code: function moveOffset(offset) //{{{
        {
          var ox = offset[0],
              oy = offset[1];
  
          if (0 > x1 + ox) {
            ox -= ox + x1;
          }
          if (0 > y1 + oy) {
            oy -= oy + y1;
          }
  
          if (boundy < y2 + oy) {
            oy += boundy - (y2 + oy);
          }
          if (boundx < x2 + ox) {
            ox += boundx - (x2 + ox);
          }
  
          x1 += ox;
          x2 += ox;
          y1 += oy;
          y2 += oy;
        }
docs: }}}