Read computed geometry

getLayout returns a plain, JSON-serializable snapshot of the graph's computed node positions, edge spline points, and bounding box — after layout has run.

Basic usage

import { createGraph, render, getLayout } from 'graphviz-ts';

const b = createGraph({ directed: true });
b.addNode('a');
b.addNode('b');
b.addEdge('a', 'b');

// render runs layout and mutates the graph in place.
// Geometry is retained on the graph after render returns.
render(b.graph, 'svg');

const layout = getLayout(b.graph);
// layout.bounds  → { x: 0, y: 0, width: ..., height: ... }
// layout.nodes   → [{ name: 'a', x: ..., y: ..., width: ..., height: ... }, ...]
// layout.edges   → [{ tail: 'a', head: 'b', points: [{x,y}, ...] }]

render lays out the graph before rendering. The computed geometry (coord, width, height on each node; spline points on each edge) is retained on the graph object after render returns and is readable via getLayout.

Snapshot shape

interface LayoutSnapshot {
  bounds: BoundsGeometry;          // overall bounding box
  nodes:  NodeGeometry[];          // one entry per node
  edges:  EdgeGeometry[];          // one entry per edge
}

interface BoundsGeometry {
  x: number; y: number;            // origin (0,0 in y-down mode)
  width: number; height: number;   // in points
}

interface NodeGeometry {
  name:   string;
  x:      number;   // centre x, in points
  y:      number;   // centre y, in points
  width:  number;   // in points (converted from model inches × 72)
  height: number;   // in points (converted from model inches × 72)
}

interface EdgeGeometry {
  tail:    string;
  head:    string;
  points:  { x: number; y: number }[];  // bezier control points, in points
  label?:  { x: number; y: number };    // centre label position (if present)
}

Units

All coordinates and dimensions are in points (1 inch = 72 points), matching graphviz's native unit.

Node width and height are stored internally in inches on the model; getLayout converts them to points before returning.

Coordinate system (yAxis)

graphviz's native coordinate system is y-up (origin at the lower-left corner). Screen and browser contexts use y-down (origin at the upper-left corner).

// Default: y-down — origin top-left, y increases downward (screen convention)
const screen = getLayout(g);

// y-up — native graphviz coordinates, origin bottom-left
const native = getLayout(g, { yAxis: 'up' });

yAxis	Origin	y direction	Use when
'down' (default)	top-left	increases downward	canvas, SVG, HTML
'up'	bottom-left	increases upward	native graphviz output, PDF

In y-down mode the bounds origin is normalised to (0, 0). In y-up mode bounds.x and bounds.y reflect the raw lower-left corner of the graph bounding box.

Signature

function getLayout(g: Graph, opts?: { yAxis?: 'up' | 'down' }): LayoutSnapshot;

getLayout does not modify the graph. Call it as many times as needed after layout.