efterscript

Try it in your browser → The try-it page runs this package; nothing you convert is uploaded.

A memory-safe interpreter compatible with the PostScript language, compiled to WebAssembly: a program in, a PDF out, in the browser or in Node.js. Vectors stay vectors, text stays text, colour spaces are preserved; nothing is rasterised.

The engine is the same Rust code that is published as the efterscript crates, built for wasm32-unknown-unknown with no imports: it cannot reach the network, the file system, or anything else in its host. The package has no dependencies.

Use

import { load } from "efterscript";

const engine = await load();
const result = await engine.convert(`%!PS
/Helvetica findfont 24 scalefont setfont
72 700 moveto (Hello, PDF) show
showpage`);

result.outcome; // "ok", "error", or "budget"
result.pdf;     // Uint8Array holding the document
result.stdout;  // what the program printed

load() fetches efterscript.wasm from beside the module (from the file system under Node.js). Pass a URL, a Response, the bytes, or a compiled WebAssembly.Module to load it from somewhere else; a bundler can resolve efterscript/efterscript.wasm to a URL for you.

Programs arriving in pieces can be fed as they come, which is how a host acting as a printer answers queries while a job is still arriving:

const job = await engine.job({ identity: { product: "(Fictional Press)" } });
job.feed(firstChunk);     // { stdout, stderr, done }
job.feed(secondChunk);
const result = job.finish();
job.free();

Each job runs in a fresh instance of the module, so nothing survives from one job to the next.

Options

| Option | Default | Meaning | |---|---|---| | budget | 100000000 | Objects the program may execute before it stops with the budget outcome; null for no limit. | | identity | {} | statusdict entries, each value as literal text in the PostScript language. | | prelude | none | A program run once at the server level before the job. | | compress | true | Compress page content. | | embedAllFonts | false | Embed every font, the resident ones included. | | serverPassword | 0 | The password exitserver expects. |

The engine runs synchronously inside feed and finish. In a browser, run it in a Web Worker so the page stays responsive, and terminate the worker to cancel a job; engine.module can be posted to the worker and passed to load there.

Licence

MIT for the project's own code. The module contains the resident font set and its data, which carry their own terms; see THIRD-PARTY-NOTICES.md. PDFs produced with these fonts carry no obligation.

PostScript is a registered trademark of Adobe. EfterScript is an independent interpreter compatible with the PostScript language and is not affiliated with or endorsed by Adobe.