# Drag Plugin

The `drag` plugin allows for modifying the planet's projection's rotation with the mouse. It supports dragging vertically with hard stops at the north and south poles, and dragging horizontally without restriction.

## API

`planetaryjs.plugins.drag([config])`

Valid keys for `config` are:

- `onDragStart`, `onDragEnd`, `onDrag`, `afterDrag`: hooks to the `d3.behavior.drag` object's `dragstart`, `dragend`, and `drag` events; each defaults to a no-op. `onDrag` fires at the start of the `drag` event, `afterDrag` at the end. The planet instance is available as `this` inside the each of the functions.

JavaScript

    planetaryjs.plugins.drag({
      onDrag: function() {
        console.log("The planet was dragged!", this, d3.event);
      }
    });