The view for the joint.dia.Link model. It inherits from joint.dia.CellView and is responsible for:

- Rendering a link inside a paper
- Handling the link's pointer events
- Providing various methods for working with the link (visually)

To find the view associated with a specific link model, use the `paper.findViewByModel()` method:

    var linkView = paper.findViewByModel(link);

#### Custom LinkView

It is possible to use a custom default link view for all your links in a paper. This can be set up via the `linkView` option on the paper object. Several options in `joint.dia.LinkView` may be overridden in a custom LinkView:

- shortLinkLength - if link is shorter than the length specified, the size of link tools is scaled down by half. Defaults to `105`.
- doubleLinkTools - render link tools on both ends of the link (only if the link is longer than `longLinkLength`). Defaults to `false`.
- longLinkLength - if length is longer than the length specified and `doubleLinkTools: true`, render link tools on both ends of the link. Defaults to `155`.
- linkToolsOffset - the offset of link tools from the beginning of the link. Defaults to `40`.
- doubleLinkToolsOffset - the offset of duplicate link tools from the end of the link, if length is longer than `longLinkLength` and `doubleLinkTools: true`. Defaults to `65`.

A custom LinkView type may also override default LinkView event handlers, or provide new ones. It may be necessary to modify the `interactive` paper option to prevent interference from builtin event handlers (most notably `vertexAdd` which listens for pointerdown events).

Example:

    var CustomLinkView = joint.dia.LinkView.extend({
        // custom interactions:
        pointerdblclick: function(evt, x, y) {
            this.addVertex(x, y);
        },
        contextmenu: function(evt, x, y) {
            this.addLabel(x, y);
        },

        // custom options:
        options: joint.util.defaults({
            doubleLinkTools: true,
        }, joint.dia.LinkView.prototype.options)
    });

    var paper = new joint.dia.Paper({
        //...
        linkView: CustomLinkView,
        interactive: { vertexAdd: false } // disable default vertexAdd interaction
    });