Loop

4 min read

A built-in edge Line has the default style as below.
img

⚠️Attention:
loop edge is appropriate for the self-loop edges whose target node and the source node are the same. In other words, a loop edge connect a node to itself. There will be a strange result if the loop edge is applied to the edge which is not a self-loop.
img

Usage

As stated in Built-in Edges , there are three methods to configure edges: Configure edges globally when instantiating a Graph; Configure edges in their data; Configure edges by graph.edge(edgeFn). Their priorities are:

graph.edge(edgeFn) > Configure in data > Configure globally

⚠️ Attention: Expect for id, source, target, label which should be assigned to every single edge data, the other configurations in The Common Property and in each edge type (refer to doc of each edge type) support to be assigned by the three ways.

1 Global Configure When Instantiating a Graph

Assign type to 'cubic' in the defaultEdge object when instantiating a Graph:

const graph = new G6.Graph({
  container: 'mountNode',
  width: 800,
  height: 600,
  defaultEdge: {
    type: 'loop', // The type of the edge
    // ...  Other configuraltions
  },
});

2 Configure in the Data

To configure different edges with different properties, you can write the properties into the edge data.

const data = {
  nodes: [
    ... // nodes
  ],
  edges: [{
    source: 'node0',
    target: 'node0'
    type: 'loop',
    //... // Other configurations for edges
    style: {
      //...  // Style properties for edges
    }
  },
    //... // Other edges
  ]
}

Property

Loop edge has the Common Edge Properties, and some commonly used properties are shown below. The properties with object type will be described in detail after the table, where loopCfg is the special property for loop edge.

loop 边支持以下的配置项,对于 Object 类型的配置项将在后面有详细讲解:

NameDescriptionTypeRemark
colorThe color of the edgeStringThe priority id lower than stroke in style
styleThe default style of edgeObjectCorrespond to the styles in Canvas
labelThe text of the labelString
labelCfgThe configurations of the labelObject
stateStylesThe styles in different statesObjectRefer to Configure Styles for State
loopCfgSpecial property for loop edgeObject

style

style is an object which is the same as the Common Edge Style Properties. The following code shows how to configure the style globally when instantiating a Graph.
img

const data = {
  nodes: [
    {
      id: 'node0',
      x: 100,
      y: 100,
      size: 20,
    },
  ],
  edges: [
    {
      source: 'node0',
      target: 'node0',
      type: 'loop',
      label: 'loop',
    },
  ],
};
const graph = new G6.Graph({
  container: 'mountNode',
  width: 800,
  height: 600,
  defaultEdge: {
    // type: 'loop',  // The type has been assigned in the data, we do not have to define it any more
    style: {
      endArrow: true,
      stroke: '#088',
      lineWidth: 3,
    },
  },
});
graph.data(data);
graph.render();

labelCfg

labelCfg is an object which is the same as the Common Edge Label Properties. Base on the code in style section, we add labelCfg to defaultEdge.
img

const data = {
  // ... data
};
const graph = new G6.Graph({
  // ... Other configurations for graph
  defaultEdge: {
    // ... Other properties for edges
    labelCfg: {
      refY: -5,
      refX: 30,
    },
  },
});
// ...

loopCfg

loopCfg is an object that configures the direction, height, and clockwise.

  • position: The relative position to the source/target node. Options: toptop-rightright,bottom-rightbottombottom-leftlefttop-left. top by default.
  • dist: The distance between the keyShape of the source/target node to the highest position of the loop. It is equal to the height of the source/target node by default.
  • clockwise: Whether to draw the loop clockwisely. true by default

Base on the code in style section, we add loopCfg to defaultEdge.
img

const data = {
  // ... data
};
const graph = new G6.Graph({
  // ... Other configurations for graph
  defaultEdge: {
    // ... Other properties for edges
    loopCfg: {
      position: 'left',
      dist: 100,
      clockwise: false,
    },
  },
});
// ...