pcbjam/wasm/README.md
Viktor Vaczi 3034d9d76f Add KiCad WASM build infrastructure and dependency scripts
- Add build environment setup (scripts/common/env.sh, versions.sh, functions.sh)
- Add dependency build scripts for Zstd, GLM, FreeType, HarfBuzz, Pixman, Cairo
- Add placeholder scripts for OpenCASCADE, ngspice, protobuf
- Add WASM compatibility layer (wasm/kiplatform/, wasm/libcontext/)
- Add CMake modules for KiCad WASM cross-compilation
- Add PCBnew test infrastructure (tests/kicad/)
- Add build plan documentation

Successfully tested builds: Zstd 1.5.5, GLM 0.9.9.8, FreeType 2.13.2,
HarfBuzz 8.3.0, Pixman 0.42.2, Cairo 1.18.0

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
2025-12-04 13:15:04 +01:00

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Markdown

# WASM Compatibility Layer
This directory contains WASM-specific implementations that allow KiCad to run in a web browser **without modifying KiCad's source code**.
## Principle
Instead of patching KiCad source files, we:
1. Override include paths to use our headers first
2. Provide alternative implementations for platform-specific code
3. Link our libraries instead of system libraries
## Directory Structure
```
wasm/
├── CMakeLists.txt # Master CMake for compatibility layer
├── README.md # This file
├── kiplatform/ # Platform abstraction implementations
│ ├── CMakeLists.txt
│ ├── app.cpp # App lifecycle (paths, startup)
│ ├── drivers.cpp # GPU detection (returns "WebGL")
│ ├── environment.cpp # Environment variables (localStorage)
│ ├── io.cpp # File I/O (WASM virtual filesystem)
│ ├── policy.cpp # Security policy (always permissive)
│ ├── secrets.cpp # Credential storage (localStorage)
│ ├── sysinfo.cpp # System information
│ └── printing.cpp # Print support (browser print())
├── libcontext/ # Coroutine/fiber implementation
│ ├── CMakeLists.txt
│ └── fcontext_wasm.cpp # Emscripten Asyncify fibers
├── shims/ # Header overrides
│ └── *.h # Headers that redirect to our impls
└── config/ # Build configuration
├── kicad_wasm_config.h # Version and feature config
└── setup.h # Platform setup
```
## How It Works
### Include Path Override
When building KiCad for WASM, we add our directories first in the include path:
```bash
-I$PROJECT_ROOT/wasm/shims
-I$PROJECT_ROOT/wasm/kiplatform
-I$PROJECT_ROOT/stubs/include
```
This means when KiCad includes `<kiplatform/app.h>`, it finds our version first.
### Library Override
We build `libkiplatform_wasm.a` and link it instead of the native kiplatform:
```bash
-L$BUILD_ROOT/wasm -lkiplatform_wasm
```
### CMake Integration
The main KiCad build is configured to find our implementations:
```cmake
-DCMAKE_MODULE_PATH="$PROJECT_ROOT/cmake"
-DKIPLATFORM_LIBRARY="$BUILD_ROOT/wasm/libkiplatform_wasm.a"
```
## Adding New Implementations
1. Create the implementation file in the appropriate directory
2. Add it to the CMakeLists.txt
3. Ensure the header interface matches KiCad's expected interface
4. Test with a minimal build before full integration