fix: tests

sandboxes/orca_preset_update_demo.py

@@ -0,0 +1,957 @@
+# /// script
+# requires-python = ">=3.12"
+#
+# [tool.orcaslicer.plugin]
+# id = "preset-update-demo"
+# name = "Preset Update Demo"
+# description = "Edits any setting of the currently edited process, printer, or filament preset through the preset host API."
+# author = "OrcaSlicer contributors"
+# version = "0.2.0"
+# type = "script"
+# ///
+"""Preset Update Demo — edit any setting of the current preset from a plugin window.
+
+Install this file in the local ``orca_plugins`` directory, enable the plugin, then run
+"Preset Update Demo" from the Plugins dialog. The window lists every setting of the
+preset the matching settings tab is editing right now — process, printer, or filament —
+with its current serialized value, and writes a value back through
+``orca.host.preset.<type>.update(...)``.
+
+Process and printer each have one edited preset, taken from
+``current_process_preset()`` / ``current_printer_preset()``. Filament presets are
+addressed by slot instead: the window reads one preset per slot from
+``current_filament_presets()`` (slot numbers are one-based, matching Orca's labels),
+shows the selected slot's preset, and writes through
+``orca.host.preset.filament.update(slot, key, value)``.
+
+Any assigned slot can be edited: the backend selects that slot's preset through Orca's
+normal preset selection before it writes, so applying can switch the filament tab and Orca
+may ask about unsaved changes first. Only an empty slot, whose mount resolves to no preset,
+is unavailable — the window says so instead of offering an edit. A slot whose preset is not
+the one the filament settings already have open gets an informational note that applying
+will switch to it; it is never presented as a refusal. Two slots that mount the same preset
+are one preset, so editing through either of them changes both; the window marks those
+slots and says which they are.
+
+Every row is one ``config_keys()`` entry carrying ``config_value(key)``.
+
+What ``update()`` does, and what it does not:
+
+  * it runs the same validation and UI update path as editing the setting by hand, so
+    the change lands in the preset the tab is editing and is never written to disk here
+    — the preset shows as modified in OrcaSlicer once it differs from the saved one;
+  * it accepts only settings of that preset category. A key that belongs to another
+    category, or a value the setting would reject, raises an error and writes nothing;
+  * it is refused when the selected printer's technology does not use that tab (the
+    print and filament tabs do nothing under SLA), so this demo covers the three FFF
+    categories only;
+  * a setting whose page has not been built yet still runs its owning settings group's
+    checks and callbacks; behavior that requires an actual widget (such as widget-specific
+    parsing or clamping) only runs when the field exists;
+  * on a filament slot it selects that slot's preset first, so Orca may prompt about
+    unsaved changes in the filament tab before the value is written.
+
+Values are OrcaSlicer's serialized config syntax — the same text a preset file stores —
+so numbers are plain, percentages keep their ``%``, booleans are ``1``/``0``, choices use
+the setting's internal key, and lists are semicolon-separated.
+"""
+
+import orca
+
+
+# The three preset categories the main tabs edit. Each key is both the value the page
+# sends and the attribute name on orca.host.preset that carries the matching editor.
+KINDS = (
+    {"kind": "process", "label": "Process"},
+    {"kind": "printer", "label": "Printer"},
+    {"kind": "filament", "label": "Filament"},
+)
+KIND_KEYS = {item["kind"] for item in KINDS}
+
+
+def _editor(kind):
+    """The host.PresetEditor for a category (orca.host.preset.process / printer).
+
+    Filament is not reached through this helper: it is addressed by slot, so it calls
+    orca.host.preset.filament.update(slot, key, value) directly.
+    """
+    return getattr(orca.host.preset, kind)
+
+
+def _current_preset(bundle, kind):
+    """The single preset the matching settings tab edits right now, as a host.Preset.
+
+    Only the process and printer categories have one such preset; filament presets are
+    addressed by slot instead (see _slot_presets).
+    """
+    if kind == "process":
+        return bundle.current_process_preset()
+    return bundle.current_printer_preset()
+
+
+def _slot_presets(bundle):
+    """The filament preset mounted in each slot, in slot order; a slot may be None."""
+    return list(bundle.current_filament_presets())
+
+
+def _preset_is_open(preset, edited):
+    """Whether this slot's preset is the one the filament settings already have open.
+
+    A slot with an assigned preset can be edited either way: applying to another slot makes
+    the backend select that slot's preset first. This only distinguishes the slot that
+    switches nothing from the ones that will switch the filament tab.
+    """
+    return preset is not None and preset.name == edited.name
+
+
+def _filament_slots(presets, edited):
+    """One entry per mounted slot: its one-based number, preset name, and open flag.
+
+    The number is the slot label Orca shows; the name is None for a slot that mounts no
+    preset, which is the only kind that cannot be edited.
+    """
+    return [
+        {
+            "slot": index + 1,
+            "name": None if preset is None else preset.name,
+            "open": _preset_is_open(preset, edited),
+        }
+        for index, preset in enumerate(presets)
+    ]
+
+
+def _as_slot(value):
+    """A requested slot as an int, or None when it is not a whole number."""
+    if isinstance(value, bool):
+        return None
+    if isinstance(value, int):
+        return value
+    if isinstance(value, float) and value.is_integer():
+        return int(value)
+    return None
+
+
+def _clamp_slot(slot, count):
+    """The slot to display: the requested one, kept inside the available range."""
+    if count <= 0:
+        return 0
+    number = _as_slot(slot)
+    if number is None or number < 1:
+        return 1
+    return number if number <= count else count
+
+
+def _parse_slot(slot, count):
+    """Validate a requested filament slot against the mounted slots (one-based)."""
+    if count == 0:
+        raise RuntimeError("No filament slots are mounted")
+    number = _as_slot(slot)
+    if number is None:
+        raise RuntimeError("A filament slot number is required")
+    if number < 1 or number > count:
+        raise RuntimeError("Filament slot %d is out of range (1-%d)" % (number, count))
+    return number
+
+
+def _rows(preset):
+    """Every setting of the preset, sorted by key, as [{k, v}].
+
+    config_value() returns None for a key the preset does not carry; the page shows
+    those as empty rather than "None".
+    """
+    rows = []
+    for key in sorted(preset.config_keys()):
+        value = preset.config_value(key)
+        rows.append({"k": key, "v": "" if value is None else str(value)})
+    return rows
+
+
+def _state(bundle, kind, slot, message="", error=""):
+    """The payload the page renders: shown preset, rows, slots, result line."""
+    payload = {"command": "state", "kind": kind, "message": message, "error": error}
+    if kind == "filament":
+        presets = _slot_presets(bundle)
+        edited = bundle.filaments.edited_preset()
+        effective = _clamp_slot(slot, len(presets))
+        preset = None if effective == 0 else presets[effective - 1]
+        payload["slots"] = _filament_slots(presets, edited)
+        payload["slot"] = effective
+        # An empty slot has nothing to edit; any assigned slot is editable, and one that is
+        # not already open makes the backend select it first.
+        payload["assigned"] = preset is not None
+        payload["switches"] = preset is not None and not _preset_is_open(preset, edited)
+        payload["edited_name"] = edited.name
+    else:
+        preset = _current_preset(bundle, kind)
+    payload["preset"] = None if preset is None else {
+        "name": preset.name,
+        "is_dirty": bool(preset.is_dirty),
+        "is_system": bool(preset.is_system),
+    }
+    payload["rows"] = [] if preset is None else _rows(preset)
+    return payload
+
+
+def _apply(kind, key, value, slot=None):
+    """Set one setting of the preset the page is showing, through the host API.
+
+    A filament preset is addressed by slot number; process and printer each resolve
+    their single edited preset themselves, so no slot is passed to them.
+    """
+    if kind == "filament":
+        orca.host.preset.filament.update(slot, key, value)
+        return
+    _editor(kind).update(key, value)
+
+
+PAGE = r"""<!doctype html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<style>
+  :root {
+    --bg:        var(--orca-bg, #fafafa);
+    --fg:        var(--orca-fg, #1b1e23);
+    --muted:     var(--orca-muted, #6b7280);
+    --border:    var(--orca-border, #dadee3);
+    --accent:    var(--orca-accent, #0e7c86);
+    --accent-fg: var(--orca-accent-fg, #ffffff);
+    --ui:        var(--orca-font, system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif);
+    --mono:      ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
+    --surface:   rgba(127, 127, 127, .09);
+  }
+  @media (prefers-color-scheme: dark) {
+    :root {
+      --bg:     var(--orca-bg, #23262a);
+      --fg:     var(--orca-fg, #e6e8ea);
+      --muted:  var(--orca-muted, #9aa1a9);
+      --border: var(--orca-border, #383c42);
+    }
+  }
+  * { box-sizing: border-box; }
+  html, body { height: 100%; }
+  body {
+    margin: 0; background: var(--bg); color: var(--fg);
+    font: 13px/1.45 var(--ui);
+    display: flex; flex-direction: column; overflow: hidden;
+  }
+  button { font: inherit; cursor: pointer; }
+  :focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
+
+  /* header ------------------------------------------------------------- */
+  header {
+    flex: none; display: flex; align-items: center; gap: 10px;
+    padding: 9px 14px; border-bottom: 1px solid var(--border);
+  }
+  .logo { color: var(--accent); font-size: 15px; line-height: 1; }
+  h1 { margin: 0; font-size: 14px; font-weight: 650; letter-spacing: .01em; }
+
+  .seg {
+    display: flex; gap: 2px; margin-left: auto; padding: 2px;
+    border: 1px solid var(--border); border-radius: 9px; background: var(--surface);
+  }
+  .seg button {
+    border: 0; background: transparent; color: var(--muted);
+    padding: 4px 13px; border-radius: 7px;
+    transition: background .15s ease, color .15s ease;
+  }
+  .seg button:hover { color: var(--fg); }
+  .seg button[aria-pressed="true"] { background: var(--accent); color: var(--accent-fg); }
+
+  .iconbtn {
+    width: 28px; height: 28px; border: 1px solid var(--border); border-radius: 7px;
+    background: transparent; color: var(--fg); display: grid; place-items: center;
+    font-size: 13px; transition: background .15s ease;
+  }
+  .iconbtn:hover:enabled { background: var(--surface); }
+  .iconbtn:disabled { opacity: .5; }
+
+  /* preset bar --------------------------------------------------------- */
+  .presetbar {
+    flex: none; display: flex; align-items: center; gap: 8px;
+    padding: 7px 14px; border-bottom: 1px solid var(--border); font-size: 12px;
+  }
+  .presetbar .name {
+    font-weight: 600; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
+    max-width: 60%;
+  }
+  .spacer { flex: 1; }
+  .tag {
+    border: 1px solid var(--border); color: var(--muted); border-radius: 999px;
+    padding: 1px 8px; font-size: 11px; white-space: nowrap;
+  }
+  .tag.on { border-color: transparent; background: var(--accent); color: var(--accent-fg); }
+
+  /* filament slots ----------------------------------------------------- */
+  .slotbar { flex: none; padding: 7px 14px 8px; border-bottom: 1px solid var(--border); }
+  .slotrow { display: flex; align-items: center; gap: 9px; min-width: 0; }
+  .slotlabel {
+    flex: none; font-size: 11px; letter-spacing: .06em; text-transform: uppercase;
+    color: var(--muted);
+  }
+  .slots { flex: 1; min-width: 0; display: flex; flex-wrap: wrap; gap: 6px;
+           max-height: 84px; overflow-y: auto; }
+  .chip {
+    display: inline-flex; align-items: center; gap: 6px; flex: none; max-width: 190px;
+    padding: 2px 10px 2px 3px; border: 1px solid var(--border); border-radius: 999px;
+    background: transparent; color: var(--fg);
+    transition: background .15s ease, color .15s ease, border-color .15s ease;
+  }
+  .chip:hover { background: var(--surface); }
+  .chip .n {
+    flex: none; min-width: 19px; height: 19px; padding: 0 4px; border-radius: 999px;
+    display: grid; place-items: center; background: var(--surface); color: var(--muted);
+    font-size: 11px; font-variant-numeric: tabular-nums;
+  }
+  /* the slot whose preset the filament settings already have open, so applying switches nothing */
+  .chip.open .n { box-shadow: inset 0 0 0 1px var(--accent); color: var(--fg); }
+  .chip .s {
+    min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
+    font-size: 11px; color: var(--muted);
+  }
+  .chip[aria-pressed="true"] { background: var(--accent); border-color: var(--accent); color: var(--accent-fg); }
+  .chip[aria-pressed="true"] .n {
+    background: rgba(255, 255, 255, .22); color: var(--accent-fg); box-shadow: none;
+  }
+  .chip[aria-pressed="true"] .s { color: var(--accent-fg); }
+  /* a slot that mounts the preset the page is showing: editing either changes both */
+  .chip.linked::after {
+    content: ""; flex: none; width: 5px; height: 5px;
+    border-radius: 50%; background: var(--accent);
+  }
+  .slotnote {
+    margin-top: 7px; padding-left: 8px; border-left: 2px solid var(--accent);
+    font-size: 11px; line-height: 1.5; color: var(--muted);
+  }
+  .slotnote:empty { display: none; }
+
+  /* panes -------------------------------------------------------------- */
+  main { flex: 1; display: flex; min-height: 0; }
+
+  .list-pane {
+    flex: none; width: 45%; min-width: 250px; min-height: 0;
+    display: flex; flex-direction: column; border-right: 1px solid var(--border);
+  }
+  .search {
+    flex: none; display: flex; align-items: center; gap: 8px;
+    padding: 8px 10px; border-bottom: 1px solid var(--border);
+  }
+  .search input {
+    flex: 1; min-width: 0; font: inherit; color: var(--fg); background: var(--bg);
+    border: 1px solid var(--border); border-radius: 7px; padding: 4px 9px;
+  }
+  .rows { flex: 1; min-height: 0; overflow-y: auto; padding: 3px 0; }
+
+  .row {
+    display: flex; align-items: baseline; gap: 8px; width: 100%;
+    padding: 5px 10px; text-align: left; border: 0; border-left: 3px solid transparent;
+    background: transparent; color: var(--fg);
+  }
+  .row:hover { background: var(--surface); }
+  .row[aria-selected="true"] { background: var(--surface); border-left-color: var(--accent); }
+  .row .k {
+    flex: 1; min-width: 0; font-family: var(--mono); font-size: 12px;
+    overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
+  }
+  .row .v {
+    flex: none; max-width: 40%; font-family: var(--mono); font-size: 11px;
+    color: var(--muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
+  }
+  .row .dot {
+    flex: none; align-self: center; width: 6px; height: 6px; border-radius: 50%;
+    background: var(--accent); visibility: hidden;
+  }
+  .row.changed .dot { visibility: visible; }
+  @keyframes flash {
+    0%   { box-shadow: inset 0 0 0 2px var(--accent); }
+    100% { box-shadow: inset 0 0 0 2px transparent; }
+  }
+  .row.flash { animation: flash .7s ease-out; }
+  @media (prefers-reduced-motion: reduce) {
+    .row.flash { animation: none; }
+  }
+
+  .empty { color: var(--muted); padding: 14px 12px; }
+  .nil { font-style: italic; opacity: .75; }
+
+  /* editor ------------------------------------------------------------- */
+  .edit-pane {
+    flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 9px;
+    padding: 12px 14px; overflow-y: auto;
+  }
+  .edit-key { font-family: var(--mono); font-size: 13px; font-weight: 600; overflow-wrap: anywhere; }
+  .lbl { font-size: 11px; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); }
+  .current {
+    margin: 0; max-height: 108px; overflow: auto;
+    font-family: var(--mono); font-size: 12px;
+    background: var(--surface); border: 1px solid var(--border); border-radius: 7px;
+    padding: 7px 10px; white-space: pre-wrap; overflow-wrap: anywhere;
+  }
+  textarea {
+    width: 100%; min-height: 74px; resize: vertical;
+    font-family: var(--mono); font-size: 12px; color: var(--fg); background: var(--bg);
+    border: 1px solid var(--border); border-radius: 7px; padding: 7px 10px;
+  }
+  .actions { display: flex; gap: 8px; align-items: center; }
+  button.primary {
+    padding: 5px 14px; border-radius: 7px; border: 1px solid var(--accent);
+    background: var(--accent); color: var(--accent-fg);
+  }
+  button.ghost {
+    padding: 5px 12px; border-radius: 7px; border: 1px solid var(--border);
+    background: transparent; color: var(--fg);
+  }
+  button.primary:disabled, button.ghost:disabled { opacity: .5; cursor: default; }
+  button.primary:hover:enabled { filter: brightness(1.08); }
+  button.ghost:hover:enabled { background: var(--surface); }
+
+  .notice {
+    padding: 8px 11px; border: 1px solid var(--border); border-left: 3px solid var(--accent);
+    border-radius: 7px; background: var(--surface);
+    font-size: 12px; line-height: 1.5; color: var(--muted);
+  }
+  .notice b { color: var(--fg); font-weight: 600; }
+  .notice:empty { display: none; }
+
+  .syntax {
+    margin-top: 2px; padding: 9px 11px; border: 1px solid var(--border);
+    border-left: 3px solid var(--accent); border-radius: 7px;
+    font-size: 12px; line-height: 1.55; color: var(--muted);
+  }
+  .syntax b { color: var(--fg); font-weight: 600; }
+  .syntax code { font-family: var(--mono); font-size: 11.5px; color: var(--fg); }
+
+  /* status ------------------------------------------------------------- */
+  footer {
+    flex: none; min-height: 30px; padding: 7px 14px;
+    border-top: 1px solid var(--border); font-size: 12px; color: var(--muted);
+  }
+  footer.ok { color: #0f8a5f; }
+  footer.err { color: #c8382c; }
+</style>
+</head>
+<body>
+  <header>
+    <span class="logo">◈</span>
+    <h1>Preset update</h1>
+    <div class="seg" id="seg"></div>
+    <button class="iconbtn" id="refresh" title="Reload the current values">⟳</button>
+    <button class="iconbtn" id="close" title="Close">✕</button>
+  </header>
+
+  <div class="presetbar">
+    <span class="name" id="pname">Loading…</span>
+    <span id="ptag"></span>
+    <span class="spacer"></span>
+    <span class="tag" id="pcount">0 settings</span>
+  </div>
+
+  <div class="slotbar" id="slotbar" hidden>
+    <div class="slotrow">
+      <span class="slotlabel">Filament slots</span>
+      <div class="slots" id="slots"></div>
+    </div>
+    <div class="slotnote" id="slotnote"></div>
+  </div>
+
+  <main>
+    <section class="list-pane">
+      <div class="search">
+        <input id="q" type="search" placeholder="Search settings…" autocomplete="off" spellcheck="false">
+        <span class="tag" id="qcount">0</span>
+      </div>
+      <div class="rows" id="rows"></div>
+    </section>
+
+    <section class="edit-pane">
+      <div class="edit-key" id="ekey">Select a setting</div>
+      <div class="lbl">Current value</div>
+      <pre class="current" id="ecur">—</pre>
+      <label class="lbl" for="evalue">New value</label>
+      <textarea id="evalue" spellcheck="false" autocomplete="off"
+                placeholder="Serialized value" disabled></textarea>
+      <div class="notice" id="notice"></div>
+      <div class="actions">
+        <button class="primary" id="apply" disabled>Apply</button>
+        <button class="ghost" id="reset" disabled>Reset to current</button>
+      </div>
+      <div class="syntax">
+        <b>Values use OrcaSlicer's serialized config syntax</b> — the same text a preset
+        file stores. Numbers are plain (<code>0.2</code>, <code>3</code>) and percentages keep
+        their sign (<code>15%</code>). On/off is <code>1</code> or <code>0</code>. A choice uses
+        the setting's own key, e.g. <code>grid</code>. Lists are semicolon-separated
+        (<code>0.4;0.4;0.4</code>, or <code>"#FF0000";"#00FF00"</code>). Text keeps its
+        escapes, so a line break stays <code>\n</code>. A key that does not belong to this
+        preset, or a value the setting would reject, comes back as an error and writes
+        nothing. The edit lands in the preset the tab is editing and stays unsaved.
+      </div>
+    </section>
+  </main>
+
+  <footer id="status"></footer>
+
+<script>
+'use strict';
+
+const SEG = [['process', 'Process'], ['printer', 'Printer'], ['filament', 'Filament']];
+const IDLE = 'Edits apply to the preset shown here and stay unsaved until you save '
+  + 'or export it.';
+
+const S = {
+  kind: 'process',
+  slot: 1,              // selected filament slot (one-based); ignored by the other kinds
+  slots: [],            // [{slot, name, open}] from current_filament_presets()
+  preset: null,
+  rows: [],
+  selected: null,
+  changed: {},          // "kind/preset/key" -> true, for edits made in this window
+  pending: null,        // {kind, slot, preset, key} of an apply awaiting its reply
+  error: '',            // the last error the plugin reported, if any
+  assigned: true,       // filament only: the shown slot mounts a preset, so it is editable
+  switches: false,      // filament only: applying will select that preset in the filament tab
+  editedName: null,     // filament only: the preset the filament settings have open
+  busy: true,
+  filter: '',
+  statusText: '',
+  statusCls: '',
+};
+
+const $ = id => document.getElementById(id);
+const esc = s => String(s == null ? '' : s)
+  .replace(/[&<>"']/g, c => ({'&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;'}[c]));
+
+/* ------------------------------------------------------------------ paint */
+function paint() {
+  paintSeg();
+  const p = S.preset;
+  const slotTag = S.kind === 'filament' && S.slot
+    ? '<span class="tag">slot ' + S.slot + '</span>' : '';
+  $('pname').textContent = p ? p.name : (S.busy ? 'Loading…' : 'No preset');
+  $('pname').title = p ? p.name : '';
+  $('ptag').innerHTML = slotTag + (p
+    ? '<span class="tag">' + (p.is_system ? 'system' : 'user') + '</span>'
+      + (p.is_dirty ? '<span class="tag on">modified</span>' : '<span class="tag">saved</span>')
+    : '');
+  $('pcount').textContent = S.rows.length + (S.rows.length === 1 ? ' setting' : ' settings');
+  $('refresh').disabled = S.busy;
+  paintSlots();
+  paintNotice();
+  renderList();
+  paintEditor();
+  paintStatus();
+}
+
+function paintSeg() {
+  // Built once (see buildSeg) so a click never loses focus; only the state is repainted.
+  document.querySelectorAll('#seg button').forEach(b =>
+    b.setAttribute('aria-pressed', String(b.dataset.kind === S.kind)));
+}
+
+/* the filament slot strip: one chip per mounted slot, shown for filament only */
+function paintSlots() {
+  const show = S.kind === 'filament' && (S.slots.length > 0 || S.busy);
+  $('slotbar').hidden = !show;
+  if (!show) { $('slots').innerHTML = ''; $('slotnote').innerHTML = ''; return; }
+  // Rebuilding the chips drops keyboard focus; put it back on the same slot's chip.
+  const focused = document.activeElement && document.activeElement.dataset
+    ? document.activeElement.dataset.slot : null;
+  $('slots').innerHTML = S.slots.map(s => {
+    const selected = s.slot === S.slot;
+    const linked = !selected && sharesSelected(s.name);
+    const label = s.name == null ? '<span class="nil">empty slot</span>' : esc(s.name);
+    const hint = s.name ? ': ' + s.name : ': no preset';
+    return '<button type="button" class="chip' + (linked ? ' linked' : '')
+      + (s.open ? ' open' : '') + '"'
+      + ' data-slot="' + s.slot + '" aria-pressed="' + selected + '"'
+      + ' title="' + esc('Filament slot ' + s.slot + hint
+                         + (s.open ? ' — open in the filament settings' : '')) + '">'
+      + '<span class="n">' + s.slot + '</span><span class="s">' + label + '</span></button>';
+  }).join('');
+  $('slotnote').innerHTML = shareNote();
+  if (focused) {
+    const chip = document.querySelector('#slots .chip[data-slot="' + focused + '"]');
+    if (chip) chip.focus();
+  }
+}
+
+function slotName(slot) {
+  const found = S.slots.find(s => s.slot === slot);
+  return found && found.name ? found.name : null;
+}
+
+// Applying selects the slot's preset first, so say when that switches the filament tab. An
+// empty slot is the only unavailable one, and it says so instead of offering an edit.
+function paintNotice() {
+  const el = $('notice');
+  if (S.kind !== 'filament' || S.busy) { el.innerHTML = ''; return; }
+  // With nothing mounted the list already says so; avoid naming a slot number here.
+  if (!S.slots.length) { el.innerHTML = ''; return; }
+  const name = S.preset ? S.preset.name : null;
+  if (!name) {
+    el.innerHTML = 'Slot ' + S.slot + ' holds no filament preset. Assign one in the '
+      + 'OrcaSlicer filament settings first.';
+    return;
+  }
+  if (!S.switches) { el.innerHTML = ''; return; }
+  const open = S.editedName
+    ? ', while the filament settings have <b>' + esc(S.editedName) + '</b> open'
+    : '';
+  el.innerHTML = 'Slot ' + S.slot + ' uses <b>' + esc(name) + '</b>' + open
+    + '. Applying switches the filament tab to <b>' + esc(name) + '</b> first — Orca may '
+    + 'ask about unsaved changes there — then sets the value.';
+}
+
+function sharesSelected(name) {
+  const current = slotName(S.slot);
+  return !!name && !!current && name === current;
+}
+
+function listSlots(numbers) {
+  if (numbers.length === 1) return String(numbers[0]);
+  return numbers.slice(0, -1).join(', ') + ' and ' + numbers[numbers.length - 1];
+}
+
+// Slots mounting the same preset are one preset, so say which slots an edit reaches.
+function shareNote() {
+  const name = slotName(S.slot);
+  if (!name) return '';
+  const sharing = S.slots.filter(s => s.name === name).map(s => s.slot);
+  if (sharing.length < 2) return '';
+  return 'Slots ' + listSlots(sharing) + ' mount the same filament preset, so an edit '
+    + 'here changes every one of them.';
+}
+
+function changedKey(presetName, key) {
+  return S.kind + '/' + (presetName || '?') + '/' + key;
+}
+
+function paintStatus() {
+  const el = $('status');
+  if (S.statusText) {
+    el.textContent = S.statusText;
+    el.className = S.statusCls;
+  } else if (S.busy) {
+    el.textContent = 'Working…';
+    el.className = '';
+  } else {
+    el.textContent = IDLE;
+    el.className = '';
+  }
+}
+
+function setStatus(text, cls) {
+  S.statusText = text || '';
+  S.statusCls = cls || '';
+  paintStatus();
+}
+
+function visibleRows() {
+  const q = S.filter.trim().toLowerCase();
+  if (!q) return S.rows;
+  return S.rows.filter(r => r.k.toLowerCase().includes(q) || r.v.toLowerCase().includes(q));
+}
+
+function renderList() {
+  const scroller = $('rows');
+  const top = scroller.scrollTop;
+  $('qcount').textContent = String(visibleRows().length);
+
+  if (!S.rows.length) {
+    let text = 'This preset reports no settings.';
+    if (S.busy) text = 'Loading settings…';
+    else if (S.error) text = 'These values could not be read — see the message below.';
+    else if (S.kind === 'filament' && !S.slots.length) text = 'No filament slots are mounted.';
+    else if (S.kind === 'filament' && !S.preset) text = 'This filament slot has no preset.';
+    scroller.innerHTML = '<div class="empty">' + text + '</div>';
+    return;
+  }
+  const rows = visibleRows();
+  if (!rows.length) {
+    scroller.innerHTML = '<div class="empty">No setting matches “' + esc(S.filter) + '”.</div>';
+    return;
+  }
+  scroller.innerHTML = rows.map(r => {
+    const value = r.v === '' ? '<span class="nil">empty</span>' : esc(r.v);
+    return '<button type="button" class="row'
+      + (S.changed[changedKey(S.preset && S.preset.name, r.k)] ? ' changed' : '') + '"'
+      + ' data-key="' + esc(r.k) + '"'
+      + ' aria-selected="' + (r.k === S.selected) + '"'
+      + ' title="' + esc(r.k + ' = ' + r.v) + '">'
+      + '<span class="k">' + esc(r.k) + '</span>'
+      + '<span class="v">' + value + '</span>'
+      + '<span class="dot"></span></button>';
+  }).join('');
+  scroller.scrollTop = top;
+}
+
+function paintEditor() {
+  const row = S.rows.find(r => r.k === S.selected) || null;
+  // Every assigned slot is editable now that applying selects the slot's preset first, so
+  // Apply is off only for an empty slot, a missing selection, or a request in flight.
+  const selected = !!row && !S.busy;
+  $('ekey').textContent = row ? row.k : 'Select a setting';
+  $('ecur').textContent = row ? (row.v === '' ? '(empty)' : row.v) : '—';
+  $('evalue').disabled = !selected;
+  $('apply').disabled = !selected || !S.assigned;
+  $('reset').disabled = !selected;
+}
+
+/* --------------------------------------------------------------- actions */
+function buildSeg() {
+  $('seg').innerHTML = SEG.map(([kind, label]) =>
+    '<button type="button" data-kind="' + kind + '">' + label + '</button>').join('');
+}
+
+function selectKey(key) {
+  S.selected = key;
+  const row = S.rows.find(r => r.k === key);
+  $('evalue').value = row ? row.v : '';
+  // Repaint the rows in place so the scroll position of a long list is kept.
+  document.querySelectorAll('#rows .row').forEach(el =>
+    el.setAttribute('aria-selected', String(el.dataset.key === key)));
+  paintEditor();
+}
+
+function switchKind(kind) {
+  S.kind = kind;
+  S.selected = null;
+  S.pending = null;
+  S.preset = null;
+  S.rows = [];
+  S.busy = true;
+  $('evalue').value = '';
+  setStatus('', '');
+  paint();
+  orca.postMessage({command: 'state', kind: kind, slot: S.slot});
+}
+
+// Two slots that mount the same preset show the same settings, so only a switch to a
+// different preset drops the current selection and the value being typed.
+function selectSlot(slot) {
+  if (S.busy || slot === S.slot) return;
+  const same = !!slotName(slot) && slotName(slot) === slotName(S.slot);
+  S.slot = slot;
+  S.pending = null;
+  S.busy = true;
+  if (!same) {
+    S.preset = null;
+    S.rows = [];
+    S.selected = null;
+    $('evalue').value = '';
+  }
+  setStatus('', '');
+  paint();
+  orca.postMessage({command: 'state', kind: S.kind, slot: slot});
+}
+
+function reload() {
+  if (S.busy) return;
+  S.busy = true;
+  S.pending = null;
+  setStatus('', '');
+  paint();
+  orca.postMessage({command: 'state', kind: S.kind, slot: S.slot});
+}
+
+function applyValue() {
+  const row = S.rows.find(r => r.k === S.selected);
+  // Mirror the Apply button: only a missing selection, a request in flight, or an empty
+  // slot blocks an edit, so Enter cannot send one the button itself would refuse.
+  if (!row || S.busy || !S.assigned) return;
+  S.pending = {
+    kind: S.kind, slot: S.slot,
+    preset: S.preset ? S.preset.name : null, key: row.k,
+  };
+  S.busy = true;
+  setStatus('', '');
+  paint();
+  orca.postMessage({command: 'apply', kind: S.kind, slot: S.slot, key: row.k,
+                    value: $('evalue').value});
+}
+
+function flashKey(key) {
+  document.querySelectorAll('#rows .row').forEach(el => {
+    if (el.dataset.key !== key) return;
+    el.classList.remove('flash');
+    void el.offsetWidth;    // restart the animation if it ran on this row already
+    el.classList.add('flash');
+    el.addEventListener('animationend', () => el.classList.remove('flash'), {once: true});
+  });
+}
+
+/* ----------------------------------------------------------------- wiring */
+buildSeg();
+
+$('seg').addEventListener('click', e => {
+  const button = e.target.closest('[data-kind]');
+  if (!button || S.busy || button.dataset.kind === S.kind) return;
+  switchKind(button.dataset.kind);
+});
+
+$('rows').addEventListener('click', e => {
+  const row = e.target.closest('.row');
+  if (row && !S.busy) selectKey(row.dataset.key);
+});
+
+$('slots').addEventListener('click', e => {
+  const chip = e.target.closest('[data-slot]');
+  if (chip && !S.busy) selectSlot(Number(chip.dataset.slot));
+});
+
+$('q').addEventListener('input', e => {
+  S.filter = e.target.value;
+  renderList();
+});
+
+$('apply').addEventListener('click', applyValue);
+
+$('reset').addEventListener('click', () => {
+  const row = S.rows.find(r => r.k === S.selected);
+  if (row) $('evalue').value = row.v;
+});
+
+$('evalue').addEventListener('keydown', e => {
+  if (e.key === 'Enter' && !e.shiftKey) { e.preventDefault(); applyValue(); }
+  else if (e.key === 'Escape') { e.preventDefault(); $('reset').click(); }
+});
+
+$('refresh').addEventListener('click', reload);
+$('close').addEventListener('click', () => orca.close());
+
+/* -------------------------------------------------------------- messages */
+orca.onMessage(msg => {
+  if (!msg || msg.command !== 'state') return;
+  if (msg.kind !== S.kind) return;      // a reply for a category we already left
+
+  const pending = S.pending;
+  S.busy = false;
+  S.pending = null;
+  S.slots = msg.slots || [];
+  // Adopt the slot the plugin actually used (it clamps a slot that no longer exists).
+  if (S.kind === 'filament' && typeof msg.slot === 'number') S.slot = msg.slot;
+  S.preset = msg.preset || null;
+  S.rows = msg.rows || [];
+  S.error = msg.error || '';
+  // Filament editability is a slot concern; process and printer have a single edited preset.
+  S.assigned = S.kind === 'filament' ? !!msg.assigned : true;
+  S.switches = S.kind === 'filament' ? !!msg.switches : false;
+  S.editedName = S.kind === 'filament' ? (msg.edited_name || null) : null;
+  if (S.selected && !S.rows.some(r => r.k === S.selected)) S.selected = null;
+
+  if (msg.error) {
+    // Keep the typed value so it can be corrected, and keep the current selection.
+    setStatus('⚠ ' + msg.error, 'err');
+  } else {
+    if (pending) S.changed[changedKey(pending.preset, pending.key)] = true;
+    setStatus(msg.message || '', msg.message ? 'ok' : '');
+  }
+
+  paint();
+
+  if (!msg.error && pending) {
+    const row = S.rows.find(r => r.k === pending.key);
+    if (row) {                       // show the value as the preset now stores it
+      $('evalue').value = row.v;
+      flashKey(row.k);
+    }
+  }
+});
+
+paint();
+orca.postMessage({command: 'state', kind: S.kind, slot: S.slot});
+</script>
+</body>
+</html>"""
+
+
+class PresetUpdateDemo(orca.script.ScriptPluginCapabilityBase):
+    window = None
+    kind = "process"      # the category the open window is showing, for a re-run refresh
+    slot = 1              # the filament slot the open window is showing
+
+    def get_name(self):
+        return "Preset update demo"
+
+    def execute(self):
+        try:
+            if self.window is not None and self.window.is_open():
+                self._post_state(self.kind, self.slot)
+                return orca.ExecutionResult.success("Preset update demo refreshed.")
+            self.window = orca.host.ui.create_window(
+                title="Preset update demo", html=PAGE, width=820, height=560,
+                on_message=self.on_message, on_close=self.on_close,
+            )
+            return orca.ExecutionResult.success("Preset update demo opened.")
+        except Exception as error:
+            message = "Preset update demo failed: %s" % error
+            orca.host.ui.message(message, title="Preset update demo", buttons="ok", icon="error")
+            return orca.ExecutionResult.failure(orca.PluginResult.RecoverableError, message)
+
+    def on_close(self):
+        self.window = None
+
+    def _post_state(self, kind="process", slot=1, message="", error=""):
+        try:
+            payload = _state(orca.host.preset_bundle(), kind, slot, message, error)
+        except Exception as state_error:
+            payload = {"command": "state", "kind": kind, "slot": slot, "slots": [],
+                       "assigned": False, "switches": False, "edited_name": None,
+                       "preset": None, "rows": [], "message": message,
+                       "error": str(state_error)}
+        if self.window is not None and self.window.is_open():
+            self.window.post(payload)
+
+    def on_message(self, message):
+        kind = "process"
+        slot = 1
+        try:
+            message = message or {}
+            kind = message.get("kind", "process")
+            if not isinstance(kind, str) or kind not in KIND_KEYS:
+                raise RuntimeError("Unknown preset category %r" % (kind,))
+            self.kind = kind
+            slot = message.get("slot", 1)
+
+            command = message.get("command")
+            if command == "state":
+                self.slot = slot
+                self._post_state(kind, slot)
+                return
+            if command == "apply":
+                key = message.get("key")
+                value = message.get("value")
+                if not isinstance(key, str) or not key:
+                    raise RuntimeError("A setting key is required")
+                if not isinstance(value, str):
+                    raise RuntimeError("A value string is required")
+                where = ""
+                if kind == "filament":
+                    presets = _slot_presets(orca.host.preset_bundle())
+                    # Validate the slot strictly: an out-of-range slot must fail loudly
+                    # rather than edit a different filament. A slot with no preset has
+                    # nothing to write, which is the only slot shape the backend refuses.
+                    slot = _parse_slot(slot, len(presets))
+                    if presets[slot - 1] is None:
+                        raise RuntimeError("Filament slot %d has no preset to edit" % slot)
+                    _apply(kind, key, value, slot)
+                    where = " on slot %d" % slot
+                else:
+                    _apply(kind, key, value)
+                shown = value if value else "(empty)"
+                self.slot = slot
+                self._post_state(
+                    kind, slot,
+                    message='Set %s = "%s"%s. The edit stays in the preset tab until you save it.'
+                            % (key, shown, where),
+                )
+                return
+            raise RuntimeError("Unknown command %r" % (command,))
+        except Exception as error:
+            safe_kind = kind if isinstance(kind, str) and kind in KIND_KEYS else "process"
+            self._post_state(safe_kind, slot, error=str(error))
+
+
+@orca.plugin
+class PresetUpdateDemoPackage(orca.base):
+    def register_capabilities(self):
+        orca.register_capability(PresetUpdateDemo)

src/slic3r/GUI/OptionsGroup.cpp

@@ -1332,6 +1332,21 @@ boost::any ConfigOptionsGroup::get_config_value2(const DynamicPrintConfig& confi
     return ret;
 }
 
+bool ConfigOptionsGroup::commit_config_value(const t_config_option_key& opt_key, int opt_index)
+{
+    if (m_config == nullptr)
+        return false;
+
+    // m_opt_map is filled while the option lines are created, so it still resolves the option when
+    // the group's controls (and thus its fields) have not been built yet.
+    const std::string opt_id = option_id_in_map(m_opt_map, opt_key, opt_index);
+    if (opt_id.empty())
+        return false;
+
+    on_change_OG(opt_id, get_config_value2(*m_config, opt_key, opt_index));
+    return true;
+}
+
 Field* ConfigOptionsGroup::get_fieldc(const t_config_option_key& opt_key, int opt_index)
 {
     Field* field = get_field(opt_key);

src/slic3r/GUI/OptionsGroup.hpp

@@ -119,6 +119,37 @@ using column_t = std::function<wxWindow*(wxWindow* parent, const Line&)>;
 using t_optionfield_map = std::map<t_config_option_key, t_field>;
 using t_opt_map = std::map< std::string, std::pair<std::string, int> >;
 
+// The option id a group's option map holds for opt_key, and the index it carries. `opt_index` is
+// an in/out parameter: a negative value asks for the option's single entry, an explicit one selects
+// that index. Returns an empty string when the map does not own the option, or when a negative index
+// matches several entries -- a vector option the GUI edits one index at a time, which has no single
+// value to commit. A group fills the map while its option lines are created (OptionsGroup::append_line
+// / ConfigOptionsGroup::get_option), so this resolves an option even before its controls (and its
+// field) have been built.
+inline std::string option_id_in_map(const t_opt_map& options, const t_config_option_key& opt_key, int& opt_index)
+{
+    if (opt_index >= 0) {
+        for (const auto& opt : options) {
+            if (opt.second.first == opt_key && opt.second.second == opt_index) {
+                opt_index = opt.second.second;
+                return opt.first;
+            }
+        }
+        return {};
+    }
+
+    std::string opt_id;
+    for (const auto& opt : options) {
+        if (opt.second.first != opt_key)
+            continue;
+        if (!opt_id.empty())
+            return {}; // several entries: a vector option, not one value
+        opt_id    = opt.first;
+        opt_index = opt.second.second;
+    }
+    return opt_id;
+}
+
 class OptionsGroup {
 public:
     const bool staticbox{true};
@@ -332,6 +363,15 @@ public:
 	boost::any	get_config_value(const DynamicPrintConfig& config, const std::string& opt_key, int opt_index = -1);
 	// BBS: restore all pages in preset
 	boost::any	get_config_value2(const DynamicPrintConfig& config, const std::string& opt_key, int opt_index = -1);
+	// Re-run this group's committed-change path for one of its options without a widget event:
+	// build the option's value from the config this group edits (get_config_value2, the same form
+	// the option's field reports) and dispatch on_change_OG(), so the group's option-specific
+	// conversion (e.g. the printer_agent canonicalization) and its registered change handler run
+	// exactly as for a hand edit. The option map is filled while the option lines are created, so
+	// this resolves an option whose field is not built yet (a lazy page, or an option the GUI has
+	// no field for). Returns false when this group does not own the option, or when opt_index < 0
+	// matches several entries (a vector option the GUI edits index by index has no single value).
+	bool		commit_config_value(const t_config_option_key& opt_key, int opt_index = -1);
 	Field*		get_fieldc(const t_config_option_key& opt_key, int opt_index);
 	std::pair<OG_CustomCtrl*, bool*>	get_custom_ctrl_with_blinking_ptr(const t_config_option_key& opt_key, int opt_index/* = -1*/);
 

src/slic3r/GUI/Tab.cpp

@@ -46,6 +46,7 @@
 #include "slic3r/GUI/DeviceCore/DevConfigUtil.h"
 #include <deque>
 #include <exception>
+#include <stdexcept>
 #include "libslic3r/LifecycleEvents.hpp"
 #include "libslic3r/Point.hpp"
 #include "slic3r/GUI/SettingsIndex.hpp"
@@ -1645,6 +1646,101 @@ void Tab::load_config(const DynamicPrintConfig& config)
     }
 }
 
+// The option keys a preset of `type` may hold. The tab's config shares the global
+// print_config_def with every other preset type, so membership has to be checked against the
+// preset type's own key list instead of the config definition, or a printer setting could be
+// written into the process preset.
+static const std::vector<std::string>& preset_type_options(Preset::Type type)
+{
+    static const std::vector<std::string> none;
+    switch (type) {
+    case Preset::TYPE_PRINT:    return Preset::print_options();
+    case Preset::TYPE_FILAMENT: return Preset::filament_options();
+    case Preset::TYPE_PRINTER:  return Preset::printer_options();
+    default:                    return none;
+    }
+}
+
+static const char* preset_type_name(Preset::Type type)
+{
+    switch (type) {
+    case Preset::TYPE_PRINT:    return "process";
+    case Preset::TYPE_FILAMENT: return "filament";
+    case Preset::TYPE_PRINTER:  return "printer";
+    default:                    return "preset";
+    }
+}
+
+// Set one option of the currently edited preset from its serialized string form, then run the
+// same update path a hand edit runs. The edited preset is not saved: it only becomes dirty,
+// exactly as if the field had been edited by hand.
+void Tab::apply_preset_config_value(const std::string& opt_key, const std::string& value)
+{
+    if (m_config == nullptr)
+        throw std::runtime_error("The preset configuration is not available");
+    if (wxGetApp().plater() == nullptr)
+        throw std::runtime_error("OrcaSlicer main window is not available");
+
+    const std::vector<std::string>& options = preset_type_options(m_type);
+    if (std::find(options.begin(), options.end(), opt_key) == options.end())
+        throw std::invalid_argument(format("Unknown %1% preset setting \"%2%\"", preset_type_name(m_type), opt_key));
+
+    // Parse strictly, keeping a backup: the strict deserializer can already have mutated the option
+    // when it rejects a bad value, so a failed update has to restore the preset it was given.
+    const ConfigOption*           previous_option = m_config->option(opt_key);
+    std::unique_ptr<ConfigOption> previous(previous_option != nullptr ? previous_option->clone() : nullptr);
+    try {
+        m_config->set_deserialize_strict(opt_key, value);
+    } catch (const ConfigurationError& err) {
+        if (previous)
+            m_config->set_key_value(opt_key, previous.release());
+        else
+            m_config->erase(opt_key);
+        throw std::invalid_argument(err.what());
+    }
+
+    // Run the same commit path the GUI runs for this setting, so its key-specific behaviour
+    // (ConfigOptionsGroup::on_change_OG, including the printer_agent canonicalization, the group's
+    // pre-checks and Tab::on_value_change()) runs exactly as for a hand edit. A built field supplies
+    // the field's typed/clamped value; otherwise the owning ConfigOptionsGroup builds the value from
+    // the config it edits and dispatches the same on_change_OG(). The field is refreshed from the
+    // config just committed first, so it reports the committed value rather than a stale one.
+    bool committed = false;
+    if (Page* field_page = nullptr; Field* field = get_field(opt_key, &field_page)) {
+        field_page->reload_config();
+        field->field_changed();
+        committed = true;
+    } else {
+        for (const PageShp& page : m_pages) {
+            for (const ConfigOptionsGroupShp& group : page->m_optgroups) {
+                if (group->commit_config_value(opt_key)) {
+                    committed = true;
+                    break;
+                }
+            }
+            if (committed)
+                break;
+        }
+    }
+
+    if (committed) {
+        // The commit path already ran update_dirty() (dirty flag, preset combo and, on the printer
+        // tab, the printer-agent switch); refresh the visible page and push the config to the plater.
+        reload_config();
+        update();
+    } else {
+        // The GUI edits this setting through a custom widget rather than a group (e.g.
+        // compatible_printers), so take the same shared no-field commit path the widget uses. Saved
+        // mode skips the value write (the strict parse above already did it) and keeps the path's
+        // compatibility recompute, dirty flag, preset-combo and plater updates.
+        load_key_value(opt_key, boost::any(), /*saved_value=*/true);
+        // The widget itself normally re-reads its value after load_key_value(); with no widget to do
+        // that, sync the visible page so a custom widget (the compatible-printers row) reflects the
+        // new value.
+        reload_config();
+    }
+}
+
 // Reload current $self->{config} (aka $self->{presets}->edited_preset->config) into the UI fields.
 void Tab::reload_config()
 {

src/slic3r/GUI/Tab.hpp

@@ -424,6 +424,17 @@ public:
 	//BBS update plater presets if update_plater_presets = true
 	void			update_tab_ui(bool update_plater_presets = false);
 	void			load_config(const DynamicPrintConfig& config);
+	// Host/plugin API: set one option of this tab's currently edited preset from its serialized
+	// string value, then run the same committed-change path a field edit runs. `opt_key` must be a
+	// setting of this tab's preset type, so a key of another preset type (e.g. a printer setting
+	// passed to the process tab) is rejected instead of written silently. `value` is parsed by the
+	// strict config deserializer, which raises std::invalid_argument for an unknown key or a value
+	// the option cannot parse, and leaves the preset unchanged. The key-specific behaviour runs
+	// through its ConfigOptionsGroup::on_change_OG(): with the option's built field it uses the
+	// field's typed value, otherwise the owning group builds the value and dispatches the same call,
+	// so a not-yet-built field still gets it. A key the GUI edits through a custom widget instead
+	// takes the shared no-field commit path, Tab::load_key_value() in saved mode.
+	void			apply_preset_config_value(const std::string& opt_key, const std::string& value);
 	virtual void	reload_config();
     void            update_mode();
     void            update_visibility();

src/slic3r/plugin/host/PluginHostPresets.cpp

@@ -17,6 +17,7 @@
 #include <slic3r/GUI/GUI_App.hpp>
 #include <slic3r/GUI/MainFrame.hpp>
 #include <slic3r/GUI/Plater.hpp>
+#include <slic3r/GUI/PresetComboBoxes.hpp> // TabPresetComboBox::set_filament_idx
 #include <slic3r/GUI/Tab.hpp>
 
 #include <pybind11/stl.h>
@@ -48,6 +49,110 @@ PresetCollection& printer_presets(PresetBundle& bundle)
     return static_cast<PresetCollection&>(bundle.printers);
 }
 
+// Handle to one category of currently edited preset. It is a category, not a snapshot: it always
+// resolves the preset the matching tab edits now, so it stays valid across preset switches.
+struct PresetEditor
+{
+    Preset::Type type = Preset::TYPE_INVALID;
+};
+
+const char* preset_tab_name(Preset::Type type)
+{
+    switch (type) {
+    case Preset::TYPE_PRINT:    return "process";
+    case Preset::TYPE_FILAMENT: return "filament";
+    case Preset::TYPE_PRINTER:  return "printer";
+    default:                    return "preset";
+    }
+}
+
+void update_edited_preset(Preset::Type type, const std::string& key, const std::string& value)
+{
+    PluginHostUi::run_on_ui_thread([&] {
+        GUI::GUI_App& app = GUI::wxGetApp();
+        if (app.is_closing())
+            throw std::runtime_error("OrcaSlicer is closing");
+        if (app.preset_bundle == nullptr)
+            throw std::runtime_error("Preset bundle is not available");
+        if (app.plater() == nullptr)
+            throw std::runtime_error("OrcaSlicer main window is not available");
+
+        GUI::Tab* tab = app.get_tab(type);
+        if (tab == nullptr)
+            throw std::runtime_error(std::string("The ") + preset_tab_name(type) + " preset tab is not available");
+        // The tab for this preset type exists, but the selected printer's technology may not use it
+        // (the print tab no-ops under SLA); refuse instead of writing a value the UI cannot apply.
+        if (!tab->supports_printer_technology(app.preset_bundle->printers.get_selected_preset().printer_technology()))
+            throw std::runtime_error(std::string("The ") + preset_tab_name(type)
+                                     + " preset is not available for the selected printer technology");
+
+        tab->apply_preset_config_value(key, value);
+    });
+}
+
+// Slot-addressed filament update. `slot_number` is 1-based, matching the GUI's filament slots and
+// the values PresetBundle::filament_presets holds. The slot's assigned preset is resolved to its
+// internal name; when that is not the preset the filament tab edits, the tab is switched through
+// Tab::select_preset() - the normal UI preselection flow, so a dirty edited preset still prompts
+// the user and a declined prompt cancels the call with a clear error and no change.
+void update_filament_slot(int slot_number, const std::string& key, const std::string& value)
+{
+    PluginHostUi::run_on_ui_thread([&] {
+        GUI::GUI_App& app = GUI::wxGetApp();
+        if (app.is_closing())
+            throw std::runtime_error("OrcaSlicer is closing");
+        if (app.preset_bundle == nullptr)
+            throw std::runtime_error("Preset bundle is not available");
+        if (app.plater() == nullptr)
+            throw std::runtime_error("OrcaSlicer main window is not available");
+
+        PresetBundle& bundle = *app.preset_bundle;
+        if (slot_number < 1 || static_cast<size_t>(slot_number) > bundle.filament_presets.size())
+            throw std::out_of_range("Filament slot " + std::to_string(slot_number) + " is out of range; slot numbers are 1-based and this printer has "
+                                    + std::to_string(bundle.filament_presets.size()) + " filament slot(s)");
+
+        const std::string& assigned_name = bundle.filament_presets[static_cast<size_t>(slot_number) - 1];
+        if (assigned_name.empty())
+            throw std::runtime_error("Filament slot " + std::to_string(slot_number) + " has no assigned filament preset");
+
+        // Resolve the assigned name the way the app does, so a renamed/aliased entry maps to the
+        // internal preset it now identifies. Copy the name out before selecting anything: the
+        // collection can be reallocated while switching.
+        Preset* slot_preset = bundle.filaments.find_preset(assigned_name);
+        if (slot_preset == nullptr)
+            throw std::runtime_error("Filament slot " + std::to_string(slot_number) + " is assigned \"" + assigned_name
+                                     + "\", which does not resolve to a filament preset");
+        const std::string target_name = slot_preset->name;
+
+        GUI::Tab* tab = app.get_tab(Preset::TYPE_FILAMENT);
+        if (tab == nullptr)
+            throw std::runtime_error("The filament preset tab is not available");
+        if (!tab->supports_printer_technology(bundle.printers.get_selected_preset().printer_technology()))
+            throw std::runtime_error("The filament preset is not available for the selected printer technology");
+
+        // Switch to the slot's preset through the normal preset selection, never a forced one, so the
+        // user's unsaved-changes prompt is honoured. A declined prompt returns false here.
+        if (bundle.filaments.get_edited_preset().name != target_name) {
+            if (!tab->select_preset(target_name))
+                throw std::runtime_error("Switching the edited filament preset to \"" + target_name + "\" for filament slot "
+                                         + std::to_string(slot_number) + " was canceled; the setting was not changed");
+        }
+
+        // select_preset() can still leave a different preset edited (e.g. the target disappeared), so
+        // re-check before writing anything.
+        if (bundle.filaments.get_edited_preset().name != target_name)
+            throw std::runtime_error("The edited filament preset is \"" + bundle.filaments.get_edited_preset().name
+                                     + "\", not \"" + target_name + "\"; the setting was not changed");
+
+        // Match PlaterPresetComboBox::switch_to_tab(): record which 0-based filament slot this tab
+        // combobox now edits, so the GUI shows the slot the value was written for.
+        if (GUI::TabPresetComboBox* combo = tab->get_combo_box())
+            combo->set_filament_idx(slot_number - 1);
+
+        tab->apply_preset_config_value(key, value);
+    });
+}
+
 void reload_local_bundle(const std::string& bundle_id)
 {
     bool        reloaded = false;
@@ -119,6 +224,47 @@ void host_bindings::register_presets(py::module_& host)
         .value("Plate", Preset::TYPE_PLATE)
         .value("Model", Preset::TYPE_MODEL);
 
+    py::class_<PresetEditor>(preset, "PresetEditor",
+                             "Handle to a category of currently edited preset. It is not a snapshot: it always "
+                             "resolves the preset the matching tab edits now, so it stays usable across preset "
+                             "switches. update() edits the preset in place; the change is not saved to disk.")
+        .def_readonly("type", &PresetEditor::type)
+        .def(
+            "update",
+            [](const PresetEditor& editor, const std::string& key, const std::string& value) {
+                update_edited_preset(editor.type, key, value);
+            },
+            py::arg("key"), py::arg("value"),
+            "Set one setting of the currently edited preset and run the same committed-change path as "
+            "editing the setting in the GUI; the edited preset becomes dirty until saved/exported. "
+            "key must be a setting of this preset category and value its serialized string form, "
+            "otherwise ValueError is raised and nothing is written. A setting edited through a field "
+            "runs that field's validation even before its page has been opened; one the GUI edits "
+            "outside a field (such as compatible printers) also recomputes preset compatibility.")
+        .def(
+            "update",
+            [](const PresetEditor& editor, int slot_number, const std::string& key, const std::string& value) {
+                if (editor.type != Preset::TYPE_FILAMENT)
+                    throw std::invalid_argument("The slot_number form of update() is only available on "
+                                                "orca.host.preset.filament; call update(key, value) on this editor");
+                update_filament_slot(slot_number, key, value);
+            },
+            py::arg("slot_number"), py::arg("key"), py::arg("value"),
+            "Set one setting of the filament preset assigned to a 1-based filament slot. When that preset "
+            "is not the one currently edited the call switches to it through the normal preset-selection "
+            "flow, so an unsaved edited preset still prompts the user and a declined prompt cancels the "
+            "call with an error and no change. An out-of-range, empty or unresolved slot is rejected with "
+            "a clear error. Other preset editors accept only update(key, value); this form raises "
+            "ValueError on them.");
+
+    // The three preset categories edited by the main tabs. `process` is the print/process preset,
+    // `printer` the machine preset and `filament` the currently edited filament preset (its
+    // 3-argument form addresses a 1-based filament slot); each only accepts its own settings, so a
+    // printer setting passed to `process` is rejected instead of written silently.
+    preset.attr("process")  = py::cast(PresetEditor{Preset::TYPE_PRINT});
+    preset.attr("printer")  = py::cast(PresetEditor{Preset::TYPE_PRINTER});
+    preset.attr("filament") = py::cast(PresetEditor{Preset::TYPE_FILAMENT});
+
     py::class_<Preset, std::unique_ptr<Preset, py::nodelete>>(host, "Preset")
         .def_readonly("type", &Preset::type)
         .def_readonly("name", &Preset::name)

tests/slic3rutils/test_plugin_host_api.cpp

@@ -1,3 +1,19 @@
+// why: keep the Windows headers ahead of libslic3r. Model.hpp pulls in Format/STEP.hpp, and
+// OCCT's Standard_Macro.hxx defines NOUSER and NOGDI on Windows so that windows.h does not
+// collide with OCCT's identifiers. Defined that early they also hide the USER and GDI
+// declarations, and the wx MSW headers Field.hpp reaches (wx/wxprec.h -> wx/msw/private.h)
+// need WNDPROC, RGB and the ::GetWindowRect family. Including windows.h first, as
+// libslic3r_gui does through pchheader.hpp or win_platform.hpp, keeps them.
+#ifdef WIN32
+    #ifndef WIN32_LEAN_AND_MEAN
+        #define WIN32_LEAN_AND_MEAN
+    #endif
+    #ifndef NOMINMAX
+        #define NOMINMAX
+    #endif
+    #include <Windows.h>
+#endif
+
 #include <catch2/catch_all.hpp>
 
 #include <cstddef>
@@ -6,8 +22,12 @@
 #include <libslic3r/TriangleMesh.hpp>
 #include <slic3r/GUI/DockPanel.hpp>
 #include <slic3r/GUI/AuiPaneLayout.hpp>
+#include <slic3r/GUI/OptionsGroup.hpp>
 #include <slic3r/GUI/Widgets/WebHosting.hpp>
 
+#include <map>
+#include <utility>
+
 #include <catch2/catch_test_macros.hpp>
 #include <catch2/catch_message.hpp>
 #include <catch2/matchers/catch_matchers_floating_point.hpp>
@@ -137,6 +157,106 @@ TEST_CASE("Plugin host API exposes host-owned bundle and preset surface to Pytho
     CHECK(printers.attr("find_preset")(printer_preset.name).attr("name").cast<std::string>() == printer_preset.name);
 }
 
+TEST_CASE("Plugin host API exposes the editable preset category handles and guards them before Orca app initialization",
+          "[PluginHost][Python]")
+{
+    py::object host   = import_orca_module().attr("host");
+    py::object preset = host.attr("preset");
+
+    REQUIRE(has_attr(preset, "PresetEditor"));
+    REQUIRE(has_attr(preset, "process"));
+    REQUIRE(has_attr(preset, "printer"));
+    REQUIRE(has_attr(preset, "filament"));
+
+    py::object process  = preset.attr("process");
+    py::object printer  = preset.attr("printer");
+    py::object filament = preset.attr("filament");
+
+    CHECK(process.attr("type").cast<Slic3r::Preset::Type>() == Slic3r::Preset::TYPE_PRINT);
+    CHECK(printer.attr("type").cast<Slic3r::Preset::Type>() == Slic3r::Preset::TYPE_PRINTER);
+    CHECK(filament.attr("type").cast<Slic3r::Preset::Type>() == Slic3r::Preset::TYPE_FILAMENT);
+    for (const py::object& editor : { process, printer, filament })
+        CHECK(has_attr(editor, "update"));
+
+    // With no wx application the call must fail cleanly, like the rest of host.preset, and must not
+    // be mistaken for a missing attribute or an argument error.
+    for (const py::object& editor : { process, printer, filament }) {
+        try {
+            editor.attr("update")("layer_height", "0.25");
+            FAIL("preset editor update unexpectedly succeeded without a wx application");
+        } catch (const py::error_already_set& error) {
+            CHECK(error.matches(PyExc_RuntimeError));
+            CHECK(std::string(error.what()).find("OrcaSlicer application is not initialized") != std::string::npos);
+        }
+    }
+}
+
+TEST_CASE("Plugin host API exposes the filament slot form of preset update and guards it", "[PluginHost][Python]")
+{
+    py::object host   = import_orca_module().attr("host");
+    py::object preset = host.attr("preset");
+
+    // The filament editor accepts update(slot_number, key, value) as well as update(key, value); with
+    // no wx application it reaches the same clean failure as the rest of host.preset. The slot
+    // validation and the switch/cancel path need a running app, so they are not exercised here.
+    try {
+        preset.attr("filament").attr("update")(1, "layer_height", "0.25");
+        FAIL("slot-addressed filament update unexpectedly succeeded without a wx application");
+    } catch (const py::error_already_set& error) {
+        CHECK(error.matches(PyExc_RuntimeError));
+        CHECK(std::string(error.what()).find("OrcaSlicer application is not initialized") != std::string::npos);
+    }
+
+    // The process and printer editors accept only update(key, value); the slot form is rejected
+    // before any application access, naming the editor that does accept it.
+    for (const char* name : { "process", "printer" }) {
+        CAPTURE(name);
+        try {
+            preset.attr(name).attr("update")(1, "layer_height", "0.25");
+            FAIL("slot-addressed update on a non-filament editor unexpectedly succeeded");
+        } catch (const py::error_already_set& error) {
+            CHECK(error.matches(PyExc_ValueError));
+            CHECK(std::string(error.what()).find("only available on") != std::string::npos);
+        }
+    }
+}
+
+TEST_CASE("A settings group resolves an option's id from its option map", "[PluginHost]")
+{
+    using Slic3r::GUI::option_id_in_map;
+    using Slic3r::GUI::t_opt_map;
+
+    // The map ConfigOptionsGroup::get_option leaves: a scalar option, and a per-extruder option
+    // whose entries carry their index.
+    t_opt_map options;
+    options.emplace("layer_height", std::make_pair(std::string("layer_height"), -1));
+    options.emplace("nozzle_diameter#0", std::make_pair(std::string("nozzle_diameter"), 0));
+    options.emplace("nozzle_diameter#1", std::make_pair(std::string("nozzle_diameter"), 1));
+
+    // A negative index resolves a scalar option and yields its own (negative) index.
+    int index = -1;
+    CHECK(option_id_in_map(options, "layer_height", index) == "layer_height");
+    CHECK(index == -1);
+
+    // A negative index on a vector option matches several entries, so it resolves to nothing.
+    index = -1;
+    CHECK(option_id_in_map(options, "nozzle_diameter", index).empty());
+
+    // An explicit index selects that entry.
+    index = 1;
+    CHECK(option_id_in_map(options, "nozzle_diameter", index) == "nozzle_diameter#1");
+    CHECK(index == 1);
+
+    // An index no entry carries, and a key the map does not own, resolve to nothing.
+    index = 7;
+    CHECK(option_id_in_map(options, "nozzle_diameter", index).empty());
+    index = -1;
+    CHECK(option_id_in_map(options, "wall_loops", index).empty());
+
+    const t_opt_map empty;
+    CHECK(option_id_in_map(empty, "layer_height", index).empty());
+}
+
 TEST_CASE("Plugin host API reports unavailable GUI objects before Orca app initialization", "[PluginHost][Python]")
 {
     py::object host = import_orca_module().attr("host");