max / makeover-immediate

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1	//! The immediate-mode renderer for [`makeover_layout`].
2	//!
3	//! <!-- wiki: makeover-immediate -->
4	//!
5	//! Named for the mode, not the library, the way `makeover-tui` is named for
6	//! the target and not for ratatui. Immediate mode is the constraint that
7	//! actually separates this renderer from the other two, and egui is the
8	//! backend it is written against.
9	//!
10	//! It is the harshest renderer the description has to survive: no
11	//! `box-shadow`, no `inset`, no cascade, no retained tree to mutate, and
12	//! `Visuals.widgets.*.bg_stroke` is a single stroke with no per-side control.
13	//! A two-tone lit edge is not something egui can be configured into producing,
14	//! so it gets painted by hand here, once, instead of in every consuming app.
15	//!
16	//! # What this crate does and does not own
17	//!
18	//! It owns the expression: two mitred polylines for a bevel and a `Frame`
19	//! for a filled region. It owns no colours and no sizes, and no longer owns a
20	//! substitution: it briefly supplied the page for a well, which was a stand-in
21	//! for `surface-well` before makeover derived it, and every consumer reads the
22	//! real token now. [`Palette`] is supplied by the caller,
23	//! already resolved, and every radius, margin and stroke width arrives in
24	//! [`FrameStyle`].
25	//!
26	//! That split is why the crate has no dependency on `makeover` itself: the app
27	//! already resolves a theme, and coupling a renderer to a colour crate's
28	//! version would buy nothing.
29	//!
30	//! # The cascade is the real difference
31	//!
32	//! A stylesheet can say "a pressed button inverts its bevel" once and let the
33	//! cascade carry it. An immediate-mode renderer has nowhere to put that, so
34	//! every call site decides. [`makeover_layout::Depth::pressed`] is what keeps
35	//! the decision from being re-derived per widget.
36	//!
37	//! # 0.11.0: the overlay becomes reachable
38	//!
39	//! 0.10.0 answered what overlaying means in immediate mode with
40	//! [`Palette::cast`], and nothing could ask: the description had no
41	//! `Depth::Overlay` until `makeover-layout` 0.14.0, so the answer sat beside a
42	//! question that could not be posed. [`frame`] now hands the cast shadow to the
43	//! `egui::Frame` for any depth whose fill is [`Fill::Overlay`], keyed off the
44	//! fill rather than the variant.
45	//!
46	//! The same release brings `makeover_layout::CellPart`, which 0.11.0 carried
47	//! and did not draw. [`table`] draws it, below.
48	//!
49	//! # 0.12.0: the table
50	//!
51	//! [`table`] is the vocabulary 0.11.0 took without using. The consumer is
52	//! audiofiles, whose file list is the only table in the tree exercising all four
53	//! of what the description says about one at once: sortable headings with
54	//! carets, fixed and remainder tracks, and buttons inside cells.
55	//!
56	//! Two things it forces, both named where they land:
57	//!
58	//! - `egui_extras`, this crate's first dependency past egui. egui has no
59	//! table, and `Grid` gives no per-column sizing, no sticky header and no
60	//! scroll sync, which is why audiofiles reached for `egui_extras` rather than
61	//! building on `Grid`. A third answer here would reimplement that crate worse.
62	//! - [`Palette::action`], on the footing [`Palette::content`] arrived on: a
63	//! link in a cell is the first thing here needing the action intent.
64	//!
65	//! Narrowing works differently from the terminal's and the module header says
66	//! why: a content column cannot be measured before the app's closure has drawn
67	//! it, so `egui_extras` sizes it and the declared floor budgets it.
68	//!
69	//! # 0.13.0: what the adoption found missing
70	//!
71	//! 0.12.0 shipped [`table`] before audiofiles had taken it, and taking it found
72	//! three things the file list already did that the function could not say. All
73	//! three are host idiom rather than description, which is why they land here and
74	//! not in `makeover-layout`, and all three are answered on a handle the app
75	//! never sees: the `egui_extras` row and builder this crate owns. That is
76	//! [`table::cell`]'s reasoning again: what the app cannot reach, the renderer
77	//! owes it.
78	//!
79	//! - A selected row. [`table::Body::selected`], a predicate asked per row,
80	//! because `set_selected` is a method on the row. Without it a file list has
81	//! no way to show what is selected, which is most of what a file list does.
82	//! - Scrolling a row into view. [`table::Body::scroll_to`], because
83	//! `scroll_to_row` is a method on the builder. A keyboard cursor that moves
84	//! off-screen and stays there is the bug this prevents.
85	//! - Dragging a divider. [`table::TableStyle::resizable`], which passes the
86	//! test `sticky_header` failed in 0.12.0: egui_extras offers two settings here
87	//! and a renderer can honestly make either choice.
88	//!
89	//! A fourth was found and is not a knob. Cells are centred on the row's centre
90	//! line, always, because there is no second honest answer and egui's own default
91	//! (top-aligned) is the one thing it cannot be.
92	//!
93	//! [`table::Body`] is also what splits a table's per-frame facts from its
94	//! description and from its style. A row count, a selection and a scroll request
95	//! are none of them style, and none of them survive the frame.
96	//!
97	//! # 0.18.0: the nodes that were not fields, tables or frames
98	//!
99	//! [`widget`] draws a meter, a token, a control and a figure. `makeover-tui` has
100	//! had all four for releases and this crate had none of them, which stayed
101	//! invisible while the only consumer was an app calling [`field`] and [`table`]
102	//! directly. It stopped being invisible the moment anything tried to draw a
103	//! whole `quasi_router::Screen` in egui: the four are ordinary nodes, so a
104	//! screen walk would have had to draw them itself, one copy per consumer.
105	//!
106	//! [`Palette`] grows the three status intents with it. They arrive together
107	//! rather than one per widget for the reason [`Palette::fill`] is an `Option`:
108	//! `Tone` is five members wide, and a resolver missing one has to invent a
109	//! colour, which is the substitution 0.2.0 spent a release removing.
110	//!
111	//! # Forms
112	//!
113	//! 0.5.0 adds the field vocabulary on top of the depth vocabulary:
114	//! [`makeover_layout::Field`] rendered to egui widgets, in [`field`], and a set
115	//! of them laid down a column in [`group`]. Before it, a description saying
116	//! "text field, labelled, required, with this hint" had no way to become a
117	//! widget here, and audiofiles' forms stayed hand-rolled.
118	//!
119	//! `makeover-webview` got there first and its form emitter is the precedent
120	//! followed rather than re-derived, including the parts that are bug fixes: a
121	//! select handed a value none of its options carries keeps that value visible
122	//! instead of silently reading as the first option, which is a save-the-wrong-
123	//! thing bug goingson hit for real.
124	//!
125	//! What differs is forced by the mode and not chosen:
126	//!
127	//! - The value arrives as a `&mut`. [`Filling`] borrows the app's own field
128	//! and the widget writes through it. There is no DOM to read back out of,
129	//! which is also why the description deliberately does not carry the value.
130	//! - A text control is drawn as a well and a select is not. The description
131	//! holds that a well is for anything the user looks into, and a text field
132	//! is its own example; a select and a checkbox are pressed rather than looked
133	//! into, so they keep egui's own control painting.
134	//! - Focus is not describable, and egui owns all of it here. Reach,
135	//! focus and the focus ring are this renderer's three answers and
136	//! egui already has all three: its own id stack decides what is reachable,
137	//! its own state decides what holds the keyboard, and it paints exactly one
138	//! ring. A description states none of them — `makeover_layout` removed the
139	//! member that used to try in 0.19.0 — and drawing a second ring on top of
140	//! egui's would break the one-ring rule it would have come from. The terms
141	//! are defined once in `makeover_layout`'s crate header, "Reach, focus and
142	//! the focus ring". [`makeover_layout::State::Disabled`] is drawn, because
143	//! egui has no opinion about it until told.
144	//! - **App-level chrome is not drawn here, and it is not this crate's to
145	//! draw.** `quasi-router` names the affordances that outlive one screen: a
146	//! `Chrome` of key bindings, and an `Outcome::Over` for a screen drawn over
147	//! another. Both are answered by `quasi-webview` and `quasi-tui`, and neither
148	//! is answerable here, because this crate depends on `makeover-layout` and
149	//! not on `quasi-router` — it is the peer of `makeover-webview` and
150	//! `makeover-tui`, one layer below the renderers that consume a `Screen`.
151	//! What is missing is the egui crate at that layer, which does not exist:
152	//! nothing renders a quasi `Screen` in egui at all, and chrome is one item on
153	//! the list such a crate would owe. Said here because this is where a reader
154	//! looks for it, and because the silent version reads as "egui does not need
155	//! a palette" rather than "nobody has built the renderer yet".
156
157	//! # 0.33.0: an interval is a sixth control shape
158	//!
159	//! `makeover-layout` 0.34.0's [`FieldKind::Interval`], drawn as `Control::Spanned`:
160	//! two drag boxes on one row with the word `to` between them.
161	//!
162	//! - Dragged rather than typed, because that is what these controls already
163	//! were. audiofiles' six filter axes are `DragValue` pairs sharing an extent,
164	//! a speed and a suffix, and describing them into two text boxes would be a
165	//! port that cost the app a control.
166	//! - One row, not two wells stacked. Two wells are two questions on screen
167	//! whatever the description says, and the arrangement is the whole content of
168	//! the kind.
169	//! - An empty end reads as the bound it stands for. An unset minimum sits
170	//! on the low edge and stores no filter, which is what the shipped control
171	//! did; egui's `DragValue` has no empty state, and a text box in its place
172	//! would be the regression above. With no extent to fall back on it reads
173	//! zero -- the one number this renderer invents, invented where the
174	//! description declined to say anything.
175	//! - The word rather than a dash, which on a signed axis is a minus sign.
176	//! audiofiles filters loudness in dBFS.
177	//!
178	//! `Axis` holds the four facts both boxes share, because they are one axis:
179	//! reading `min`, `max`, `step` and `unit` once is what stops the two ends
180	//! drifting apart.
181	//!
182	//! # 0.32.0: a number draws its unit
183	//!
184	//! `makeover-layout` 0.33.0's [`Field::unit`], and this host is the one the
185	//! member was argued from: egui's `Slider` already draws a suffix beside its
186	//! readout, which is where these controls put the unit before they were
187	//! described and is somewhere a label cannot reach.
188	//!
189	//! So a slider takes it as a suffix, inside the control. A typed number has no
190	//! readout of its own and takes it as a muted label after the box. Every other
191	//! kind ignores it, and the description says which those are --
192	//! `FieldKind::measurable`, rather than a `matches!` kept here.
193	//!
194	//! # 0.31.0: the slider's track is a curve
195	//!
196	//! `makeover-layout` 0.32.0 says what a slider is: a fraction and a function
197	//! taking numbers to numbers, with `min` and `max` being `f(0)` and `f(1)`
198	//! rather than the control's extent. This host has the easiest job of the
199	//! three, because egui already has the control -- `Slider::logarithmic` is a
200	//! constant-ratio track, so the mapping is a builder call rather than an
201	//! arithmetic of its own.
202	//!
203	//! Two things worth knowing. The granularity moved onto the curve, so a range
204	//! reads `Field::curve.step()` and every other kind still reads `Field::step`;
205	//! the step is in the value's own units under either curve, so the display
206	//! precision is derived exactly as before. And the fallback for a ratio curve
207	//! across zero is asked of `Curve::is_ratio` rather than matched on the
208	//! variant, so this renderer and a terminal cannot disagree about when a
209	//! logarithmic request is honoured.
210	//!
211	//! # 0.28.0: the slider, the unanswered chooser, and the option that is not
212	//! offered yet
213	//!
214	//! Three things `makeover-layout` 0.28.0 lets a description say, all three
215	//! found by audiofiles' forms port hitting a wall it could not describe its way
216	//! past.
217	//!
218	//! - [`FieldKind::Range`] is a fifth control shape, `Control::Slid`, and
219	//! the first one added since 0.5.0. egui has `Slider` and this crate had no
220	//! way to be asked for one, so four sliders in the only consuming app stayed
221	//! hand-rolled against a vocabulary that could not name them. A range missing
222	//! an end falls back to a well rather than to invented bounds, which is what
223	//! `makeover_layout::Field::bounded` is for.
224	//! - `Field::placeholder` finally reads on a chooser. It was sayable and
225	//! this renderer ignored it, so a select with nothing chosen showed an empty
226	//! box. Nothing new is described; the renderer caught up.
227	//! - `Choice::unavailable` is drawn rather than dropped. The option stays
228	//! in the list, inert, with its precondition beside it instead of behind a
229	//! hover — a greyed row with no reason reads as a dead end, which is the
230	//! whole finding.
231	//!
232	//! The value still arrives as a `&mut String` and a slider is a number, so the
233	//! parse and the write-back are this renderer's, and the write happens only on
234	//! a real drag: a value the app put there that this host cannot read survives
235	//! being looked at.
236
237	#![forbid(unsafe_code)]
238
239	use egui::{
240	Color32, ComboBox, CornerRadius, DragValue, Margin, Painter, Rect, Response, RichText, Shape,
241	Slider, Stroke, TextEdit, Ui,
242	};
243	use makeover_layout::{
244	Bevel, Choice, Depth, Edge, Field, FieldKind, Fill, State, ThemeVariant, Tone,
245	};
246	use std::ops::RangeInclusive;
247
248	/// Columns, narrowing, cell parts and the sort caret, over `egui_extras`.
249	pub mod table;
250	pub mod widget;
251
252	/// The resolved colours this renderer needs, as flat values.
253	///
254	/// Built by the app from whatever it already uses to resolve a theme, then
255	/// held and reused. Deliberately not a trait and not string-keyed: a bevel is
256	/// painted per widget per frame, and a map lookup per edge is a cost with
257	/// nothing to show for it.
258	#[derive(Debug, Clone, Copy, PartialEq, Eq)]
259	pub struct Palette {
260	/// `surface-page`.
261	pub page: Color32,
262	/// `surface-raised`.
263	pub raised: Color32,
264	/// `surface-overlay`.
265	pub overlay: Color32,
266	/// `surface-well`.
267	///
268	/// Required, not optional. makeover derives it for every theme from 2.3.0,
269	/// so a resolved palette without a well is not a thing that exists here.
270	/// It was an `Option` while that was untrue, and this renderer substituted
271	/// the page; `makeover-tui` keeps its own `Option` for a different reason,
272	/// since a terminal can have the colour and still be unable to show it.
273	pub well: Color32,
274	/// `surface-sunken`.
275	///
276	/// A surface set back from the one it sits on, by colour and nothing else.
277	/// Not a well: a well is a hole with an edge, and this has no edge. An
278	/// immediate-mode renderer paints an arbitrary rect, so unlike
279	/// `makeover-tui` it has no excuse for declining this one.
280	///
281	/// Required rather than optional, on the same footing as `well`: all 31
282	/// themes makeover embeds author it.
283	pub sunken: Color32,
284	/// `bevel-light`.
285	pub bevel_light: Color32,
286	/// `bevel-dark`.
287	pub bevel_dark: Color32,
288	/// `elevation`.
289	///
290	/// What a surface that floats OVER the page is cast onto it with. The one
291	/// intent here that is about a surface's relationship to the page rather
292	/// than about the surface, which is why it is a translucent near-black on
293	/// every theme rather than something read off the palette's own ramp.
294	///
295	/// Only for a surface that overlays. A menu, a tooltip, a modal. A
296	/// surface in the layout takes a bevel, and reaching for this on a panel
297	/// or a card is how a pre-Platinum look survives a conversion under a new
298	/// name.
299	///
300	/// egui has a real answer for this where a terminal does not: see
301	/// [`Palette::cast`], which is the shadow to hand an
302	/// [`egui::Frame`](egui::Frame).
303	pub elevation: Color32,
304	/// `content`.
305	///
306	/// Ordinary text. Added 0.5.0 with the field renderer, which is the first
307	/// thing here that draws any: until then this crate painted surfaces and
308	/// edges and let the caller's own egui visuals answer for text.
309	pub content: Color32,
310	/// `content-secondary`.
311	///
312	/// Inactive but usable: it still answers a press. The middle tone of the
313	/// three (wiki `three-tone-convention`), and the one an unchosen option in
314	/// a choice field takes. Added 0.26.0 for that widget, which drew every
315	/// option at full `content` and so said nothing about which one was
316	/// chosen beyond the dot egui paints.
317	///
318	/// Not [`content_muted`](Self::content_muted), which carries a claim:
319	/// `State::Disabled` resolves to it, so a live control wearing it tells the
320	/// user it will not answer. `makeover-tui` draws the same widget the same
321	/// way from `makeover-tui@230bf63`.
322	///
323	/// A step of `content` toward the page, derived at load by `makeover`
324	/// rather than authored, so it is read off the resolved theme here like
325	/// any other token and never re-derived.
326	pub content_secondary: Color32,
327	/// `content-muted`.
328	///
329	/// A field's hint, and what
330	/// [`makeover_layout::State::Disabled`](makeover_layout::State::Disabled)
331	/// resolves to. Both readings come from the description rather than from
332	/// here: `State::Disabled` names this intent by token.
333	pub content_muted: Color32,
334	/// `action-primary`.
335	///
336	/// What a control is drawn in. Added 0.12.0 with the table renderer, for the
337	/// reason `content` was added 0.5.0 with the field renderer: a link in a
338	/// cell is the first thing here that needs the action intent, and a palette
339	/// should carry what is used.
340	///
341	/// This is the intent [`CellPart`](makeover_layout::CellPart) exists to
342	/// separate. A cell holding a control took the cell's text colour until the
343	/// description could say otherwise, which is the drift `makeover-layout`
344	/// 0.14.0 named and `makeover-webview` 0.25.0 fixed on its own side.
345	pub action: Color32,
346	/// `danger`.
347	///
348	/// A field's error message, a destructive control, a bar that has run over.
349	pub danger: Color32,
350	/// `success`.
351	///
352	/// Added 0.18.0 with [`widget`], which is the first thing here that draws a
353	/// [`Tone`]. The three status intents arrive together and not one at a
354	/// time: [`Tone`] is five members wide and a resolver missing one has to
355	/// invent a colour for it, which is the substitution this crate spent
356	/// 0.2.0 removing from [`Palette::fill`].
357	pub success: Color32,
358	/// `warning`.
359	pub warning: Color32,
360	/// `info`.
361	pub info: Color32,
362	}
363
364	impl Palette {
365	/// Resolve a surface intent, or `None` for one this renderer does not know.
366	///
367	/// A plain lookup. There is still no substitution: the old one existed only
368	/// while `surface-well` was underived, and every consumer reads the real
369	/// token now.
370	///
371	/// `Option` since 0.3.0, because [`Fill`] became `#[non_exhaustive]` in
372	/// `makeover-layout` 0.4.0 and a total function over an open enum can only
373	/// stay total by inventing a colour for a member it has never heard of.
374	/// That is the substitution this crate spent 0.2.0 removing, so the return
375	/// type moved instead. Every member the description has today is answered
376	/// with `Some`.
377	#[must_use]
378	pub const fn fill(&self, fill: Fill) -> Option<Color32> {
379	match fill {
380	Fill::Page => Some(self.page),
381	Fill::Raised => Some(self.raised),
382	Fill::Overlay => Some(self.overlay),
383	Fill::Well => Some(self.well),
384	Fill::Sunken => Some(self.sunken),
385	_ => None,
386	}
387	}
388
389	/// The colour a [`Tone`] reads as.
390	///
391	/// Total, unlike [`fill`](Self::fill), and the difference is not an
392	/// inconsistency. `Fill` is `#[non_exhaustive]` and `Tone` is not: the
393	/// description layer settled tone at five members and grows surfaces, so a
394	/// total function here cannot be made to invent a colour by an upstream
395	/// release the way a total `fill` could.
396	///
397	/// [`Tone::Neutral`] is [`content`](Self::content) rather than a colour of
398	/// its own, which is what "an ordinary fact" means: a neutral badge is text
399	/// in a box, not a fifth status.
400	#[must_use]
401	pub const fn tone(&self, tone: Tone) -> Color32 {
402	match tone {
403	Tone::Neutral => self.content,
404	Tone::Info => self.info,
405	Tone::Success => self.success,
406	Tone::Warning => self.warning,
407	Tone::Danger => self.danger,
408	}
409	}
410
411	/// The cast shadow for a surface that overlays the page.
412	///
413	/// What "overlaying" means in immediate mode, answered rather than skipped.
414	/// egui already paints shadows for its menus and windows through
415	/// [`egui::Frame::shadow`], so the honest port is to hand that machinery the
416	/// theme's tone instead of egui's own default, not to invent a painter here
417	/// the way [`paint_bevel`] had to.
418	///
419	/// The geometry matches what `makeover-webview` composes, in points rather
420	/// than pixels: a small downward offset and a wide soft blur. A Platinum-era
421	/// menu sits just off the page rather than hovering above it.
422	///
423	/// ```no_run
424	/// # let palette: makeover_immediate::Palette = unimplemented!();
425	/// # let ui: &mut egui::Ui = unimplemented!();
426	/// egui::Frame::popup(ui.style())
427	/// .shadow(palette.cast())
428	/// .show(ui, \|ui\| { ui.label("over the page"); });
429	/// ```
430	#[must_use]
431	pub const fn cast(&self) -> egui::Shadow {
432	egui::Shadow {
433	offset: [0, 2],
434	blur: 24,
435	spread: 0,
436	color: self.elevation,
437	}
438	}
439
440	/// Resolve a bevel edge intent.
441	#[must_use]
442	pub const fn edge(&self, edge: Edge) -> Color32 {
443	match edge {
444	Edge::Light => self.bevel_light,
445	Edge::Dark => self.bevel_dark,
446	}
447	}
448	}
449
450	/// The geometry a framed region is drawn with.
451	///
452	/// Every field is a value, which is why they all arrive from the caller:
453	/// radius and border width belong to `makeover-geometry`, and margins come
454	/// from its relational gaps.
455	#[derive(Debug, Clone, Copy, PartialEq)]
456	pub struct FrameStyle {
457	/// Corner radius. Square under the Platinum default.
458	pub radius: CornerRadius,
459	/// Inner margin between the frame and its contents.
460	pub margin: Margin,
461	/// Bevel stroke width, in points.
462	pub stroke: f32,
463	}
464
465	impl Default for FrameStyle {
466	/// A one-point square frame with no inner margin.
467	fn default() -> Self {
468	Self {
469	radius: CornerRadius::ZERO,
470	margin: Margin::ZERO,
471	stroke: 1.0,
472	}
473	}
474	}
475
476	/// Paint a two-tone edge just inside `rect`.
477	///
478	/// Fill first, bevel after: this adds two polylines and nothing else, so it
479	/// composes over whatever is already there. That is what lets it go over an
480	/// [`egui::TextEdit`] after `ui.add`, where the widget's own fill has landed.
481	///
482	/// Two three-point polylines meeting at opposite corners, rather than four
483	/// segments, so egui mitres the corner joins instead of leaving a notch.
484	///
485	/// The dark polyline is drawn second, so the two corners where the runs meet
486	/// take its tone. That is the right answer here rather than a concession.
487	/// [`makeover_layout::Bevel`] holds those corners to belong to both edges, and
488	/// a renderer with room to divide one should; at the default one-point stroke
489	/// the corner is a one-point square, so the division is sub-pixel and
490	/// antialiasing resolves it to the same blend the mitre already gives. Splitting
491	/// it would add a seam and no information. `makeover-tui` does split, because a
492	/// terminal cell is large enough that not splitting costs a visible cell of edge
493	/// weight — the same rule, at a resolution where it has something to say.
494	pub fn paint_bevel(painter: &Painter, rect: Rect, bevel: Bevel, palette: &Palette, stroke: f32) {
495	let (top_left, bottom_right) = bevel.edges();
496
497	// Inset by half a stroke so the line lands inside `rect` rather than
498	// straddling its edge, which on a fractional-scale display is the
499	// difference between one crisp pixel and two dim ones.
500	let r = rect.shrink(stroke / 2.0);
501
502	painter.add(Shape::line(
503	vec![r.left_bottom(), r.left_top(), r.right_top()],
504	Stroke::new(stroke, palette.edge(top_left)),
505	));
506	painter.add(Shape::line(
507	vec![r.right_top(), r.right_bottom(), r.left_bottom()],
508	Stroke::new(stroke, palette.edge(bottom_right)),
509	));
510	}
511
512	/// Draw a region at a given [`Depth`]: its fill and its edge, together.
513	///
514	/// [`Depth::Flat`] gets neither, and inherits whatever it sits on. That is the
515	/// difference between level-with and painted-the-same-colour, and it is the
516	/// reason `Depth::fill` returns an [`Option`] rather than defaulting to the
517	/// page.
518	pub fn frame<R>(
519	ui: &mut Ui,
520	depth: Depth,
521	palette: &Palette,
522	style: FrameStyle,
523	add_contents: impl FnOnce(&mut Ui) -> R,
524	) -> R {
525	let mut f = egui::Frame::new()
526	.corner_radius(style.radius)
527	.inner_margin(style.margin);
528	// Two ways there is no fill to paint, and they collapse to the same
529	// outcome: the depth names none (Depth::Flat), or it names one this
530	// renderer cannot resolve. Either way the frame goes unfilled and the
531	// bevel below carries the depth on its own, which is the rule this
532	// module already documents for Flat.
533	if let Some(fill) = depth.fill().and_then(\|f\| palette.fill(f)) {
534	f = f.fill(fill);
535	}
536	// A surface that overlays the page is cast onto it. [`Palette::cast`] has
537	// answered what that means here since 0.10.0 and nothing could reach it: a
538	// description had no way to say Overlay until makeover-layout 0.14.0, so
539	// the answer sat beside the question. Keyed off the fill rather than the
540	// variant, so it stays right for whatever else the description calls an
541	// overlay later.
542	if depth.fill() == Some(Fill::Overlay) {
543	f = f.shadow(palette.cast());
544	}
545	let framed = f.show(ui, add_contents);
546	if let Some(bevel) = depth.bevel() {
547	paint_bevel(
548	ui.painter(),
549	framed.response.rect,
550	bevel,
551	palette,
552	style.stroke,
553	);
554	}
555	framed.inner
556	}
557
558	/// The geometry a field group is drawn with.
559	///
560	/// Values again, for the reason [`FrameStyle`] is: every number here belongs to
561	/// `makeover-geometry` and arrives already resolved.
562	#[derive(Debug, Clone, Copy, PartialEq)]
563	pub struct FieldStyle {
564	/// The well a text control sits in.
565	pub frame: FrameStyle,
566	/// Between a field's own parts: its label, its control, its hint and its
567	/// error.
568	pub gap: f32,
569	/// Between one field and the next.
570	pub group_gap: f32,
571	/// What marks a required field, appended to its label.
572	///
573	/// A knob rather than a constant, because it is the one piece of copy in
574	/// this crate and copy is not a renderer's call. A webview does not need it
575	/// at all — it emits the `required` attribute and the browser answers — so
576	/// this renderer is the first place where a compulsory field either shows
577	/// that it is or silently does not.
578	pub required_marker: &'static str,
579	}
580
581	impl Default for FieldStyle {
582	/// The default frame, no gaps, and an asterisk.
583	fn default() -> Self {
584	Self {
585	frame: FrameStyle::default(),
586	gap: 0.0,
587	group_gap: 0.0,
588	required_marker: "*",
589	}
590	}
591	}
592
593	/// What the field currently holds, borrowed from wherever the app keeps it.
594	///
595	/// The immediate-mode counterpart of `makeover_webview::form::Value`, and the
596	/// place the two renderers are forced apart: there the value is read back out
597	/// of the DOM after the fact, and here the widget writes through this borrow as
598	/// it is edited. Same reason the description carries neither.
599	///
600	/// An enum rather than a bag of options, on the reasoning
601	/// `makeover_webview::form::Value` records: a checkbox holding a string is
602	/// unsayable here, where a struct would let it be said and then have to cope.
603	#[derive(Debug, Default)]
604	pub enum Filling<'a> {
605	/// Nothing to edit. The control is drawn and does not answer.
606	#[default]
607	Absent,
608	/// The buffer behind anything that takes typed text, a select included:
609	/// what a select holds is the `value` of one of its [`Choice`]s.
610	///
611	/// [`Choice`]: makeover_layout::Choice
612	Text(&'a mut String),
613	/// A checkbox, on or off.
614	On(&'a mut bool),
615	/// The two buffers behind a [`FieldKind::Interval`], lower first.
616	///
617	/// Two buffers rather than one string with a separator, which is
618	/// [`makeover_layout::Field::upper_name`]'s reason one level down: an
619	/// interval is submitted under two names, so it is edited as two values,
620	/// and a delimiter this crate owned could appear inside either of them.
621	///
622	/// Either end may be empty while the other stands. An open end is an
623	/// answer -- "over 120 BPM" -- rather than a half-filled box.
624	///
625	/// Added 0.33.0 with makeover-layout 0.34.0.
626	Between {
627	/// The lower end's buffer.
628	lower: &'a mut String,
629	/// The upper end's buffer.
630	upper: &'a mut String,
631	},
632	}
633
634	/// The label, marked if the field is compulsory.
635	fn label_text(field: &Field<'_>, style: &FieldStyle) -> String {
636	if field.required {
637	format!("{} {}", field.label, style.required_marker)
638	} else {
639	field.label.to_owned()
640	}
641	}
642
643	/// The four shapes a control comes in here, which is fewer than there are
644	/// kinds.
645	///
646	/// [`FieldKind`] is `#[non_exhaustive]` and grows; this does not, because the
647	/// ways egui has of asking for a value do not. Reducing the open set to this
648	/// closed one in one total function is what keeps a new kind from needing a new
649	/// arm at every match below.
650	#[derive(Debug, Clone, Copy, PartialEq, Eq)]
651	enum Control {
652	/// Typed into, so it is drawn as a well: the user looks into it.
653	Typed,
654	/// Picked from a control that shows one option at a time. Pressed rather
655	/// than looked into, so egui's own control painting stands.
656	Chosen,
657	/// Picked from options that are all on screen at once.
658	///
659	/// Apart from [`Chosen`](Self::Chosen) because the description holds them
660	/// apart, and holding them apart is the whole content of
661	/// [`FieldKind::Radio`]: same question, and an answer the user can read
662	/// without opening anything.
663	Listed,
664	/// Held on or off.
665	Toggled,
666	/// Dragged across an extent that is on screen the whole time.
667	///
668	/// Apart from [`Typed`](Self::Typed) for the reason
669	/// [`FieldKind::Range`] is apart from `Number`: the two ends are what the
670	/// question means, so a well with a figure in it is not a quieter version
671	/// of this control, it is a different one.
672	Slid,
673	/// Picked from a list of themes that arrives grouped and marked.
674	///
675	/// Apart from [`Chosen`](Self::Chosen) rather than folded into it, and the
676	/// distinction is the same one [`Listed`](Self::Listed) draws: it is not a
677	/// different question, it is a different amount of structure on screen. A
678	/// theme picker's rows carry a group heading and a contrast mark, and both
679	/// come from members [`Field::options`] does not have, so a shared arm
680	/// would be a `matches!` on the kind inside the loop rather than one arm
681	/// less.
682	///
683	/// Added with makeover-layout 0.38.0's [`FieldKind::Theme`].
684	Themed,
685	/// Two values dragged across one axis, drawn as one question.
686	///
687	/// Apart from [`Typed`](Self::Typed) for the reason
688	/// [`FieldKind::Interval`] is apart from `Number`: two wells one under the
689	/// other are two questions on screen, whatever the description says, and
690	/// the arrangement is the whole content of the kind.
691	Spanned,
692	}
693
694	/// Which shape a kind takes.
695	///
696	/// The wildcard falls to [`Control::Typed`] on purpose: a kind added to the
697	/// description since this renderer was built degrades to a text box, which
698	/// accepts any value the others would, rather than to nothing drawn at all.
699	///
700	/// `FieldKind::File` lands there as of makeover-layout 0.11.0, and it is left
701	/// there rather than grown a shape of its own. egui's honest answer is a button
702	/// that opens a native picker, which is a fifth control and a file-dialog
703	/// dependency; no consumer of this crate asks for a file field yet. Same
704	/// position this crate took on `Meter` at 0.10.0: the membership test is that
705	/// every renderer could answer honestly, not that each one does on the day.
706	/// A path in a text box is not nothing, and it is what an app that needs this
707	/// tomorrow gets today.
708	///
709	/// makeover-layout 0.31.0 added `Field::accept` and `Field::multiple`, and this
710	/// position is what they land on: both are the picker's arguments, and this
711	/// renderer has no picker to give them to. They are not lost — the description
712	/// still carries them, and the day the native dialog arrives here it is opened
713	/// with them rather than with a filter written twice.
714	///
715	/// `FieldKind::Date` and `FieldKind::DateTime` land there too, as of
716	/// makeover-layout 0.15.0, on the same footing and with one thing owed. A
717	/// calendar is a sixth control and bare `egui` has none, so a typed value is
718	/// the honest answer here; what the app gets is the format the description
719	/// names, `makeover_layout::DATE_FORMAT` and `DATETIME_FORMAT`, which is why
720	/// those are constants rather than a sentence. audiofiles is the only consumer
721	/// of this crate and asks for neither today. A calendar popup is the upgrade
722	/// whenever one does.
723	///
724	/// `Field::as_instant` (makeover-layout 0.37.0) is carried and not honoured, on
725	/// the same footing. It asks for the typed wall-clock value to be submitted as
726	/// the moment it names, and this renderer has no submission to convert on: it
727	/// draws the control and the app reads the value back, so the conversion would
728	/// belong wherever that read happens rather than here. What the app gets is the
729	/// local value in `DATETIME_FORMAT`, which is what it got before the member
730	/// existed. No described site on this host asks for it today.
731	const fn control_shape(kind: FieldKind) -> Control {
732	match kind {
733	FieldKind::Select => Control::Chosen,
734	FieldKind::Radio => Control::Listed,
735	FieldKind::Checkbox => Control::Toggled,
736	FieldKind::Range => Control::Slid,
737	FieldKind::Interval => Control::Spanned,
738	FieldKind::Theme => Control::Themed,
739	_ => Control::Typed,
740	}
741	}
742
743	/// The shape the field actually gets, which is the kind's unless the field is
744	/// missing what that shape needs.
745	///
746	/// One case, and `makeover-layout` names it: a [`FieldKind::Range`] carries its
747	/// extent in [`Field::min`] and [`Field::max`], and a range missing an end has
748	/// nothing to slide across. egui's `Slider` demands a `RangeInclusive`, so
749	/// inventing one would be this renderer picking bounds the app never stated and
750	/// the user then dragging against them.
751	///
752	/// It falls back to [`Control::Typed`], which is where every kind this renderer
753	/// cannot draw natively already lands: a number in a well is a true report of
754	/// the value and takes any answer the slider would.
755	fn shape_of(field: &Field<'_>) -> Control {
756	match control_shape(field.kind) {
757	Control::Slid if !field.bounded() => Control::Typed,
758	shape => shape,
759	}
760	}
761
762	/// The unit to draw beside this field's value, if there is one to draw.
763	///
764	/// Two conditions rather than one: the field has to carry a unit and its kind
765	/// has to be one that means anything by it. `FieldKind::measurable` is the
766	/// description answering the second, so this renderer does not keep its own
767	/// list of which kinds are quantities -- which is the drift that predicate
768	/// exists to stop.
769	fn unit_of<'a>(field: &Field<'a>) -> Option<&'a str> {
770	field.unit.filter(\|_\| field.kind.measurable())
771	}
772
773	/// The two ends of a range, as egui wants them.
774	///
775	/// `None` when either end is missing or is not a number this host can read.
776	/// The description carries the bounds as text on purpose — the bound of a date
777	/// is a date — so parsing them is the renderer's job and failing to is a real
778	/// outcome rather than an assertion.
779	fn extent(field: &Field<'_>) -> Option<RangeInclusive<f64>> {
780	let min = field.min?.parse::<f64>().ok()?;
781	let max = field.max?.parse::<f64>().ok()?;
782	Some(min..=max)
783	}
784
785	/// How many decimals to write a dragged value back with.
786	///
787	/// Read off [`Field::step`], which is the only thing that says what
788	/// granularity the question has: a step of `0.01` is a two-decimal question and
789	/// a step of `1` is a whole-number one. Without a step the host's own
790	/// granularity stands, and egui's is continuous, so the value is written back
791	/// at whatever precision it round-trips at.
792	fn decimals(step: Option<&str>) -> Option<usize> {
793	let step = step?;
794	Some(match step.split_once('.') {
795	Some((_, fraction)) => fraction.trim_end_matches('0').len(),
796	None => 0,
797	})
798	}
799
800	/// What a select shows for the value it currently holds.
801	///
802	/// A value no option carries stays on screen as itself rather than reading as
803	/// whichever option happens to be first. goingson saved a backup retention of
804	/// 10 against a 1/3/7/14/0 list and the browser silently showed it as 1, so the
805	/// next save wrote a value nobody chose; `makeover-webview` grew the fix as a
806	/// stray `<option>` and this is the same fix in the shape egui allows.
807	///
808	/// The empty value is the one case that reads as unanswered rather than as an
809	/// answer, and [`chosen_text`] is what puts the field's ghost text there.
810	fn shown_label<'a>(options: &'a [Choice<'a>], value: &'a str) -> &'a str {
811	options
812	.iter()
813	.find(\|opt\| opt.value == value)
814	.map_or(value, \|opt\| opt.label)
815	}
816
817	/// What a select's closed control reads, and in which tone.
818	///
819	/// A chooser with nothing chosen showed an empty box: `shown_label` falls back
820	/// to the value, and the unanswered value is the empty string. So an app with
821	/// an instruction to give — audiofiles' "Select device..." — had nowhere to put
822	/// it but a disabled button elsewhere on the screen, which is the affordance
823	/// this vocabulary keeps moving messages off.
824	///
825	/// [`Field::placeholder`] is already the description's word for "what the field
826	/// reads while it is empty" and was honoured by the typed kinds alone, so
827	/// nothing new is said here; the renderer is what had not caught up. Muted
828	/// because it is not an answer, the same tone the typed kinds' ghost text takes
829	/// three lines up.
830	///
831	/// A value no option carries but that is not empty stays as itself, in
832	/// `content`: that is the goingson retention bug and it is a wrong answer
833	/// rather than an absent one.
834	///
835	/// Returns the words and the tone rather than a built [`RichText`], because
836	/// what it decides is both of them and only one of them is readable back off a
837	/// `RichText`.
838	///
839	/// [`Field::placeholder`]: makeover_layout::Field::placeholder
840	fn chosen_text<'a>(field: &'a Field<'a>, value: &'a str, palette: &Palette) -> (&'a str, Color32) {
841	match field.placeholder {
842	Some(ghost) if value.is_empty() => (ghost, palette.content_muted),
843	_ => (shown_label(field.options, value), palette.content),
844	}
845	}
846
847	/// What one option in a choice field is drawn in.
848	///
849	/// The chosen one is the emphasised thing and takes `content`; the rest take
850	/// [`content_secondary`](Palette::content_secondary), because an option that is
851	/// not chosen is still an option and pressing it chooses it. Muted would be the
852	/// lie: [`State::Disabled`] resolves to it, so a five-option field read as one
853	/// live row and four dead ones. `makeover-tui` draws it the same way
854	/// (`makeover-tui@230bf63`); wiki `three-tone-convention` is the table.
855	fn option_color(value: &str, option: &str, palette: &Palette) -> Color32 {
856	if value == option {
857	palette.content
858	} else {
859	palette.content_secondary
860	}
861	}
862
863	/// Which end of an interval a box is.
864	///
865	/// Named rather than a bool, because what it selects is not a side but a
866	/// fallback: an empty end reads as the bound it stands for, and which bound
867	/// that is depends on the end.
868	#[derive(Debug, Clone, Copy, PartialEq, Eq)]
869	enum Bound {
870	/// The lower end, falling back to the start of the extent.
871	Low,
872	/// The upper end, falling back to its end.
873	High,
874	}
875
876	/// The facts an interval's two boxes share.
877	///
878	/// One struct because they are one axis: [`Field::min`], [`Field::max`],
879	/// [`Field::step`] and [`Field::unit`] describe the question rather than either
880	/// end of it, so reading them once is what stops the two boxes drifting apart.
881	struct Axis<'a> {
882	/// The extent both ends are dragged inside, when it is one this host can
883	/// read.
884	extent: Option<RangeInclusive<f64>>,
885	/// The granularity, as the description writes it.
886	step: Option<&'a str>,
887	/// What the axis is measured in.
888	unit: Option<&'a str>,
889	}
890
891	impl Axis<'_> {
892	/// What an empty end reads as: the bound it stands for.
893	///
894	/// Zero with no extent to fall back on. That is the one number this
895	/// renderer invents, and it invents it where the description declined to
896	/// say anything: an unbounded interval has no edge for the end to sit on,
897	/// and a drag box has to start somewhere.
898	fn edge(&self, which: Bound) -> f64 {
899	self.extent.as_ref().map_or(0.0, \|extent\| match which {
900	Bound::Low => *extent.start(),
901	Bound::High => *extent.end(),
902	})
903	}
904
905	/// One end of the interval, as a drag box.
906	///
907	/// # An empty end reads as its bound
908	///
909	/// Which is what the shipped control did before it was described: an unset
910	/// minimum sits on the low edge and stores no filter. egui's `DragValue`
911	/// holds a number and has no empty state to offer, so the alternative was a
912	/// text box, and that would cost the app a control on the way into being
913	/// described.
914	///
915	/// With no extent to fall back on, an empty end reads zero. That is the one
916	/// number this renderer invents, and it invents it where the description
917	/// declined to say anything: an unbounded interval has no edge for the end
918	/// to sit on, and a drag box has to start somewhere.
919	///
920	/// Nothing is written back until the user drags, so a value the app put
921	/// there survives being looked at -- the same guarantee the slider makes.
922	fn end(&self, ui: &mut Ui, value: &mut String, which: Bound) -> Response {
923	let mut number = value.parse::<f64>().unwrap_or(self.edge(which));
924	let mut drag = DragValue::new(&mut number);
925	if let Some(extent) = self.extent.clone() {
926	drag = drag.range(extent);
927	}
928	if let Some(places) = decimals(self.step) {
929	drag = drag.max_decimals(places);
930	}
931	if let Some(step) = self.step.and_then(\|s\| s.parse::<f64>().ok()) {
932	drag = drag.speed(step);
933	}
934	// Inside the control, beside the readout, which is where `Field::unit`
935	// was decided to belong and where these boxes already put it.
936	if let Some(unit) = self.unit {
937	drag = drag.suffix(format!(" {unit}"));
938	}
939	let response = ui.add(drag);
940	if response.changed() {
941	*value = match decimals(self.step) {
942	Some(places) => format!("{number:.places$}"),
943	None => number.to_string(),
944	};
945	}
946	response
947	}
948	}
949
950	/// The control alone, without its label, hint or error.
951	fn control(
952	ui: &mut Ui,
953	field: &Field<'_>,
954	filling: Filling<'_>,
955	palette: &Palette,
956	style: &FieldStyle,
957	named_by: Option<egui::Id>,
958	) -> Response {
959	// The mismatch path: described as one thing and filled as another. Nothing
960	// here can fix it, so it is drawn as the empty, inert version of what was
961	// described — visible on screen, in the way an empty select is at the
962	// webview renderer, rather than reported in a log nobody reads.
963	let mut discard = String::new();
964	// The interval's second scratch buffer. Two ends means the mismatch path
965	// needs two places to write nothing to.
966	let mut spare = String::new();
967	let mut off = false;
968
969	match shape_of(field) {
970	Control::Slid => {
971	let value = match filling {
972	Filling::Text(text) => text,
973	_ => &mut discard,
974	};
975	// `shape_of` has already refused an unbounded range, so the extent
976	// is only missing here if a bound is not a number — a date range,
977	// say, which this control cannot draw either.
978	let Some(extent) = extent(field) else {
979	return ui.label(RichText::new(value.as_str()).color(palette.content));
980	};
981
982	// A value the host cannot read starts at the low end rather than at
983	// zero, which may be outside the extent entirely. Nothing is
984	// written back until the user drags, so an unreadable value the app
985	// put there survives being looked at.
986	let mut number = value.parse::<f64>().unwrap_or(*extent.start());
987	// The granularity is the curve's as of makeover-layout 0.32.0. It
988	// is still in the value's own units, so the display precision is
989	// read off it exactly as before.
990	let step = field.curve.step();
991	let mut slider = Slider::new(&mut number, extent.clone()).text("");
992	if let Some(places) = decimals(step) {
993	slider = slider.max_decimals(places);
994	}
995	if let Some(step) = step.and_then(\|s\| s.parse::<f64>().ok()) {
996	slider = slider.step_by(step);
997	}
998	// egui's own constant-ratio track, which is this host's answer to
999	// `Curve::Logarithmic`. `is_ratio` rather than a match on the
1000	// variant, because a ratio across zero is not one: makeover-layout
1001	// decides the fallback so that four renderers cannot disagree about
1002	// when it applies.
1003	if field.curve.is_ratio(extent.start(), extent.end()) {
1004	slider = slider.logarithmic(true);
1005	}
1006	// The unit goes inside the control, beside the readout egui already
1007	// draws. That placement is the argument `Field::unit` was decided
1008	// on: it is where these controls put it before they were described,
1009	// and it is the one a label could never reach.
1010	if let Some(unit) = unit_of(field) {
1011	slider = slider.suffix(format!(" {unit}"));
1012	}
1013	let response = ui.add(slider);
1014	if response.changed() {
1015	*value = match decimals(step) {
1016	Some(places) => format!("{number:.places$}"),
1017	None => number.to_string(),
1018	};
1019	}
1020	response
1021	}
1022	// One question, so one row. Two wells stacked would be two questions on
1023	// screen whatever the description said, which is the reading
1024	// `FieldKind::Interval` exists to prevent.
1025	//
1026	// Dragged rather than typed, because that is what these controls
1027	// already were: audiofiles' six filter axes are `DragValue` pairs with
1028	// a shared extent, a speed and a suffix, and a port that turned them
1029	// into text boxes would be a description costing the app a control.
1030	Control::Spanned => {
1031	let (lower, upper) = match filling {
1032	Filling::Between { lower, upper } => (lower, upper),
1033	_ => (&mut discard, &mut spare),
1034	};
1035	let axis = Axis {
1036	extent: extent(field),
1037	step: field.step,
1038	unit: unit_of(field),
1039	};
1040	ui.horizontal(\|ui\| {
1041	let low = axis.end(ui, lower, Bound::Low);
1042	// The word rather than a dash. A dash between two numbers is a
1043	// minus sign on a signed axis, and audiofiles filters loudness
1044	// in dBFS.
1045	ui.label(RichText::new("to").color(palette.content_secondary));
1046	let high = axis.end(ui, upper, Bound::High);
1047	// Both ends, by name. A union response carries the first id, so
1048	// labelling the union outside this arm names the lower box and
1049	// leaves the upper one announced as whatever number is in it --
1050	// which is how an interval half-kept the fix that gave every
1051	// other shape its question.
1052	if let Some(id) = named_by {
1053	low.clone().labelled_by(id);
1054	high.clone().labelled_by(id);
1055	}
1056	low \| high
1057	})
1058	.inner
1059	}
1060	Control::Typed => {
1061	let text = match filling {
1062	Filling::Text(text) => text,
1063	_ => &mut discard,
1064	};
1065	// An empty frame and no margin: the well is this crate's, and egui's
1066	// own control background and padding would sit underneath it saying
1067	// something different about both.
1068	// Keyed on the description's own `multiline` and not on the
1069	// member: a markdown field is several lines by definition, and a
1070	// single-line edit would be a control the value cannot fit in. egui
1071	// does nothing else with the markdown, which is the honest answer
1072	// rather than a gap -- the source is text, and editing it as text
1073	// loses none of it.
1074	let mut edit = if field.kind.multiline() {
1075	TextEdit::multiline(text)
1076	} else {
1077	TextEdit::singleline(text)
1078	}
1079	.frame(egui::Frame::NONE)
1080	.margin(Margin::ZERO)
1081	.text_color(palette.content)
1082	.password(field.kind.confidential());
1083	if let Some(ghost) = field.placeholder {
1084	edit = edit.hint_text(RichText::new(ghost).color(palette.content_muted));
1085	}
1086	let response = frame(ui, Depth::Well, palette, style.frame, \|ui\| ui.add(edit));
1087	// A typed number has no readout of its own to sit beside, so the
1088	// unit follows the box. Muted, because it is a fact about the value
1089	// rather than a second thing to read.
1090	match unit_of(field) {
1091	Some(unit) => {
1092	ui.label(RichText::new(unit).color(palette.content_muted));
1093	response
1094	}
1095	None => response,
1096	}
1097	}
1098	Control::Toggled => {
1099	let on = match filling {
1100	Filling::On(on) => on,
1101	_ => &mut off,
1102	};
1103	ui.checkbox(on, RichText::new(field.label).color(palette.content))
1104	}
1105	Control::Listed => {
1106	let value = match filling {
1107	Filling::Text(text) => text,
1108	_ => &mut discard,
1109	};
1110	// No `shown_label` counterpart, and none is needed: a value no
1111	// option carries leaves every button unfilled, which is already
1112	// the honest report on screen. The select needs the fix because it
1113	// has one slot and must put something in it.
1114	let group = ui.vertical(\|ui\| {
1115	let mut answered: Option<Response> = None;
1116	for opt in field.options {
1117	// An option that cannot be picked yet is drawn and does not
1118	// answer, with the precondition beside it rather than
1119	// behind a hover: a greyed row with no reason reads as a
1120	// dead end, which is the state `Choice::unavailable` exists
1121	// to stop being sayable.
1122	let picked = if let Some(reason) = opt.unavailable {
1123	ui.horizontal(\|ui\| {
1124	let picked = ui
1125	.add_enabled_ui(false, \|ui\| {
1126	ui.radio_value(
1127	value,
1128	opt.value.to_owned(),
1129	RichText::new(opt.label).color(palette.content_muted),
1130	)
1131	})
1132	.inner;
1133	ui.label(RichText::new(reason).color(palette.content_muted));
1134	picked
1135	})
1136	.inner
1137	} else {
1138	ui.radio_value(
1139	value,
1140	opt.value.to_owned(),
1141	RichText::new(opt.label).color(option_color(value, opt.value, palette)),
1142	)
1143	};
1144	answered = Some(match answered {
1145	Some(prev) => prev.union(picked),
1146	None => picked,
1147	});
1148	}
1149	answered
1150	});
1151	// A group described with no options answers as its own empty area
1152	// rather than as no response at all, which keeps the caller's
1153	// `.changed()` chain working on a field whose option list has not
1154	// loaded yet.
1155	group.inner.unwrap_or(group.response)
1156	}
1157	Control::Chosen => {
1158	let value = match filling {
1159	Filling::Text(text) => text,
1160	_ => &mut discard,
1161	};
1162	let (shown, tone) = chosen_text(field, value, palette);
1163	ComboBox::from_id_salt(field.name)
1164	.selected_text(RichText::new(shown).color(tone))
1165	.show_ui(ui, \|ui\| {
1166	for opt in field.options {
1167	// Same rule as the radio group: shown, inert, and
1168	// saying why. A closed control hides its list, so the
1169	// reason has to travel with the row it belongs to.
1170	if let Some(reason) = opt.unavailable {
1171	ui.add_enabled_ui(false, \|ui\| {
1172	ui.selectable_value(
1173	value,
1174	opt.value.to_owned(),
1175	RichText::new(format!("{} {reason}", opt.label))
1176	.color(palette.content_muted),
1177	);
1178	});
1179	continue;
1180	}
1181	ui.selectable_value(
1182	value,
1183	opt.value.to_owned(),
1184	RichText::new(opt.label).color(option_color(value, opt.value, palette)),
1185	);
1186	}
1187	})
1188	.response
1189	}
1190	// The grouping comes out of the order rather than out of a group list:
1191	// `Field::themes` arrives sorted by variant, so the run of one variant
1192	// is the group and a heading opens whenever the variant changes. Same
1193	// walk as `makeover-webview`'s `<optgroup>` emission, which is what
1194	// keeps two renderers from disagreeing about where a group starts.
1195	Control::Themed => {
1196	let value = match filling {
1197	Filling::Text(text) => text,
1198	_ => &mut discard,
1199	};
1200	let shown = themed_text(field, value);
1201	ComboBox::from_id_salt(field.name)
1202	.selected_text(RichText::new(shown).color(palette.content))
1203	.show_ui(ui, \|ui\| {
1204	if let Some(follow) = field.follows {
1205	// First and outside every heading. It names no theme
1206	// and sits in no variant, so a heading over it would be
1207	// inventing a fourth variant for one row.
1208	ui.selectable_value(
1209	value,
1210	follow.value.to_owned(),
1211	RichText::new(follow.label).color(option_color(
1212	value,
1213	follow.value,
1214	palette,
1215	)),
1216	);
1217	}
1218	let mut open: Option<ThemeVariant> = None;
1219	for theme in field.themes {
1220	if open != Some(theme.variant) {
1221	// A heading rather than a `selectable_value`: it is
1222	// not pickable, and egui has no inert row that
1223	// still reads as a row. `content_muted` is the tone
1224	// for something that is not an answer, which is the
1225	// ghost text's tone eight lines up.
1226	if open.is_some() {
1227	ui.separator();
1228	}
1229	ui.label(
1230	RichText::new(theme.variant.heading()).color(palette.content_muted),
1231	);
1232	open = Some(theme.variant);
1233	}
1234	ui.selectable_value(
1235	value,
1236	theme.id.to_owned(),
1237	RichText::new(format!("{} {}", theme.name, theme.contrast.badge()))
1238	.color(option_color(value, theme.id, palette)),
1239	);
1240	}
1241	})
1242	.response
1243	}
1244	}
1245	}
1246
1247	/// What a theme picker's closed control reads.
1248	///
1249	/// [`chosen_text`]'s counterpart, and it is separate for the reason
1250	/// [`Control::Themed`] is: the label lives on a [`makeover_layout::ThemeChoice`]
1251	/// rather than on a [`Choice`], and the follow row is a third place to look.
1252	///
1253	/// No placeholder arm. A theme picker is never unanswered in the way a select
1254	/// is — an app that resolved a theme to paint this control with has one — and
1255	/// falling back to the raw value is the honest report on a stored id whose
1256	/// theme has since been deleted.
1257	fn themed_text<'a>(field: &'a Field<'a>, value: &'a str) -> &'a str {
1258	if let Some(follow) = field.follows
1259	&& follow.value == value
1260	{
1261	return follow.label;
1262	}
1263	field
1264	.themes
1265	.iter()
1266	.find(\|theme\| theme.id == value)
1267	.map_or(value, \|theme\| theme.name)
1268	}
1269
1270	/// One field, as the column the app drops into its form.
1271	///
1272	/// The anatomy is `makeover-webview`'s, so the two renderers put a form
1273	/// together the same way: label, control, hint, error, top to bottom, with a
1274	/// checkbox labelling itself instead of taking a label above.
1275	///
1276	/// Returns [`None`] for a [`FieldKind::Hidden`] field, which is what
1277	/// [`FieldKind::visible`] means and is the honest answer here: a webview still
1278	/// emits an input for it because the form submits, and an immediate-mode
1279	/// renderer has no form and no submission, so a hidden field is a value the app
1280	/// already holds and there is nothing to draw or to respond to.
1281	///
1282	/// `state` is the description's interaction axis.
1283	/// [`State::Disabled`] greys the field and stops it answering, through
1284	/// [`State::suppresses_interaction`] rather than through a second reading of
1285	/// what disabled means. Focus is not on that axis and never reaches here: egui
1286	/// owns reach, focus and the ring for this renderer, and one ring means not a
1287	/// second one per renderer that happens to have opinions.
1288	pub fn field(
1289	ui: &mut Ui,
1290	field: &Field<'_>,
1291	filling: Filling<'_>,
1292	state: Option<State>,
1293	palette: &Palette,
1294	style: &FieldStyle,
1295	) -> Option<Response> {
1296	if !field.kind.visible() {
1297	return None;
1298	}
1299	let enabled = !state.is_some_and(State::suppresses_interaction);
1300	let text = if enabled {
1301	palette.content
1302	} else {
1303	palette.content_muted
1304	};
1305
1306	let response = ui
1307	.vertical(\|ui\| {
1308	ui.spacing_mut().item_spacing.y = style.gap;
1309
1310	// A checkbox labels itself, on the right of the box.
1311	// `FieldKind::labels_itself` is the description saying so, and both
1312	// webview apps special-cased it inline before it did.
1313	let named_by = (!field.kind.labels_itself())
1314	.then(\|\| ui.label(RichText::new(label_text(field, style)).color(text)));
1315
1316	let response = ui
1317	.add_enabled_ui(enabled, \|ui\| {
1318	control(
1319	ui,
1320	field,
1321	filling,
1322	palette,
1323	style,
1324	named_by.as_ref().map(\|l\| l.id),
1325	)
1326	})
1327	.inner;
1328
1329	// The label, attached rather than merely adjacent.
1330	//
1331	// Drawing it above the control and stopping there is what this did
1332	// until 2026-08-22, and it put an unnamed box in the accessibility
1333	// tree with some text near it: a screen reader announced a text
1334	// field with no question, and a prefilled one announced its own
1335	// contents instead. audiofiles' four name modals were the site that
1336	// measured it, through a harness reading what the panel drew.
1337	//
1338	// Worth stating why it was worth fixing here rather than in each
1339	// app: `Field::label` is a member the description carries so a
1340	// renderer does not have to guess, `makeover-webview` has always
1341	// named it in `aria-describedby`, and the two renderers disagreeing
1342	// about a fact the description states is the one thing this layer
1343	// exists to prevent. A checkbox is unaffected -- egui names one from
1344	// its own text, which is what `labels_itself` already says.
1345	let response = match named_by {
1346	Some(label) => response.labelled_by(label.id),
1347	None => response,
1348	};
1349
1350	// Standing help, then what the answer costs, then what is wrong
1351	// now. All three, in that order, for the reason the webview
1352	// renderer names all three in `aria-describedby`: an error
1353	// appearing must not take the hint away with it. This host has the
1354	// room, so unlike makeover-tui it never has to choose -- the
1355	// precedence rule on `Field::note` is for the renderer that does.
1356	if let Some(hint) = field.hint {
1357	ui.label(RichText::new(hint).color(palette.content_muted));
1358	}
1359	// The note carries its own tone, and `Palette::tone` is what
1360	// resolves it, so a Neutral note is ordinary content rather than
1361	// a colour this renderer picked.
1362	if let Some((tone, note)) = field.note {
1363	ui.label(RichText::new(note).color(palette.tone(tone)));
1364	}
1365	if let Some(error) = field.error {
1366	ui.label(RichText::new(error).color(palette.danger));
1367	}
1368	response
1369	})
1370	.inner;
1371
1372	Some(response)
1373	}
1374
1375	/// A set of fields, laid down a column.
1376	///
1377	/// `show_extended` is the disclosure, and it is a parameter rather than state
1378	/// held here because the disclosure belongs to the form and not to any field:
1379	/// [`Field::extended`] marks which fields are behind one, and the app owns
1380	/// whether it is open. That is the same division `makeover-webview` draws when
1381	/// it marks the group `data-extended` and emits no control to toggle it.
1382	///
1383	/// `draw` is called once per field that should be visible, in order. Taking a
1384	/// callback rather than a slice of [`Filling`]s is what keeps the app's own
1385	/// values borrowed one at a time: a form's fields usually live in different
1386	/// structs, and a parallel array would have to be built each frame and kept in
1387	/// step with the description by hand.
1388	pub fn group<'a>(
1389	ui: &mut Ui,
1390	fields: &'a [Field<'a>],
1391	show_extended: bool,
1392	style: &FieldStyle,
1393	mut draw: impl FnMut(&mut Ui, &'a Field<'a>),
1394	) {
1395	ui.vertical(\|ui\| {
1396	ui.spacing_mut().item_spacing.y = style.group_gap;
1397	for f in fields {
1398	if f.extended && !show_extended {
1399	continue;
1400	}
1401	draw(ui, f);
1402	}
1403	});
1404	}
1405
1406	#[cfg(test)]
1407	mod tests {
1408	use super::*;
1409
1410	fn palette(well: Color32) -> Palette {
1411	Palette {
1412	page: Color32::from_rgb(1, 1, 1),
1413	raised: Color32::from_rgb(2, 2, 2),
1414	overlay: Color32::from_rgb(3, 3, 3),
1415	well,
1416	sunken: Color32::from_rgb(4, 4, 4),
1417	bevel_light: Color32::WHITE,
1418	bevel_dark: Color32::BLACK,
1419	elevation: Color32::from_black_alpha(46),
1420	content: Color32::from_rgb(5, 5, 5),
1421	content_secondary: Color32::from_rgb(55, 55, 55),
1422	content_muted: Color32::from_rgb(6, 6, 6),
1423	action: Color32::from_rgb(7, 7, 7),
1424	danger: Color32::from_rgb(8, 8, 8),
1425	success: Color32::from_rgb(9, 9, 9),
1426	warning: Color32::from_rgb(10, 10, 10),
1427	info: Color32::from_rgb(11, 11, 11),
1428	}
1429	}
1430
1431	/// The cast is egui's own shadow type carrying the theme's tone, which is
1432	/// the whole of what this crate had to decide for it: unlike a bevel, egui
1433	/// already knows how to paint one.
1434	#[test]
1435	fn a_unit_is_drawn_only_where_the_kind_is_a_quantity() {
1436	// egui-drawing has no harness here, so what is tested is the decision
1437	// that precedes it: which fields have a unit to draw at all. The kind
1438	// half comes from the description rather than from a `matches!` in this
1439	// crate, which is the drift `FieldKind::measurable` exists to stop.
1440	let ranged = makeover_layout::Field {
1441	unit: Some("s"),
1442	..makeover_layout::Field::range("attack", "Attack", "0", "5")
1443	};
1444	assert_eq!(unit_of(&ranged), Some("s"));
1445
1446	let typed = makeover_layout::Field {
1447	unit: Some("ms"),
1448	..makeover_layout::Field::new(makeover_layout::FieldKind::Number, "fade", "Fade")
1449	};
1450	assert_eq!(unit_of(&typed), Some("ms"));
1451
1452	let worded = makeover_layout::Field {
1453	unit: Some("s"),
1454	..makeover_layout::Field::new(makeover_layout::FieldKind::Text, "name", "Name")
1455	};
1456	assert_eq!(unit_of(&worded), None);
1457
1458	let bare = makeover_layout::Field::range("attack", "Attack", "0", "5");
1459	assert_eq!(unit_of(&bare), None);
1460	}
1461
1462	#[test]
1463	fn the_cast_hands_egui_the_themes_tone() {
1464	let p = palette(Color32::from_rgb(9, 9, 9));
1465	let cast = p.cast();
1466	assert_eq!(cast.color, p.elevation);
1467	assert!(cast.blur > 0, "a cast shadow is soft");
1468	assert_eq!(cast.offset, [0, 2], "it falls downward and only a little");
1469	}
1470
1471	#[test]
1472	fn a_well_resolves_to_its_own_token() {
1473	// No substitution left. The page-filled well was a stand-in for a
1474	// token that did not exist yet; it exists now.
1475	let w = Color32::from_rgb(9, 9, 9);
1476	let p = palette(w);
1477	assert_eq!(p.fill(Fill::Well), Some(w));
1478	assert_ne!(p.fill(Fill::Well), Some(p.page));
1479	}
1480
1481	#[test]
1482	fn every_intent_is_a_plain_lookup() {
1483	let p = palette(Color32::from_rgb(9, 9, 9));
1484	assert_eq!(p.fill(Fill::Page), Some(p.page));
1485	assert_eq!(p.fill(Fill::Raised), Some(p.raised));
1486	assert_eq!(p.fill(Fill::Overlay), Some(p.overlay));
1487	}
1488
1489	/// Sunken is its own colour, not the well's and not the page's. The two
1490	/// are authored in opposite directions and an earlier cut of the
1491	/// description conflated them.
1492	#[test]
1493	fn sunken_is_neither_the_well_nor_the_page() {
1494	let p = palette(Color32::from_rgb(9, 9, 9));
1495	assert_eq!(p.fill(Fill::Sunken), Some(p.sunken));
1496	assert_ne!(p.fill(Fill::Sunken), p.fill(Fill::Well));
1497	assert_ne!(p.fill(Fill::Sunken), p.fill(Fill::Page));
1498	}
1499
1500	#[test]
1501	fn a_raised_region_never_resolves_to_the_well_fill() {
1502	// The cross-app bug, asserted at the renderer boundary this time.
1503	let p = palette(Color32::from_rgb(9, 9, 9));
1504	let raised = Depth::Raised.fill().and_then(\|f\| p.fill(f));
1505	let well = Depth::Well.fill().and_then(\|f\| p.fill(f));
1506	assert_eq!(raised, Some(p.raised));
1507	assert_ne!(raised, well);
1508	}
1509
1510	#[test]
1511	fn an_overlay_is_cast_onto_the_page_and_takes_no_edge() {
1512	// makeover-layout 0.14.0 is what made this reachable. The answer was
1513	// already here at 0.10.0 and the question could not be asked.
1514	let p = palette(Color32::from_rgb(9, 9, 9));
1515	assert_eq!(
1516	Depth::Overlay.fill().and_then(\|f\| p.fill(f)),
1517	Some(p.overlay)
1518	);
1519	assert_eq!(Depth::Overlay.bevel(), None);
1520	// The shadow `frame` reaches for is the theme's tone rather than
1521	// egui's default, which is the whole reason `cast` exists.
1522	assert_eq!(p.cast().color, p.elevation);
1523	}
1524
1525	#[test]
1526	fn the_lit_edge_swaps_when_a_card_is_pressed() {
1527	let p = palette(Color32::from_rgb(9, 9, 9));
1528	let (tl, _) = Depth::Raised.bevel().unwrap().edges();
1529	let (ptl, _) = Depth::Raised.pressed().bevel().unwrap().edges();
1530	assert_eq!(p.edge(tl), p.bevel_light);
1531	assert_eq!(p.edge(ptl), p.bevel_dark);
1532	}
1533
1534	#[test]
1535	fn flat_asks_for_neither_fill_nor_edge() {
1536	assert!(Depth::Flat.fill().is_none());
1537	assert!(Depth::Flat.bevel().is_none());
1538	}
1539
1540	#[test]
1541	fn a_select_keeps_a_value_none_of_its_options_carries() {
1542	// The save-the-wrong-thing bug, asserted at the second renderer so it
1543	// is not re-found there. goingson's own numbers.
1544	let options = [
1545	Choice::plain("1"),
1546	Choice::plain("3"),
1547	Choice::plain("7"),
1548	Choice::plain("14"),
1549	];
1550	assert_eq!(shown_label(&options, "10"), "10");
1551	// And a value that does match reads as its label, not as itself.
1552	let spelled = [Choice::new("7", "One week")];
1553	assert_eq!(shown_label(&spelled, "7"), "One week");
1554	}
1555
1556	#[test]
1557	fn an_unanswered_chooser_reads_its_ghost_text_and_reads_it_muted() {
1558	let p = palette(Color32::from_rgb(9, 9, 9));
1559	let options = [Choice::new("sp404", "SP-404")];
1560	let field = Field {
1561	placeholder: Some("Select device..."),
1562	..Field::select("device", "Conform for device", &options)
1563	};
1564
1565	assert_eq!(
1566	chosen_text(&field, "", &p),
1567	("Select device...", p.content_muted),
1568	"ghost text is not an answer, so it takes the tone the typed kinds' ghost text does"
1569	);
1570
1571	// Answered, and it is the label that reads rather than the value.
1572	assert_eq!(chosen_text(&field, "sp404", &p), ("SP-404", p.content));
1573	}
1574
1575	#[test]
1576	fn a_wrong_answer_is_not_an_absent_one() {
1577	// The retention-10 bug and the ghost text meet here: a value no option
1578	// carries still reads as itself, because the field IS answered and the
1579	// answer is wrong. Only the empty value is unanswered.
1580	let p = palette(Color32::from_rgb(9, 9, 9));
1581	let options = [Choice::plain("1"), Choice::plain("7")];
1582	let field = Field {
1583	placeholder: Some("Pick one"),
1584	..Field::select("retention", "Keep backups for", &options)
1585	};
1586
1587	assert_eq!(chosen_text(&field, "10", &p), ("10", p.content));
1588	}
1589
1590	#[test]
1591	fn a_chooser_with_no_ghost_text_is_unchanged() {
1592	// The whole change is opt-in from the description. A field that says
1593	// nothing about its empty state still shows an empty box.
1594	let p = palette(Color32::from_rgb(9, 9, 9));
1595	let options = [Choice::plain("1")];
1596	let field = Field::select("retention", "Keep backups for", &options);
1597	assert_eq!(chosen_text(&field, "", &p), ("", p.content));
1598	}
1599
1600	#[test]
1601	fn a_range_is_slid_and_a_number_is_typed_into() {
1602	// The distinction the kind was added for, at the renderer that has to
1603	// act on it. A well with a figure in it is not a quiet slider.
1604	assert_eq!(control_shape(FieldKind::Range), Control::Slid);
1605	assert_eq!(control_shape(FieldKind::Number), Control::Typed);
1606	}
1607
1608	#[test]
1609	fn a_range_missing_an_end_falls_back_to_a_well() {
1610	// egui's `Slider` demands both ends, so inventing one would be this
1611	// renderer picking bounds the app never stated and the user then
1612	// dragging against them. A typed number takes every answer the slider
1613	// would.
1614	let whole = Field::range("review", "Review above", "0", "1");
1615	assert_eq!(shape_of(&whole), Control::Slid);
1616
1617	let half = Field {
1618	max: Some("1"),
1619	..Field::new(FieldKind::Range, "review", "Review above")
1620	};
1621	assert_eq!(shape_of(&half), Control::Typed);
1622	assert_eq!(extent(&half), None);
1623
1624	// A bound this host cannot read is the same outcome by a different
1625	// route: the description carries bounds as text because the bound of a
1626	// date is a date.
1627	let dated = Field::range("when", "When", "2026-08-01", "2026-08-31");
1628	assert_eq!(extent(&dated), None);
1629	}
1630
1631	#[test]
1632	fn an_interval_is_its_own_shape_and_not_two_numbers() {
1633	// The distinction the kind was added for, at the renderer that has to
1634	// arrange it: two wells stacked are two questions on screen, whatever
1635	// the description says.
1636	assert_eq!(control_shape(FieldKind::Interval), Control::Spanned);
1637	assert_eq!(shape_of(&Field::interval("a", "b", "A")), Control::Spanned);
1638
1639	// Unlike a range, it owes no extent: its bounds are a rule on each end
1640	// rather than the control, so a missing one is an open end.
1641	let axis = Field {
1642	min: Some("0"),
1643	max: Some("300"),
1644	..Field::interval("bpm_min", "bpm_max", "BPM")
1645	};
1646	assert_eq!(shape_of(&axis), Control::Spanned);
1647	}
1648
1649	#[test]
1650	fn an_empty_end_reads_as_the_bound_it_stands_for() {
1651	// Which is what the shipped control did before it was described: an
1652	// unset minimum sits on the low edge and stores no filter. `DragValue`
1653	// has no empty state, and a text box instead would cost the app a
1654	// control on the way into being described.
1655	let axis = Axis {
1656	extent: Some(0.0..=300.0),
1657	step: Some("1"),
1658	unit: Some("BPM"),
1659	};
1660	assert!((axis.edge(Bound::Low) - 0.0).abs() < f64::EPSILON);
1661	assert!((axis.edge(Bound::High) - 300.0).abs() < f64::EPSILON);
1662
1663	// With no extent there is no edge to sit on, and a drag box has to
1664	// start somewhere. The one number this renderer invents, invented where
1665	// the description declined to say anything.
1666	let open = Axis {
1667	extent: None,
1668	step: None,
1669	unit: None,
1670	};
1671	assert!((open.edge(Bound::Low) - 0.0).abs() < f64::EPSILON);
1672	assert!((open.edge(Bound::High) - 0.0).abs() < f64::EPSILON);
1673	}
1674
1675	#[test]
1676	fn the_step_decides_how_a_dragged_value_is_written_back() {
1677	// Without it a 0-to-1 threshold writes back whatever float the drag
1678	// landed on, which is the host's granularity and is what the
1679	// description says an absent step means.
1680	assert_eq!(decimals(None), None);
1681	assert_eq!(decimals(Some("1")), Some(0));
1682	assert_eq!(decimals(Some("0.01")), Some(2));
1683	// Trailing zeros are not precision: 0.10 is a one-decimal question.
1684	assert_eq!(decimals(Some("0.10")), Some(1));
1685	}
1686
1687	#[test]
1688	fn an_unavailable_option_is_drawn_muted_rather_than_dropped() {
1689	// The tone rule, at the one place it is a claim rather than a
1690	// preference: this option genuinely will not answer, so muted is the
1691	// truth. The available ones beside it keep the secondary intent.
1692	let p = palette(Color32::from_rgb(9, 9, 9));
1693	let options = [
1694	Choice::new("chromatic", "Chromatic"),
1695	Choice::new("multi", "Multi-sample").unless("Drop a second sample."),
1696	];
1697	assert!(options[0].available());
1698	assert!(!options[1].available());
1699	assert_eq!(
1700	option_color("chromatic", options[0].value, &p),
1701	p.content,
1702	"the chosen option is the emphasised thing"
1703	);
1704	assert_eq!(
1705	option_color("chromatic", options[1].value, &p),
1706	p.content_secondary,
1707	"and `option_color` never mutes: the unavailable path is what does"
1708	);
1709	}
1710
1711	#[test]
1712	fn only_a_required_field_is_marked() {
1713	let style = FieldStyle::default();
1714	let plain = Field::new(FieldKind::Text, "title", "Title");
1715	assert_eq!(label_text(&plain, &style), "Title");
1716
1717	let required = Field {
1718	required: true,
1719	..plain
1720	};
1721	assert_eq!(label_text(&required, &style), "Title *");
1722
1723	// The marker is copy and the app owns it, which is why it is a knob.
1724	let house = FieldStyle {
1725	required_marker: "(required)",
1726	..style
1727	};
1728	assert_eq!(label_text(&required, &house), "Title (required)");
1729	}
1730
1731	#[test]
1732	fn a_select_and_a_checkbox_are_pressed_and_everything_else_is_typed_into() {
1733	// What decides whether the control gets a well. A well is for what the
1734	// user looks into, and only one of these is.
1735	assert_eq!(control_shape(FieldKind::Select), Control::Chosen);
1736	// Not the wildcard. A theme picker falling to `Control::Typed` would
1737	// draw a text box over a resolved list, which is worse than the select
1738	// every app had before the member existed.
1739	assert_eq!(control_shape(FieldKind::Theme), Control::Themed);
1740	assert_eq!(control_shape(FieldKind::Radio), Control::Listed);
1741	assert_eq!(control_shape(FieldKind::Checkbox), Control::Toggled);
1742	for k in [
1743	FieldKind::Text,
1744	FieldKind::Secret,
1745	FieldKind::Number,
1746	FieldKind::Email,
1747	FieldKind::Url,
1748	FieldKind::Tel,
1749	FieldKind::Textarea,
1750	FieldKind::Rich,
1751	] {
1752	assert_eq!(control_shape(k), Control::Typed, "{k:?} is typed into");
1753	}
1754	// And the two multi-line ones get a multi-line edit, which is the half
1755	// `control_shape` alone does not say: both are typed into, and only one
1756	// of the two edit shapes can hold a markdown document.
1757	assert!(FieldKind::Rich.multiline());
1758	assert!(FieldKind::Textarea.multiline());
1759	assert!(!FieldKind::Text.multiline());
1760	}
1761
1762	#[test]
1763	fn the_two_option_taking_kinds_are_drawn_differently_on_purpose() {
1764	// The description holds Select and Radio apart, and a renderer that
1765	// collapsed them would silently answer a question the app did not ask:
1766	// audiofiles' storage style is irreversible and its alternatives have
1767	// to be readable without opening anything. Asserting the two shapes
1768	// differ is asserting that distinction survives the trip.
1769	assert!(FieldKind::Select.offers_options());
1770	assert!(FieldKind::Radio.offers_options());
1771	assert_ne!(
1772	control_shape(FieldKind::Select),
1773	control_shape(FieldKind::Radio)
1774	);
1775	}
1776
1777	#[test]
1778	fn an_unchosen_option_is_secondary_and_never_muted() {
1779	let p = palette(Color32::from_rgb(4, 4, 4));
1780	assert_eq!(option_color("wav", "wav", &p), p.content);
1781	assert_eq!(option_color("wav", "aiff", &p), p.content_secondary);
1782	// The whole point of the distinction: muted is what Disabled resolves
1783	// to, so an option wearing it would claim it does not answer a press.
1784	assert_ne!(option_color("wav", "aiff", &p), p.content_muted);
1785	}
1786
1787	/// What the accessibility tree says a screen drew, as `(role, name)` pairs.
1788	///
1789	/// egui builds this from the same `WidgetInfo` every widget already reports,
1790	/// so it is what a screen reader would be handed rather than a second
1791	/// opinion about it. A name that arrives through `labelled_by` is resolved
1792	/// the way a client resolves it: the relation names another node, and that
1793	/// node's text is the control's accessible name.
1794	fn announced(draw: impl FnMut(&mut egui::Ui)) -> Vec<(egui::accesskit::Role, String)> {
1795	let ctx = egui::Context::default();
1796	ctx.enable_accesskit();
1797	let mut draw = draw;
1798	let input = \|\| egui::RawInput {
1799	screen_rect: Some(egui::Rect::from_min_size(
1800	egui::Pos2::ZERO,
1801	egui::vec2(800.0, 600.0),
1802	)),
1803	..Default::default()
1804	};
1805	// Two passes: egui lays out against the previous frame, so the first
1806	// sees widgets at the wrong rect.
1807	let _ = ctx.run_ui(input(), &mut draw);
1808	let out = ctx.run_ui(input(), &mut draw);
1809
1810	let update = out
1811	.platform_output
1812	.accesskit_update
1813	.expect("accesskit is on, so a tree was built");
1814	let by_id: std::collections::HashMap<_, _> = update.nodes.iter().cloned().collect();
1815	update
1816	.nodes
1817	.iter()
1818	.map(\|(_, node)\| {
1819	let named = node.label().map(str::to_owned).or_else(\|\| {
1820	node.labelled_by()
1821	.iter()
1822	.find_map(\|id\| by_id.get(id))
1823	.and_then(\|by\| by.label().or_else(\|\| by.value()).map(str::to_owned))
1824	});
1825	(node.role(), named.unwrap_or_default())
1826	})
1827	.collect()
1828	}
1829
1830	#[test]
1831	fn a_fields_label_names_its_control_rather_than_sitting_beside_it() {
1832	let f = Field::new(FieldKind::Text, "name", "Vault name");
1833	let p = palette(Color32::from_rgb(9, 9, 9));
1834	let drawn = announced(\|ui\| {
1835	let mut text = String::new();
1836	field(
1837	ui,
1838	&f,
1839	Filling::Text(&mut text),
1840	None,
1841	&p,
1842	&FieldStyle::default(),
1843	);
1844	});
1845
1846	let box_ = drawn
1847	.iter()
1848	.find(\|(role, _)\| *role == egui::accesskit::Role::TextInput)
1849	.expect("a text field draws a text input");
1850	assert_eq!(
1851	box_.1, "Vault name",
1852	"the box is announced by the question rather than unnamed: {drawn:?}"
1853	);
1854	}
1855
1856	#[test]
1857	fn a_prefilled_box_is_still_announced_by_its_question() {
1858	// The sharper half. With nothing attached, a box carrying a value is
1859	// announced as that value, so a rename field read out the name it was
1860	// seeded with and never said what was being asked.
1861	let f = Field::new(FieldKind::Text, "name", "New name");
1862	let p = palette(Color32::from_rgb(9, 9, 9));
1863	let drawn = announced(\|ui\| {
1864	let mut text = String::from("Drums");
1865	field(
1866	ui,
1867	&f,
1868	Filling::Text(&mut text),
1869	None,
1870	&p,
1871	&FieldStyle::default(),
1872	);
1873	});
1874
1875	let box_ = drawn
1876	.iter()
1877	.find(\|(role, _)\| *role == egui::accesskit::Role::TextInput)
1878	.expect("a text field draws a text input");
1879	assert_eq!(box_.1, "New name", "{drawn:?}");
1880	}
1881
1882	#[test]
1883	fn both_ends_of_an_interval_are_named_by_the_one_question() {
1884	// A union response carries the first id, so labelling the pair outside
1885	// the arm named the lower box and left the upper one announced as
1886	// whatever number was in it.
1887	let f = Field::new(FieldKind::Interval, "bpm", "BPM Range");
1888	let p = palette(Color32::from_rgb(9, 9, 9));
1889	let drawn = announced(\|ui\| {
1890	let mut lower = String::from("90");
1891	let mut upper = String::from("300");
1892	field(
1893	ui,
1894	&f,
1895	Filling::Between {
1896	lower: &mut lower,
1897	upper: &mut upper,
1898	},
1899	None,
1900	&p,
1901	&FieldStyle::default(),
1902	);
1903	});
1904
1905	// A `SpinButton`: an interval's ends are drag values, not text boxes.
1906	let ends: Vec<_> = drawn
1907	.iter()
1908	.filter(\|(role, _)\| *role == egui::accesskit::Role::SpinButton)
1909	.collect();
1910	assert_eq!(ends.len(), 2, "an interval draws two boxes: {drawn:?}");
1911	for end in ends {
1912	assert_eq!(end.1, "BPM Range", "{drawn:?}");
1913	}
1914	}
1915
1916	#[test]
1917	fn a_checkbox_keeps_naming_itself() {
1918	// `FieldKind::labels_itself` routes past the label, and egui names a
1919	// checkbox from its own text, so there is nothing to attach and
1920	// attaching one would say the name twice.
1921	let f = Field::new(FieldKind::Checkbox, "loop", "Loop playback");
1922	let p = palette(Color32::from_rgb(9, 9, 9));
1923	let drawn = announced(\|ui\| {
1924	let mut ticked = false;
1925	field(
1926	ui,
1927	&f,
1928	Filling::On(&mut ticked),
1929	None,
1930	&p,
1931	&FieldStyle::default(),
1932	);
1933	});
1934
1935	assert!(
1936	drawn
1937	.iter()
1938	.any(\|(role, name)\| *role == egui::accesskit::Role::CheckBox
1939	&& name == "Loop playback"),
1940	"{drawn:?}"
1941	);
1942	}
1943
1944	#[test]
1945	fn a_hidden_field_draws_nothing_and_answers_nothing() {
1946	// Where the two renderers legitimately part: a webview still emits an
1947	// input because the form submits, and there is no form here.
1948	let f = Field::new(FieldKind::Hidden, "id", "Id");
1949	let p = palette(Color32::from_rgb(9, 9, 9));
1950	egui::__run_test_ui(\|ui\| {
1951	let drawn = field(ui, &f, Filling::Absent, None, &p, &FieldStyle::default());
1952	assert!(drawn.is_none());
1953	});
1954	}
1955
1956	#[test]
1957	fn a_disabled_field_stops_answering_and_an_unstated_one_does_not() {
1958	let f = Field::new(FieldKind::Text, "title", "Title");
1959	let p = palette(Color32::from_rgb(9, 9, 9));
1960	let style = FieldStyle::default();
1961	egui::__run_test_ui(\|ui\| {
1962	let mut text = String::from("x");
1963	let disabled = field(
1964	ui,
1965	&f,
1966	Filling::Text(&mut text),
1967	Some(State::Disabled),
1968	&p,
1969	&style,
1970	)
1971	.unwrap();
1972	assert!(!disabled.enabled());
1973
1974	// Stating no state is the ordinary case and answers. Focus used to
1975	// be the counter-example here; it is egui's now and a description
1976	// cannot state it at all.
1977	let mut text = String::from("x");
1978	let plain = field(ui, &f, Filling::Text(&mut text), None, &p, &style).unwrap();
1979	assert!(plain.enabled(), "an unstated field still answers");
1980	});
1981	}
1982
1983	#[test]
1984	fn a_field_described_one_way_and_filled_another_is_drawn_inert() {
1985	// No panic and no write-through. A checkbox handed a string cannot be
1986	// filled, so it is drawn off and left alone.
1987	let f = Field::new(FieldKind::Checkbox, "done", "Done");
1988	let p = palette(Color32::from_rgb(9, 9, 9));
1989	let mut text = String::from("untouched");
1990	egui::__run_test_ui(\|ui\| {
1991	let drawn = field(
1992	ui,
1993	&f,
1994	Filling::Text(&mut text),
1995	None,
1996	&p,
1997	&FieldStyle::default(),
1998	);
1999	assert!(drawn.is_some());
2000	});
2001	assert_eq!(text, "untouched");
2002	}
2003
2004	#[test]
2005	fn the_disclosure_belongs_to_the_form_and_not_to_the_field() {
2006	let fields = [
2007	Field::new(FieldKind::Text, "title", "Title"),
2008	Field {
2009	extended: true,
2010	..Field::new(FieldKind::Text, "notes", "Notes")
2011	},
2012	];
2013	let style = FieldStyle::default();
2014
2015	let mut closed = Vec::new();
2016	egui::__run_test_ui(\|ui\| {
2017	group(ui, &fields, false, &style, \|_, f\| closed.push(f.name));
2018	});
2019	assert_eq!(closed, ["title"]);
2020
2021	let mut open = Vec::new();
2022	egui::__run_test_ui(\|ui\| {
2023	group(ui, &fields, true, &style, \|_, f\| open.push(f.name));
2024	});
2025	assert_eq!(open, ["title", "notes"]);
2026	}
2027
2028	#[test]
2029	fn the_default_frame_is_square_and_one_point() {
2030	let d = FrameStyle::default();
2031	assert_eq!(d.radius, CornerRadius::ZERO);
2032	assert_eq!(d.margin, Margin::ZERO);
2033	assert!((d.stroke - 1.0).abs() < f32::EPSILON);
2034	}
2035
2036	#[test]
2037	fn a_theme_picker_reads_its_chosen_theme_by_name() {
2038	const THEMES: &[makeover_layout::ThemeChoice<'_>] = &[makeover_layout::ThemeChoice::new(
2039	"carbonfox",
2040	"Carbonfox",
2041	ThemeVariant::Dark,
2042	makeover_layout::Contrast::High,
2043	)];
2044	let field = Field::theme("theme", "Theme", THEMES)
2045	.following(Choice::new("system", "Follow System"));
2046
2047	assert_eq!(themed_text(&field, "carbonfox"), "Carbonfox");
2048	assert_eq!(themed_text(&field, "system"), "Follow System");
2049	// A stored id whose theme has been deleted reads as itself rather than
2050	// as an empty box, which is the honest report on the config as it
2051	// stands.
2052	assert_eq!(themed_text(&field, "gone"), "gone");
2053	}
2054	}
2055