layout method
给定一个区域范围和节点,对该节点的Children进行布局(不包含孩子的孩子)
Implementation
@override
void layout(TreeMapNode root, Rect area) {
if(root.deep%2==0){
SliceLayout.layoutChildren(area, root.children);
}else{
DiceLayout.layoutChildren(area, root.children);
}
}