`restrictTranslate` - restrict the translation (movement) of elements by a given bouding box. If set to `true`, the user will not be able to move elements outside the boundary of the paper area. It's set to `false` by default. This option also accepts a function with signature `function(elementView)` in which case it must return a bounding box (an object of the form `{ x: Number, y: Number, width: Number, height: Number }`) that defines the area in which the element represented by `elementView` can be moved. For example, to restrict translatoin of embedded elements by the bounding box defined by their parent element, you can do:

    restrictTranslate: function(elementView) {
        var parentId = elementView.model.get('parent');
        return parentId && this.model.getCell(parentId).getBBox();
    }