The complexity of minimizing wire lengths in VLSI layouts
Information Processing Letters
A node-positioning algorithm for general trees
Software—Practice & Experience
A note on optimal area algorithms for upward drawings of binary trees
Computational Geometry: Theory and Applications
Aesthetic layout of generalized trees
Software—Practice & Experience
Area-efficient algorithms for straight-line tree drawings
Computational Geometry: Theory and Applications
Optimizing area and aspect ratio in straight-line orthogonal tree drawings
Computational Geometry: Theory and Applications
WG '92 Proceedings of the 18th International Workshop on Graph-Theoretic Concepts in Computer Science
On linear area embedding of planar graphs
On linear area embedding of planar graphs
IEEE Transactions on Software Engineering
Straight-line orthogonal drawings of binary and ternary trees
GD'07 Proceedings of the 15th international conference on Graph drawing
Really straight graph drawings
GD'04 Proceedings of the 12th international conference on Graph Drawing
Drawing ordered (k - 1)-ary trees on k-grids
GD'10 Proceedings of the 18th international conference on Graph drawing
Pinning balloons with perfect angles and optimal area
GD'11 Proceedings of the 19th international conference on Graph Drawing
Drawing unordered trees on k-grids
WALCOM'12 Proceedings of the 6th international conference on Algorithms and computation
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We consider straight-line drawings of trees on a hexagonal grid. The hexagonal grid is an extension of the common grid with inner nodes of degree six. We restrict the number of directions used for the edges from each node to its children from one to five, and to five patterns: straight, Y, ψ, X, and full. The ψ–drawings generalize hv- or strictly upward drawings to ternary trees. We show that complete ternary trees have a ψ–drawing on a square of size $\O(n^{1.262})$ and general ternary trees can be drawn within $\O(n^{1.631})$ area. Both bounds are optimal. Sub–quadratic bounds are also obtained for X–pattern drawings of complete tetra trees, and for full–pattern drawings of complete penta trees, which are 4–ary and 5–ary trees. These results parallel and complement the ones of Frati [8] for straight–line orthogonal drawings of ternary trees. Moreover, we provide an algorithm for compacted straight–line drawings of penta trees on the hexagonal grid, such that the direction of the edges from a node to its children is given by our patterns and these edges have the same length. However, drawing trees on a hexagonal grid within a prescribed area or with unit length edges is $\mathcal{NP}$–hard.