63 lines
4.3 KiB
Markdown
63 lines
4.3 KiB
Markdown
# Control protocol
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`lightcraft --control 7980` (or `LIGHTCRAFT_CONTROL_PORT=7980`) starts a JSON-lines server on
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`127.0.0.1:7980` (loopback only). One request per line, one reply per line, in order:
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```text
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→ {"id": 1, "method": "engine.execute", "params": {"command": "photo.rate", "params": {"rating": 4}}}
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← {"id": 1, "ok": true, "result": null}
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← {"id": 2, "ok": false, "error": "unknown command `nope`"}
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```
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Requests are answered on the UI thread between frames (timeout 60 s). The MCP server's connect
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mode ([mcp.md](mcp.md)) is a thin layer over this channel. Implementation:
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`crates/ui-egui/src/control.rs` (methods) and `apps/lightcraft/src/control_server.rs` (transport).
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## Methods
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| Method | Params | Result |
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|---|---|---|
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| `engine.execute` (alias `ui.menu.invoke`) | `{command, params?}` | Run any engine or UI command (see `engine.commands`) |
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| `engine.commands` | — | Engine + UI commands: id, label, menu, shortcut, params doc, enabled |
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| `ui.menu.list` | — | Menu entries (flat: id, label, menu path, shortcut, enabled) |
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| `ui.menu.tree` | — | The menu bar as shown (File … Help): items `{id, params?, label, shortcut?, enabled, checked?}`, separators, submenus — the model behind the native macOS menu bar and the in-window menus |
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| `ui.inspect` | — | UI state, window, canvas/image rects, active photo, selection, perf, status, memory (bytes per cache, see `library.memory`; plus stage caches and textures) |
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| `ui.widgets` | `{filter?}` | On-screen widgets `{id, rect: [x, y, w, h]}` (screen points) |
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| `ui.clickWidget` / `ui.dragWidget` / `ui.hoverWidget` | `{id, count?, fx?, fy?}` / `{id, toX?, toY?, dx?, dy?, steps?}` / `{id, fx?, fy?}` | Real egui input on a widget (hover: the pointer rests on it, e.g. for preset/profile previews) |
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| `ui.move` / `ui.click` / `ui.drag` | `{x, y, count?, button?}` / `{x, y, toX, toY, steps?}` | Raw pointer input, screen points |
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| `ui.pointer` | `{events: [{kind: down\|drag\|up, x, y}], alt?, shift?, cmd?}` | Gesture in normalized image coordinates (Detail view) |
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| `ui.key` | `{key, cmd?, shift?, alt?, ctrl?}` | Key press |
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| `ui.text` | `{text}` | Text input |
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| `ui.scroll` | `{dx, dy}` | Mouse wheel |
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| `ui.set` | partial UI state, e.g. `{"view": "detail"}` | Resulting UI state |
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| `ui.dialog.confirm` / `ui.dialog.cancel` | — | Close the open dialog |
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| `ui.resize` | `{width, height}` | Resize the window |
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| `ui.screenshot` | `{path?, headless?}` | `{path, width, height}` once the frame (with finished renders) is captured. `headless: true` draws the UI on the CPU (no compositor needed); a windowed capture that gets no frame within 2 s falls back to headless automatically |
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| `ui.render` | `{id?, size?, path?}` | Render a photo (PNG to `path`), `{width, height}` |
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| `app.quit` | — | Close the app |
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## Headless rendering (no window, no GPU)
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The egui UI can be rasterized on the CPU (`crates/ui-egui/src/softpaint.rs`, driven by
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`crates/ui-egui/src/headless.rs`): same tessellation, gamma-space premultiplied blending and
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scissor clipping as egui's GPU backends, so the image matches the window (minus GPU dithering).
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- **In the running app:** `{"method": "ui.screenshot", "params": {"path": "a.png", "headless": true}}`.
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The UI is drawn into an offscreen context from the app's logic tick, which keeps running when the
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window is occluded or the display sleeps/locks. Windowed screenshots fall back to this after 2 s.
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- **Without any app window:** `lightcraft-cli snapshot` runs a whole app session headlessly and
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answers the same control requests (same handler) from a JSON-lines script:
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```text
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lightcraft-cli snapshot --demo -o grid.png --size 1600x1000 [--scale 2]
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lightcraft-cli snapshot --library DIR --script tour.jsonl -o shot.png
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```
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`tour.jsonl` holds one request per line (`#` comments allowed), e.g.
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`{"method": "ui.set", "params": {"view": "detail", "right": "edit", "openSections": ["optics"]}}`
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then `{"method": "ui.screenshot"}`. Replies are printed to stdout. A `ui.screenshot` without
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`path` writes `-o` (then `OUT-2.png`, `OUT-3.png`, …); `ui.settle {timeoutMs?}` waits until no
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renders are in flight. Each request runs frames until it is answered and its injected input
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(clicks, keys, drags) has played out. Widget ids for `ui.clickWidget` come from `ui.widgets`
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(e.g. `button:upright-auto`). A 1600×1000 demo snapshot takes ~1–2 s (debug build).
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