layli

layli

This tools produces diagrams and has 2 simple aims:

1. Define components and connections as code
2. Look pretty

Using layli

Installation

$ go install github.com/dnnrly/layli/cmd/layli

A simple examples

Your first layli file:

node: "Hello World"

$ layli hello-world.layli

Discovering Available Options

To see all available layout algorithms, pathfinding algorithms, and heuristics:

$ layli config

Output:

{
  "algorithms": ["dijkstra", "astar", "bidirectional"],
  "heuristics": ["euclidean", "manhattan"],
  "layouts": ["flow-square", "topo-sort", "tarjan", "absolute", "random-shortest-square"]
}

Programmatic access (Go):

import "github.com/dnnrly/layli/layout"

layouts := layout.GetLayoutOptions()
algorithms := layout.GetPathfindingAlgorithms()
heuristics := layout.GetHeuristics()

layli principles

layli aims to let you specify nodes and edges (boxes and lines) and looks after arranging them in a pleasing way. If you've ever used plantuml you'll be familiar with describing the diagrams in a simple to understand text file to generate a pretty diagram. Well, perhaps not as pretty as you would hope. This tool aims to solve this.

Here are some principles that hope to tackle this problem head on:

1. Edge paths must travel across a "path grid"
2. Node borders must be on the "path grid"
3. Edges must meet nodes at "ports"
4. Ports must sit on the "path grid"
5. Where a port is not specified, layli may select a "default" port on any side of the node
6. Nodes must be layed out so that the total area marked by the outside bounds of every node is as small as possible
7. Nodes must be seperated by at least 1 space on the "path grid"
8. Edges must must not cross!
9. Edges must follow a grid path (ie. not curved or diagonal)
10. Edges must be as short as possible
11. Edges must have as few corners as possible
12. Edge paths may sit on top of each other at the beginning or at the end

Defining nodes

Specifying a simple node:

Complex nodes:

nodes:
  - id: node-1
    contents: "A\nwith formatting"

Connecting nodes:

edges:
  - from: node-1
    to: "The node name"

Defining the layout style:

layout: flow-square

There are currently 3 different layout styles:

• flow-square - nodes are arranged into rows and columns, much the way you read words on a page
• topo-sort - nodes are sorted in order of the edges, all in a single row
• tarjan - uses Tarjan's Algorithm to arrange the nodes an a 'pleasing' way
• absolute - lets you specify where you want nodes to appear on the diagram

An example diagram

Here's an image that is generated by this command layli ./demo.layli --show-grid:

layout: flow-square
nodes:
    - id: a
      contents: Node A
    - id: b
      contents: Node B
    - id: c
      contents: Node C
    - id: d
      contents: Node D
    - id: e
      contents: Node E
    - id: f
      contents: Node F
    - id: g
      contents: Node G
    - id: h
      contents: Node H
    - id: i
      contents: Node J

edges:
    - from: a
      to: b
    - from: b
      to: c
    - from: c
      to: d
    - from: d
      to: e
    - from: c
      to: e
    - from: e
      to: d
    - from: d
      to: f
    - from: f
      to: g
    - from: f
      to: h
    - from: g
      to: i

width: 7
height: 4
border: 2
margin: 2

# You can also add comments to your file, like so.

$ make test

$ make acceptance-test