Data.Graph.Layout

data TreeLayout

Tree layout orientation

Constructors

• Radial
• Horizontal
• Vertical

Instances

• Eq TreeLayout
• Ord TreeLayout
• Show TreeLayout

type Point = { x :: Number, y :: Number }

A 2D point

type LayoutNode node = { id :: node, layer :: Int, x :: Number, y :: Number }

A node with computed layout position

type LayoutConfig = { nodeHeight :: Number, nodeWidth :: Number, orientation :: TreeLayout, reversed :: Boolean }

Configuration for layout algorithms

treeLayout :: forall node. Ord node => LayoutConfig -> node -> TreeAdj node -> Array (LayoutNode node)

Compute tree layout with the given root node

Uses a simple recursive algorithm:

• Children are placed side by side
• Parent is centered above its children

layeredTreeLayout :: forall node. Ord node => LayoutConfig -> Array (LayeredInput node) -> Array (LayoutNode node)

Layout nodes that already have layer assignments

Useful when you've computed layers separately (e.g., from topological sort).

defaultLayoutConfig :: LayoutConfig

Default layout configuration

dagLayout :: forall node. Ord node => LayoutConfig -> Array node -> GraphAdj node -> Array (LayoutNode node)

Layout a DAG using Sugiyama-style algorithm

Steps:

1. Compute layers (topological)
2. Order nodes within layers to minimize crossings
3. Assign x coordinates

sugiyamaLayout :: forall node. Ord node => LayoutConfig -> Array node -> GraphAdj node -> Array (LayoutNode node)

Sugiyama hierarchical layout algorithm

A simplified version that:

1. Assigns layers based on longest path from sources
2. Orders nodes to reduce crossings (barycenter heuristic)
3. Assigns coordinates