TreeDiagram

This library provides functions drawing diagrams of trees.

Building a tree

type Tree a

A tree data structure

node : a -> List (Tree a) -> Tree a

Constructs a tree out of a root value and a list of subtrees

Drawing a tree

type alias Coord =

( Float, Float )

2D coordinate

type alias Drawable fmt out =

{ position : Coord -> fmt -> fmt

, compose : Int -> Int -> List fmt -> out

, transform : Int -> Int -> Coord -> Coord

}

Functions for moving around and composing drawings

type alias NodeDrawer a fmt =

a -> fmt

Alias for functions that draw nodes

type alias EdgeDrawer fmt =

Coord -> fmt

Alias for functions that draw edges between nodes

draw_ :

Drawable fmt out

-> TreeLayout

-> NodeDrawer a fmt

-> EdgeDrawer fmt

-> Tree a

-> out

Draws the tree using the provided functions for drawings nodes and edges. TreeLayout contains some more options for positioning the tree.

Tree layout options

type alias TreeLayout =

{ orientation : TreeOrientation

, levelHeight : Int

, siblingDistance : Int

, subtreeDistance : Int

, padding : Int

}

Options to be passed to draw_ for laying out the tree:

orientation: direction of the tree from root to leaves.
levelHeight: vertical distance between parent and child nodes.
subtreeDistance: horizontal distance between subtrees.
siblingDistance: horizontal distance between siblings. This is usually set below subtreeDistance to produce a clearer distinction between sibling nodes and non-siblings on the same level of the tree.
padding: amount of space to leave around the edges of the diagram.

defaultTreeLayout : TreeLayout

A set of default values that should be modified to create your TreeLayout

type TreeOrientation

Direction of the tree from root to leaves

leftToRight : TreeOrientation

Left-to-right tree orientation

rightToLeft : TreeOrientation

Right-to-left tree orientation

bottomToTop : TreeOrientation

Bottom-to-top tree orientation

topToBottom : TreeOrientation

Top-to-bottom tree orientation