Diagram and container layout modes

A diagram (or a container) places its shapes with one of several layout modes, set by layout = :<mode>. The default is free placement from explicit coordinates; the auto-layout modes derive positions from the connection graph instead.

Mode	Behaviour
:free	Default — shapes sit at the explicit x/y coordinates you give them
:grid	Shapes flow into rows and columns of a regular grid
:layered	Shapes are topologically ranked from the edges and stacked top-to-bottom, elbow-routed (flowcharts)
:force	A force-directed solver spreads connected shapes apart and pulls neighbours together
:radial	One hub sits at the centre with every other shape on a ring around it (hub-and-spoke)

§ 1The auto-layout modes in action

Each derives positions from the same shapes + edges — only layout changes.

§ 1.1:grid

Children flow into a regular grid (here on a container, which also takes the grid sizing fields):

Preview

Example

diagram {
  width = 240
  height = 140
  container {
    anchor_left = 8.0
    anchor_top = 8.0
    fill = "#eef"
    stroke = "#88a"
    padding = 10.0
    layout = :grid
    columns = 3
    cell_width = 56.0
    cell_height = 40.0
    gap = 10.0
    rect {
      fill = "#88c0d0"
    }
    rect {
      fill = "#a3be8c"
    }
    rect {
      fill = "#ebcb8b"
    }
    rect {
      fill = "#b48ead"
    }
    rect {
      fill = "#bf616a"
    }
    rect {
      fill = "#d08770"
    }
  }
}

§ 1.2:layered

Shapes are topologically ranked from the edges and stacked top-to-bottom, elbow-routed:

Preview

Example

diagram {
  width = 300
  height = 220
  layout = :layered
  layer_gap = 22.0
  process "Fetch" {
    id = fetch
    width = 90.0
    height = 38.0
    fill = "#88c0d0"
  }
  process "Parse" {
    id = parse
    width = 90.0
    height = 38.0
    fill = "#a3be8c"
  }
  process "Store" {
    id = store
    width = 90.0
    height = 38.0
    fill = "#ebcb8b"
  }
  fetch -> parse :flow
  parse -> store :flow
}

§ 1.3:radial

One hub sits at the centre with the rest ringed around it (pairs well with routing = :straight):

Preview

Example

diagram {
  width = 320
  height = 260
  layout = :radial
  hub = core
  routing = :straight
  process "Core" {
    id = core
    width = 84.0
    height = 40.0
    fill = "#b48ead"
  }
  process "Auth" {
    id = auth
    width = 84.0
    height = 40.0
  }
  process "Cache" {
    id = cache
    width = 84.0
    height = 40.0
  }
  process "Queue" {
    id = queue
    width = 84.0
    height = 40.0
  }
  core -> auth :flow
  core -> cache :flow
  core -> queue :flow
}

§ 1.4:force

A force-directed solver spreads connected shapes apart and pulls neighbours together:

Preview

Example

diagram {
  width = 320
  height = 240
  layout = :force
  routing = :straight
  process "A" {
    id = na
    width = 56.0
    height = 36.0
    fill = "#88c0d0"
  }
  process "B" {
    id = nb
    width = 56.0
    height = 36.0
    fill = "#a3be8c"
  }
  process "C" {
    id = nc
    width = 56.0
    height = 36.0
    fill = "#ebcb8b"
  }
  process "D" {
    id = nd
    width = 56.0
    height = 36.0
    fill = "#b48ead"
  }
  na -> nb
  na -> nc
  nb -> nd
  nc -> nd
}