emcc only runs Binaryen at link -O2+ (link.py: should_run_binaryen_optimizer
returns OPT_LEVEL >= 2) and we link at -O1, so the shipped module had never seen
wasm-opt at all — it kept its entire 19.56 MB name section, ~20% of the editor
(-sJSPI sets ASYNCIFY=2, which suppresses wasm-ld's --strip-debug, leaving
wasm-opt as the only thing that would drop it). Step 8.2 runs it post-link and
in-container, so CI's cached compile phase covers it and the host post-process
stays pure-host.
Default -O2, picked by measuring every level on the same module: -O0 already
captures 27% of the raw win (it is mostly the name section), -O2 costs 23 s and
gives the best frame rate, and -O3/-O4/-Os/-Oz cost 48-132 s for at most 1.5%
more brotli — -O4 is not even smaller than -O3. Targets that already link -O2/-Oz
(occ_service, kicad_tools) are skipped by testing for the target_features
section, which emcc strips whenever it ran the optimizer itself, so there is no
hard-coded target list to drift. Feature flags come from the module's own
target_features section and so cannot diverge from the link.
The perf specs reported requestAnimationFrame ticks as "FPS". That is not a frame
rate: rAF fires on the compositor's schedule whether or not the GAL redrew, and
it read 120/s on a board where the renderer completed zero frames in six seconds.
measureInteractionFps now counts completed GAL frames — runs of draws to the
default framebuffer, exactly one per frame in every AA mode — and drives a pure
middle-drag pan after a zoom-to-fit. Mixing wheel zoom into the drive made the
result depend on where the wheel left the view: +-20% across identical repeats,
against +-2% for pan alone. The report gains a GAL fps column with a regression
flag on the 1x number; rAF is kept so historical runs stay comparable.
CI has no GPU, so its number is a software-rasteriser redraw rate — a regression
signal, not a user-facing frame rate. Method and measurements in the bench report.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016X9eh1s5sTx1o9Em9KBuwR
New tooling in tests/tools/screenshots/ (TypeScript via tsx):
- compare.ts: one pixelmatch engine (AA-excluded), connected-component
"where to look" boxes, old|new+boxes|heatmap triptych, per-engine floors.
- promote.ts: churn-free updater — overwrite a baseline only when decoded
pixels differ beyond the floor, copying CI bytes verbatim (no re-encode
churn); pulls a CI run via `gh run download` or a local --from dir.
- post-discord.ts: always-on CI-on-main report (SHA + e2e status + the
track-only runtime-perf table), then screenshot triptychs, batched +
size-capped + flood-collapsed + 429-aware.
- perf-report.ts: perf table with Δ vs the previous main run (via gh).
- changelog.ts: no-build git-history baseline differ (Discord trigger B).
- noise.ts / gen-manifest.ts: calibration + manifest generation.
CI wiring:
- wasm-build.yml: post-test step runs the gate + report on the already-
produced test-results (no extra build); report-only (continue-on-error),
posts only on push to main, inert without DISCORD_WEBHOOK_URL.
- ci-ubicloud.yml: secrets: inherit (pass the webhook through).
- screenshot-changelog.yml: ~30s no-build changelog on baseline changes.
screenshot-manifest.json: canonical 354-name set + best-effort engine tags
(313 chromium-swiftshader / 41 firefox-llvmpipe).
Normalize scale:'device'->'css' across 18 spec files (no-op at CI DSF=1)
so committed baselines are uniformly css-scaled.
Design: CI's Linux render is the single source of truth; no pinned
container (accept rare env drift -> re-promote); dev commits via promote.
Replaces the byte-cmp compare-screenshots.sh + file-size-proxy
update-baseline-screenshots.sh (kept for now until the first re-baseline).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
