_onFabricMouseDown(fEvent) {
    const canvas = this.getCanvas();

    if (fEvent.target) {
      return;
    }

    canvas.selection = false;
    const coord = canvas.getPointer(fEvent.e);

    this._startX = coord.x;
    this._startY = coord.y;

    canvas.on({
      'mouse:move': this._listeners.mousemove,
      'mouse:up': this._listeners.mouseup,
    });
  }
onMousedown handler in fabric canvas
@param {{target: fabric.Object, e: MouseEvent}} fEvent - Fabric event
@private