text: function(size, character) {
    var total = size - this.size;
    if (total<=0) return this;
    var right = Math.ceil(total / 2);
    var left = total - right;
    var c = (character || ' ').string;
    return Array(left+1).join(c) + this + 
           Array(right+1).join(c);
  }
  