QUICKSTART.md

Quickstart

Render a document

npm install @vmprint/engine @vmprint/local-fonts @vmprint/context-pdf

import { VMPrintEngine, loadDocument } from '@vmprint/engine';
import LocalFontManager from '@vmprint/local-fonts';
import { PdfContext } from '@vmprint/context-pdf';
import { createWriteStream } from 'fs';

const doc = loadDocument(JSON.parse(await fs.readFile('document.json', 'utf8')));
const engine = new VMPrintEngine(doc, new LocalFontManager());

const stream = createWriteStream('output.pdf');
const context = new PdfContext(stream);
await engine.render(context);
await context.waitForFinish();

render() runs layout and renders in one call. To inspect pages before rendering:

const pages = await engine.layout();
console.log(`${pages.length} pages, ${engine.info.pageSize.width}×${engine.info.pageSize.height}pt`);
await engine.render(context);

For a prefix preview or an incremental flow tool, limit layout to a page prefix:

const firstTwoPages = await engine.layout({ stopAtPage: 1 });

stopAtPage is zero-based and inclusive.

Document shape

Documents are JSON objects conforming to AST version 1.1:

{
  "documentVersion": "1.1",
  "layout": {
    "pageSize": "A4",
    "margins": { "top": 72, "right": 72, "bottom": 72, "left": 72 },
    "fontFamily": "Tinos",
    "fontSize": 12,
    "lineHeight": 1.4
  },
  "elements": [
    { "type": "story", "content": "Hello, world." }
  ]
}

Use layout.pageTemplates when individual pages need different dimensions or margins. The engine resolves those templates before measuring each page, and PDF rendering preserves the resulting per-page media size.

Built-in font families (Arimo, Tinos, Cousine, Caladea, Carlito, and Noto variants for CJK/Arabic/Thai/Devanagari) require no fonts block. For custom font files, add a role map:

"fonts": {
  "regular":    "fonts/MyFont-Regular.ttf",
  "bold":       "fonts/MyFont-Bold.ttf",
  "italic":     "fonts/MyFont-Italic.ttf",
  "bolditalic": "fonts/MyFont-BoldItalic.ttf"
}

See guides/ for the full element reference and layout options.

CLI

For batch JSON-to-PDF workflows, use the vmprint CLI:

npm install -g @vmprint/cli
vmprint --input document.json --output output.pdf

See cli/QUICKSTART.md for all flags.