Scale SVGMarker With the Link

Using `markerUnits` within the `targetMarker`

by Roman Bruckner

HTML

<html>
<head>
    <link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/jointjs/3.4.4/joint.css" />
</head>
<body>
      <!-- content -->
      <div id="paper"></div>

      <!-- dependencies -->
        <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.js"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.20/lodash.min.js"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.4.0/backbone.js"></script>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/jointjs/3.4.4/joint.js"></script>
    
    </body>
</html>

JavaScript

const graph = new joint.dia.Graph({}, {
  cellNamespace: joint.shapes
});

const paper = new joint.dia.Paper({
  el: document.getElementById('paper'),
  width: 800,
  height: 900,
  model: graph,
  cellViewNamespace: joint.shapes,
  async: true,
  sorting: joint.dia.Paper.sorting.APPROX
});

const Link = joint.dia.Link.define('Link', {
  attrs: {
    line: {
      connection: true,
      fill: 'none',
      targetMarker: {
        'stroke-width': 1,
        'markerUnits': 'strokeWidth', // the default is `userSpaceOnUse` 
        'd': 'M 1,-1 0,0 1,1 Z'
        // fill: 'blue',  if not defined, we use 'stroke' of the line`
        // stroke: 'blue',  if not defined, we use 'stroke' of the line`        
      }
    },
  }
}, {
  markup: [{
    tagName: 'path',
    selector: 'wrapper',
  }, {
    tagName: 'path',
    selector: 'line',

  }]
});


const link1 = new Link({
  attrs: {
    line: {
      stroke: 'red',
      strokeWidth: 2
    }
  }
});
link1.source(new g.Point(50, 50));
link1.target(new g.Point(300, 50));
link1.addTo(graph);

const link2 = new Link({
  attrs: {
    line: {
      stroke: 'blue',
      strokeWidth: 4
    }
  }
});
link2.source(new g.Point(50, 150));
link2.target(new g.Point(300, 150));
link2.addTo(graph);

const link3 = new Link({
  attrs: {
    line: {
      stroke: 'green',
      strokeWidth: 6
    }
  }
});
link3.source(new g.Point(50, 250));
link3.target(new g.Point(300, 250));
link3.addTo(graph);