fe5249567f
Codex stop-hook flagged: "web Step 3 cannot render the claimed
canvas text". Root cause: WebBackend::draw_text was a Phase A
no-op stub. CanvasViewport calls draw_text for "Hello
OpenPencil" / "Click me" / Layer panel labels / etc — none of
those text strings actually rendered in the browser.
# Fix
`crates/openpencil-shell-web/src/backend/mod.rs::WebBackend`:
- Embeds `assets/Roboto-Regular.ttf` (Apache 2.0, 35 KB, copied
from rust-skia test resources) via `include_bytes!`. The
C-hard wasm32-unknown-unknown skia build uses
`skia_enable_fontmgr_custom_empty=yes` (see
`vendor/skia-safe-op/skia-bindings/build_support/platform/
wasm_unknown.rs`), so there are no system fonts and we have
to bake the bytes in.
- New `typeface: Option<Typeface>` field, lazy-init on first
draw_text via `FontMgr::custom_empty().and_then(|m|
m.new_from_data(ROBOTO_TTF, None))`. Build failure → None
silently no-ops subsequent draws (no panic — text just
doesn't render).
- `draw_text` now iterates `layout.runs()` and calls
`Canvas::draw_str` per run with a `Font::new(typeface,
font_size)` + `Paint` from the run color.
`crates/openpencil-shell-web/Cargo.toml`:
- Drops `textlayout` skia-safe feature. We use raw `draw_str`
not paragraph builder; textlayout pulled ICU + Harfbuzz +
~400 KB gzip + a swarm of font-lookup imports we don't
exercise.
# 24 new env.* imports — wasm-libc-shim expansion
Even without textlayout, Skia's font path imports 24 libc
symbols our prior C-hard.2 shim didn't cover. All resolved:
`crates/wasm-libc-shim/src/imp.rs` — Rust extern "C" shims:
- string ops (real impls): strncmp, strncpy, strstr, strrchr,
strcat, strtol, tolower, qsort (insertion sort, fits Skia's
small-array call sites; debug_assert on element size > 256)
- file I/O (sentinel error returns, no filesystem on wasm):
fopen → null, fread → 0, fclose → 0, fputc → c, fileno → -1,
fstat → -1, pread → -1, ftell → -1, fseek → -1
- env: getenv → null
- mmap: returns MAP_FAILED ((void*)-1); munmap → -1
- setjmp/longjmp: setjmp returns 0 (treat as initial call);
longjmp panics — happy text path through in-memory TTF parse
should never trigger it
- C++ nothrow new: `_ZnwmRKSt9nothrow_t` forwards to malloc,
returns nullptr on OOM (the nothrow contract)
`crates/wasm-libc-shim/src/stdio_stub.c`:
- fprintf C-side variadic stub (Skia diagnostic path) that
routes into the same panic helper as snprintf / vsnprintf /
vfprintf — same fail-fast policy.
# Verification
- `cargo build -p openpencil-shell-web --target
wasm32-unknown-unknown --features skia --release` — green
- `wasm-bindgen --target web` produces ../pkg/openpencil_shell
_web.{js,_bg.wasm}
- `bash tools/check-wasm-bundle.sh` — PASS:
- 0 env.* imports preserved (24 new ones absorbed by shim)
- 906 935 bytes gzip = 86% of 1 MiB ceiling (+286 KB vs
pre-text — Skia font/freetype subsystem is substantial.
Headroom: 14% of ceiling)
- `cargo test -p openpencil-shell-core --lib` — 39 tests
- `cargo build -p openpencil-shell-native --example
inspector_window` — green (desktop demo unchanged — uses
jian-skia textlayout via NativeBackend, not the web font
path)
- `cargo check -p openpencil-shell-native --target
aarch64-apple-ios` — green
- `cargo check -p openpencil-shell-native --target
aarch64-linux-android` — green
# Re-run the demo
```
EMSDK="$HOME/.emsdk" cargo build -p openpencil-shell-web \
--target wasm32-unknown-unknown --features skia --release
wasm-bindgen --target web --out-dir crates/openpencil-shell-web/pkg \
target/wasm32-unknown-unknown/release/openpencil_shell_web.wasm
cd crates/openpencil-shell-web/smoke
python3 -m http.server 8000
# Browser: http://localhost:8000/step-1b.html
```
Now the canvas viewport renders "Hello OpenPencil" + "Click me"
text in addition to the rect/stroke geometry.
90 lines
3.5 KiB
TOML
90 lines
3.5 KiB
TOML
[package]
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name = "openpencil-shell-web"
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version.workspace = true
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edition.workspace = true
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rust-version.workspace = true
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license.workspace = true
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description = "OpenPencil shell — wasm32-unknown-unknown web bundle entry (Step 1b §1.2, C-hard pipeline)"
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[lib]
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name = "openpencil_shell_web"
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path = "src/lib.rs"
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crate-type = ["cdylib", "rlib"]
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[dependencies]
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openpencil-shell-core = { path = "../openpencil-shell-core", version = "0.1.0" }
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# Step 1b §3.6: handwritten DOM mirror consumes accesskit::TreeUpdate (0.24).
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accesskit = "0.24"
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console_error_panic_hook = "0.1"
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js-sys = "0.3"
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# Phase C1 DOM event mappers build `jian_core::gesture::WheelEvent` etc
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# whose position/delta fields use `jian_core::geometry::Point`. The
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# `geometry` module is not re-exported by shell-core (which only
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# re-exports `gesture::*`), so pull jian-core directly. Same path-with-
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# version pattern as shell-core's own jian-core dep.
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jian-core = { path = "../../vendor/jian/crates/jian-core", version = "0.0.1" }
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# Pin to 0.2.117 — last wasm-bindgen-cli release compatible with the
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# workspace's Rust 1.85 toolchain. Newer 0.2.120+ requires rustc 1.86.
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# When the workspace bumps Rust, raise this bound.
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wasm-bindgen = "=0.2.117"
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# Step 1b §2.2 (post C-hard.2 lock-in 2026-05-09): wasm32-unknown-unknown
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# via the vendor/skia-safe-op fork + crates/wasm-libc-shim. Optional dep
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# behind the `skia` feature so `cargo check --target wasm32-unknown-
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# unknown --no-default-features --features web` (the kickoff §1.2
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# wasm32-clean CI baseline) still compile-checks without pulling skia
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# — that path uses the stub mount entry. Phase A and onward opt in via
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# `--features skia` to get the real WebBackend + raster paint loop.
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[dependencies.skia-safe]
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version = "0.97.0"
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default-features = false
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# Step 3 codex stop-hook fix: text rendering uses
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# `Canvas::draw_str` + raw Font + Typeface (NOT skia paragraph
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# builder), so the `textlayout` feature is unnecessary on web.
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# Dropping it removes ICU + Harfbuzz from the bundle (~400 KB
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# gzip) and avoids the env.* import explosion that came with
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# textlayout's filesystem font lookups.
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features = ["binary-cache"]
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optional = true
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# C-hard.2 libc/libcxx/libm shim — only linked when targeting
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# wasm32-unknown-unknown with the `skia` feature on. The crate's lib.rs
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# guards every symbol with `cfg(all(target_arch = "wasm32", target_os
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# = "unknown"))` so native builds (where this would conflict with the
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# host C runtime) link an empty crate.
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[target.'cfg(all(target_arch = "wasm32", target_os = "unknown"))'.dependencies]
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wasm-libc-shim = { path = "../wasm-libc-shim", optional = true }
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[dependencies.web-sys]
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version = "0.3"
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features = [
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"CanvasRenderingContext2d",
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"CompositionEvent",
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"console",
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"Document",
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"Element",
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"Event",
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"EventTarget",
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"FocusEvent",
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"HtmlCanvasElement",
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"HtmlElement",
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"ImageData",
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"KeyboardEvent",
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"PointerEvent",
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"WheelEvent",
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"Window",
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]
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[features]
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# `web` keeps the kickoff §1.2 wasm32-unknown-unknown CI baseline green —
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# the crate compile-checks as a wasm32-clean stub without pulling skia.
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default = ["web"]
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web = []
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# `skia` opts into the Phase A WebBackend (skia-safe + raster surface).
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# When the cargo target is wasm32-unknown-unknown the build also links
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# the libc/libcxx/libm shim crate so the bundle is runtime-loadable.
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# Native targets resolve the target-conditional shim dep to nothing.
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skia = ["dep:skia-safe", "wasm-libc-shim"]
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# Internal feature toggled on by `skia` to flip the cfg-target dep.
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wasm-libc-shim = ["dep:wasm-libc-shim"]
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