KiCad WebAssembly Port

Run KiCad PCBnew in the browser using WebAssembly.

Quick Start

Full Build (KiCad + All Tests)

# 1. Initialize submodules
git submodule update --init --recursive

# 2. Build KiCad WASM (Docker, ~10 min incremental, ~1-2 hours full)
./docker/build.sh

# 3. Build wxWidgets for local testing
./scripts/build-wx-wasm.sh

# 4. Build wxWidgets test apps
./scripts/build-wasm-test.sh

# 5. Run all tests
cd tests && npm install
npm test              # wxWidgets tests (256 tests)
npm run test:kicad    # KiCad tests (2 tests)

wxWidgets Only (No Docker)

# Requires: Node.js 18+ (Emscripten SDK auto-installed on first build)
./scripts/build-wx-wasm.sh
./scripts/build-wasm-test.sh
cd tests && npm install && npm test

Project Structure

kicad-wasm/
├── kicad/                  # KiCad source (git submodule)
├── wxwidgets/              # wxWidgets source (git submodule)
├── wasm/                   # WASM compatibility layer
│   ├── bindings/           # Embind bindings for JavaScript
│   ├── cmake/              # CMake find modules
│   ├── kiplatform/         # Platform abstraction (app, UI, printing)
│   ├── libcontext/         # Coroutine/fiber implementation
│   ├── shims/              # Runtime JavaScript shims
│   └── stubs/              # Stub implementations (libgit2, curl)
├── scripts/                # Build scripts
│   ├── build-wx-wasm.sh   # Build wxWidgets for WASM
│   ├── build-wasm-test.sh          # Build wxWidgets test apps
│   ├── deps/               # Dependency build scripts
│   ├── kicad/              # KiCad build scripts
│   ├── common/             # Shared utilities
│   └── config/             # Build config wrappers
├── docker/                 # Docker build environment
├── tests/                  # Playwright E2E tests
│   ├── e2e/                # Test specs
│   └── apps/               # WASM test applications
├── tools/                  # External tools (binaryen)
└── output/                 # Build output (pcbnew.js, pcbnew.wasm)

Feature Branches

Curated design docs and research notes for each feature live in docs/features/<branch-name>/ (committed).

./scripts/create-feature-patches.sh [branch-name] generates per-branch patches (root.patch, kicad.patch, wxwidgets.patch) into a local features/<branch-name>/ scratch dir. That dir is gitignored — the patches are local history, not committed.

Two Build Workflows

1. KiCad Build (Docker)

Full KiCad PCBnew build using Docker:

# Build KiCad WASM
./docker/build.sh

# Copy output to test directory
./tests/scripts/setup-kicad-wasm.sh

# Run KiCad tests
cd tests && npm install && npm run test:kicad

Output: output/pcbnew.js, output/pcbnew.wasm

See docs/build.md for detailed build documentation.

Creating an isolated worktree (with submodule branches)

For an experiment or feature you can work in a disposable git worktree so the main checkout stays pristine. This repo has four submodules (kicad, wxwidgets, binaryen, web/pcbjam-shared); a new worktree starts with them empty, so initialize and branch each one:

# 1. Create the worktree on a new branch (off main), at a sibling path
git worktree add -b experiment/my-thing ../kicad-wasm-my-thing main

# 2. Check out the submodules INSIDE the worktree (working trees only;
#    git objects are shared with the main checkout)
cd ../kicad-wasm-my-thing
git submodule update --init kicad wxwidgets binaryen web/pcbjam-shared

# 3. Create a matching branch in each submodule (they start at detached HEAD)
git checkout -b experiment/my-thing                 # root already on it via -b above
for sm in kicad wxwidgets binaryen web/pcbjam-shared; do
  git -C "$sm" checkout -b experiment/my-thing
done

Then build from inside the worktree. Use an isolated Docker project — do NOT set COMPOSE_PROJECT_NAME to another branch's project (e.g. kicad-wasm-main), which can collide with other workflows; docker/build.sh auto-derives an isolated project name from the worktree branch. The first build provisions deps (wxWidgets + OCC) from scratch. To keep the machine responsive / bound wasm-opt RAM, cap parallelism and skip the slow release optimization:

KICAD_DOCKER_CPUS=4 BINARYEN_CORES=4 BINARYEN_OPT_LEVEL=-O1 \
  ./docker/build.sh pcbnew -j 4

Tear down afterward with git worktree remove ../kicad-wasm-my-thing (and docker compose -p <project> down -v to drop the isolated volumes).

Fresh worktree provisioning

Some test artifacts are gitignored and are NOT produced by the build pipeline, so they don't carry into a newly-created git worktree — without them the gal-webgl tests 404 ("Loading WASM...") and the collab specs fail with Could not resolve "@pcbjam/shared". After building (docker/build.sh + scripts/build-wx-wasm.sh) and cd tests && npm i, run once per worktree:

./scripts/setup-worktree.sh   # idempotent: sysroot headers, gal-webgl harness, web/ pnpm install, collab bundle

2. wxWidgets Test Apps (Local)

Build standalone wxWidgets test apps for feature testing:

# Build wxWidgets for WASM
./scripts/build-wx-wasm.sh

# Build test apps
./scripts/build-wasm-test.sh

# Run wxWidgets tests
cd tests && npm install && npm test

Output: tests/apps/standalone/

Prerequisites

For KiCad Build (Docker)

• Docker Desktop with 16GB+ RAM allocated
• 10+ GB disk space for build cache

For wxWidgets Build (Local)

• Node.js 18+ (for tests)
• Emscripten SDK (auto-installed on first build)

# Initialize submodules
git submodule update --init --recursive

# Install Emscripten SDK (auto-runs on first build, or run manually)
./scripts/setup-emsdk.sh

Testing

cd tests
npm install

# Run all tests
npm test

# Run specific tests
npm run test:kicad          # KiCad tests only
npx playwright test menu    # Menu tests only

See tests/README.md for test documentation.

Screenshots

CI's Linux render is the source of truth for baseline screenshots. On each main push, CI compares its render against the committed baselines and posts the diff (plus the runtime-perf numbers) to Discord. To update baselines after an intended render change, promote a CI run's render — only meaningfully-changed images restage, so it stays churn-free:

cd tests
npm run screenshots:check                          # local gate: current vs baselines
npm run screenshots:promote -- --run <ci-run-id>   # adopt a CI run's render, then commit

See tests/tools/screenshots/README.md.

Current Status

• wxWidgets WASM: Core widgets working (menus, dialogs, grids, trees, OpenGL)
• KiCad PCBnew: Builds and loads in browser, canvas rendering working
• In Progress: Testing wxWidgets features used by KiCad

Documentation

See docs/README.md for the full documentation map. Highlights:

• Build System - Docker build details
• Docker README - Container setup
• Debugging Guide - Asyncify/WASM debugging
• Tests README - Test infrastructure

Landing page / website

The marketing site and landing page live in site/ (Astro), deployed as static assets to Cloudflare R2.

On every release, bump the build SHA. site/src/components/Footer.astro has a hardcoded BUILD_SHA constant that is shown in the footer and links to the corresponding commit. Because the main-repo commit pins the KiCad and wxWidgets submodule revisions implicitly, this is our GPLv3 corresponding-source pointer (surfaced on /licenses). The site is static, so nothing sets it automatically — update BUILD_SHA by hand to the deployed pcbjam commit each time you release.

License

KiCad is GPL-3.0. This project follows the same license.

The site combines KiCad (GPLv3) with the wxWidgets fork; the wxWidgets WebAssembly port files are LGPL v2 (without the wxWindows binary exception). See the /licenses page (site/src/content/legal/licenses.md) for the full breakdown and the corresponding-source offer.