 _cardSizes = new List();

  for (int i = 0; i &lt; _stackNum; i++) {
    _cardSizes.add(new Size(minWidth + (widthGap &#47; _stackNum) * i,
        minHeight + (heightGap &#47; _stackNum) * i));

    switch (orientation) {
      case AmassOrientation.BOTTOM:
        _cardAligns.add(
            new Alignment(0.0, (0.5 &#47; (_stackNum - 1)) * (stackNum - i)));
        break;
      case AmassOrientation.TOP:
        _cardAligns.add(
            new Alignment(0.0, (-0.5 &#47; (_stackNum - 1)) * (stackNum - i