photocraft/packaging/web

Hosting PhotoCraft for the web

photocraft-web-<version>.zip (from the GitHub release, or packaging/web/package.sh) holds a static site in photocraft-web-<version>/:

File	What it is
index.html	The page. It loads everything through relative URLs.
photocraft-web-boot-<hash>.js, photocraft-web-boot-<hash>_bg.wasm	A small module (about 120 KB) that starts the app from its parts, with its wasm-bindgen glue
app/photocraft-web-<hash>.part-aa, -ab, …	The app's WebAssembly, gzipped and cut into parts of at most 20 MiB (see Sizes)
app/parts.txt	The parts, in order
app/photocraft-web.js	The app's wasm-bindgen glue (generated, ES module)
_headers, .htaccess	Sample header rules for Netlify/Cloudflare Pages and Apache
fonts/ (optional)	Fonts loaded on demand, listed in fonts/manifest.txt (see Fonts)

There is no server-side code. Upload the folder's contents anywhere that serves static files.

Docker

The Docker recipe (Dockerfile, .dockerignore, packaging/web/nginx.conf) is community-maintained: it is not built in CI or used for releases, so it can lag behind the official web build above. Fixes are welcome.

From the repository root (Docker is the only build prerequisite):

docker build --load -t photocraft-web:local .
docker run -d --name photocraft-web --restart unless-stopped \
  -p 8080:8080 photocraft-web:local

Open http://localhost:8080/. The multi-stage Dockerfile builds the existing Rust/Wasm app with Trunk, including HEIF support, then copies only the static site into NGINX. The runtime runs as the nginx user on port 8080, with a /healthz endpoint and Docker health check. It serves precompressed gzip assets, the Wasm MIME type, immutable hashed assets, and an HTML page that revalidates after deployments. No Rust installation, Node.js, database, GPU passthrough, or document volume is needed on the host.

The first build downloads Rust dependencies and Trunk's Wasm tools and can take several minutes. Subsequent builds reuse Cargo caches. The builder supports Linux amd64 and arm64; the default Rust version is the stable release CI used when the Dockerfile was last updated (CI and releases always use the latest stable), and Trunk is pinned to the release workflow's TRUNK_VERSION. RUST_VERSION, TRUNK_VERSION, and NGINX_VERSION can be overridden with --build-arg. To stamp the About dialog with the commit and date instead of "dev build", pass --build-arg PHOTOCRAFT_BUILD_SHA=$(git rev-parse HEAD) --build-arg PHOTOCRAFT_BUILD_DATE=$(date -u +%F). The web build does not embed the optional craft-fonts checkout.

The Docker build uses thin LTO and one Cargo build job to reduce peak memory, while keeping the web profile's size optimizations and wasm-opt -Oz. Its Wasm size may differ from the release zip figures below; NGINX has no 25 MiB file limit. To use the release zip's fat LTO on a builder with more memory, pass --build-arg CARGO_PROFILE_WASM_RELEASE_LTO=fat. --build-arg CARGO_BUILD_JOBS=4 enables more concurrent compilation on larger builders. A compiler killed with SIGKILL/cannot allocate memory means the Docker/Podman VM needs more memory or swap.

For a public deployment, put an HTTPS reverse proxy or your hosting platform's TLS endpoint in front of container port 8080. With a reverse proxy on the same host, bind only loopback (-p 127.0.0.1:8080:8080); with a proxy container, connect both through a Docker network. HTTPS enables WebGPU and browser clipboard APIs. If hosting under /photocraft/, redirect /photocraft to /photocraft/ and strip that prefix when proxying to the container. Relative asset URLs then work without rebuilding. For example, in an existing HTTPS NGINX server:

location = /photocraft { return 301 /photocraft/; }
location /photocraft/ {
    proxy_pass http://127.0.0.1:8080/;
}

The editor and image processing run on the visitor's device. Open uses the browser file picker; Save and Export download files. Preferences use browser localStorage. There is no server-side document storage, desktop TCP control server, or web autosave/crash recovery; save/download work before closing or reloading the page. A browser with WebGPU or WebGL2 is required; ?webgl forces the fallback when troubleshooting. In a browser that can't inflate a stream itself (no DecompressionStream: before Safari 16.4 and Firefox 113), the release zip's site inflates the app's parts in its own code, a little slower.

To verify the browser deployment, open the page, open an image and save/export it.

Sizes

Measured on 2026-10-13 (0.8.2, packaging/web/package.sh):

File	Size
app/photocraft-web-<hash>.part-aa (the only part today)	11,401,527 bytes (10.9 MiB)
app/photocraft-web.js	about 170 KB (26 KB with gzip)
photocraft-web-boot-<hash>_bg.wasm and .js	about 120 KB together

The app's WebAssembly is 25,019,043 bytes (23.9 MiB) before gzip.

Per-file upload limits: Cloudflare Pages and Workers static assets reject any file over 25 MiB (26,214,400 bytes), and the app's WebAssembly is at that size. (Releases up to 0.2.0 shipped a 25.8 MiB wasm, which Cloudflare rejected; issue #198.) So the site doesn't hold it as one file: packaging gzips it and cuts the result into parts of at most 20 MiB, and the page puts them back together while it downloads them. packaging/web/package.sh fails if any file in the site is over 24 MiB, so a release can't ship a file a common host refuses, and the app can grow without reaching that limit (issue #5302). A build straight from Trunk (trunk build --release in apps/photocraft-web, or the Docker image above) still has the app in one .wasm, for hosts without such a cap.

The app is built with the wasm-release Cargo profile (fat LTO, size-optimized code with the pixel and file-decoding crates kept at speed) plus wasm-opt -Oz, and stores the bundled fonts (PhotoCraft's and egui's) and the translation catalogs compressed, unpacked on first use.

Any path works

All URLs in index.html are relative (public_url = "./" in apps/photocraft-web/Trunk.toml), so the site works at a domain root (https://example.com/), under a prefix (https://example.com/tools/photocraft/) and from a CDN bucket. The asset names carry a content hash, so they can be cached forever. index.html, app/photocraft-web.js and app/parts.txt keep their names and need revalidation.

Required server settings

• MIME type: serve .wasm as application/wasm. Browsers refuse to stream-compile it under any other type, and the app then loads slowly or not at all. Serve .js as text/javascript. Most hosts already do both. For nginx, check that mime.types has application/wasm wasm;.
• The parts as they are: serve app/*.part-* byte for byte, with no Content-Encoding (they are gzip already, and the page inflates them). Their extension is one servers don't know, so the usual result, application/octet-stream and no compression, is right.
• Missing files are 404s: a host that answers every unknown path with index.html (a single-page-app fallback) hides a failed upload. PhotoCraft notices and says the download failed, but a 404 is clearer in the server's logs.
• Compression: turn on gzip or Brotli for .wasm, .js and .html. It matters little for the download, since the parts are compressed already; it shrinks the two .js files and the small boot module. You can also precompress and let the server send Content-Encoding: br.
• Caching: Cache-Control: public, max-age=31536000, immutable on the files whose names carry a hash (the parts and photocraft-web-boot-<hash>.*), and no-cache on index.html, app/photocraft-web.js and app/parts.txt. The sample _headers and .htaccess do this.
• HTTPS: WebGPU (and the clipboard) only work in a secure context, which means https:// or http://localhost. Over plain HTTP elsewhere, the app falls back to WebGL2.
• No special isolation headers: PhotoCraft doesn't use SharedArrayBuffer, so it doesn't need Cross-Origin-Opener-Policy or Cross-Origin-Embedder-Policy. If your site already sends COEP require-corp, also send Cross-Origin-Resource-Policy: same-origin (or cross-origin when the files live on a CDN) on the app's files.

nginx example:

location /photocraft/ {
    types { application/wasm wasm; text/javascript js; text/html html; }
    gzip on;
    gzip_types application/wasm text/javascript text/html;
    # The first matching line wins, so the files that keep their names come first.
    location ~* (index\.html|app/photocraft-web\.js|app/parts\.txt)$ { add_header Cache-Control "no-cache"; }
    location ~* (\.(wasm|js)|\.part-[a-z]+)$ { add_header Cache-Control "public, max-age=31536000, immutable"; }
}

Local test: python3 -m http.server 8765 inside the folder, then open http://localhost:8765/.

Fonts

The app has two fonts of its own, Inter and JetBrains Mono: a browser offers no system fonts, and embedding more would push the wasm over the size gate. A host can serve more fonts next to the app. They show in the font menus straight away, and a family's files are downloaded the first time it is picked or a document's text needs it, so starting the app costs one small text file.

1. Put the font files (.ttf, .otf, .ttc) anywhere under fonts/ next to index.html.

2. List them in fonts/manifest.txt, one file per line, in the format of craft-fonts' own fonts/manifest.txt:

   # family | style | file (relative to the site root) | scripts | licence | licence file | sha256 | source
   Open Sans | Regular | fonts/open-sans/OpenSans[wdth,wght].ttf
   Open Sans | Italic | fonts/open-sans/OpenSans-Italic[wdth,wght].ttf
   Lobster | Regular | fonts/lobster/Lobster-Regular.ttf | Latn,Cyrl | OFL-1.1 | fonts/lobster/OFL.txt
   

   The app reads the first three fields; the others are optional here. family must be the font's own family name (the typographic family in its name table, else the family), which is what the font menu shows once the file is in. The path is relative to the site root and can't leave it (no .., no / at the start, no other host). A variable font is one line: the style menu offers the weights of its wght axis.

3. Put each font's licence next to it; the SIL Open Font License, for one, requires that.

A craft-fonts checkout is already laid out this way, and so is any folder with a fonts/manifest.txt and the files it lists: PHOTOCRAFT_WEB_FONTS_DIR=<that folder> packaging/web/package.sh copies the manifest, the fonts and their licences into the zip, keeping their paths. Without fonts/manifest.txt (a 404) nothing changes.

Serving: let fonts/manifest.txt revalidate (Cache-Control: no-cache) so edits show up; cache the font files for long only if their names change with their contents. Serve .ttf as font/ttf and .otf as font/otf, and compress them (Brotli roughly halves a TrueType file). The app fetches them with fetch(), so a Content Security Policy needs them allowed by connect-src.

Embedding in a page (iframe)

<iframe
  src="https://example.com/photocraft/"
  title="PhotoCraft image editor"
  style="width: 100%; height: 720px; border: 0;"
  allow="fullscreen; clipboard-read; clipboard-write"
  allowfullscreen>
</iframe>

• The app fills the iframe and follows its size, so size the iframe and not the app.
• Keyboard shortcuts go to the iframe after the user clicks into it, as with any embedded app.
• Cross-origin embeds work. Preferences are kept in the iframe's localStorage. Browsers that partition or block third-party storage may forget them between visits, and the app then starts with defaults.
• Sandboxed iframes need at least sandbox="allow-scripts allow-same-origin allow-downloads allow-popups". Without allow-same-origin there's no storage. Without allow-downloads, Save and Export (browser downloads) are blocked.
• Don't send X-Frame-Options: DENY or a frame-ancestors CSP that excludes the embedding page.

Renderer selection and fallback flags

PhotoCraft renders with wgpu. It uses WebGPU when the browser has it and falls back to WebGL2 on its own. URL query flags override this, and they work on the iframe src too:

Flag	Effect
(none)	WebGPU if available, otherwise WebGL2
?webgl	Force the WebGL2 backend (useful when a WebGPU driver misbehaves)
?cpu	Force the CPU canvas path (slowest, most compatible)

For example: <iframe src="https://example.com/photocraft/?webgl" ...>.

A browser with neither WebGPU nor WebGL2 gets a message in place of the app.