pscat

pscat

pscat is a PostScript interpreter written in Rust. PostScript is a programming language for drawing pages; pscat runs your program and shows the picture as it is drawn, in a live window, or renders it to PNG, SVG or PDF. It also runs in a browser tab, and it ships with PostScript libraries for making art: generative patterns, paint and watercolor, printmaking, lettering, charts and more. It was built for fun, not as a Ghostscript replacement, though it aims for broad PostScript coverage over time.

pscatlabs.github.io/pscat has the docs, the full gallery, a specimen of every font, and a live playground that runs the interpreter in your browser, no install.

Install

cargo install pscat          # pscat and pscat-mcp, from crates.io
pscat fonts install          # optional: the full font catalog, as font packs
npm install pscat            # from 0.6.2: the wasm renderer for browsers and Node

Or download a ready-built binary for macOS, Linux or Windows from the releases page (no Rust needed). Getting started has the details. Then:

pscat --png out.png some_file.ps

Quick start from a checkout

You need a stable Rust toolchain.

cargo run -- --page 500x500 examples/sierpinski.ps   # watch it draw, live
cargo run -- --png out.png examples/sierpinski.ps    # render to a PNG instead
cargo run -- -i                                      # REPL + window: type PostScript, watch it draw

A taste of the REPL:

PS> 40 2 add =
42
PS> mark 1 2 3
PS<4> pstack
3
2
1
-mark-

To try it with nothing installed, open the playground. New to PostScript? Start with Learn PostScript. More sample programs live in examples/, and finished pieces in gallery/.

Guides

Everything else is in docs/guides/:

• Getting started: build, install, command-line flags, output formats
• pscat in the browser and for AI agents
• Fonts and handwriting
• artkit: the generative-art toolkit, and style packs and page templates
• Painting and the landscape cookbook
• Printmaking and etching and dry media
• Lettering, headlines and apparel
• Charts and plots

For AI agents

pscat works well from a coding agent. The skills in plugin/skills/ (pscat, psart, psviz) are plain Markdown any agent can read, and pscat-mcp is an MCP server with four tools. In Claude Code, both come as one plugin: /plugin install pscat --marketplace PSCatLabs/pscat (after installing pscat; see plugin/README.md). In Codex: codex plugin marketplace add PSCatLabs/pscat, then codex plugin add pscat@pscat. See the agents guide. Any other MCP client can run pscat mcp (the same server as pscat-mcp), and pscat is listed in the MCP Registry from 0.6.3:

• MCP Registry name: mcp-name: io.github.PSCatLabs/pscat

Contributing

Start with CONTRIBUTING.md (including how contributions are licensed), then AGENTS.md for conventions and SDLC.md for how changes land. Report security problems as SECURITY.md describes, and see docs/STABILITY.md for what stays stable between releases. docs/dev/HANDOFF.md orients you in the code, docs/dev/ARCHITECTURE.md explains the design, and docs/dev/ has the contributor notes, such as how to preview the website. docs/archive/ holds the project's history, including the original stage-by-stage status log.

Why

I used to write raw PostScript by hand in college and send it straight to a LaserWriter. This is a from-scratch Rust interpreter built to relive that — watching a hand-written recursive PostScript program draw itself, live, without depending on a decades-old C codebase to do it.

Licence

pscat's code is dual-licensed under MIT or Apache-2.0, at your option. The package also embeds font data: the Liberation faces and the Courier Prime-derived typewriter outlines, both under the SIL Open Font License 1.1. That's why Cargo.toml says (MIT OR Apache-2.0) AND OFL-1.1. The OFL term covers only the embedded font data, not pscat's code.

The fonts in fonts/catalog/ keep their own upstream licences. The original gallery, example and shirt art is dedicated to the public domain under CC0-1.0, with a few exceptions. CC0 grants no rights in the pscat name or logo. THIRD_PARTY_NOTICES.md lists what is under which terms.

SDLC

See SDLC.md for how this repo's development lifecycle works (issue → branch → PR → review → merge → cleanup) and the branch-protection/merge policy currently enforced on GitHub — generated and kept in sync by the sdlcify skill.