Angular Draggable Directive

draggable.coffee

'use strict'

angular.module('ip')
  .directive('draggable', ($document) ->
    restrict: "EA"

    link: (scope, element, attr) ->

      pos_y = pos_x = drg_h = drg_w = 0
      
      mousemove = (event) ->
        element.css
          top: event.pageY + pos_y - drg_h + "px"
          left: event.pageX + pos_x - drg_w + "px"

      mouseup = ->
        $document.unbind "mousemove", mousemove
        $document.unbind "mouseup", mouseup

      element.on "mousedown", (event) ->
        event.preventDefault()
        
        drg_h = element[0].offsetHeight
        drg_w = element[0].offsetWidth

        pos_y = element[0].offsetTop + drg_h - event.pageY
        pos_x = element[0].offsetLeft + drg_w - event.pageX

        $document.on "mousemove", mousemove
        $document.on "mouseup", mouseup

  )