text: export var MODE_IDLE = 'idle';
  export var MODE_PANNING = 'panning';
  export var MODE_ZOOMING = 'zooming';
  
  export var TOOL_AUTO = 'auto';
  export var TOOL_NONE = 'none';
  export var TOOL_PAN = 'pan';
  export var TOOL_ZOOM_IN = 'zoom-in';
  export var TOOL_ZOOM_OUT = 'zoom-out';
  
  export var POSITION_NONE = 'none';
  export var POSITION_TOP = 'top';
  export var POSITION_RIGHT = 'right';
  export var POSITION_BOTTOM = 'bottom';
  export var POSITION_LEFT = 'left';
  
  export var ACTION_ZOOM = 'zoom';
  export var ACTION_PAN = 'pan';