SLICE
Implementation of the Slice-and-dice algorithm described in the original treemap paper. It is described in:
Ben Shneiderman. 'Tree Visualization with Tree-Maps: 2-d Space-filling Approach." ACM Transactions on Graphics, 11(1), pp. 92-99, 1992.
It uses parallel lines to divide a rectangle representing an item into smaller rectangles representing its children. At each level of hierarchy the orientation of the lines - vertical or horizontal - is switched (alternate), computed according to the aspect ratio (Best), or fixed (Vertical, Horizontal).
Complexity: O(n), where n is the number of nodes in the tree.