cadcraft/packaging/web/README.md

Hosting CADCraft for the web

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

File	What it is
index.html	The page. It loads everything through relative URLs.
cadcraft-web-<hash>.js	wasm-bindgen glue (generated, ES module)
cadcraft-web-<hash>_bg.wasm	The app, about 13 MB, or 5 MB with compression
_headers, .htaccess	Sample header rules for Netlify/Cloudflare Pages and Apache

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

Any path works

All URLs in index.html are relative (public_url = "./" in apps/cadcraft-web/Trunk.toml), so the site works at a domain root (https://example.com/), under a prefix (https://example.com/tools/cadcraft/) and from a CDN bucket. The asset names carry a content hash, so they can be cached forever. Only index.html needs 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;.
• Compression: turn on gzip or Brotli for .wasm, .js and .html. That takes the download from about 13 MB to about 5 MB. You can also precompress (brotli -k *.wasm) and let the server send Content-Encoding: br.
• Caching: Cache-Control: public, max-age=31536000, immutable on the hashed .wasm and .js files, and no-cache on index.html.
• 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: CADCraft 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 /cadcraft/ {
    types { application/wasm wasm; text/javascript js; text/html html; }
    gzip on;
    gzip_types application/wasm text/javascript text/html;
    location ~* \.(wasm|js)$ { add_header Cache-Control "public, max-age=31536000, immutable"; }
    location ~* index\.html$ { add_header Cache-Control "no-cache"; }
}

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

Panel layout storage

The browser host saves docked, floating and hidden palette arrangements alongside interface preferences in its local storage. Floating palettes remain embedded in the browser canvas; they do not become native operating-system windows. Window > Reset Palettes restores the default arrangement. This record contains panel placement and visibility, not drawing data.

The optional cadcraft.panel-layout record uses the shared docking layout version and is limited to 64 KiB. Malformed, incompatible or invalid arrangements are ignored atomically, leaving the startup defaults usable. Storage availability and autosave follow the browser host's existing eframe persistence; clearing site data removes the saved layout.

Embedding in a page (iframe)

<iframe
  src="https://example.com/cadcraft/"
  title="CADCraft 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

CADCraft 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/cadcraft/?webgl" ...>.

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