Export

SVG

const { svg, clip } = await editor.exportAsSVG({ svgMode: "web" })

• svg: string — serialised SVG markup
• clip: { x, y, width, height } — viewport of the rendered diagram

ExportOptions:

Field	Type	Default	Effect
svgMode	"web" | "compat"	"web"	"web" keeps CSS variables for theme-adaptive rendering; "compat" resolves them and inlines fonts/attributes (PDF/PPT/Inkscape).
margin	number | { top?, right?, bottom?, left?: number }	0	Extra space around the diagram bounding box.
keepOriginalSize	boolean	false	If true, do not normalise the viewBox to the diagram bounds — preserve the editor's current pan/zoom framing.
include	string[]	—	Render only the listed element ids. Mutually exclusive with exclude.
exclude	string[]	—	Render everything except the listed element ids.

Headless SVG export (no mounted editor)

import { ApollonEditor, importDiagram } from "@tumaet/apollon"

const svgExport = await ApollonEditor.exportModelAsSvg(importDiagram(model), {
  svgMode: "compat",
})

exportModelAsSvg mounts the editor off-screen and serialises the rendered SVG, so it needs a DOM plus canvas measureText and getBBox. To render saved models in a batch — e.g. reviewing diagram submission versions — without a browser, use the jsdom + canvas recipe in Headless rendering (a browser is the heavier, pixel-exact alternative).

In a real browser the export is self-contained: it injects the layout CSS and Inter font it needs, so you do not import @tumaet/apollon/style.css just to export. (style.css is still required to mount the interactive editor.)

:::tip Always normalise first Pass models through importDiagram(...) before exporting. It upgrades v2 / v3 payloads to the current v4 shape; feeding a stale shape straight in is a common cause of garbled output. :::

The standalone server's conversion worker is the reference jsdom setup: it registers Inter on a Skia canvas, shims getBBox, and pre-seeds handle geometry. See Headless rendering.

PNG / PDF

For browsers and embedders, import the ready-made helpers from @tumaet/apollon/export. They consume the compat-mode SVG produced above and work around the browser's canvas-area limit — svgToPng rasterises in wasm memory instead of a <canvas>, and svgToPdf emits true vector PDF.

import { svgToPng, svgToPdf } from "@tumaet/apollon/export"
import resvgWasmUrl from "@resvg/resvg-wasm/index_bg.wasm?url" // Vite — see below

const { svg, clip } = await editor.exportAsSVG({ svgMode: "compat" })

const { blob, clamped } = await svgToPng(svg, clip, {
  scale: 1.5,
  background: "#ffffff", // or null for transparent
  wasmInput: fetch(resvgWasmUrl),
})
const pdfBlob = await svgToPdf(svg, clip, { title: "diagram" })

@resvg/resvg-wasm, jspdf and svg2pdf.js are optional dependencies the consumer installs (npm install @resvg/resvg-wasm jspdf svg2pdf.js); they load lazily, so importing the editor never pulls them in. Over-budget diagrams come back with clamped: true and a reduced appliedScale; an over-budget PNG throws RasterTooLargeError. Inter ships Regular + Bold only, so italics render upright — matching the server.

Loading the resvg wasm per bundler

svgToPng needs the @resvg/resvg-wasm binary, passed as wasmInput (anything resvg's initWasm accepts — fetch(url) is idiomatic). The library does not bundle the wasm, so how you get the URL depends on your bundler:

• Vite — import resvgWasmUrl from "@resvg/resvg-wasm/index_bg.wasm?url" (the snippet above).
• Webpack 5 — add a rule { test: /\.wasm$/, type: "asset/resource" }, then const resvgWasmUrl = new URL("@resvg/resvg-wasm/index_bg.wasm", import.meta.url).href.
• Angular — copy the binary with an assets glob (node_modules/@resvg/resvg-wasm/index_bg.wasm → assets/resvg/), then wasmInput: fetch("assets/resvg/index_bg.wasm").

svgToPdf needs no wasm. Both helpers inline the Inter font in the browser, so you only set fontBuffers / fonts for headless Node.

Server-side instead? The standalone server renders SVG, PNG, and PDF over HTTP via a Skia canvas + pdfmake — see the Conversion API.

JSON

const model = editor.model // UMLModel
const json = JSON.stringify(model)

Round-trip safe: editor.model = JSON.parse(json).

Wire-format versions

The library reads v2, v3, and v4 model JSON. Use importDiagram(any) to normalise any version to the current v4 shape before assigning to editor.model or passing to exportModelAsSvg.

import { importDiagram } from "@tumaet/apollon"

editor.model = importDiagram(maybeV2OrV3Json)

The v4 shape is published as a versioned JSON Schema — see the Model JSON contract for the schema, the field-by-field shape, and the versioning policy.