NAPLPS 📺✨

A modern .NET 10 toolkit for the North American Presentation Level Protocol Syntax, ANSI X3.110-1983, with live-rendering examples from the historical corpus. Click any tile below to open the full-size APNG; each is a bit-identical render from a real .nap file in Examples/.

All 372 renders in one gallery, with transport controls to scrub through the drawing sequence frame by frame, and before/after diffs for every recent change to the renderer. For background on the format, Prodigy, and Telidon, see the Wikipedia articles: NAPLPS, Prodigy (online service), Telidon. ⚠️WARNING:⚠️ These are various amazing rabbit holes, be warned! 🐇🕳️

girl.nap	dragon.nap	seaport.nap
earth.nap	SAIL.NAP	santa.nap

A from-scratch, spec-focused parser, renderer, encoder, and authoring toolchain, with 375+ historical example files. The 1983 BYTE Magazine NAPLPS articles and historical spec documents are bundled in docs/ as reference. 📚

Current version	0.12.0
Tests	800+ unit tests, plus round-trip Telidraw and visual regression baselines across the corpus
Spec coverage	98% (see docs/gaps.md for needs, and docs/naplps.md for the knowns)

What's in the box 📦

• 🧩 NAPLPS/. The library: parser, renderer, encoder, command builder. Reads and writes .nap byte streams, renders to ImageSharp Image<Rgba32>, and is AOT-compatible (<IsAotCompatible>true</IsAotCompatible>).
• 🖥️ Telidraw/. The multi-platform Avalonia desktop editor, viewer, and exporter. Canvas drawing tools, attribute editors, DRCS / Texture designers, sequence inspector, a Telidraw text-source pane (AvaloniaEdit-backed), TCP networking, and APNG export.
• ✍️ Telidraw. A word-number DSL (.td files) that compiles to .nap and decompiles back byte-identical. The canonical human-editable source format. See docs/telidraw.md for the language reference.
• 🧪 NAPLPSTests/. Full suite: per-command unit tests, Telidraw lexer/parser/compiler tests, the headline round-trip test across every example, and the visual regression suite (renders each example to APNG and byte-compares against a curated baseline).

Quick start 🚀

# Build everything
dotnet build NAPLPS.sln

# Launch the editor
dotnet run --project Telidraw

# Compile a .td source file to .nap
dotnet run --project Telidraw -- compile path/to/scene.td -o path/to/scene.nap

# Export .nap as APNG
dotnet run --project Telidraw -- export path/to/scene.nap --format=apng

# Dump file metadata
dotnet run --project Telidraw -- info path/to/scene.nap

Open any file from Examples/ to see it render. The repo includes 375+ historical NAPLPS files, plus hand-authored Telidraw templates in Examples/telidraw/ (hello, house, star, spirograph, snowflake, clock, palette demo, menu page). 🎨

Toggle View > Toolbox to enter authoring mode. Toggle View > Properties for the attribute panel. The Telidraw source pane is accessible from the main canvas area when a file is loaded; edits sync back to the visual canvas.

Documentation map 🗺️

Doc	What's in it
README.md	You are here. Cliff notes and pointers.
Visual corpus	🖼️ Every render in the corpus, frame-by-frame playback, and the change history of the renderer
docs/app.md	🖥️ The editor: tools, panels, menus, keyboard shortcuts, CLI commands, export formats, network mode, macro recorder, DRCS / Texture designers
docs/naplps.md	📖 The spec: byte-stream layout, G-set invocation, ESC sequences, PDI command family, coordinate encoding, text / color / texture semantics, mosaic + DRCS, plus how the parser implements the state machine
docs/telidraw.md	✍️ The DSL: keyword reference, directives, block structure, expression grammar, round-trip guarantees
docs/quickref.md	🔖 Normative reference: opcode tables, operand layouts, in-use table rules
docs/gaps.md	🕳️ Spec gaps and deliberate deviations, by category
docs/tools.md	🔧 Developer workflow: running tests, visual regression workflow, AOT status, dev commands, native interop examples
tools/aot/README.md	🌐 Ten native interop demos (C, C++, Rust, Python, Node.js, Go, Zig, PHP, Ruby, Swift) that link against the AOT-published library
IDEAS.md	💡 Ideas and open TODOs
docs/	📚 Original source material: 1983 BYTE Magazine NAPLPS articles, ANSI X3.110-1983 standard PDF

Key invariants ✅

Every commit must maintain:

1. ✅ All unit tests pass (spec, commands, DSL, encoder, decoder, Telidraw compiler, renderer)
2. 🔁 Telidraw round-trip byte-identical across the full corpus (.nap → decompile → recompile → same bytes)
3. 💾 Disk-honest (FromFile → ToBytes matches source bytes; the parser preserves every byte, even spec-undefined ones, for lossless round-trip)
4. 🖼️ Visual regression baselines pass (APNG bit-identical to a curated corpus)
5. 🧪 Editor launches, renders, saves (smoke test)

Running the full suite:

dotnet test NAPLPSTests/NAPLPSTests.csproj

License 📄

MIT. See LICENSE.

Contributing 🤝

Pull requests welcome, especially for:

• Long-tail spec items in docs/gaps.md (text rendering, G2 visual accent composition on opt-in, proportional spacing spec-strict mode)
• Additional BBS / Telidon / Prodigy file format support in the parser
• Fresh ideas for the editor (see IDEAS.md for the current wishlist: networked multiplayer drawing, macro recording, Telidraw extensions, export formats, accessibility features)

Please run the full test suite before submitting. The round-trip and visual regression tests catch most regressions that type-level unit tests miss. 🎯