Symbol Editor WASM port — design notes

Goal

Bring up KiCad's Symbol Editor (FRAME_SCH_SYMBOL_EDITOR, the .kicad_sym library editor) in the browser, to the same "boots, canvas visible, click around" level as the other ported apps. Scope is launch-only — library load/save and the symbol viewer/chooser sub-frames are out of scope for now.

Key insight

Unlike pcbnew / pl_editor, the symbol editor is not a separate program. It is served by the eeschema kiface: its sources already compile into eeschema_kiface_objects (EESCHEMA_LIBEDIT_SRCS + the symbol_editor_* tools in kicad/eeschema/CMakeLists.txt). KiCad's universal launcher common/single_top.cpp opens whichever frame the compile-time TOP_FRAME macro names.

So the port is just a second launcher executable (symbol_editor) that links the same eeschema kiface but compiles single_top.cpp with TOP_FRAME=FRAME_SCH_SYMBOL_EDITOR — no new sources, no new kiface, no extracting symbol-editor code. The eeschema kiface (deps, navlib, stubs, libraries) is reused verbatim.

Changes

kicad submodule (2 files)

kicad/eeschema/CMakeLists.txt — a WASM-only (if( EMSCRIPTEN )) block adds the symbol_editor executable. Because single_top.cpp's COMPILE_DEFINITIONS are directory-scoped (already pinned to TOP_FRAME=FRAME_SCH for the eeschema exe), we configure_file-copy it to a private TU (symbol_editor_single_top.cpp) and set that copy's TOP_FRAME=FRAME_SCH_SYMBOL_EDITOR;PGM_DATA_FILE_EXT="kicad_sym". The exe links EESCHEMA_KIFACE_LIBRARIES directly with LINKER:--allow-multiple-definition, mirroring the eeschema/pcbnew static-link pattern.
kicad/eeschema/eeschema.cpp — IFACE::CreateKiWindow's FRAME_SCH_SYMBOL_EDITOR case was stubbed to return nullptr on __EMSCRIPTEN__ during the eeschema MVP (see ../schematic/0001-eeschema-iface-stubs.md). That stub is now removed so the frame is constructed in WASM like the native build. This was THE blocker: with the stub, Kiway.Player(FRAME_SCH_SYMBOL_EDITOR) returned null, single_top's OnInit bailed, and the app sat idle with a blank canvas (no abort, no error).

The symbol viewer (FRAME_SCH_VIEWER) and chooser (FRAME_SYMBOL_CHOOSER) remain stubbed — out of scope, and the chooser needs bundled libraries we don't ship.

Root repo

scripts/kicad/build-symbol_editor.sh — thin wrapper around build-kicad-target.sh symbol_editor.
scripts/kicad/build-kicad-target.sh — adds symbol_editor to the case. CMake target is symbol_editor but its build subdir is eeschema (it's part of that kiface), so a KICAD_SUBDIR variable now distinguishes target name from subdir for the output-path log and embind include.
docker/build.sh — adds symbol_editor to valid apps, the all loop, and kicad_subdir_for (symbol_editor → eeschema); artifacts land at build-wasm/kicad-symbol_editor/eeschema/symbol_editor.{js,wasm}.
tests/apps/kicad/symbol_editor.html — browser shell (copy of eeschema.html with title + thisProgram=/usr/bin/symbol_editor + symbol_editor.js).
tests/scripts/setup-kicad-wasm.sh — copy_app symbol_editor + subdir map entry.
tests/kicad/symbol_editor.spec.ts + tests/package.json — launch-scope smoke test (canvas visible, registry populated, toolbars present, no WASM abort), mirroring eeschema's wizard-aware flow.

wxwidgets submodule

No changes needed — the file-dialog and double-click fixes landed with the pl_editor port.

Build & verify

./docker/build.sh symbol_editor
cd tests && npm run setup:kicad && npm run test:symbol_editor
# or serve tests/apps/kicad and open symbol_editor.html

Expect: the symbol editor window opens — menu bar, top + left + right toolbars (incl. pin/rect/circle/line drawing tools), the symbol library tree pane with the filter box, the gridded canvas with the symbol-origin crosshair, and a status bar.

Known limitations

No bundled symbol libraries, so the library tree is empty (SyncLibraries reports libCount=0). Opening/creating/saving .kicad_sym files is untested (out of scope).
Symbol viewer and symbol chooser frames are still stubbed out for WASM.
No persistent storage (MEMFS only).

4.2 KiB Raw Blame History