code: function (b) {
          var a = this;
          var sx = b.width / a.width;
          var sy = b.height / a.height;
  
          var m = matrix.create();
  
          // 矩阵右乘
          matrix.translate(m, m, [-a.x, -a.y]);
          matrix.scale(m, m, [sx, sy]);
          matrix.translate(m, m, [b.x, b.y]);
  
          return m;
      }
docs: Calculate matrix of transforming from self to target rect
  @param  {module:zrender/core/BoundingRect} b
  @return {Array.<number>}