controll the process by async/await. If you are curious about fetch and async/await, please refer to: async function, Fetch API

We will get the following result with the code above:

The data has been loaded correctly. But the result is a little bit strange due to the large amount of nodes and edges. Limited by the size of canvas, part of the graph is arranged out of the view. We are going to solve all these problems now.

Here goes a part of tutorial-data.json. There are x and y in node data, and some of them are not in the range of width: 800, height: 600.

{
  "nodes": [
    { "id": "0", "label": "n0", "class": "c0", "x": 1000, "y": -100 },
    { "id": "1", "label": "n1", "class": "c0", "x": 300, "y": -10 }
    //...
  ],
  "edges": [
    //...
  ]
}

G6 will render the graph according to the position information in the data once G6 finds x and y in the data. This mechanism satisfies the requirement that rendering the source data. To solve the problem of the graph out of the view port partially, two configurations are provided:

  •  fitView: Whether to fit the graph to the canvas;
  •  fitViewPadding: The padding between the content of the graph and the borders of the canvas.

We modify the code about instantiating Graph as shown below:

const graph = new G6.Graph({
  // ...
  fitView: true,
  fitViewPadding: [20, 40, 50, 20],
});

The result from this code shows that the graph has been fitted to the canvas:

Common Configuration

The configurations below will be used in the following Tutorial:

Name Type Options / Example Default Description
renderer String 'canvas' / 'svg' 'canvas' Render engine of the graph.
fitView Boolean true / false false Whether to fit the graph to the canvas.
fitViewPadding Number / Array 20 / [ 20, 40, 50, 20 ] 0 The padding between the content of the graph and the borders of the canvas.
animate Boolean true / false false Whether to activate the global animation.
modes Object {
  default: [ 'drag-node', 'drag-canvas' ]
}		 null The set of graph interaction modes. This is a complicated concept, refer to Mode for more detial.
defaultNode Object {
  shape: 'circle',
  color: '#000',
  style: {
    ......
  }
}		 null The default global properties for nodes, includes styles properties and other properties.
defaultEdge Object {
  shape: 'polyline',
  color: '#000',
  style: {
    ......
  }
}		 null The default global properties for edges, includes styles properties and other properties.
nodeStateStyles Object {
  hover: {
    ......
  },
  select: {
    ......
  }
}		 null The style properties of nodes in different states except for default state. Such as hover, select.
edgeStateStyles Object {
  hover: {
    ......
  },
  select: {
    ......
  }
}		 null The style properties of edges in different states except for default state. Such as hover, select.

Complete Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Tutorial Demo</title>
</head>
<body>
  <div id="mountNode"></div>
  <script src="https://gw.alipayobjects.com/os/antv/pkg/_antv.g6-3.1.0/build/g6.js"></script>
  <script>
    const graph = new G6.Graph({
      container: 'mountNode',
      width: 1000,
      height: 600,
      renderer: 'svg',
      fitView: true,
      fitViewPadding: [ 20, 40, 50, 20 ]
    });

    const main = async () => {
      const response = await fetch('https://gw.alipayobjects.com/os/basement_prod/6cae02ab-4c29-44b2-b1fd-4005688febcb.json');
      const remoteData = await response.json();
      graph.data(remoteData);
      graph.render();
    };
    main();
  </script>
</body>
</html>

⚠️注意:
Replace the url 'https://gw.alipayobjects.com/os/basement_prod/6cae02ab-4c29-44b2-b1fd-4005688febcb.json' to change the data into yours.