code: function Vertical(images, spriteDef, layout){
    this.images = images;
    this.spriteDef = spriteDef;
    this.layout = layout;
    this.width = 0;
    this.height = 0;
    this.labels = {
      //固定定位
      fix: [],
      //占独立一行
      line: [],
      //紧凑拼图
      close: [],
      //放置在最后
      end: []
    };
    this.blocks = [];
    this.init();
  }
docs: 垂直布局算法，计算图片位置spritepos_left和spritepos_top，大图的宽度高度
  @param {object} images 图片对象，记录align, height, width, repeat
  @param {object} spriteDef 图片对应的css规则