onTouchStart: function(e, win, eventInfo) {
    if(!this.config.panning) return;
    if(this.config.panning == 'avoid nodes' && (this.dom? this.isLabel(e, win) : eventInfo.getNode())) return;
    this.pressed = true;
    this.pos = eventInfo.getPos();
    var canvas = this.canvas,
        ox = canvas.translateOffsetX,
        oy = canvas.translateOffsetY,
        sx = canvas.scaleOffsetX,
        sy = canvas.scaleOffsetY;
    this.pos.x *= sx;
    this.pos.x += ox;
    this.pos.y *= sy;
    this.pos.y += oy;
  },

  onTouchMove: function(e, win, eventInfo) {
    if(!this.config.panning) return;
    if(!this.pressed) return;
    if(this.config.panning == 'avoid nodes' && (this.dom? this.isLabel(e, win) : eventInfo.getNode())) return;
    var thispos = this.pos,
        currentPos = eventInfo.getPos(),
        canvas = this.canvas,
        ox = canvas.translateOffsetX,
        oy = canvas.translateOffsetY,
        sx = canvas.scaleOffsetX,
        sy = canvas.scaleOffsetY;
    currentPos.x *= sx;
    currentPos.y *= sy;
    currentPos.x += ox;
    currentPos.y += oy;
    var x = currentPos.x - thispos.x,
        y = currentPos.y - thispos.y;
    this.pos = currentPos;
    this.canvas.translate(x * 1/sx, y * 1/sy);
  },

  onTouchEnd: function(e, win, eventInfo) {
    if(!this.config.panning) return;
    this.pressed = false;
  },
  onTouchCancel: function(e, win, eventInfo) {
        if(!this.config.panning) return;
        this.pressed = false;
      }

event.touches.length

e.touches.length