Presets

A preset is the session: every engine parameter (the layout, the medium, the look, the routing rows, the operators’ knobs), the input dialect, the custom palette, the CC map, the control values a shell sends on its routed CCs (the ripple’s, the Chladni’s, the strip’s wheels), the strip’s two assignable CCs, the fingering defaults of the stateful layouts, and Suzu’s patch. It is not the ink: loading a preset replaces the session’s settings and leaves the sheet as it is.

Where

• Desktop — Settings → Presets: the list, Load, Delete, Save as (a name), Export and Import (a file you choose). Named presets live as <config>/presets/<name>.json; the last session is written as <config>/last_session.json and restored at launch.
• iPad — Presets on the sheet: Save (named), the Saved list, Export this session…, Import a preset…; the files are in Files → On My iPad → midi-sink → Presets, and an imported one is applied and added to the list.
• Android — the same page, the files in the app’s documents folder with the system file picker for export and import.
• Web — the panel’s presets, kept in the browser’s localStorage with a download for export.

All of them are the same file; a preset exported from the Tab loads on the desktop. The web page’s own form round-trips byte for byte; a desktop session’s file carries a suzu block the page has no engine for, which it ignores.

The file

JSON, one object, documented in the tree as presets/SCHEMA.md. The rule that keeps it safe across versions: a reader ignores keys it does not know and keeps its defaults for keys that are missing, and the engine clamps everything on apply, so a hand-edited file cannot wound it. A preset from a version that knew fewer parameters loads with the defaults for the rest; one from a newer version loads what this one understands. The file names its schema (1) and the engine version that wrote it.

{
  "midi_sink_preset": 1,
  "sumi_version": [1, 5, 0],
  "name": "Indigo evening",
  "input_mode": 1,
  "params": { "fluid_viscosity": 0.5, "active_palette_id": 1, "medium": 0 },
  "palette": { "stops": [[0.6, 0.05, 0.02, 0], [0.01, 0.01, 0.01, 1]], "hue_drift": 0.3 },
  "cc_map": [[255, 1, 5], [255, 74, 8]],
  "controls": [[9, 32]],
  "strip": { "assign_a": 23, "assign_b": 24 },
  "layout_state": { "buttons": 0, "slider": 0 },
  "suzu": { "source": 1, "voice": 1, "level": 0.5 }
}

A replay begins with the session in exactly this form, so a recording also carries the look it was played with.

Not built: a preset-next pad on the control strip (which presets would cycle is a performance question still open); the strip’s Next cycles layouts, not presets.