JointJS: Custom Attribute To Set CSS Property

by Roman Bruckner

HTML

<html>

  <head>
    <link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/jointjs/3.7.4/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/3.7.4/joint.js"></script>

  </body>

</html>

CSS

.joint-element:hover .circle-body {
    fill: var(--color);
}

.joint-element:hover .circle-icon {
    stroke: white;
}

JavaScript

const Circle = joint.dia.Element.define('Circle', {
    // defaults
    size: { width: 100, height: 100 },
    markup: [{
        tagName: 'ellipse',
        selector: 'body'
    }, {
        tagName: 'path',
        selector: 'cross'
    }],
    attrs: {
        root: {
            cssProperty: { name: 'color', value: 'red' },
            stroke: 'red',
        },
        body: {
            class: 'circle-body',
            fill: '#FFFFFF',
            strokeWidth: 3,
            rx: 'calc(w / 2)',
            ry: 'calc(h / 2)',
            cx: 'calc(w / 2)',
            cy: 'calc(h / 2)',
        },
        cross: {
            class: 'circle-icon',
            d: 'M calc(w / 2) 10 L calc(w / 2) calc(h - 10) M 10 calc(h / 2) L calc(w - 10) calc(h / 2)',
            strokeWidth: 10,
        }
    }
}, {
    // prototype properties
}, {
    // static properties
    attributes: {
        cssProperty: {
            set: function(property, refBBox, node, attrs) {
                node.style.setProperty(`--${property.name}`, property.value);
            }
        }
    }
});

const namespace = { Circle };

const graph = new joint.dia.Graph({}, { cellNamespace: namespace });
const paper = new joint.dia.Paper({
    el: document.getElementById('paper'),
    width: 800,
    height: 600,
    model: graph,
    async: true,
    sorting: joint.dia.Paper.sorting.APPROX,
    cellViewNamespace: namespace,
});


const c1 = new Circle({
    position: { x: 100, y: 100 },
});

const c2 = new Circle({
    position: { x: 400, y: 100 },
    attrs: {
        root: {
            cssProperty: { name: 'color', value: 'blue' },
            stroke: 'blue',
        },
    }
});

graph.addCells([c1, c2]);