lightcraft/docs/control-protocol.md

2.1 KiB

Control protocol

lightcraft --control 7980 (or LIGHTCRAFT_CONTROL_PORT=7980) starts a JSON-lines server on 127.0.0.1:7980 (loopback only). One request per line, one reply per line, in order:

→ {"id": 1, "method": "engine.execute", "params": {"command": "photo.rate", "params": {"rating": 4}}}
← {"id": 1, "ok": true, "result": null}
← {"id": 2, "ok": false, "error": "unknown command `nope`"}

Requests are answered on the UI thread between frames (timeout 60 s). The MCP server's connect mode (mcp.md) is a thin layer over this channel. Implementation: crates/ui-egui/src/control.rs (methods) and apps/lightcraft/src/control_server.rs (transport).

Methods

Method Params Result
engine.execute (alias ui.menu.invoke) {command, params?} Run any engine or UI command (see engine.commands)
engine.commands — Engine + UI commands: id, label, menu, shortcut, params doc, enabled
ui.menu.list — Menu entries
ui.inspect — UI state, window, canvas/image rects, active photo, selection, perf, status
ui.widgets {filter?} On-screen widgets {id, rect: [x, y, w, h]} (screen points)
ui.clickWidget / ui.dragWidget {id, count?, fx?, fy?} / {id, toX?, toY?, dx?, dy?, steps?} Real egui input on a widget
ui.move / ui.click / ui.drag {x, y, count?, button?} / {x, y, toX, toY, steps?} Raw pointer input, screen points
ui.pointer {events: [{kind: down|drag|up, x, y}], alt?, shift?, cmd?} Gesture in normalized image coordinates (Detail view)
ui.key {key, cmd?, shift?, alt?, ctrl?} Key press
ui.text {text} Text input
ui.scroll {dx, dy} Mouse wheel
ui.set partial UI state, e.g. {"view": "detail"} Resulting UI state
ui.dialog.confirm / ui.dialog.cancel — Close the open dialog
ui.resize {width, height} Resize the window
ui.screenshot {path?} {path, width, height} once the frame (with finished renders) is captured
ui.render {id?, size?, path?} Render a photo (PNG to path), {width, height}
app.quit — Close the app