code: function handlerWheel(event) {
        var parentRect = this.$refs.stripContainer.getBoundingClientRect();
        var rect = this.$refs.strip.getBoundingClientRect();
        // 滚动条相对于容器的offset
        var contrastParentOffset = rect[this.config.direction] - parentRect[this.config.direction];
        // 滚动条最终要设置的偏移量    event[this.config.wheelDelta] => 获取鼠标滚轮的滚动值
        var offset = contrastParentOffset + event[this.config.wheelDelta];
  
        this.changeOffset(offset, event);
      }
docs: 鼠标滚轮滚动事件