The web control channel gains a save operation that serializes the
active drawing in the requested format and returns it as base64 in the
reply, clearing the dirty flag, the counterpart of opening from bytes.
A host page can also define window.openCadStudioSaveFile(name, bytes)
to receive every saved or exported file in place of a browser
download; while it is set no file picker opens.
Fixes#1704Fixes#1705
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ported from 2c38de53 (#1717). Main already carries the hatch PDF draw
order fix (#1345), the numeric set_properties compare (#1348) and the
web open from bytes, so those parts stay out; what remains:
#1349 — window.ocsControl.ready/request promise wrapper with an
ocs-ready event (web/ocs-control.js, loaded by the web page), and the
startup donation prompt is suppressed once a control request is seen
(opt-in pre-boot via localStorage["opencadstudio.automation"] = "1").
docs/automation/web.md documents both. The control protocol stays at 1.
DATALINK CSV-to-table works on web (picker + bytes through the session
registry — was std::fs, silently dead); COLORSCHEME accepts System
(prefers-color-scheme on web, AppsUseLightTheme on Windows).
Decode accounting, made honest per the fix-of-fix review: into_rgba8
allocates the RGBA destination while the native buffer is alive for
every non-Rgba8 layout (L8 5, La8 6, Rgb8 7, L16 6, La16 8 B/px
peaks — the formula now says so), GIF bills the screen+frame
coexistence at 8 B/px, and TIFF drops the 3x multipliers both ways —
tiff 0.11 splits the given budget between frame and scratch (a total
ceiling), so the old double-billing refused honest 16-bit GeoTIFFs
~2.25x early while admitting hostile chunk transients at 3x.
(cherry picked from commit 2c38de53)
Describe the two JavaScript functions the web build exposes
(ocs_control_submit / ocs_control_take), how to poll them, the queue and reply
limits, opening a drawing from bytes with data_base64, and closing the startup
dialog before new. Everything is taken from src/app/control/mod.rs,
src/app/startup.rs and docs/automation/web_save_smoke.cjs.
