How to add an arrow links in d3.js?

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by daisha , in category: Javascript , a month ago

How to add an arrow links in d3.js?

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1 answer

Member

by mac , a month ago

@daisha 

To add arrow links in D3.js, you can use the "marker-end" attribute along with the "defs" element to create an arrowhead marker. Here's an example of how you can create arrow links in D3.js:

  1. Create an SVG element in your HTML file:
1
<svg width="500" height="500"></svg>


  1. Add the following code in your JavaScript file to create arrow links using D3.js:
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// Create sample data
const nodes = [
  { id: 1, name: "Node 1" },
  { id: 2, name: "Node 2" },
  { id: 3, name: "Node 3" }
];

const links = [
  { source: 1, target: 2 },
  { source: 2, target: 3 }
];

// Create SVG element
const svg = d3.select("svg");

// Create arrowhead marker
svg.append("defs").append("marker")
  .attr("id", "arrow")
  .attr("viewBox", "0 -5 10 10")
  .attr("refX", 15)
  .attr("markerWidth", 6)
  .attr("markerHeight", 6)
  .attr("orient", "auto")
  .append("path")
  .attr("d", "M0,-5L10,0L0,5");

// Create links
svg.selectAll("line")
  .data(links)
  .enter()
  .append("line")
  .attr("x1", d => nodes[d.source - 1].id * 100)
  .attr("y1", 250)
  .attr("x2", d => nodes[d.target - 1].id * 100)
  .attr("y2", 250)
  .attr("stroke", "black")
  .attr("marker-end", "url(#arrow)");

// Create nodes
svg.selectAll("circle")
  .data(nodes)
  .enter()
  .append("circle")
  .attr("cx", d => d.id * 100)
  .attr("cy", 250)
  .attr("r", 10)
  .attr("fill", "blue");


In this code snippet, we first create an SVG element and define some sample data for nodes and links. Then, we create an arrowhead marker with ID "arrow" using the "defs" element. Finally, we create links between the nodes using the "line" elements and set the "marker-end" attribute to refer to the arrowhead marker.


When you run this code, you should see arrow links between the nodes in the SVG element. Feel free to customize the appearance of the arrowhead marker and the links according to your requirements.