Template:Canvas Widget Style Template

 DefaultStyle.widgets.mywidget = {
    new: func(parent, cfg){
        me._root = parent.createChild("group", "mywidget");
    },
    setSize: func(model, w, h){
        # ...
        # code for changing size
        # ...

        return me;
    },
    update: func(model){}
    # other APIs below, e.g., setBackground()
};