load 'joint.dia.Element.define' by 'graph.fromJSON'

[YongheeMinnovation]

Hi there,

Here is custom element function which draw image as element.

const r5 = joint.dia.Element.define('example.Sensor', {
            size: {
                width: 120,
                height: 48
            },
            attrs: {
                image: {
                xlinkHref: src,
                width: 'calc(w - 6)',
                height: 'calc(h - 6)'
                }
            },
            label: {
                text: deviceid,
                x: 'calc(0.7*w)',
                y: 'calc(0.5*h)'
            },
            ports: {
                items: [ port ] // add a port in constructor
            }
        }, {
            markup: [{
                tagName: 'image',
                selector: 'image'
            }
        ]
        });
        // draw elements
        const e1 = new r5();
        e1.position(100, 100);

        graph.addCells([e1]);

I saved this element using toJSON(); and drew again by fromJSON();

jsonObject = graph.toJSON();
graph.fromJSON(jsonObject );

And following error message comes up.

And yes, when I see jsonObject, there is no markup saved.

How can I reload 'joint.dia.Element.define' element?

Thanks

[kumilingus]

Please see #1133.