jointjs/docs/src/joint/api/dia/Cell/define.html

JavaScript diagramming library

<pre class="docs-method-signature"><code>define(type [, defaultAttributes, prototypeProperties, staticProperties])</code></pre>
<p>Helper to define a new Cell class or extend an existing one.</p>

<p>The <code>type</code> must be a unique identifier of the class, which determines the location of the class definition in the <code>joint.shapes</code> namespace (<code>type</code> is the path to the class definition delimited by dots: <code>.</code>). When creating an instance of the cell, attributes will be set to the value from the <code>defaultAttributes</code>, unless overridden by subclass or instance attributes.</p>

<pre><code>// Define a new Ellipse class in `joint.shapes.examples` namespace
// Inherits from generic Element class
var Ellipse = joint.dia.Element.define('examples.Ellipse', {
    // default attributes
    markup: [{
        tagName: 'ellipse',
        selector: 'ellipse' // not necessary but faster
    ],
    attrs: {
        ellipse: {
            fill: 'white',
            stroke: 'black',
            strokeWidth: 4,
            refRx: .5,
            refRy: .5,
            refCx: .5,
            refCy: .5
        }
    }
});

// Instantiate an element
var ellipse = (new Ellipse()).position(100, 100).size(120, 50).addTo(graph);

// Define a new ColoredEllipse class
// Inherits from Ellipse
var ColoredEllipse = Ellipse.define('examples.ColoredEllipse', {
    // overridden Ellipse default attributes
    // other Ellipse attributes preserved
    attrs: {
        ellipse: {
            fill: 'lightgray'
        }
    }
}, {
    // prototype properties
    // accessible on `this.(...)` - as well as, more precisely, `this.prototype.(...)`
    // useful for custom methods that need access to this instance
    // shared by all instances of the class
    randomizeStrokeColor: function() {
        var randomColor = '#' + ('000000' + Math.floor(Math.random() * 16777215).toString(16)).slice(-6);
        return this.attr('ellipse/stroke', randomColor);
    }
}, {
    // static properties
    // accessible on `this.constructor.(...)`
    // useful for custom methods and constants that do not need an instance to operate
    // however, a new set of static properties is generated every time the constructor is called
    // (try to only use static properties if absolutely necessary)
    createRandom: function() {
        return (new ColoredEllipse()).randomizeStrokeColor();
    }
});

// Instantiate an element
var coloredEllipse = ColoredEllipse.createRandom().position(300, 100).size(120, 50).addTo(graph);</code></pre>