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1 //! The webview renderer for [`makeover_layout`].
2 //!
3 //! <!-- wiki: makeover-webview -->
4 //!
5 //! # The renderer that needs no palette
6 //!
7 //! `makeover-immediate` and `makeover-tui` both take a `Palette`, because egui
8 //! and a terminal need an actual colour before they can put anything on
9 //! screen. A webview does not: `var(--surface-raised)` *is* the late binding,
10 //! and the browser resolves it against whatever `themes.js` last wrote onto
11 //! `:root`.
12 //!
13 //! So this crate emits text naming intents, and never learns a colour. It is
14 //! the deferral rule with no adapter in the way, and it is why the webview was
15 //! always the wrong renderer to derive a vocabulary from: it can express
16 //! anything, so it never pushes back.
17 //!
18 //! # Phase A: the stylesheet
19 //!
20 //! This module emits component CSS and no markup, deliberately. GoingsOn has
21 //! 145 `innerHTML` sites and Balanced Breakfast 175 `createElement` sites, so
22 //! moving markup is a migration where adopting a generated stylesheet is not.
23 //! The apps keep every line of their markup and gain the classes.
24 //!
25 //! It is not a deletion either, which this header claimed until the measurement
26 //! came in. Adoption across goingson removed 49 declarations net and *added* 25
27 //! lines: a rule loses its depth declarations and gains a variant selector next
28 //! to it, so the file stays the same size. What phase A moves is where depth is
29 //! defined, not how much CSS exists. Numbers and method in the wiki note under
30 //! "The deletion test, run".
31 //!
32 //! The bevel properties are byte-identical to what both apps already
33 //! hand-write, which is asserted below.
34 //!
35 //! Some of what phase A emits is not a look but the withdrawal of one. A
36 //! renderer that picks its element from the description inherits that element's
37 //! user-agent chrome, and [`reset`] is where a primitive says which parts of it
38 //! were never asked for.
39 //!
40 //! # Phase B: the markup, one description at a time
41 //!
42 //! [`form`] renders [`makeover_layout::Field`], which is the half of phase B
43 //! whose description is settled. It emits strings, because both apps
44 //! interpolate their fields into larger string-built forms and returning nodes
45 //! would rewrite those too. It owns its own escaping, on the reasoning in that
46 //! module: a Rust encoder can cover element text and attribute values with one
47 //! function, where the apps need four and have to choose correctly at every
48 //! call site.
49 //!
50 //! [`facet`] renders `makeover_layout::Facet`: a dimension a set is narrowed by,
51 //! and the one phase-B emitter whose markup an app is not keeping, because the
52 //! markup it replaces was two mechanisms rather than one. A tag's selection and
53 //! a tag's browse position were separate state on MNW's discover page, which is
54 //! why every filter row there carries a tick box *and* a chevron; one gesture
55 //! doing both is what lets the second one go.
56 //!
57 //! [`list`] is the other half: column tracks, the narrowing rules, and the cell
58 //! containers a row is made of. It stops at the cell boundary and does not
59 //! render what goes inside one, on the reasoning in that module. So phase B is
60 //! now the frame around content in both directions, and what an app still owns
61 //! is the content itself.
62 //!
63 //! # What phase A settled, and what it costs
64 //!
65 //! Measured against goingson's `styles.css` rather than against a component
66 //! list: `.btn`, `.card` and `.tag, .badge` each hand-write the same
67 //! composition, so three quarters of phase A is one rule with several names.
68 //!
69 //! Two of the four decisions change how goingson looks, and adoption should
70 //! not be described as a pure deletion:
71 //!
72 //! - **Pressed carries its fill.** [`interactive_rules`] emits
73 //! [`Depth::pressed`] whole. goingson presses to `--surface-sunken` today and
74 //! will press to `--surface-well`, and hovers to `--surface-overlay` today
75 //! and will hover to `--hover-surface`. Since `surface-well` inverts by theme
76 //! where `surface-sunken` does not, a dark theme presses *lighter* than it
77 //! hovers. That falls out of `makeover`'s own derivation, which says outright
78 //! that `surface-sunken` cannot serve as a well, so if it reads wrong the
79 //! answer is there and not here.
80 //! - **Badges go flat.** See [`token_rules`].
81 //!
82 //! The other two: the progress trough is renderer-local and the scrollbar
83 //! track was dropped ([`component_rules`]), and no class prefix ships by
84 //! default, so adoption means deleting the app's hand-written rule in the same
85 //! commit that adds the generated one. `.card`, `.badge` and the tab classes
86 //! all already exist in goingson, and while both rules exist the cascade order
87 //! decides which wins. That is the one real risk in adopting this, and it is
88 //! why the migration lands per component rather than in one commit.
89 //!
90 //! # Interaction states
91 //!
92 //! [`interactive_rules`] emits four states, in emission order, and the order is
93 //! load-bearing: they are all specificity (0,2,0), so disabled beats hover by
94 //! coming last and by nothing else. Nothing here reaches for `:not(:disabled)`,
95 //! which would raise a selector this crate wraps in its own layer.
96 //!
97 //! Emitting the states here is what keeps an app from completing the primitive
98 //! from outside, by out-specifying a rule it does not own. Those overrides are
99 //! also what breaks under cascade layers: an app that declares `@layer` puts
100 //! its own rules in a named layer, and unlayered declarations outrank every
101 //! named layer regardless of specificity.
102 //!
103 //! Hover sits inside a capability query. `makeover-touch` answers whether a
104 //! fingertip has hover and `makeover-geometry` spells the condition; this crate
105 //! asks and does not decide, so no app has to take the hover state back on
106 //! touch.
107 //!
108 //! # The layer contract
109 //!
110 //! [`stylesheet`] emits into the `makeover` cascade layer ([`CSS_LAYER`], which
111 //! lives in `makeover-geometry` because that is the one crate every CSS emitter
112 //! in the family already depends on). `makeover-geometry` does the same for
113 //! `geometry.css`.
114 //!
115 //! The cascade resolves origin and importance, then layer, then specificity,
116 //! then source order, and **unlayered normal declarations outrank every named
117 //! layer**. An unlayered generated file therefore beats every rule an app owns,
118 //! regardless of specificity and regardless of loading last. Nothing errors when
119 //! that happens: the CSS is valid, the minifier is happy, and buttons and badges
120 //! look subtly wrong. The layer belongs here rather than in each app, because an
121 //! app cannot fix it from its own stylesheet: the fix is to layer the file it
122 //! does not own.
123 //!
124 //! An app should declare the order once, or the layer's position is decided by
125 //! whichever generated file the browser happens to see first:
126 //!
127 //! ```css
128 //! @layer makeover, base, components, responsive;
129 //! ```
130 //!
131 //! [`in_css_layer`] is re-exported for an app that assembles its own stylesheet
132 //! from this crate's pieces. Rules an app generates from
133 //! [`list::narrowing_css`] and [`list::grid_template_columns`] are as generated
134 //! as the ones here, so they belong in the same layer and this crate cannot put
135 //! them there on the app's behalf.
136 //!
137 //! # Suggestions
138 //!
139 //! `Outcome::Suggestions` carries `Candidate` rather than `Choice`, and a
140 //! candidate has no `unavailable`: a suggestion that cannot be picked is a row
141 //! a route should not have offered. What it has instead is a `detail`, the line
142 //! that tells it from a row reading the same, and it is drawn in
143 //! `--content-muted` rather than in the disabled token. A detail orients rather
144 //! than refuses, and every other secondary line in this crate reads the same
145 //! way. The class is `.form-suggestion-detail`.
146 //!
147 //! # An interval is one question with two ends
148 //!
149 //! [`makeover_layout::FieldKind::Interval`] emits a `role="group"` named by the
150 //! field's label, holding one `<input type="number">` per end.
151 //!
152 //! - **The group carries the error and the descriptions**, on the split
153 //! [`makeover_layout::FieldKind::Radio`] already uses here: what is wrong is
154 //! the answer, and a crossed interval is not the fault of either end.
155 //! - **Both boxes take the whole extent.** `min`, `max` and `step` describe the
156 //! axis, so they are written twice. The crossing rule is not emitted, because
157 //! HTML has no attribute for it and the description does not carry it: it
158 //! comes back as an error on the group, like every other refusal.
159 //! - **Which end is which is `aria-label` and nothing more.** The description
160 //! states direction structurally, by which member holds which name, and never
161 //! in words. Visible Min and Max captions are a page's own and reach the
162 //! group through [`form::Filling::trailing`].
163 //!
164 //! [`form::Value::Between`] is the second value. A separator inside one string
165 //! would make this crate the owner of a delimiter that either end could contain.
166 //!
167 //! # A number's unit is adjacent text
168 //!
169 //! HTML has no unit attribute and inventing one would be markup nothing reads,
170 //! so `Field::unit` is a `<span>` after the control. It is named in
171 //! `aria-describedby` rather than left as decoration, because a number and what
172 //! it is measured in are one fact and reading the first without the second is
173 //! reading it wrong. What that buys is a unit a consumer can read back rather
174 //! than a suffix on a label it would have to parse.
175 //!
176 //! # A curve this renderer can carry, and one it declines
177 //!
178 //! A range takes its granularity from the curve (`Field::curve.step()`), every
179 //! other kind keeps `Field::step`, and `Curve::Linear` emits a plain range.
180 //!
181 //! **A constant-ratio curve emits a linear track, and that is the answer, not a
182 //! debt.** HTML has no logarithmic range input, so a described screen asking
183 //! for one is asking the browser for something it does not have, the same class
184 //! of request as [`makeover_layout::FieldKind::Date`] on a host with no
185 //! calendar. The renderer answers with the nearest control the host really
186 //! offers and keeps every fact that survives the translation: the extent, the
187 //! granularity, and the value's own units. What does not survive is resolution
188 //! at the small end. The value submitted is still a value in the field's own
189 //! units, which is what every handler on this path reads.
190 //!
191 //! The alternatives are worse in the specific way this stack exists to avoid.
192 //! Shipping JS that maps thumb position to value puts app code back in the
193 //! renderer. Changing what the control submits from a value to a fraction moves
194 //! the mapping to whoever reads the form, and a server reading these forms with
195 //! its own handlers would take a fraction where a value is expected, silently.
196 //!
197 //! When this reopens: the day a described screen on the webview path asks for a
198 //! non-linear range. The answer then is mapping in `quasi-router`, where one
199 //! implementation serves every host, not JS here.
200 //!
201 //! # A markdown field gets a preview
202 //!
203 //! A [`makeover_layout::FieldKind::Rich`] field is marked
204 //! `data-format="markdown"`, and [`form::editor_rules`] is what spends that
205 //! mark. The Write/Preview pair is a segmented control, so it takes the depth,
206 //! the focus ring and the chosen state from rules that already exist; the
207 //! preview pane is a well, because it stands where the control stood. Both are
208 //! gated on the attribute rather than on a class, which is what the attribute is
209 //! for. A permission taken and not spent turns every conversion into a
210 //! regression.
211 //!
212 //! **This crate renders no markdown.** The pane arrives empty and is filled by
213 //! whatever binds the editor, which is where the host's sanitiser already is. A
214 //! converter here would move that guarantee into a crate with no view of the
215 //! host's content-security posture.
216 //!
217 //! # Ranges, ghost text, and an option that cannot be picked
218 //!
219 //! - `FieldKind::Range` emits `<input type="range">`, and `Field::step` emits
220 //! `step`. The step is emitted only when the description carries one: the
221 //! browser's own default is `step="1"`, which is what a description means by
222 //! saying nothing, and is also what turns a 0-to-1 threshold into a
223 //! two-position control.
224 //! - A select with nothing chosen emits a disabled, selected, valueless first
225 //! option carrying `Field::placeholder`. HTML has no placeholder attribute on
226 //! `<select>`; this is the idiom, and `required` keeps working through it
227 //! because the option's value is empty.
228 //! - `Choice::unavailable` emits `disabled` plus the reason. Where it goes
229 //! differs by control and the difference is forced: a radio group gets a
230 //! `.form-option-reason` span beside the label, and a `<select>` option has
231 //! room for no element at all, so the reason runs into its text.
232 //! - `Choice::detail` takes the same split for the same reason: a
233 //! `.form-option-detail` span in a radio group, run into the text of a
234 //! `<select>`'s option. An option carrying both reads what it is before why it
235 //! cannot be picked.
236 //!
237 //! # A cell says what it holds
238 //!
239 //! [`CellPart`](makeover_layout::CellPart) names the four things a cell holds,
240 //! and [`table_rules`] turns them into `.cell-value`, `.cell-tokens`,
241 //! `.cell-actions` and `.cell-link`. Only the first takes a colour: a token
242 //! carries its own tone, an action is a control rather than text, and a link
243 //! takes the action colour from the anchor it is.
244 //!
245 //! The colour goes on `.cell-value` rather than on `.cell`. On the container it
246 //! cascades into the parts that are not text, and a control in a cell is painted
247 //! as text, which is the drift
248 //! [`RowPart::intent`](makeover_layout::RowPart) prevents for list rows.
249 //!
250 //! [`list::Cell::part`] is `Option<CellPart>` and never `Option<RowPart>`: the
251 //! two answer different questions, and only one of them is about a cell.
252 //!
253 //! # A table lays itself out
254 //!
255 //! [`list::narrowing_css`] emits the track list and has to be called with the
256 //! columns, so it works where the columns are known at build time. A table a
257 //! description produced knows its columns at render time, and the rules would
258 //! have to travel with the markup: a `<style>` element per table, which needs
259 //! `style-src 'unsafe-inline'`, or the head, which an htmx fragment swap does
260 //! not carry. [`table_rules`] lays a table out with `display: table` instead,
261 //! which aligns columns across rows knowing nothing about how many there are.
262 //! [`Priority`](makeover_layout::Priority) hiding is one rule per drop class,
263 //! and [`list::column_classes`] is what puts those classes on a cell. **A header
264 //! row emitted by a renderer's own code has to call it too**, or the header and
265 //! the body disagree about which column just dropped.
266 //!
267 //! `.button` takes the four tones as colour, off `data-tone`, the way the badge
268 //! does, so a destructive button has somewhere for its tone to land. A list is
269 //! reset rather than left as a bulleted list.
270 //!
271 //! `RowPart::revealed_on_hover` is not honoured. Hiding a row's actions until
272 //! hover hides them from pointer users alone, who are the ones scanning a list
273 //! to learn what can be done to a row, and every escape the rule grows
274 //! (`focus-within` for the keyboard, a capability gate for a fingertip) is a
275 //! report that hiding was wrong for somebody.
276 //!
277 //! # The depth classes are not controls
278 //!
279 //! `.raised` is a statement about shape and carries no interactive set, so the
280 //! vocabulary has a raised surface that is merely an object. An app that wants
281 //! one does not have to take a control class and cancel the control half.
282 //!
283 //! `.card` and `.button` are the same depth *and* controls, and they take their
284 //! states from [`surface_rules`], which is where a state belongs: on the thing
285 //! that claims to answer a pointer.
286 //!
287 //! # Substitution, three ways
288 //!
289 //! A theme with no `surface-well` is answered differently by each renderer,
290 //! which is why substitution belongs to a renderer and not to the description:
291 //!
292 //! - `makeover-immediate` substitutes the page in Rust.
293 //! - `makeover-tui` refuses to substitute and draws an edge instead, because a
294 //! terminal would quantise the two together.
295 //! - here, CSS already has the mechanism: `var(--surface-well,
296 //! var(--surface-page))` falls back in the browser, and nothing in Rust
297 //! decides anything.
298
299 #![forbid(unsafe_code)]
300
301 pub mod facet;
302 pub mod figure;
303 pub mod form;
304 pub mod list;
305 pub mod meter;
306 pub mod placeholder;
307 pub mod reset;
308 pub mod vocabulary;
309
310 /// A render of every emitter, scraped for the classes it wrote.
311 ///
312 /// Test-only, and the guard behind [`vocabulary::names`]. See the module's own
313 /// header for why the check renders rather than reads the source.
314 #[cfg(test)]
315 mod corpus;
316
317 use crate::list::{cell_part_class, part_class};
318 use crate::reset::{Chrome, Reset};
319 use makeover_geometry::{Density, SizeClass};
320 // Re-exported rather than redefined. An app assembling its own stylesheet out
321 // of this crate's pieces needs the same layer name, and most such apps depend
322 // on this crate and not on `makeover-geometry` directly: goingson builds
323 // `tables.css` in its own build.rs from [`list::narrowing_css`], and those
324 // rules are as generated as the ones here.
325 pub use makeover_geometry::{CSS_LAYER, in_css_layer};
326
327 /// This crate's version, as the generated stylesheet reports it.
328 ///
329 /// A consumer whose lockfile still pins an old `makeover-webview` gets a
330 /// well-formed sheet with components missing and no error anywhere, so the
331 /// emitter has to name itself in what it writes. Read by
332 /// `makeover_build::layout_css` through [`stylesheet`].
333 pub const VERSION: &str = env!("CARGO_PKG_VERSION");
334 use makeover_layout::{
335 Bevel, CellPart, Depth, Fallback, Fill, Flow, Intent, RowPart, Selector, Sort, State, Token,
336 Tone,
337 };
338 use makeover_touch::Affordance;
339 use std::fmt::Write as _;
340
341 /// How the emitted CSS is shaped.
342 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
343 pub struct Emit {
344 /// Bevel thickness, as a CSS length.
345 ///
346 /// A value, so it arrives from the caller: border widths belong to
347 /// `makeover-geometry` and will come from there once it carries them.
348 pub border_width: &'static str,
349 /// Focus ring thickness, as a CSS length.
350 ///
351 /// Separate from [`border_width`](Self::border_width), and never derived
352 /// from it: a bevel and a focus indicator answer different questions, and
353 /// only one of them has to be noticed from across a desk.
354 ///
355 /// The default is the measured consensus rather than a new opinion. Every
356 /// consumer had already written its own ring and all three chose at least
357 /// 2px: the MNW server 2px across 10 rules, Balanced Breakfast 2px,
358 /// goingson 2px on three rules and 3px on the one covering twelve
359 /// selectors. The design system was the only thing in the tree saying 1px.
360 pub focus_width: &'static str,
361 /// Prefix for emitted class names, without the leading dot.
362 pub class_prefix: &'static str,
363 }
364
365 impl Default for Emit {
366 fn default() -> Self {
367 Self {
368 border_width: "1px",
369 focus_width: "2px",
370 class_prefix: "",
371 }
372 }
373 }
374
375 /// A string as CSS escapes, for a `content` value.
376 ///
377 /// `\u{25B2}` becomes `\25B2`. Emitted escaped rather than literally so the
378 /// stylesheet is ASCII whatever the description spells: a `content` string is
379 /// read by whatever encoding the consumer serves the file as, and a caret that
380 /// depends on that is a caret that works on one machine.
381 ///
382 /// Terminated by the closing quote at every site here. A CSS hex escape takes
383 /// up to six digits and ends at the first character that cannot be one, so an
384 /// escape followed by more text would need a space that these do not.
385 fn css_escape(text: &str) -> String {
386 text.chars().fold(String::new(), |mut out, c| {
387 let _ = write!(out, "\\{:X}", c as u32);
388 out
389 })
390 }
391
392 /// The CSS custom property holding a bevel's composition.
393 #[must_use]
394 pub fn bevel_var(bevel: Bevel) -> &'static str {
395 match bevel {
396 Bevel::Raised => "--bevel-raised",
397 Bevel::Inset => "--bevel-inset",
398 }
399 }
400
401 /// A `var()` reference to a fill intent, with the browser's own fallback where
402 /// the intent may be absent.
403 ///
404 /// The fallback is CSS syntax, not a decision made here. That is the whole
405 /// difference between this renderer and the other two.
406 #[must_use]
407 pub fn fill_var(fill: Fill) -> String {
408 match fill {
409 Fill::Well => format!("var(--{}, var(--{}))", fill.token(), Fill::Page.token()),
410 other => format!("var(--{})", other.token()),
411 }
412 }
413
414 /// The two-tone edge as a `box-shadow` value.
415 ///
416 /// Two inset shadows, one per corner pair: the light one offset down and
417 /// right so it lands on the top and left edges, the dark one the other way.
418 /// The same assignment `makeover-immediate` draws with polylines and
419 /// `makeover-tui` draws with box-drawing characters.
420 #[must_use]
421 pub fn bevel_shadow(bevel: Bevel, opts: &Emit) -> String {
422 let (top_left, bottom_right) = bevel.edges();
423 let w = opts.border_width;
424 format!(
425 "inset {w} {w} 0 var(--{}), inset -{w} -{w} 0 var(--{})",
426 top_left.token(),
427 bottom_right.token()
428 )
429 }
430
431 /// The custom properties both bevels resolve through.
432 ///
433 /// Emitted as properties rather than inlined into every rule because that is
434 /// what the apps already do, and because a consumer that wants the edge
435 /// without the fill reads the property directly.
436 #[must_use]
437 pub fn bevel_properties(opts: &Emit) -> String {
438 let mut css = String::new();
439 for bevel in [Bevel::Raised, Bevel::Inset] {
440 let _ = writeln!(
441 css,
442 " {}: {};",
443 bevel_var(bevel),
444 bevel_shadow(bevel, opts)
445 );
446 }
447 css.push_str(ELEVATION_PROPERTY);
448 css
449 }
450
451 /// The cast shadow of a surface that floats over the page.
452 ///
453 /// Composed here for the reason the bevel pair is: `makeover` derives the tone,
454 /// this crate owns the geometry, and neither has to know the other's numbers.
455 ///
456 /// **Only for a surface that overlays the page.** A menu, a toast, a popover, a
457 /// dropdown. A surface *in* the page takes `.raised` and its bevel, and a rule
458 /// that reaches for this on a card or a plate has renamed a literal rather than
459 /// replaced it.
460 ///
461 /// Two lengths rather than one, because a single blur reads as a smudge at
462 /// plate size and as a halo at menu size. The offset is small and downward: a
463 /// Platinum-era menu sits just off the page rather than hovering above it.
464 const ELEVATION_PROPERTY: &str =
465 " --elevation-overlay: 0 2px 4px var(--elevation), 0 8px 24px var(--elevation);\n";
466
467 /// The class name for a depth.
468 #[must_use]
469 pub fn depth_class(depth: Depth, opts: &Emit) -> Option<String> {
470 let name = match depth {
471 Depth::Flat => return None,
472 Depth::Raised => "raised",
473 Depth::Well => "well",
474 Depth::Sunken => "sunken",
475 // A depth added to the description since this renderer was last
476 // built. No class, on the same footing as Flat: emitting a name
477 // whose rule body we cannot write would put a class in the markup
478 // that the stylesheet never defines.
479 _ => return None,
480 };
481 Some(format!("{}{name}", opts.class_prefix))
482 }
483
484 /// A prefixed class name.
485 ///
486 /// Public, for the renderers that emit markup this crate does not. A screen
487 /// renderer writing `class="row"` has to prefix it the way the stylesheet half
488 /// does, or a prefixed app gets rules matching everything except the elements
489 /// that renderer wrote, and the failure is invisible: the CSS stays valid and
490 /// one element is unstyled. Call this rather than copying it.
491 #[must_use]
492 pub fn class(name: &str, opts: &Emit) -> String {
493 let mut out = String::with_capacity(opts.class_prefix.len() + name.len());
494 push_class(&mut out, name, opts);
495 out
496 }
497
498 /// A prefixed class name, written into a buffer the caller already has.
499 ///
500 /// The form the emitters use, and the reason it exists is [`escape_into`]'s:
501 /// putting every class on every element through a `format!` allocates even in
502 /// the default case, where the prefix is empty and the answer is the argument.
503 /// A described table row carries roughly eighty transient allocations that way,
504 /// and this and the escaper are most of them.
505 ///
506 /// [`class`] stays for callers holding a name rather than a buffer.
507 ///
508 /// [`escape_into`]: crate::form::escape_into
509 pub fn push_class(out: &mut String, name: &str, opts: &Emit) {
510 out.push_str(opts.class_prefix);
511 out.push_str(name);
512 }
513
514 /// The class an option of a selector carries, which is what the rules key off.
515 ///
516 /// Named for the option and not for the group: [`selector_rules`] styles the
517 /// thing that gets picked, so `Selector::Tabs` is `tab` and not `tabs`. The
518 /// distinction is not pedantry. quasi-webview spelled these `tabs`, `segmented`
519 /// and `option`, put `toggle` on the wrapping element rather than on the
520 /// buttons inside it, and every described selector in that renderer came out
521 /// with no depth, no focus ring and no chosen state, while the toggle group got
522 /// a bevel meant for its buttons.
523 ///
524 /// The chosen option additionally carries `chosen`, the same way a latched chip
525 /// carries `latched`. That name is this crate's too; there is no reason for a
526 /// caller to spell it, and [`selector_rules`] is where it is written down.
527 #[must_use]
528 pub fn option_class(selector: Selector) -> &'static str {
529 match selector {
530 Selector::Tabs => "tab",
531 Selector::Segmented => "segment",
532 Selector::Toggle => "toggle",
533 }
534 }
535
536 /// The fill and edge declarations for a depth, as a rule body.
537 ///
538 /// Empty for [`Depth::Flat`], which has neither and inherits what it sits on.
539 /// Callers lean on the emptiness to skip the rule rather than emit a class that
540 /// sets nothing: a class that sets no properties is a class that means "I
541 /// thought about this", which is what comments are for.
542 ///
543 /// The two halves are emitted independently because [`Depth::Sunken`] has a
544 /// fill and no bevel. Requiring both would silently drop the fill for exactly
545 /// that case. Independent does not
546 /// mean unpaired: both halves still come off one `Depth`, so they cannot
547 /// disagree about what the region is.
548 #[must_use]
549 pub fn depth_declarations(depth: Depth) -> String {
550 let mut css = String::new();
551 if let Some(fill) = depth.fill() {
552 let _ = writeln!(css, " background: {};", fill_var(fill));
553 }
554 if let Some(bevel) = depth.bevel() {
555 let _ = writeln!(css, " box-shadow: var({});", bevel_var(bevel));
556 }
557 css
558 }
559
560 /// One rule giving a selector a depth, or nothing when the depth declares
561 /// nothing.
562 #[must_use]
563 pub fn depth_rule(selector: &str, depth: Depth) -> String {
564 let body = depth_declarations(depth);
565 if body.is_empty() {
566 return String::new();
567 }
568 format!(".{selector} {{\n{body}}}\n")
569 }
570
571 /// The media condition a hover rule has to sit inside, or `None` if hover is
572 /// unconditional.
573 ///
574 /// Two crates answer this and neither answer is made here. `makeover-touch`
575 /// owns *whether* hover exists at a density, and `makeover-geometry` owns how
576 /// that capability is spelled as a media condition. Asking both is what stops
577 /// this renderer minting a third opinion, which is what all three apps did:
578 /// goingson sniffed the user agent, Balanced Breakfast used `(hover: none)`
579 /// alone, and the MNW server had no gate at all.
580 ///
581 /// [`SizeClass`] is required by [`Affordance::available`] and ignored by this
582 /// member, which reports as much through `reads_size`. Passing Compact is not
583 /// a claim about width; the test below pins that every class agrees.
584 fn hover_condition() -> Option<&'static str> {
585 if Affordance::Hover.available(Density::Touch, SizeClass::Compact) {
586 // A fingertip grew a hover state. Nothing to gate, and this renderer
587 // should not invent a reason to gate anyway.
588 None
589 } else {
590 Some(Density::Pointer.media_condition())
591 }
592 }
593
594 /// Put a rule inside a media query, or leave it alone.
595 fn gated(condition: Option<&str>, rule: &str) -> String {
596 let Some(condition) = condition else {
597 return rule.to_string();
598 };
599 let mut css = format!("@media {condition} {{\n");
600 for line in rule.lines() {
601 // Blank lines stay blank. Indenting one leaves trailing whitespace,
602 // which is the sort of thing a formatter later reverts and calls a diff.
603 if line.is_empty() {
604 css.push('\n');
605 } else {
606 let _ = writeln!(css, " {line}");
607 }
608 }
609 css.push_str("}\n");
610 css
611 }
612
613 /// The keyboard focus ring, placed by the depth it lands on.
614 ///
615 /// This is the webview's **focus ring** and nothing more. **Reach** and
616 /// **focus** are both the browser's — the document decides what is reachable
617 /// and `:focus-visible` decides which reached thing wears the ring — and no
618 /// description states either. The three terms are defined once in
619 /// `makeover_layout`'s crate header, "Reach, focus and the focus ring".
620 ///
621 /// One ring for the whole system, because a focus ring's job is to be
622 /// recognised and three apps having three of them is the failure. What varies
623 /// is where it sits, and that comes off [`Depth`] rather than off a per-
624 /// component choice: a well takes the ring inside its own edge, and anything
625 /// standing proud of the page takes it outside.
626 ///
627 /// `outline` rather than the composed `box-shadow` the invalid-field ring at
628 /// [`field_rules`] uses, and deliberately the one place the two rings are built
629 /// differently. A `box-shadow` ring has to restate the bevel beside it, because
630 /// `box-shadow` is not additive and a lone ring silently drops the well out
631 /// from under the element. That restatement is a second copy of the depth,
632 /// living in a different function from the first, and it is exactly the
633 /// duplication `Depth` exists to prevent. `outline` occupies its own property,
634 /// so the bevel survives untouched and there is nothing to keep in agreement.
635 /// They render the same: both are a flush ring one border-width wide.
636 #[must_use]
637 pub fn focus_rule(selector: &str, depth: Depth, opts: &Emit) -> String {
638 let w = opts.focus_width;
639 // Same magnitude either way, and only the sign comes off the depth. Both
640 // values are what the consumers had already converged on independently:
641 // 2px out is what all three wrote, and 2px in is the MNW server's own
642 // answer for the one inset ring it had.
643 let offset = match depth.bevel() {
644 // Inside the well, clear of its edge rather than painted over it.
645 Some(Bevel::Inset) => format!("calc(-1 * {w})"),
646 // Raised, or no edge at all. Outside, standing off by its own width.
647 _ => w.to_string(),
648 };
649 // The token by name. It is `makeover`'s, derived from the action colour,
650 // and reaching it through a description member was a second path to the
651 // same variable for as long as one existed.
652 format!(
653 ".{selector}:focus-visible {{\n outline: {w} solid var(--focus-ring);\n outline-offset: {offset};\n}}\n"
654 )
655 }
656
657 /// A rest depth said out loud on both axes, for a rule that has to beat the
658 /// states above it.
659 ///
660 /// [`depth_declarations`] states an axis only when the depth has something to
661 /// say about it, which is right for a rest rule: a [`Depth::Flat`] region
662 /// inherits what it sits on, and asserting `background: none` there would be
663 /// the difference between level-with and painted-transparent. It is wrong for
664 /// a rule whose whole job is to take a state back. An axis left unstated is an
665 /// axis the state above keeps, so `Flat` re-asserted nothing at all and a
666 /// disabled control kept whatever hover had given it.
667 ///
668 /// So the axes the depth is silent on are withdrawn rather than skipped, and
669 /// the withdrawal is spelled by [`reset`] rather than here, so a disabled
670 /// control and a flat one say the same words. Reaches further than the fill:
671 /// [`Depth::Sunken`] and [`Depth::Overlay`] have no bevel either, and the
672 /// pressed rule above hands out an inset one.
673 fn rest_declarations(depth: Depth) -> String {
674 let mut css = String::new();
675 match depth.fill() {
676 Some(fill) => {
677 let _ = writeln!(css, " background: {};", fill_var(fill));
678 }
679 None => css.push_str(&Reset::NOTHING.and(Chrome::Fill).declarations()),
680 }
681 match depth.bevel() {
682 Some(bevel) => {
683 let _ = writeln!(css, " box-shadow: var({});", bevel_var(bevel));
684 }
685 None => css.push_str(&Reset::NOTHING.and(Chrome::Shadow).declarations()),
686 }
687 css
688 }
689
690 /// Present, visible, and not answering.
691 ///
692 /// Matches the ARIA attribute as well as the pseudo-class, because `:disabled`
693 /// only matches form elements and half the things this crate emits are not
694 /// one: a `div` carrying `.chip` or `.tab` can never be `:disabled`. Keying on
695 /// the accessible state is the pattern [`field_rules`] already establishes for
696 /// `aria-invalid`, on the reasoning that one fact read by both the styling and
697 /// the accessibility tree cannot drift from itself.
698 ///
699 /// The rest depth is re-asserted rather than assumed, because this rule has to
700 /// beat the hover and pressed rules above it. It does that on source order at
701 /// equal specificity, not by out-specifying them: every rule this function's
702 /// caller emits is (0,2,0), and adding a `:not(:disabled)` anywhere would raise
703 /// one of them and have to be unpicked when this output moves inside its own
704 /// cascade layer.
705 ///
706 /// Re-asserted on **both** axes, through [`rest_declarations`].
707 /// `depth_declarations` alone is empty for [`Depth::Flat`], so a flat control
708 /// would win the contest with nothing to say and keep the hover surface
709 /// underneath a control that had stopped answering.
710 #[must_use]
711 pub fn disabled_rule(selector: &str, depth: Depth) -> String {
712 format!(
713 ".{selector}:disabled,\n.{selector}[aria-disabled=\"true\"] {{\n{} color: var(--{});\n cursor: not-allowed;\n}}\n",
714 rest_declarations(depth),
715 State::Disabled.token()
716 )
717 }
718
719 /// Every state a selector that answers a click implies: hover, pressed, focus
720 /// and disabled, in that order.
721 ///
722 /// Order is the whole cascade mechanism here. All four selectors are
723 /// specificity (0,2,0), so disabled wins over hover and pressed by coming last
724 /// and by nothing else.
725 ///
726 /// Pressed emits [`Depth::pressed`] in full, fill and edge together. Emitting
727 /// only the edge is what left goingson hand-writing `background:
728 /// var(--surface-sunken)` on three separate rules, and a fill that does not
729 /// travel with its edge is precisely the disagreement `Depth` exists to make
730 /// unrepresentable. So the pressed fill comes from the description
731 /// (`--surface-well`) rather than from whatever each app reached for.
732 ///
733 /// Hover has no member in the description and is renderer policy: a terminal
734 /// and an immediate-mode painter have no hover to express. It resolves against
735 /// `--hover-surface`, which `makeover` already derives and which nothing
736 /// consumed until now. What it *is* gated on is capability, via
737 /// [`hover_condition`]. Before that gate existed the apps each wrote their own:
738 /// goingson's section 60 exists solely to take back the hover state this
739 /// function had just handed it, by out-specifying a rule it does not own.
740 ///
741 /// `depth` is the selector's **rest** depth, used to place the focus ring and
742 /// to restore the surface under a disabled control. The pressed rule keeps
743 /// inverting from [`Depth::Raised`] regardless: a tab's unchosen depth is
744 /// [`Depth::Sunken`], and `Sunken.pressed()` is `Sunken`, so deriving the press
745 /// from the rest depth would leave a tab with no press at all.
746 #[must_use]
747 pub fn interactive_rules(selector: &str, depth: Depth, opts: &Emit) -> String {
748 let mut css = gated(
749 hover_condition(),
750 &format!(".{selector}:hover {{\n background: var(--hover-surface);\n}}\n"),
751 );
752 css.push_str(&depth_rule(
753 &format!("{selector}:active"),
754 Depth::Raised.pressed(),
755 ));
756 css.push_str(&focus_rule(selector, depth, opts));
757 css.push_str(&disabled_rule(selector, depth));
758 css
759 }
760
761 /// One rule per depth: its fill and its edge, together.
762 ///
763 /// A depth and nothing else. `.raised` says a surface sits on what is behind
764 /// it, which is a statement about the shape and not about what happens when a
765 /// pointer arrives, so it emits no hover, press, focus or disabled rule. The
766 /// named surfaces are where interaction lives: `.card` and `.button` are the
767 /// same depth *and* controls, and they get their states from
768 /// [`surface_rules`].
769 ///
770 /// Giving this class the interactive set leaves the vocabulary with no raised
771 /// surface that is merely an object, so a consumer that needs one has to take a
772 /// control class and cancel half of it.
773 #[must_use]
774 pub fn depth_rules(opts: &Emit) -> String {
775 let mut css = String::new();
776 for depth in [Depth::Raised, Depth::Well] {
777 let Some(class) = depth_class(depth, opts) else {
778 continue;
779 };
780 css.push_str(&depth_rule(&class, depth));
781 }
782 css
783 }
784
785 /// The three surfaces that are a depth with a name.
786 ///
787 /// `button` and `card` are both [`Depth::Raised`], and `field` is a
788 /// [`Depth::Well`] because that is the reading `Depth`'s own documentation
789 /// gives a text field. Their bodies come out identical by construction rather
790 /// than by hand: three hand-written copies in goingson's stylesheet is what
791 /// phase A deletes, and generating them from one call is what stops them
792 /// drifting apart again.
793 fn surface_rules(opts: &Emit) -> String {
794 let mut css = String::new();
795 for name in ["button", "card"] {
796 let c = class(name, opts);
797 css.push_str(&depth_rule(&c, Depth::Raised));
798 css.push_str(&interactive_rules(&c, Depth::Raised, opts));
799 }
800
801 let field = class("field", opts);
802 css.push_str(&depth_rule(&field, Depth::Well));
803
804 // A field takes focus and refuses input like everything else here, and got
805 // neither until now, which is why all three apps hand-write a focus ring
806 // for it and no two of them match. No hover or pressed: a text field does
807 // not light up under the pointer and does not invert when clicked, so the
808 // two states `interactive_rules` would add are the two it does not have.
809 css.push_str(&focus_rule(&field, Depth::Well, opts));
810 css.push_str(&disabled_rule(&field, Depth::Well));
811
812 // Keyed on the ARIA attribute rather than on a class, so the visual state
813 // and the accessible state cannot drift apart: there is one fact and both
814 // read it. goingson already drove its invalid styling this way and was
815 // right to; the `.invalid` class this emitted before 0.5.0 was a second
816 // place to forget.
817 //
818 // The ring composes *after* the bevel rather than replacing it. box-shadow
819 // is not additive, so a lone ring silently dropped the well out from under
820 // an invalid field. Flat and unlit: this edge is saying "wrong", and
821 // lighting one side would have it say "raised" at the same time.
822 let _ = writeln!(
823 css,
824 ".{field}[aria-invalid=\"true\"] {{\n box-shadow: var({}), 0 0 0 {} var(--danger);\n}}",
825 bevel_var(Bevel::Inset),
826 opts.border_width
827 );
828 css
829 }
830
831 /// Badges and chips.
832 ///
833 /// The one place phase A changes how goingson looks rather than only where its
834 /// rules live. [`Token::Badge`] is [`Depth::Flat`], so a badge emits no fill
835 /// and no edge at all, where goingson ships `.tag, .badge` as a single rule
836 /// carrying the raised bevel. Splitting that means reading every call site to
837 /// decide which of the two it always was.
838 ///
839 /// What a badge does carry is a [`Tone`], the intent family it shares with
840 /// notices and nothing else. Neutral is the bare class rather than a variant,
841 /// because it is the absence of a status and not a status called "none".
842 /// Text that goes somewhere.
843 ///
844 /// The one inline control. A table cell carries `cell-link`, deliberately
845 /// unruled because the cell's own rule covers it; this is the same thing
846 /// outside a table, which is what a described run holds when a sentence
847 /// contains a link.
848 ///
849 /// Colour and underline only. Whether a link is inline in a sentence or sitting
850 /// on its own line is the app's layout, and how much room it takes is
851 /// `makeover-geometry`'s. What is here is the pair of signals that say "this
852 /// goes somewhere" and nothing that says where it sits.
853 ///
854 /// The visited arm is deliberately absent. A link inside an app points at the
855 /// app's own screens, which the user is expected to have been to, so painting
856 /// them differently marks almost everything and distinguishes nothing.
857 fn link_rules(opts: &Emit) -> String {
858 let mut css = String::new();
859 let link = class("link", opts);
860
861 let _ = writeln!(
862 css,
863 ".{link} {{\n color: var(--action);\n \
864 text-decoration: underline;\n}}"
865 );
866 // The hover step is the same one every other control takes, and it is a
867 // colour rather than a surface: a link has no box to raise.
868 let _ = writeln!(
869 css,
870 "@media (hover: hover) and (pointer: fine) {{\n .{link}:hover \
871 {{\n color: var(--action-hover);\n }}\n}}"
872 );
873 let _ = writeln!(
874 css,
875 ".{link}:focus-visible {{\n outline: {} solid var(--focus-ring);\n \
876 outline-offset: 2px;\n}}",
877 opts.focus_width
878 );
879 // A link is often a `<button>` rather than an `<a>`: a renderer picks the
880 // element from the method, so a link that writes is a button that has to
881 // stop looking like one. What that costs is named in [`reset`].
882 css.push_str(&Reset::TEXT_BUTTON.rule(&format!("button.{link}")));
883 css
884 }
885
886 fn token_rules(opts: &Emit) -> String {
887 let mut css = String::new();
888
889 // No `depth_rule` call here, deliberately: `Token::Badge.depth(_)` is Flat,
890 // and a label with an edge says it can be pressed.
891 let badge = class("badge", opts);
892 // `content-muted` literally, not `Tone::Neutral.token()`. What makes a
893 // badge quiet is `Token::Badge` answering no click, which this crate holds
894 // and `Tone` genuinely does not know. Routing it through Neutral put the
895 // claim where the evidence was not, and the bill arrived on the figure
896 // value: it took the same muting from the same call and read as its own
897 // caption. Neutral answers `content` from makeover-layout 0.36.0.
898 let _ = writeln!(css, ".{badge} {{\n color: var(--content-muted);\n}}");
899 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
900 let _ = writeln!(
901 css,
902 ".{badge}[data-tone=\"{0}\"] {{\n color: var(--{0});\n}}",
903 tone.token()
904 );
905 }
906
907 // A button carries the four tones a badge does. It had none, on the reading
908 // that a control's colour is its surface rather than its text, and that
909 // reading has one hole big enough to matter: the button that destroys
910 // something. Every consumer had written that rule itself, and a description
911 // that says `Tone::Danger` on an act had nowhere for it to land.
912 //
913 // Colour and not a fill, matching the badge. A red surface is a decision
914 // about emphasis that belongs to an app's own layer, and two of them
915 // fighting is worse than neither.
916 let button = class("button", opts);
917 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
918 let _ = writeln!(
919 css,
920 ".{button}[data-tone=\"{0}\"] {{\n color: var(--{0});\n}}",
921 tone.token()
922 );
923 }
924
925 // A chip holds itself down, which is `Depth::pressed` arrived at
926 // independently by two apps. `removable` is a remove affordance, so it is
927 // markup and waits for phase B.
928 let chip = class("chip", opts);
929 let unlatched = Token::Chip { removable: false };
930 css.push_str(&depth_rule(&chip, unlatched.depth(false)));
931 css.push_str(&interactive_rules(&chip, unlatched.depth(false), opts));
932 css.push_str(&depth_rule(
933 &format!("{chip}.latched"),
934 unlatched.depth(true),
935 ));
936 css
937 }
938
939 /// The three selectors, each named by what it picks.
940 ///
941 /// A tab comes *forward* to join the pane it opens, which is why
942 /// [`Selector::Tabs`] chooses [`Depth::Raised`] where a segment and a toggle
943 /// are held in. That is the folder semantic, and it is the whole reason the
944 /// three are not one member with a flag.
945 ///
946 /// [`Selector::abutting`] is not emitted: whether the options touch is
947 /// spacing, and spacing is `makeover-geometry`'s question to answer.
948 ///
949 /// Both states emit. Naming only the chosen option leaves an unchosen one
950 /// falling through to [`Depth::Flat`] with nothing drawn for it, so an app has
951 /// to hand-write the recess that makes its chosen tab read as forward.
952 fn selector_rules(opts: &Emit) -> String {
953 let mut css = String::new();
954 for selector in [Selector::Tabs, Selector::Segmented, Selector::Toggle] {
955 let c = class(option_class(selector), opts);
956 css.push_str(&depth_rule(&c, selector.unchosen()));
957 css.push_str(&interactive_rules(&c, selector.unchosen(), opts));
958 css.push_str(&depth_rule(&format!("{c}.chosen"), selector.chosen()));
959 }
960 css
961 }
962
963 /// The parts of a list row.
964 ///
965 /// The list is written out rather than derived because `RowPart` is
966 /// `#[non_exhaustive]`, so there is nothing to iterate. A member added upstream emits no rule until it is named here, which
967 /// is the trade `non_exhaustive` makes: a silent gap instead of a build break.
968 /// [`part_class`] carries the same list and the same obligation.
969 fn row_rules(opts: &Emit) -> String {
970 let mut css = String::new();
971
972 // The container the rows sit in, giving back what a `<ul>` brought. Not a
973 // size: there is no magnitude in it, which is the line this crate holds.
974 css.push_str(&Reset::BULLETS.rule(&format!(".{}", class("list", opts))));
975
976 for part in [
977 RowPart::Primary,
978 RowPart::Secondary,
979 RowPart::Meta,
980 RowPart::Actions,
981 RowPart::Tokens,
982 RowPart::Proportion,
983 ] {
984 let c = class(part_class(part), opts);
985
986 // Actions carry controls rather than text, and `RowPart::intent` says
987 // so by returning the same intent inheriting already gives. Pinning it
988 // would be louder than saying nothing. Tokens answer alike, for their
989 // own reason: each token carries its own tone, and a colour on the
990 // strip would fight the things sitting in it. A proportion is the same
991 // case again: the meter inside carries the tone.
992 if !matches!(
993 part,
994 RowPart::Actions | RowPart::Tokens | RowPart::Proportion
995 ) {
996 let _ = writeln!(css, ".{c} {{\n color: var(--{});\n}}", part.intent());
997 }
998
999 // A row's actions are shown at rest. `RowPart::revealed_on_hover` said
1000 // otherwise and was not honoured here from 0.23.0; makeover-layout
1001 // 0.13.0 retired the method, so there is no longer a description saying
1002 // one thing and a renderer doing another.
1003 //
1004 // The rule was `opacity: 0` gated to pointer devices, revealed on
1005 // `:hover` and on `:focus-within`. Each escape it needed was a report
1006 // that hiding was wrong for somebody: `focus-within` because tabbing
1007 // could never reach an action; the gate because a fingertip had no way
1008 // to unhide, which both webview apps had already hand-written
1009 // `opacity: 1` to undo. What was left was a control hidden from
1010 // exactly one group: people using a pointer, who are also the group
1011 // scanning a list to find out what can be done to a row.
1012 //
1013 // A settings screen is where that reads worst: the whole reason to be
1014 // on it is to remove a key, and the button doing so was invisible
1015 // until pointed at. A table cell's actions were never hidden, so the
1016 // two arrangements now agree.
1017 }
1018
1019 // A part that may take two lines. `Flow::Tight` gets no rule: one line is
1020 // what a run already does, and restating it here would put a declaration on
1021 // every part in every row to say nothing.
1022 //
1023 // This is the shape both webview apps had already written by hand and
1024 // commented -- Balanced Breakfast on a feed row's title, goingson on a
1025 // problem's body -- which is the whole argument for the description
1026 // carrying it. `-webkit-` prefixed and unprefixed together: the prefixed
1027 // trio is what every engine actually implements, and `line-clamp` is the
1028 // standard property landing behind it.
1029 let _ = writeln!(
1030 css,
1031 ".{} {{\n display: -webkit-box;\n -webkit-box-orient: vertical;\n -webkit-line-clamp: {lines};\n line-clamp: {lines};\n overflow: hidden;\n}}",
1032 class("row-relaxed", opts),
1033 lines = Flow::Relaxed.lines()
1034 );
1035
1036 // A row inside a hierarchy: a tree, an outline, a threaded list.
1037 // `edf33114`, decided 2026-08-30 (Max). makeover-layout names the concept
1038 // as `Nesting` -- deliberately not `Depth`, which is surface bevel in that
1039 // crate -- and this is the rule.
1040 //
1041 // Measured 2026-08-30: quasi-webview has been emitting `row-nested` with
1042 // `style="--row-depth:N"` on every described hierarchy, and **no stylesheet
1043 // anywhere in the tree read any of it**. So a described outline in a
1044 // browser was a flat list with chevrons in it -- the folding worked and the
1045 // indent did not exist.
1046 //
1047 // The magnitude is a custom property with a fallback, which is this crate's
1048 // own shape: `--awaiting-gap` above is the precedent, and an app overriding
1049 // `--row-indent` is how a level becomes worth more or less. What a level IS
1050 // stays the description's; what it is WORTH is a renderer's, and a terminal
1051 // spending columns for the same fact is not disagreeing.
1052 //
1053 // Here rather than in each app, and that was a live option rather than an
1054 // oversight. `row-select`, `row-current` and `row-chosen` are app-styled by
1055 // design; the indent is not decoration, it is what the description MEANS,
1056 // and three apps agreeing about it by accident is not agreement.
1057 //
1058 // `padding` and not `margin`: a row is a box that can be selected and
1059 // hovered, and indenting with margin would take the indent out of the
1060 // highlight, so the shading under a nested row would start where its text
1061 // does rather than where its row does.
1062 let _ = writeln!(
1063 css,
1064 ".{} {{\n padding-inline-start: calc(var(--row-depth, 0) * var(--row-indent, 1.5ch));\n}}",
1065 class("row-nested", opts)
1066 );
1067
1068 // The two halves of a branch, emitted by quasi-webview and unstyled until
1069 // now for the same reason.
1070 //
1071 // A branch row is the one a reader can fold, and the chevron is its hit
1072 // target. The chevron is drawn by the app or the description -- this says
1073 // where it sits and how big the target is, which is the accessibility fact
1074 // rather than the decorative one: a control smaller than this is one a
1075 // finger misses.
1076 let _ = writeln!(
1077 css,
1078 ".{} {{\n display: flex;\n align-items: baseline;\n gap: var(--row-disclose-gap, 0.5ch);\n}}",
1079 class("row-branch", opts)
1080 );
1081 let _ = writeln!(
1082 css,
1083 ".{} {{\n flex: none;\n min-inline-size: var(--tap-target, 2rem);\n min-block-size: var(--tap-target, 2rem);\n background: none;\n border: 0;\n color: inherit;\n cursor: pointer;\n}}",
1084 class("row-disclose", opts)
1085 );
1086
1087 css
1088 }
1089
1090 /// A row of things that share their space, and what each fallback gets here.
1091 ///
1092 /// Ruling: wiki `layout-room-and-fallback`, Max. Rule 1 is that every described
1093 /// member is in flow, and these rules are how that is kept rather than asked
1094 /// for. A member taken out of flow with `position: absolute` contributes zero
1095 /// width to the row it shares, so nothing can collide with it and nothing
1096 /// prevents the collision.
1097 ///
1098 /// # The floor, which is most of the fix
1099 ///
1100 /// `.run > *` gets `min-width: min-content`. That is the derived minimum the
1101 /// ruling asks for, in this renderer's own unit and stated by the browser
1102 /// rather than by anybody: a member cannot be squeezed narrower than what is
1103 /// in it, so members in one flow push each other instead of overlapping. It
1104 /// costs no query and no number, and it is what fixes all four measured widths
1105 /// whichever fallback the group declared.
1106 ///
1107 /// # What each fallback gets, exactly
1108 ///
1109 /// [`Fallback::Wrap`] is `flex-wrap: wrap`, which is exact. The browser wraps
1110 /// the run when the members no longer fit, deciding that from their own
1111 /// intrinsic widths, which is the derived minimum doing the whole job.
1112 ///
1113 /// [`Fallback::Stack`] is wrap plus `flex: 1 1 max-content` on the members, so
1114 /// a member that cannot sit beside its sibling takes a line of its own and
1115 /// fills it. For the two-member run this was ruled on -- a tab strip and a
1116 /// band -- that is precisely "a row becomes a column".
1117 ///
1118 /// [`Fallback::Shed`] and [`Fallback::Menu`] get wrap, and this renderer is
1119 /// honouring less than the description says. **CSS cannot express either one
1120 /// without breaking the ruling's own first constraint.** Both need to know that
1121 /// the run is out of room in order to take a member out of it, a container
1122 /// query is the only construct that can ask, and `@container` compares against
1123 /// a `<length>` -- there is no `@container (inline-size < min-content)`. So
1124 /// every honest spelling of Shed here needs an authored breakpoint, which is
1125 /// the thing the ruling exists to forbid, and the dishonest ones are worse: a
1126 /// clamped height clips by document order rather than by [`Priority`], and
1127 /// `display: none` under a viewport `@media` is the `nth-child(n+5)` bug the
1128 /// vocabulary replaced.
1129 ///
1130 /// Wrapping is the right thing to do instead. It keeps every member reachable,
1131 /// which is the property that was actually broken -- goingson's new-contact
1132 /// button left the viewport entirely at 560 -- and it keeps rule 1. A renderer
1133 /// answering with less than was described is precedented and deliberate here:
1134 /// [`makeover_layout::Region::Columns`] says a terminal stacking a board's
1135 /// columns is honouring the description rather than degrading it.
1136 ///
1137 /// The real mechanism needs the shed members to have somewhere to go, which is
1138 /// markup and belongs to quasi-webview: an overflow control is a member of the
1139 /// run, and the description does not yet say that a member *is* one.
1140 ///
1141 /// # Menu, once a script is measuring
1142 ///
1143 /// That is now built, in `quasi-webview`'s `menu.js`, and this crate's half of
1144 /// it is two classes and one override. A script that has taken a menu run over
1145 /// marks it `data-menu`, and a marked run goes back to `nowrap`: wrapping is
1146 /// what hides the overflow condition the script is trying to measure. The
1147 /// unmarked rule above is untouched, so a page that ships no script still
1148 /// wraps, which is rule 1 — every member reachable — rather than a strip with
1149 /// tabs squeezed off the end.
1150 ///
1151 /// `.run-overflow` is the control the shed members move into and
1152 /// `.run-overflow-items` is where they land. The geometry is this crate's the
1153 /// way every other surface's is; what is *in* it is the script's, because which
1154 /// members no longer fit is a measurement and not a description.
1155 fn run_rules(opts: &Emit) -> String {
1156 let run = class("run", opts);
1157 let mut css = String::new();
1158
1159 // `flex-wrap: nowrap` is stated rather than left to the default, because
1160 // the fallbacks below are read as overrides of this line and a reader
1161 // should not have to know which way flexbox leans to see that.
1162 //
1163 // No gap. Spacing between members is the app's, the same way this crate
1164 // states no margins anywhere else; a gap here would be a size, and the one
1165 // hardcoded size in the mechanism is makeover-geometry's contact patch.
1166 let _ = writeln!(
1167 css,
1168 ".{run} {{\n display: flex;\n flex-wrap: nowrap;\n align-items: center;\n}}"
1169 );
1170
1171 // The derived minimum, and the whole reason a member can no longer be
1172 // overlapped. `min-width: auto` is flexbox's default for a flex item and is
1173 // *not* the same thing: auto lets an item be compressed below its content
1174 // in a nowrap run, which is how a toolbar ends up drawn over a tab strip
1175 // even without anything leaving the flow.
1176 let _ = writeln!(css, ".{run} > * {{\n min-width: min-content;\n}}");
1177
1178 for fallback in [
1179 Fallback::Wrap,
1180 Fallback::Stack,
1181 Fallback::Shed,
1182 Fallback::Menu,
1183 ] {
1184 let name = fallback_class(fallback);
1185 let c = class(name, opts);
1186 let _ = writeln!(css, ".{c} {{\n flex-wrap: wrap;\n}}");
1187 if matches!(fallback, Fallback::Stack) {
1188 let _ = writeln!(css, ".{c} > * {{\n flex: 1 1 max-content;\n}}");
1189 }
1190 }
1191
1192 // A menu run a script has taken over. The mark is the script's and this is
1193 // the only rule that reads it: wrapping is what a run does when nothing is
1194 // measuring, and it is also what makes the overflow unmeasurable, since a
1195 // wrapped run always fits. The two cannot both be on.
1196 let menu = class(fallback_class(Fallback::Menu), opts);
1197 let _ = writeln!(css, ".{menu}[data-menu] {{\n flex-wrap: nowrap;\n}}");
1198
1199 // The overflow control, and it is a member of the run like any other: in
1200 // flow, at the end, taking the width of what is in it. `relative` is what
1201 // the items hang off.
1202 let overflow = class("run-overflow", opts);
1203 let items = class("run-overflow-items", opts);
1204 let _ = writeln!(css, ".{overflow} {{\n position: relative;\n}}");
1205
1206 // Overlaid rather than in flow, for the reason every menu is: a control
1207 // that pushed the page down when it opened would change the layout it was
1208 // opened to escape. `inset-inline-end: 0` rather than a left, so the panel
1209 // stays on the page in both writing directions.
1210 //
1211 // No width, no padding and no border. All three are sizes and sizes are
1212 // makeover-geometry's; what is stated here is placement, the surface and
1213 // the shadow that separates it from the page, which is the same division
1214 // `figure_rules` and the timeline entry make. The elevation shadow is what
1215 // an overlaid surface takes instead of an edge -- see `ELEVATION_PROPERTY`.
1216 let _ = writeln!(
1217 css,
1218 ".{items} {{\n \
1219 position: absolute;\n \
1220 inset-block-start: 100%;\n \
1221 inset-inline-end: 0;\n \
1222 z-index: 1;\n \
1223 display: flex;\n \
1224 flex-direction: column;\n \
1225 align-items: stretch;\n \
1226 background: var(--surface-raised);\n \
1227 box-shadow: var(--elevation-overlay);\n\
1228 }}"
1229 );
1230
1231 // `hidden` is how the script closes it, and a flex display would otherwise
1232 // beat the attribute's own `display: none`.
1233 let _ = writeln!(css, ".{items}[hidden] {{\n display: none;\n}}");
1234
1235 css
1236 }
1237
1238 /// Every class [`fallback_class`] can return, plus the run itself.
1239 ///
1240 /// [`ROW_PART_CLASSES`](crate::list::ROW_PART_CLASSES)'s reasoning and the same
1241 /// obligation: a `match` over a `#[non_exhaustive]` enum cannot be enumerated
1242 /// from outside, so the list sits beside it and a test holds the two together.
1243 /// `run` is in it because it is emitted in its own right rather than only as a
1244 /// fallback's fallback.
1245 pub const RUN_CLASSES: &[&str] = &[
1246 "run",
1247 "run-wrap",
1248 "run-stack",
1249 "run-shed",
1250 "run-menu",
1251 // Not returned by `fallback_class`: these two are the overflow control a
1252 // measuring renderer builds, and they are in the list because the list is
1253 // what a host seals its vocabulary against. A class emitted by a script and
1254 // missing from here is a control with no surface and no edge.
1255 "run-overflow",
1256 "run-overflow-items",
1257 ];
1258
1259 /// The class a run carries for what it does when it is tight.
1260 ///
1261 /// A run always carries `.run` as well, so an unrecognised fallback -- the enum
1262 /// is `#[non_exhaustive]` -- lands as a plain nowrap row with the min-content
1263 /// floor still under it. That is the safe failure: every member in flow and
1264 /// none overlapped, which is the property, with only the rearrangement missing.
1265 #[must_use]
1266 pub fn fallback_class(fallback: Fallback) -> &'static str {
1267 match fallback {
1268 Fallback::Wrap => "run-wrap",
1269 Fallback::Stack => "run-stack",
1270 Fallback::Shed => "run-shed",
1271 Fallback::Menu => "run-menu",
1272 _ => "run",
1273 }
1274 }
1275
1276 /// The progress trough these rules fill.
1277 ///
1278 /// [`meter::meter_html`](crate::meter::meter_html) is what fills these.
1279 ///
1280 /// The rules stay a superset of what a description can ask for. An app drawing
1281 /// its own bar keeps these classes, which is what the four goingson grew
1282 /// independently were adopted onto.
1283 ///
1284 /// The trough is a [`Depth::Well`], the same reading a text field gets:
1285 /// something with its content down inside it.
1286 fn progress_rules(opts: &Emit) -> String {
1287 let progress = class("progress", opts);
1288 // `progress-fill` rather than a bare `fill`: an unprefixed build claims
1289 // these names in the app's own stylesheet, and `.fill` is grabby enough to
1290 // catch things that have nothing to do with progress. goingson already
1291 // calls it `.progress-fill`, so this is also the name that deletes.
1292 let fill = class("progress-fill", opts);
1293 let mut css = depth_rule(&progress, Depth::Well);
1294
1295 // The untoned bar is `--action`, not [`Tone::Neutral`]. That is the one
1296 // place this differs from the badge rules, and deliberately: a badge with
1297 // no status is a muted label, while a bar with no status is still
1298 // reporting progress, and `content-muted` would read as disabled.
1299 let _ = writeln!(
1300 css,
1301 ".{progress} > .{fill} {{\n background: var(--action);\n}}"
1302 );
1303
1304 // A bar can be saying something, same as a badge: goingson colours subtask
1305 // progress as success and an over-estimate as danger, which is real
1306 // information rather than decoration. Emitting the tones is what lets that
1307 // survive adoption instead of staying hand-written.
1308 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
1309 let _ = writeln!(
1310 css,
1311 ".{progress} > .{fill}[data-tone=\"{0}\"] {{\n background: var(--{0});\n}}",
1312 tone.token()
1313 );
1314 }
1315 css
1316 }
1317
1318 /// What a wait looks like, for the attribute that has been describing one to
1319 /// nobody.
1320 ///
1321 /// Wiki `loading-and-progress-standard`, phase 2. `data-awaiting` is emitted
1322 /// as `data-awaiting="determinate"` with a `data-awaiting-amount` beside it, or
1323 /// `data-awaiting="indeterminate"` alone. This is the half that styles them,
1324 /// without which the two render identically.
1325 ///
1326 /// # Why it is keyed on `aria-busy` and not on the attribute alone
1327 ///
1328 /// `data-awaiting` is a fact about the control: pressing this waits. It is true
1329 /// when the page is painted and it stays true. Whether a wait is *running* is
1330 /// true only between two events, so it is the binder's to set, and `aria-busy`
1331 /// is the standard spelling of it — announced as well as drawn, which a class
1332 /// of our own would not be.
1333 ///
1334 /// That also keeps this crate out of any one client library's vocabulary.
1335 /// `quasi-webview` sets `aria-busy` from htmx's request events; a host driving
1336 /// the same markup another way sets it the same way and gets the same drawing.
1337 ///
1338 /// # The two drawings
1339 ///
1340 /// One pseudo-element either way, so no renderer has to emit an extra node.
1341 ///
1342 /// Indeterminate is the activity mark of rule 2: a small square that blinks.
1343 /// Determinate is a trough with a fill, drawn as a single gradient whose stop is
1344 /// `--awaiting-share`, a plain number from 0 to 1 that the binder sets from
1345 /// bytes it has actually watched land. A determinate control with nothing
1346 /// setting the share draws an empty trough rather than a full one, which is the
1347 /// honest reading: the size is known and the delivery is not.
1348 ///
1349 /// **What the bar may not do**, from rule 1 and from `Awaiting`'s own docs:
1350 /// what is done over what there is, and never a remaining time, an arrival time
1351 /// or a rate extrapolated forward. Nothing here can express one, which is
1352 /// deliberate — the only input is a share of a measured payload.
1353 ///
1354 /// # Sizes, and the deferral rule
1355 ///
1356 /// `progress_rules` emits the tones and never the width, because the width is
1357 /// not this crate's to know. A pseudo-element has no intrinsic size at all, so
1358 /// the same treatment would render nothing anywhere. Both sizes are therefore
1359 /// custom properties with defaults: an app that wants a different mark sets
1360 /// `--awaiting-mark` and `--awaiting-bar` once, and one that says nothing gets a
1361 /// mark that is visible.
1362 ///
1363 /// # The cadence, and what happens without it
1364 ///
1365 /// `--cadence-activity` comes from `makeover-timing` through `makeover-build`,
1366 /// and is a half-period, so a full cycle is twice it. It is used bare rather
1367 /// than with a fallback: a number written here would be a second heartbeat for
1368 /// a mark three renderers draw.
1369 ///
1370 /// A sheet assembled without the time axis leaves `animation-duration` invalid,
1371 /// which resolves to `0s`, which runs no animation and leaves the base style —
1372 /// a lit, still mark. That is also exactly what the reduced-motion block does,
1373 /// since it sets the cadence to `0ms`. Both fall out of one rule because the
1374 /// base style is lit and the keyframes do the dimming, which is the ordering
1375 /// `makeover_timing::reduced_motion_css` asks its consumers for by name.
1376 fn awaiting_rules(opts: &Emit) -> String {
1377 let mut css = String::new();
1378
1379 // Dimming rather than lighting, so a zero-length animation leaves a lit
1380 // mark rather than a blank one. See `makeover_timing::reduced_motion_css`.
1381 css.push_str(
1382 "@keyframes makeover-activity {\n \
1383 0%, 49.99% {\n background: var(--action);\n }\n \
1384 50%, 100% {\n background: var(--surface-sunken);\n }\n\
1385 }\n",
1386 );
1387
1388 // Nothing is drawn until something is waiting. `content` on the base rule
1389 // rather than on the busy one keeps the box the same box across the
1390 // transition, so a mark appearing does not reflow the line it is in.
1391 let _ = writeln!(
1392 css,
1393 "[data-awaiting]::after {{\n \
1394 content: \"\";\n \
1395 display: none;\n \
1396 margin-inline-start: var(--awaiting-gap, 0.5ch);\n \
1397 vertical-align: baseline;\n\
1398 }}"
1399 );
1400
1401 let _ = writeln!(
1402 css,
1403 "[data-awaiting][aria-busy=\"true\"]::after {{\n \
1404 display: inline-block;\n \
1405 inline-size: var(--awaiting-mark, 0.5em);\n \
1406 block-size: var(--awaiting-mark, 0.5em);\n \
1407 background: var(--action);\n \
1408 opacity: 1;\n \
1409 animation: makeover-activity calc(var(--cadence-activity) * 2) \
1410 step-end infinite;\n\
1411 }}"
1412 );
1413
1414 // The measured half. A wider box, no blink, and a gradient whose stop is
1415 // the share: the fill and the trough in one paint, so the markup stays one
1416 // pseudo-element on both branches.
1417 //
1418 // `--awaiting-share` unset is an empty trough, not a full one. A bar that
1419 // read full because nobody was counting would be the confidently-wrong
1420 // drawing rule 1 exists to forbid.
1421 //
1422 // The trough takes an edge for the reason a well does: a bar at zero share
1423 // is otherwise a rectangle of the surface it sits on, which is nothing at
1424 // all. `border_width` rather than a literal, the way `depth_rule` and
1425 // `track_rules` write theirs.
1426 let _ = writeln!(
1427 css,
1428 "[data-awaiting=\"determinate\"][aria-busy=\"true\"]::after {{\n \
1429 inline-size: var(--awaiting-bar, 6em);\n \
1430 animation: none;\n \
1431 outline: {} solid var(--border);\n \
1432 outline-offset: -{};\n \
1433 background: linear-gradient(\n \
1434 to inline-end,\n \
1435 var(--action) 0 calc(var(--awaiting-share, 0) * 100%),\n \
1436 var(--surface-sunken) 0\n \
1437 );\n\
1438 }}",
1439 opts.border_width, opts.border_width
1440 );
1441
1442 css
1443 }
1444
1445 /// A strip of figures, and the two spans inside each one.
1446 ///
1447 /// Colour only, which is the deferral rule applied to a component that badly
1448 /// wants to break it. A figure reads as a figure because the value is set large
1449 /// over a small caption, and that is a size: `makeover-geometry` answers how
1450 /// much space and this crate answers what the thing is. Emitting `font-size`
1451 /// here would be this crate naming a value, which is the one thing it is defined
1452 /// by not doing, and `progress_rules` is the precedent — it emits the tones and
1453 /// never the width, because the width is not its to know.
1454 ///
1455 /// So the arrangement and the type scale are the app's, and what is generated is
1456 /// the part an app cannot get right by itself: which of the two spans carries
1457 /// the tone.
1458 fn figure_rules(opts: &Emit) -> String {
1459 let figure = class("figure", opts);
1460 let value = class("figure-value", opts);
1461 let caption = class("figure-caption", opts);
1462 let change = class("figure-change", opts);
1463 let mut css = String::new();
1464
1465 // `content` literally. A figure's value is the thing itself, at full
1466 // weight -- wiki `three-tone-convention` classes it "active, emphasised",
1467 // and both other renderers already draw it that way (makeover-tui
1468 // `piece.rs:391` bold, makeover-immediate `widget.rs:244`). It reached
1469 // here through `Tone::Neutral.token()` and came out `content-muted`, so
1470 // the headline number sat at the colour of its own caption.
1471 let _ = writeln!(
1472 css,
1473 ".{figure} > .{value} {{\n color: var(--content);\n}}"
1474 );
1475 let _ = writeln!(
1476 css,
1477 ".{figure} > .{caption} {{\n color: var(--content-muted);\n}}"
1478 );
1479 let _ = writeln!(
1480 css,
1481 ".{figure} > .{change} {{\n color: var(--content-muted);\n}}"
1482 );
1483
1484 // A toned figure tones one part and never the caption. The caption is the
1485 // noun and stays muted.
1486 //
1487 // Which part depends on whether there is a change, and that is the whole of
1488 // what 0.13.0 changed here. A figure with a delta is an ordinary number that
1489 // has moved in a direction worth reading, so the delta takes the colour and
1490 // the number stays plain; a figure without one has nowhere else to put it.
1491 // `:has` is what lets one attribute mean both, and the alternative was the
1492 // emitter deciding by writing the attribute onto a different element, which
1493 // leaves two elements able to disagree about a figure's one meaning.
1494 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
1495 let _ = writeln!(
1496 css,
1497 ".{figure}[data-tone=\"{0}\"] > .{change} {{\n color: var(--{0});\n}}",
1498 tone.token()
1499 );
1500 let _ = writeln!(
1501 css,
1502 ".{figure}[data-tone=\"{0}\"]:not(:has(> .{change})) > .{value} \
1503 {{\n color: var(--{0});\n}}",
1504 tone.token()
1505 );
1506 }
1507 css
1508 }
1509
1510 /// A picture, its frame and its caption.
1511 ///
1512 /// # The frame is a border, and this is the one place a bevel is wrong
1513 ///
1514 /// Emitting [`Depth::Raised`] here through [`depth_rule`], the same call
1515 /// `button` and `card` make, is wrong, and MNW's landing page is where it
1516 /// showed: **the frames had no visible edge at all.**
1517 ///
1518 /// `Depth::Raised`'s edge is `--bevel-raised`, which is an *inset* shadow — a
1519 /// 1px light run at the top-left and a dark one at the bottom-right, drawn
1520 /// **inside** the element's box. On a button or a card that box is a surface
1521 /// this crate owns, so an inset edge reads as the surface catching the light.
1522 /// On a picture it is drawn on top of the picture, over whatever pixels the
1523 /// image happens to have at its border. MNW's screenshots are light-on-light
1524 /// parchment, so the light half landed on a light image and the frame
1525 /// disappeared.
1526 ///
1527 /// **You cannot bevel a surface you do not own.** A picture's content is the
1528 /// app's, arrives at request time, and can be any colour, so its edge has to
1529 /// sit *outside* the content rather than on it. That is a border.
1530 ///
1531 /// The fill stays, and it is not decoration: it is what shows through a
1532 /// transparent PNG and what stands in the frame's place while the image is
1533 /// still loading.
1534 ///
1535 /// This is a real limit on [`Depth`] rather than a special case. Every other
1536 /// consumer of a depth draws its own surface; a picture is the first member
1537 /// whose surface belongs to someone else.
1538 ///
1539 /// # No size
1540 ///
1541 /// `width: 100%` and nothing else. How large a picture is depends on the box it
1542 /// was put in, which is the app's arrangement and `makeover-geometry`'s scales,
1543 /// and a renderer that picked one would be answering for every consumer at
1544 /// once. This is where `figure_rules` landed for the same reason.
1545 fn picture_rules(opts: &Emit) -> String {
1546 let picture = class("picture", opts);
1547 let img = class("picture-img", opts);
1548 let caption = class("picture-caption", opts);
1549 let mut css = String::new();
1550
1551 // Block, or an inline image sits on the text baseline and carries a
1552 // descender's worth of space under it that no app ever wants and every app
1553 // deletes by hand. The border is the frame; see the type docs for why it is
1554 // not the bevel every other surface here gets.
1555 let _ = writeln!(
1556 css,
1557 ".{img} {{\n display: block;\n width: 100%;\n height: auto;\n \
1558 background: var(--{});\n border: {} solid var(--border);\n}}",
1559 Fill::Raised.token(),
1560 opts.border_width
1561 );
1562
1563 // The two fits that need a rule. `Fit::Natural` emits no attribute at all,
1564 // so it is the bare rule above and needs nothing here.
1565 let _ = writeln!(
1566 css,
1567 ".{img}[data-fit=\"cover\"] {{\n height: 100%;\n object-fit: cover;\n}}"
1568 );
1569 let _ = writeln!(
1570 css,
1571 ".{img}[data-fit=\"contain\"] {{\n height: 100%;\n object-fit: contain;\n}}"
1572 );
1573
1574 // A caption reads back one step, which is `figure-caption`'s answer and the
1575 // same claim: it says what the thing above it is, and it is not the thing.
1576 let _ = writeln!(
1577 css,
1578 ".{picture} > .{caption} {{\n color: var(--content-muted);\n}}"
1579 );
1580
1581 css
1582 }
1583
1584 /// A region showing one child at a time, and the chrome that moves between them.
1585 ///
1586 /// [`makeover_layout::Showing`] lets a description say that a region holds
1587 /// several children and shows some of them. A renderer derives its own chrome
1588 /// from that, which is what stops every renderer growing a `match` on a widget
1589 /// name; these are the rules the derived chrome needs.
1590 ///
1591 /// # Why the default is every child, and the enhancement takes them away
1592 ///
1593 /// The controls are a lie until something binds them. A prev button rendered
1594 /// into a document with no script is a control that looks live and answers
1595 /// nothing, and the reader it lies to is exactly the one who cannot see the
1596 /// other children either — the collapsing and the moving are the same half.
1597 ///
1598 /// So the rules run in the direction the enhancement does. Nothing here hides a
1599 /// child and nothing here shows a control. Whatever binds the region sets
1600 /// `data-ready` on it, and that is what collapses the stack to one and reveals
1601 /// the row that moves it. A reader with no script gets every child in order and
1602 /// no controls, which is more content rather than less, and a reader with
1603 /// script gets a settled page rather than a stack that jumps to one frame after
1604 /// load.
1605 ///
1606 /// MNW proved this shape by hand — a `<noscript>` stylesheet opening its
1607 /// carousel back out — and it is here rather than there because the property is
1608 /// the description's, not one app's.
1609 ///
1610 /// # Not spacing
1611 ///
1612 /// The row's gaps are `makeover-geometry`'s question and are absent for
1613 /// [`row_rules`]'s reason. What is here is `display`, which carries no
1614 /// magnitude, and the muted readout, which is the same claim `picture-caption`
1615 /// makes: it says where you are among the children and it is not one of them.
1616 fn showing_rules(opts: &Emit) -> String {
1617 let controls = class("showing", opts);
1618 let position = class("showing-position", opts);
1619 let frame = class("showing-frame", opts);
1620 let mut css = String::new();
1621
1622 // Hidden until something binds it, which is the whole argument above.
1623 let _ = writeln!(css, ".{controls} {{\n display: none;\n}}");
1624 // Block, and nothing about how the three sit in it. A button and a span are
1625 // inline already, so they make a row without this crate saying so, and
1626 // saying so is where `align-items` and a gap would follow -- both spacing,
1627 // both `makeover-geometry`'s, and `row_rules` refuses them for the same
1628 // reason.
1629 let _ = writeln!(
1630 css,
1631 "[data-ready] > .{controls} {{\n display: block;\n}}"
1632 );
1633
1634 // A child is in flow until the region is bound, and then only the current
1635 // one is. `.current` is a modifier for the reason `.chosen` and `.latched`
1636 // are: one name for the state, set by whoever knows it.
1637 let _ = writeln!(
1638 css,
1639 "[data-ready] > .{frame}:not(.current) {{\n display: none;\n}}"
1640 );
1641
1642 // Reads back one step. `picture-caption`'s rule and its reason.
1643 let _ = writeln!(css, ".{position} {{\n color: var(--content-muted);\n}}");
1644
1645 css
1646 }
1647
1648 /// A time axis: the container, its gridlines and ruler, and the placed things.
1649 ///
1650 /// [`Track`](makeover_layout::Track), the one member here whose whole point is
1651 /// *position*. That makes the magnitude line this crate keeps worth restating
1652 /// rather than assuming.
1653 ///
1654 /// # Where the numbers come from
1655 ///
1656 /// Every value that varies per item is a custom property the caller sets
1657 /// inline, and every rule here reads one. `--track-at` and `--track-for` are
1658 /// percentages of the span, which
1659 /// [`Track::fraction`](makeover_layout::Track::fraction) computes once so three
1660 /// renderers cannot disagree about it. Nothing here knows a pixel.
1661 ///
1662 /// That is what lets the stylesheet stay static while the items move: an entry
1663 /// carries `style="--track-at: 37.5%; --track-for: 4.166%"` and the rule below
1664 /// turns it into a box. The alternative was emitting a rule per item, which is
1665 /// a stylesheet that grows with the data.
1666 ///
1667 /// **The height of the track is the app's**, not this crate's. 96 quarter-hour
1668 /// slots at some slot height is a size, and a size is `makeover-geometry`'s
1669 /// question -- the same refusal `figure_rules` and `placeholder_rules` make.
1670 /// Percentages need a resolved height above them, so `.track` gets
1671 /// `position: relative` and nothing else; the app says how tall a day is.
1672 ///
1673 /// # Overlap
1674 ///
1675 /// Two things at the same time is intrinsic to an axis and has no analogue in a
1676 /// list. The description does not declare it -- `Placement::overlaps` derives it
1677 /// from the times -- so what arrives here is a lane index and a lane count, and
1678 /// the rule divides the width. A renderer that would rather stack them ignores
1679 /// both properties and the defaults give it one full-width lane.
1680 fn track_rules(opts: &Emit) -> String {
1681 let track = class("track", opts);
1682 let slot = class("track-slot", opts);
1683 let tick = class("track-tick", opts);
1684 let entry = class("track-entry", opts);
1685 let mut css = String::new();
1686
1687 // The positioning context every entry resolves against, and the whole of
1688 // what this crate says about the container. No height: see the doc above.
1689 let _ = writeln!(css, ".{track} {{\n position: relative;\n}}");
1690
1691 // Gridlines and the ruler are the axis reading itself back, which is
1692 // `picture-caption` and `showing-position`'s claim: about the thing rather
1693 // than one of the things.
1694 //
1695 // `border_width` rather than a literal, the way `depth_rule` writes its
1696 // edge. A gridline is the one place a timeline would most naturally reach
1697 // for a hardcoded 1px, and a hardcoded 1px is this crate naming a size.
1698 let _ = writeln!(
1699 css,
1700 ".{slot} {{\n border-top: {} solid var(--border);\n}}",
1701 opts.border_width
1702 );
1703 let _ = writeln!(css, ".{tick} {{\n color: var(--content-muted);\n}}");
1704
1705 // The one rule that does real work. Top and height are the placement;
1706 // left and width are the lane. Both lane properties default so an entry
1707 // that names neither is full width, which is the common case and the one a
1708 // renderer gets for free.
1709 let _ = writeln!(
1710 css,
1711 ".{entry} {{\n \
1712 position: absolute;\n \
1713 top: var(--track-at, 0%);\n \
1714 height: var(--track-for, 100%);\n \
1715 left: calc(var(--track-lane, 0) / var(--track-lanes, 1) * 100%);\n \
1716 width: calc(100% / var(--track-lanes, 1));\n\
1717 }}"
1718 );
1719
1720 css
1721 }
1722
1723 /// A region's stand-in, and the header of a table that can be reordered.
1724 ///
1725 /// Both are colour and affordance only, the same place `figure_rules` lands:
1726 /// emitting a type scale is not this crate's. How much room
1727 /// a stand-in gets is a size — goingson has the same one at three, as
1728 /// `--compact`, `--dashboard` and `--padded` — and a size is
1729 /// `makeover-geometry`'s question.
1730 ///
1731 /// The caret is the one thing here that is neither colour nor affordance, and it
1732 /// is a renderer's own expression rather than a value the description named:
1733 /// `aria-sort` is what the table actually says, and this turns it into something
1734 /// visible for everyone not using a screen reader. A terminal draws its own; an
1735 /// immediate-mode painter draws its own.
1736 fn state_rules(opts: &Emit) -> String {
1737 let placeholder = class("placeholder", opts);
1738 let text = class("placeholder-text", opts);
1739 let heading = class("table-heading", opts);
1740 let mut css = String::new();
1741
1742 let _ = writeln!(
1743 css,
1744 ".{placeholder} > .{text} {{\n color: var(--content-muted);\n}}"
1745 );
1746 // Only the failure is toned. An empty list is the normal state of a new
1747 // install, and `Readiness::tone` is what says so.
1748 let _ = writeln!(
1749 css,
1750 ".{placeholder}[data-tone=\"{0}\"] > .{text} {{\n color: var(--{0});\n}}",
1751 Tone::Danger.token()
1752 );
1753
1754 // A header that reorders the table is a control, and the pointer is the
1755 // only part of saying so that is not the app's own type and spacing.
1756 let _ = writeln!(
1757 css,
1758 ".{heading}[data-sortable] {{\n cursor: pointer;\n}}"
1759 );
1760 // The caret carries its own leading space, the way `makeover-tui` and
1761 // `makeover-immediate` both write `" \u{25B2}"`. It used to be emitted bare,
1762 // and both apps that adopted the vocabulary had to put the gap back in their
1763 // own stylesheets on the same afternoon -- each having to work out first that
1764 // app CSS outranks this crate's cascade layer, so adding the space the
1765 // obvious way, as `content`, silently wins over the glyph and leaves the
1766 // heading with no caret at all. A consumer should not have to know that, and
1767 // with the space emitted here there is nothing left for one to add.
1768 //
1769 // Three states, three tones, on the convention in wiki
1770 // `three-tone-convention`. A column in force is `content`; a column offering
1771 // to reorder and not doing it now is `content-secondary`, because it still
1772 // answers a press; a column that is not sortable emits no caret at all and
1773 // takes nothing. The idle arm used to hide its glyph and reserve the box,
1774 // which cost a reflow-free press and said nothing. It draws now, and the
1775 // reservation stops being a thing to get right.
1776 //
1777 // The glyph is `Sort::glyph`, escaped rather than written: a CSS `content`
1778 // string cannot carry the character literally through this file's own
1779 // escaping, and spelling it here as well would put the third copy back that
1780 // `makeover-layout` 0.27.5 exists to remove.
1781 let _ = writeln!(
1782 css,
1783 ".{heading}[data-sortable]::after \
1784 {{\n content: \" {}\";\n color: var(--content-secondary);\n}}",
1785 css_escape(Sort::Ascending.glyph())
1786 );
1787 for direction in [Sort::Ascending, Sort::Descending] {
1788 let _ = writeln!(
1789 css,
1790 ".{heading}[aria-sort=\"{}\"]::after \
1791 {{\n content: \" {}\";\n color: var(--content);\n}}",
1792 direction.as_str(),
1793 css_escape(direction.glyph())
1794 );
1795 }
1796 css
1797 }
1798
1799 /// The frame a table sits in.
1800 ///
1801 /// # Why this is a CSS table and not the grid the rest of the module assumes
1802 ///
1803 /// A grid row needs `grid-template-columns`, which has to name every column in
1804 /// order, so it cannot be written without knowing the columns. That is what
1805 /// [`list::narrowing_css`] is for, and it works: goingson builds `tables.css` in
1806 /// its own `build.rs` out of it, and nothing here changes that.
1807 ///
1808 /// It does not work for a table a *description* produced. Those columns are
1809 /// known at render time rather than at build time, and the rules would have to
1810 /// travel with the markup: a `<style>` element per table, which needs
1811 /// `style-src 'unsafe-inline'` and so blocks the MNW server's standing plan to
1812 /// drop it. The head is not an escape: a table swapped in by htmx after a
1813 /// delete arrives as a fragment with no head at all.
1814 ///
1815 /// A CSS table aligns its columns across rows knowing nothing about how many
1816 /// there are, so there is no track list to emit and nothing per-table to carry.
1817 /// The cost is that a described table cannot take a per-column fixed length,
1818 /// which costs nothing today: [`Sizing`](list::Sizing) is looked up by column
1819 /// name and a description carries no lengths to put in it, so every track a
1820 /// described table could ask for is already content, fill or auto.
1821 ///
1822 /// [`Priority`] hiding is unchanged in kind. It moves from a generated
1823 /// `display: none` per dropped column to one rule per drop class, which is the
1824 /// same fact addressed by class rather than by cutoff, and still never by
1825 /// position.
1826 fn table_rules(opts: &Emit) -> String {
1827 let table = class("table", opts);
1828 let head = class("table-head", opts);
1829 let row = class("table-row", opts);
1830 let heading = class("table-heading", opts);
1831 let cell = class("cell", opts);
1832 let mut css = String::new();
1833
1834 let _ = writeln!(
1835 css,
1836 ".{table} {{\n display: table;\n width: 100%;\n}}"
1837 );
1838 let _ = writeln!(css, ".{head},\n.{row} {{\n display: table-row;\n}}");
1839 // Scoped under `.{table}` rather than keyed on the classes alone. The
1840 // table model is what a cell takes *by being in a table*, and only there:
1841 // goingson's task headings are `.table-heading` inside a CSS grid, so the
1842 // unscoped rule reached them, and the sort caret and the sortable cursor
1843 // -- which `state_rules` keys on `.table-heading` and rightly still does
1844 // -- came with a `display` the grid had to blockify away.
1845 //
1846 // It costs no markup anywhere: quasi-webview always nests the heading
1847 // inside the table (`quasi-webview/src/node.rs:1591`, `:1605`, `:1615`).
1848 let _ = writeln!(
1849 css,
1850 ".{table} .{heading},\n.{table} .{cell} {{\n display: table-cell;\n}}"
1851 );
1852
1853 // A content column shrinks to what is in it. `width: 1%` is how a CSS table
1854 // is told that: auto layout hands the slack to the columns that asked for
1855 // room, and a column asking for almost none gets what it needs and no more.
1856 // The `nowrap` is what stops it being given less by wrapping.
1857 let _ = writeln!(
1858 css,
1859 ".{} {{\n white-space: nowrap;\n width: 1%;\n}}",
1860 class("cell-content", opts)
1861 );
1862
1863 // A fixed column has no length to be fixed to. The description carries none
1864 // and `Sizing` is not reachable from here, so it behaves as content: the
1865 // honest answer to a width nobody supplied, and the same one `Sizing::track`
1866 // gives it.
1867 let _ = writeln!(
1868 css,
1869 ".{} {{\n white-space: nowrap;\n}}",
1870 class("cell-fixed", opts)
1871 );
1872
1873 // Optional columns go at the narrowest class, secondary ones go with them,
1874 // which is the cutoff walk `kept_at` describes said as two media queries.
1875 // Essential columns have no rule at all, because never dropping is what not
1876 // being mentioned already means.
1877 for (size, drops) in [
1878 (
1879 SizeClass::Compact,
1880 &["cell-drops-first", "cell-drops-next"][..],
1881 ),
1882 (SizeClass::Medium, &["cell-drops-first"][..]),
1883 ] {
1884 let selectors: Vec<String> = drops
1885 .iter()
1886 .map(|drop| format!(".{}", class(drop, opts)))
1887 .collect();
1888 css.push_str(&gated(
1889 Some(&size.media_condition()),
1890 &format!("{} {{\n display: none;\n}}\n", selectors.join(",\n")),
1891 ));
1892 }
1893
1894 // What is inside a cell, which the table side could not say until
1895 // makeover-layout 0.14.0. Every cell was one `.cell` and one content
1896 // colour, so a button in a cell was painted as text -- the drift
1897 // `RowPart::intent` has prevented for list rows since 0.2.0 and prevented
1898 // for nothing here.
1899 //
1900 // The colour goes on `.cell-value` rather than on `.cell`, and that
1901 // placement is the whole fix. On the container it would cascade into the
1902 // tokens and the controls sitting beside the text, which is the bug said
1903 // in one rule; on the part that is text, it reaches text and stops.
1904 for part in [
1905 CellPart::Value,
1906 CellPart::Tokens,
1907 CellPart::Actions,
1908 CellPart::Link,
1909 ] {
1910 // Three of the four inherit, each for its own reason: a token carries
1911 // its own tone, an action is a control rather than text, and a link
1912 // takes the action colour from the anchor it is. `CellPart::intent`
1913 // says so by answering with the intent inheriting already gives, and
1914 // pinning that would be louder than saying nothing.
1915 //
1916 // Written as a skip-list rather than as a match on Value, so a member
1917 // added upstream gets its intent emitted rather than being silently
1918 // dropped. That is the same trade `part_class`'s fallback makes: land
1919 // plainly, never land as nothing.
1920 if !matches!(part, CellPart::Tokens | CellPart::Actions | CellPart::Link) {
1921 let _ = writeln!(
1922 css,
1923 ".{} {{\n color: var(--{});\n}}",
1924 class(cell_part_class(part), opts),
1925 part.intent()
1926 );
1927 }
1928 }
1929
1930 css
1931 }
1932
1933 /// The component layer: every named thing phase A emits.
1934 ///
1935 /// No scrollbar track. It was on the phase A list and came off: eight lines of
1936 /// `::-webkit-scrollbar` with no shape a terminal or an immediate-mode painter
1937 /// would want handed to it, so it stays with the apps.
1938 #[must_use]
1939 pub fn component_rules(opts: &Emit) -> String {
1940 let mut css = String::new();
1941 css.push_str(&surface_rules(opts));
1942 css.push_str(&link_rules(opts));
1943 css.push_str(&token_rules(opts));
1944 css.push_str(&selector_rules(opts));
1945 css.push_str(&row_rules(opts));
1946 css.push_str(&run_rules(opts));
1947 css.push_str(&progress_rules(opts));
1948 css.push_str(&awaiting_rules(opts));
1949 css.push_str(&figure_rules(opts));
1950 css.push_str(&picture_rules(opts));
1951 css.push_str(&showing_rules(opts));
1952 css.push_str(&track_rules(opts));
1953 css.push_str(&state_rules(opts));
1954 css.push_str(&table_rules(opts));
1955 css.push_str(&facet::facet_rules(opts));
1956 css.push_str(&form::editor_rules(opts));
1957 css.push_str(&form::suggestion_rules(opts));
1958 css.push_str(&form::unit_rules(opts));
1959 css.push_str(&form::option_detail_rules(opts));
1960 css.push_str(&form::note_rules(opts));
1961 css.push_str(&leaving_rules());
1962 css
1963 }
1964
1965 /// How a transient notice goes away.
1966 ///
1967 /// `makeover-timing` says that `Intent::Dismiss` is how long a notice lives
1968 /// *before it starts to leave*, and that the leaving itself is `Motion::Fade`.
1969 /// `makeover-build` writes `--motion-fade` into every consumer's `timing.css`,
1970 /// and this is the rule that reads it. Removing the node the moment the dismiss
1971 /// is up skips the leaving entirely.
1972 ///
1973 /// # Why an attribute and not a class
1974 ///
1975 /// [`Emit`]'s prefix moves every class this crate writes, so a class here would
1976 /// have to be resolved through `class()` by whoever sets it -- and the party
1977 /// setting it is a script, which has no prefix to hand. `data-leaving` is
1978 /// outside that namespace, so a renderer can set it from JavaScript with no
1979 /// coordination.
1980 ///
1981 /// The transition sits on the notice and the opacity on the leaving state, so
1982 /// the element is transitionable before the attribute arrives; a transition
1983 /// declared in the same rule as the value it changes has nothing to animate
1984 /// from.
1985 ///
1986 /// # Reduced motion is handled by the token, not by a second rule here
1987 ///
1988 /// `timing.css` already zeroes `--motion-fade` under `prefers-reduced-motion`.
1989 /// The reader who asked for less motion gets an instant change rather than a
1990 /// fade, and the renderer that sets the attribute must still remove the node on
1991 /// a timer rather than on `transitionend` -- a zero-length transition may fire
1992 /// no event at all, and a node waiting on one that never comes stays forever.
1993 ///
1994 /// The fallback is `0ms` and not a guessed duration: a page with no timing
1995 /// sheet has not opted into this vocabulary, and the honest answer there is the
1996 /// behaviour it had before, which is the notice going away at once.
1997 fn leaving_rules() -> String {
1998 let mut css = String::new();
1999 let _ = writeln!(
2000 css,
2001 "[data-notice] {{\n transition: opacity var(--motion-fade, 0ms) \
2002 ease-out;\n}}"
2003 );
2004 let _ = writeln!(css, "[data-notice][data-leaving] {{\n opacity: 0;\n}}");
2005 css
2006 }
2007
2008 /// The whole phase-A stylesheet: properties, depth rules and components, in
2009 /// [`CSS_LAYER`], under a generated-file banner.
2010 ///
2011 /// The banner sits outside the layer, because a comment participates in no
2012 /// cascade and a reader opening the file should see what it is before seeing
2013 /// an at-rule.
2014 #[must_use]
2015 pub fn stylesheet(opts: &Emit) -> String {
2016 let body = in_css_layer(&format!(
2017 ":root {{\n{}}}\n\n{}\n{}",
2018 bevel_properties(opts),
2019 depth_rules(opts),
2020 component_rules(opts)
2021 ));
2022 // Counted from the body rather than through `vocabulary::names`, which
2023 // calls back into here.
2024 let classes = vocabulary::classes_in_css(&body).len();
2025 let version = VERSION;
2026 format!(
2027 "/* Generated by makeover-webview {version} from makeover-layout, \
2028 {classes} classes.\n \
2029 Do not edit. The version and the count are here because a stale\n \
2030 lockfile fails silently: an older emitter writes a well-formed sheet\n \
2031 with components missing, and nothing else in the file says so. If\n \
2032 this version trails what the manifest asks for, re-resolve.\n\n \
2033 Depth is a fill and an edge together; naming them apart is what let\n \
2034 them disagree. See the crate's README and wiki note makeover-layout.\n\n \
2035 Everything below is in the `{CSS_LAYER}` cascade layer. Declare the\n \
2036 order once in your own stylesheet, or this layer's position is decided\n \
2037 by whichever generated file the browser happens to see first:\n\n \
2038 @layer {CSS_LAYER}, base, components, responsive; */\n{body}"
2039 )
2040 }
2041
2042 #[cfg(test)]
2043 mod tests {
2044 use super::*;
2045 use makeover_layout::Edge;
2046
2047 #[test]
2048 fn every_fallback_class_is_one_a_checker_knows_about() {
2049 // The obligation ROW_PART_CLASSES carries, for the same reason: a class
2050 // this crate can write and the vocabulary list does not carry is
2051 // invisible to the dead-vocabulary seal and to the overlap check both.
2052 for fallback in [
2053 Fallback::Wrap,
2054 Fallback::Stack,
2055 Fallback::Shed,
2056 Fallback::Menu,
2057 ] {
2058 assert!(
2059 RUN_CLASSES.contains(&fallback_class(fallback)),
2060 "{fallback:?} is missing from RUN_CLASSES"
2061 );
2062 }
2063 let names = crate::vocabulary::names(&Emit::default());
2064 for name in RUN_CLASSES {
2065 assert!(names.contains(*name), "{name} is not in the vocabulary");
2066 }
2067 }
2068
2069 #[test]
2070 fn a_run_gives_every_member_a_floor_it_cannot_be_squeezed_below() {
2071 // The whole of what stops the overlap, and it is not a fallback: it
2072 // applies to every run whatever the group declared. flexbox's default
2073 // min-width is auto, which lets an item be compressed below its own
2074 // content in a nowrap row, and that is how a toolbar is drawn over a
2075 // tab strip even with nothing out of flow.
2076 let css = run_rules(&Emit::default());
2077 assert!(css.contains(".run > * {\n min-width: min-content;\n}"));
2078 // No number anywhere in it. The minimum is derived by the browser from
2079 // what the members contain, which is the ruling's own requirement.
2080 assert!(!css.contains("px"));
2081 assert!(!css.contains("rem"));
2082 assert!(!css.contains("@media"));
2083 }
2084
2085 #[test]
2086 fn room_is_never_asked_of_the_viewport() {
2087 // The 913 case: a window in SizeClass::Expanded holding a group out of
2088 // room. A viewport query answers about the window and would be wrong
2089 // about the group, which is why the table's @media walk is not the
2090 // precedent this follows.
2091 let css = run_rules(&Emit::default());
2092 for size in [SizeClass::Compact, SizeClass::Medium] {
2093 assert!(!css.contains(&size.media_condition()));
2094 }
2095 }
2096
2097 #[test]
2098 fn every_fallback_lands_as_a_class_and_an_unknown_one_lands_plainly() {
2099 let css = run_rules(&Emit::default());
2100 for fallback in [
2101 Fallback::Wrap,
2102 Fallback::Stack,
2103 Fallback::Shed,
2104 Fallback::Menu,
2105 ] {
2106 let class = fallback_class(fallback);
2107 assert!(css.contains(&format!(".{class} {{")), "{class} unemitted");
2108 }
2109 // Stack is the one that also says what a member does with the line it
2110 // took, which is what separates it from wrapping.
2111 assert!(css.contains(".run-stack > * {\n flex: 1 1 max-content;\n}"));
2112 }
2113
2114 #[test]
2115 fn the_emitted_bevel_matches_what_the_apps_already_hand_write() {
2116 // Balanced Breakfast's styles.css, verbatim. Adoption has to be a
2117 // deletion, not a redesign, or nobody will take it.
2118 let opts = Emit::default();
2119 assert_eq!(
2120 bevel_shadow(Bevel::Raised, &opts),
2121 "inset 1px 1px 0 var(--bevel-light), inset -1px -1px 0 var(--bevel-dark)"
2122 );
2123 assert_eq!(
2124 bevel_shadow(Bevel::Inset, &opts),
2125 "inset 1px 1px 0 var(--bevel-dark), inset -1px -1px 0 var(--bevel-light)"
2126 );
2127 }
2128
2129 #[test]
2130 fn no_colour_ever_reaches_the_output() {
2131 let css = stylesheet(&Emit::default());
2132 assert!(!css.contains('#'), "a hex literal escaped into the CSS");
2133 assert!(
2134 !css.contains("rgb"),
2135 "a colour function escaped into the CSS"
2136 );
2137 // Every colour is named, never resolved.
2138 assert!(css.contains("var(--surface-raised)"));
2139 assert!(css.contains("var(--bevel-light)"));
2140 }
2141
2142 #[test]
2143 fn a_well_falls_back_through_css_rather_than_through_rust() {
2144 assert_eq!(
2145 fill_var(Fill::Well),
2146 "var(--surface-well, var(--surface-page))"
2147 );
2148 // Nothing else needs one.
2149 assert_eq!(fill_var(Fill::Raised), "var(--surface-raised)");
2150 assert_eq!(fill_var(Fill::Page), "var(--surface-page)");
2151 }
2152
2153 #[test]
2154 fn raised_and_well_do_not_collapse_onto_each_other() {
2155 let css = depth_rules(&Emit::default());
2156 assert!(css.contains(".raised {"));
2157 assert!(css.contains(".well {"));
2158 assert!(css.contains("var(--bevel-raised)"));
2159 assert!(css.contains("var(--bevel-inset)"));
2160 }
2161
2162 /// The cast shadow is composed here from the tone `makeover` derives, so
2163 /// neither crate has to hold the other's numbers.
2164 ///
2165 /// It is a `:root` property and deliberately not a depth class. There is no
2166 /// `Depth::Overlay` in the description layer, and adding one would be a
2167 /// claim about what a screen means rather than about how it is painted;
2168 /// until something asks for it, a consumer names the property on the rule
2169 /// for the menu or the toast it already has.
2170 #[test]
2171 fn the_cast_shadow_is_a_root_property_not_a_depth() {
2172 let css = bevel_properties(&Emit::default());
2173 assert!(css.contains("--elevation-overlay:"));
2174 assert!(css.contains("var(--elevation)"));
2175 assert!(
2176 !depth_rules(&Emit::default()).contains("elevation"),
2177 "elevation is not a depth class"
2178 );
2179 }
2180
2181 #[test]
2182 fn the_cascade_carries_the_pressed_state() {
2183 let css = surface_rules(&Emit::default());
2184 // The one thing this renderer gets free that the other two resolve by
2185 // hand, eighteen call sites deep in audiofiles' case. Asserted on a
2186 // named surface: pressing belongs to the control, not to the depth.
2187 assert!(css.contains(".card:active {"));
2188 assert!(css.contains(".button:active {"));
2189 }
2190
2191 #[test]
2192 fn the_depth_class_is_a_surface_and_not_a_control() {
2193 let css = depth_rules(&Emit::default());
2194 // The static surface the vocabulary was missing. Sixteen goingson
2195 // elements wore .card and cancelled its hover and press to get this,
2196 // because a raised object that is not pressable had no other spelling.
2197 for state in [":hover", ":active", ":focus-visible", ":disabled"] {
2198 assert!(
2199 !css.contains(&format!(".raised{state}")),
2200 "the depth class claimed {state}: {css}"
2201 );
2202 }
2203 assert!(css.contains("var(--bevel-raised)"), "still raised: {css}");
2204 }
2205
2206 #[test]
2207 fn pressing_moves_the_fill_and_not_only_the_edge() {
2208 // The decision-1 guard, and the regression that mattered: emitting the
2209 // bevel flip alone is what left goingson hand-writing `background:
2210 // var(--surface-sunken)` on .btn, .card and .tag/.badge alike, so none
2211 // of the three could be deleted.
2212 let pressed = interactive_rules("button", Depth::Raised, &Emit::default());
2213 assert!(pressed.contains(".button:active {"));
2214 assert!(
2215 pressed.contains("background: var(--surface-well, var(--surface-page))"),
2216 "pressed dropped its fill: {pressed}"
2217 );
2218 assert!(pressed.contains("box-shadow: var(--bevel-inset)"));
2219 }
2220
2221 #[test]
2222 fn pressed_takes_its_fill_from_the_description_not_from_the_app() {
2223 // goingson presses to --surface-sunken. The description says a pressed
2224 // raised region reads as a well, and makeover says outright that
2225 // surface-sunken cannot serve as one, so the app is the thing that
2226 // moves.
2227 //
2228 // Scoped to the pressed rules rather than to the whole sheet: since
2229 // makeover-layout 0.3.0 an unchosen tab is legitimately
2230 // --surface-sunken, so the token appearing somewhere in the output no
2231 // longer means the app's choice leaked in.
2232 let css = stylesheet(&Emit::default());
2233 let mut checked = 0;
2234 for rule in css.split("}\n") {
2235 if !rule.contains(":active") {
2236 continue;
2237 }
2238 checked += 1;
2239 assert!(
2240 !rule.contains("surface-sunken"),
2241 "a pressed rule took the app's fill: {rule}"
2242 );
2243 }
2244 assert!(checked > 0, "no pressed rules found to check");
2245 assert_eq!(
2246 Depth::Raised.pressed().fill(),
2247 Some(Fill::Well),
2248 "the description changed under us"
2249 );
2250 }
2251
2252 #[test]
2253 fn the_whole_stylesheet_is_emitted_in_the_family_layer() {
2254 // The point of 0.11.0. Unlayered normal declarations outrank every
2255 // named layer, so an app declaring `@layer base, components` loses
2256 // every rule it owns to this file until this file is layered too.
2257 let css = stylesheet(&Emit::default());
2258 assert!(css.contains(&format!("@layer {CSS_LAYER} {{")));
2259
2260 // Exactly one layer block, and nothing outside it but the banner.
2261 assert_eq!(css.matches("@layer").count(), 2, "banner names it once");
2262 let opened = css.find("@layer makeover {").expect("layer opens");
2263 for (i, line) in css.lines().enumerate() {
2264 let before_layer = css.lines().take(i).map(str::len).sum::<usize>() < opened;
2265 if before_layer || line.is_empty() {
2266 continue;
2267 }
2268 assert!(
2269 line.starts_with(" ") || line == "}" || line.starts_with(" "),
2270 "line outside the layer: {line:?}"
2271 );
2272 }
2273 }
2274
2275 #[test]
2276 fn the_generated_sheet_carries_no_trailing_whitespace() {
2277 // A checked-in generated file that a formatter wants to rewrite is a
2278 // diff every time somebody saves it.
2279 let css = stylesheet(&Emit::default());
2280 for (i, line) in css.lines().enumerate() {
2281 assert_eq!(line, line.trim_end(), "trailing whitespace on line {i}");
2282 }
2283 }
2284
2285 #[test]
2286 fn the_banner_tells_an_app_how_to_order_the_layer() {
2287 // Without a declared order the layer's position depends on which
2288 // generated file the browser sees first, which is not a contract.
2289 let css = stylesheet(&Emit::default());
2290 assert!(css.contains("@layer makeover, base, components, responsive;"));
2291 // And the banner is outside the layer, not a rule inside it.
2292 assert!(css.starts_with("/* Generated by makeover-webview"));
2293 }
2294
2295 #[test]
2296 fn the_banner_names_the_emitter_so_a_stale_pin_is_visible_on_sight() {
2297 // A consumer whose lockfile pins an old version gets a well-formed
2298 // sheet with components missing and no error. balanced_breakfast ran
2299 // on 657 bytes from a 0.1.0 emitter while its manifest asked for
2300 // 0.5.1, and the only way it surfaced was diffing two apps' generated
2301 // files. The version and the count are what the file says instead.
2302 let css = stylesheet(&Emit::default());
2303 let banner = css.lines().next().unwrap();
2304 assert!(
2305 banner.contains(VERSION),
2306 "{banner} does not name the emitter"
2307 );
2308 let classes = vocabulary::classes_in_css(&css).len();
2309 assert!(classes > 0);
2310 assert!(
2311 banner.contains(&format!("{classes} classes")),
2312 "{banner} does not carry the class count"
2313 );
2314 }
2315
2316 #[test]
2317 fn a_primitive_owns_every_state_it_implies() {
2318 // The whole point of 0.10.0. Anything emitting a hover rule owes the
2319 // other three, or the consuming app supplies them by out-specifying a
2320 // rule it does not own: 19 such rules in goingson, 21 in the MNW
2321 // server, and three focus rings that do not match.
2322 let css = stylesheet(&Emit::default());
2323 for selector in ["button", "card", "chip", "tab", "segment", "toggle"] {
2324 assert!(css.contains(&format!(".{selector}:hover {{")), "{selector}");
2325 assert!(
2326 css.contains(&format!(".{selector}:active {{")),
2327 "{selector}"
2328 );
2329 assert!(
2330 css.contains(&format!(".{selector}:focus-visible {{")),
2331 "{selector} has no focus ring"
2332 );
2333 assert!(
2334 css.contains(&format!(".{selector}:disabled,")),
2335 "{selector} has no disabled state"
2336 );
2337 }
2338 }
2339
2340 #[test]
2341 fn a_field_takes_focus_and_refuses_input_without_taking_a_hover() {
2342 // A text field does not light up under the pointer, so it gets the two
2343 // states it has and not the two it does not.
2344 let css = stylesheet(&Emit::default());
2345 assert!(css.contains(".field:focus-visible {"));
2346 assert!(css.contains(".field:disabled,"));
2347 assert!(!css.contains(".field:hover {"));
2348 assert!(!css.contains(".field:active {"));
2349 }
2350
2351 #[test]
2352 fn disabled_is_emitted_after_hover_so_source_order_settles_it() {
2353 // Every one of these selectors is specificity (0,2,0), so nothing but
2354 // order decides which wins. A disabled button taking the hover fill is
2355 // the exact bug goingson's `.button:disabled:hover` was written to fix,
2356 // and the reason it had to reach (0,3,0) to do it.
2357 let css = interactive_rules("button", Depth::Raised, &Emit::default());
2358 let hover = css.find(":hover").expect("hover");
2359 let active = css.find(":active").expect("active");
2360 let focus = css.find(":focus-visible").expect("focus");
2361 let disabled = css.find(":disabled").expect("disabled");
2362 assert!(hover < active && active < focus && focus < disabled);
2363
2364 // And it restores the surface, or the hover fill survives underneath.
2365 let tail = &css[disabled..];
2366 assert!(tail.contains("background: var(--surface-raised)"));
2367 }
2368
2369 #[test]
2370 fn a_flat_control_takes_its_hover_fill_back_when_it_stops_answering() {
2371 // The same contest one depth over, and the half `depth_declarations`
2372 // could not state. Flat declares neither axis, so before 0.68.0 the
2373 // disabled rule won on source order with nothing to say and the hover
2374 // surface stayed under a control that had stopped answering. Reaches
2375 // both facet arms and a suggestion entry.
2376 for depth in [Depth::Flat, Depth::Sunken, Depth::Overlay] {
2377 let css = disabled_rule("x", depth);
2378 assert!(css.contains("box-shadow"), "{depth:?}: {css}");
2379 }
2380 let flat = disabled_rule("x", Depth::Flat);
2381 assert!(flat.contains("background: none;"), "{flat}");
2382 assert!(flat.contains("box-shadow: none;"), "{flat}");
2383
2384 // Every rule the caller emits states both axes now, so whichever wins
2385 // the source-order contest leaves nothing of the one below it.
2386 let css = interactive_rules("x", Depth::Flat, &Emit::default());
2387 let disabled = css.find(":disabled").expect("disabled");
2388 assert!(css[disabled..].contains("background: none;"), "{css}");
2389 }
2390
2391 #[test]
2392 fn a_disabled_state_reaches_things_that_cannot_be_disabled() {
2393 // `:disabled` matches form elements only, and a chip is a div. Keying
2394 // on the ARIA attribute too is the pattern the invalid field already
2395 // set: one fact, read by the styling and the accessibility tree alike.
2396 let css = disabled_rule("chip", Depth::Raised);
2397 assert!(css.contains(".chip:disabled,"));
2398 assert!(css.contains(".chip[aria-disabled=\"true\"]"));
2399 assert!(css.contains("cursor: not-allowed"));
2400 }
2401
2402 #[test]
2403 fn the_focus_ring_does_not_disturb_the_bevel_it_lands_on() {
2404 // `outline` has its own property, so unlike the invalid ring there is
2405 // no bevel to restate beside it and nothing to keep in agreement.
2406 let opts = Emit::default();
2407 let css = focus_rule("button", Depth::Raised, &opts);
2408 assert!(css.contains("outline: 2px solid var(--focus-ring)"));
2409 assert!(!css.contains("box-shadow"), "the ring restated the bevel");
2410 }
2411
2412 #[test]
2413 fn a_well_takes_the_ring_inside_and_a_raised_surface_outside() {
2414 // One ring, placed by depth. The offset comes off `Depth::bevel` and
2415 // not off a per-component choice, which is what gave three apps three
2416 // different rings.
2417 let opts = Emit::default();
2418 assert!(focus_rule("field", Depth::Well, &opts).contains("outline-offset: calc(-1 * 2px)"));
2419 assert!(focus_rule("button", Depth::Raised, &opts).contains("outline-offset: 2px"));
2420 // Nothing to sit inside of, so it sits outside.
2421 assert!(focus_rule("badge", Depth::Sunken, &opts).contains("outline-offset: 2px"));
2422
2423 // And the ring is not the bevel. Reusing border_width emitted a 1px
2424 // ring that every consumer had already overridden.
2425 assert_ne!(opts.focus_width, opts.border_width);
2426 }
2427
2428 #[test]
2429 fn hover_is_gated_on_capability_and_the_keyboard_path_is_not() {
2430 // goingson's section 60 exists only to take back the hover state this
2431 // crate handed it. Gating at the source is what deletes that section
2432 // in all three apps rather than having each fight for it.
2433 let css = stylesheet(&Emit::default());
2434 let condition = format!("@media {}", Density::Pointer.media_condition());
2435 assert!(css.contains(&condition));
2436
2437 // What is gated is every hover state the surfaces carry. The row's
2438 // actions used to be the other half of this test and are not gated any
2439 // more, because they are not hidden any more: a rule that reveals
2440 // nothing needs no capability answer.
2441 let gated: Vec<&str> = css.lines().filter(|line| line.contains(":hover")).collect();
2442 assert!(!gated.is_empty(), "{css}");
2443 for line in gated {
2444 let indent = line.len() - line.trim_start().len();
2445 assert!(indent > 4, "an ungated hover rule: {line}");
2446 }
2447 assert!(!css.contains(".row:hover"), "{css}");
2448 }
2449
2450 #[test]
2451 fn the_capability_answer_is_asked_for_and_not_assumed() {
2452 // Both halves come from the crates that own them. If `makeover-touch`
2453 // ever says a fingertip has hover, this stops gating on its own.
2454 assert!(!Affordance::Hover.available(Density::Touch, SizeClass::Compact));
2455 assert!(Affordance::Hover.available(Density::Pointer, SizeClass::Compact));
2456 assert_eq!(hover_condition(), Some(Density::Pointer.media_condition()));
2457
2458 // And the size class passed to that call is not a claim about width.
2459 assert!(Affordance::Hover.reads_density());
2460 for size in [SizeClass::Compact, SizeClass::Medium, SizeClass::Expanded] {
2461 assert!(!Affordance::Hover.available(Density::Touch, size));
2462 }
2463 }
2464
2465 #[test]
2466 fn hover_resolves_against_the_token_makeover_already_derives() {
2467 let css = interactive_rules("card", Depth::Raised, &Emit::default());
2468 assert!(css.contains(".card:hover {"));
2469 assert!(css.contains("background: var(--hover-surface)"));
2470 // Not the app's choice, which was --surface-overlay.
2471 assert!(!css.contains("surface-overlay"));
2472 }
2473
2474 #[test]
2475 fn a_badge_gets_no_edge_and_no_fill() {
2476 // Decision 2, and the one visible redesign in phase A. Token::Badge is
2477 // Flat: an edge on a label says it can be pressed.
2478 let css = token_rules(&Emit::default());
2479 let badge = css
2480 .lines()
2481 .skip_while(|l| !l.starts_with(".badge {"))
2482 .take_while(|l| !l.starts_with('}'))
2483 .collect::<Vec<_>>()
2484 .join("\n");
2485 assert!(!badge.contains("box-shadow"), "badge kept an edge: {badge}");
2486 assert!(!badge.contains("background"), "badge kept a fill: {badge}");
2487 assert_eq!(Token::Badge.depth(false), Depth::Flat);
2488 assert_eq!(Token::Badge.depth(true), Depth::Flat);
2489 }
2490
2491 #[test]
2492 fn a_badge_carries_a_tone_and_neutral_is_the_bare_class() {
2493 let css = token_rules(&Emit::default());
2494 // Neutral is the absence of a status, not a status named "none".
2495 assert!(css.contains(".badge {\n color: var(--content-muted);"));
2496 assert!(!css.contains("data-tone=\"content-muted\""));
2497 for tone in ["info", "success", "warning", "danger"] {
2498 assert!(
2499 css.contains(&format!(".badge[data-tone=\"{tone}\"]")),
2500 "missing tone {tone}"
2501 );
2502 assert!(css.contains(&format!("color: var(--{tone})")));
2503 }
2504 }
2505
2506 #[test]
2507 fn a_chip_is_raised_and_latches_into_a_well() {
2508 let css = token_rules(&Emit::default());
2509 assert!(css.contains(".chip {"));
2510 assert!(css.contains(".chip.latched {"));
2511 assert!(css.contains(".chip:active {"));
2512 // The whole difference from a badge: it answers a click.
2513 assert!(Token::Chip { removable: false }.interactive());
2514 assert!(!Token::Badge.interactive());
2515 }
2516
2517 #[test]
2518 fn only_a_tab_comes_forward_when_chosen() {
2519 // The folder semantic. Collapsing the three selectors would lose it.
2520 let css = selector_rules(&Emit::default());
2521 assert!(css.contains(".tab.chosen {"));
2522 assert!(css.contains(".segment.chosen {"));
2523 assert!(css.contains(".toggle.chosen {"));
2524 assert_eq!(Selector::Tabs.chosen(), Depth::Raised);
2525 assert_eq!(Selector::Segmented.chosen(), Depth::Well);
2526 assert_eq!(Selector::Toggle.chosen(), Depth::Well);
2527
2528 let tab = css
2529 .lines()
2530 .skip_while(|l| !l.starts_with(".tab.chosen {"))
2531 .take_while(|l| !l.starts_with('}'))
2532 .collect::<Vec<_>>()
2533 .join("\n");
2534 assert!(
2535 tab.contains("var(--bevel-raised)"),
2536 "tab was held in: {tab}"
2537 );
2538 }
2539
2540 #[test]
2541 fn an_unchosen_tab_recedes_without_looking_picked() {
2542 let css = selector_rules(&Emit::default());
2543 // Recessed by colour and given no edge. An edge would make every option
2544 // look picked; flat would leave the chosen one nothing to come forward
2545 // from, which is the gap makeover-layout 0.3.0 closed.
2546 assert!(
2547 css.contains(".tab {\n background: var(--surface-sunken);\n}"),
2548 "unchosen tab is not recessed: {css}"
2549 );
2550 assert_eq!(Selector::Tabs.unchosen(), Depth::Sunken);
2551 assert!(css.contains(".tab:hover {"));
2552 }
2553
2554 #[test]
2555 fn a_segment_stands_up_so_the_chosen_one_can_be_held_in() {
2556 // The inverse of the tab, and why the three selectors are not one
2557 // member with a flag.
2558 let css = selector_rules(&Emit::default());
2559 assert!(css.contains(".segment {\n background: var(--surface-raised);"));
2560 assert_eq!(Selector::Segmented.unchosen(), Depth::Raised);
2561 assert_eq!(Selector::Segmented.chosen(), Depth::Well);
2562 }
2563
2564 #[test]
2565 fn a_rows_actions_are_shown_at_rest() {
2566 let css = row_rules(&Emit::default());
2567
2568 // The hover reveal is gone, and with it every escape it needed. What
2569 // it hid was hidden from pointer users alone, who are the ones
2570 // scanning a list to learn what can be done to a row.
2571 assert!(!css.contains("opacity"), "{css}");
2572 assert!(!css.contains("pointer-events"), "{css}");
2573 assert!(!css.contains(":hover"), "{css}");
2574 assert!(!css.contains(":focus-within"), "{css}");
2575
2576 // Nor is it hidden any other way. `display: none` would reflow the row
2577 // and `visibility: hidden` would take the actions out of the focus
2578 // order; the point is that neither is reached for.
2579 assert!(!css.contains("display: none"), "{css}");
2580 assert!(!css.contains("visibility:"), "{css}");
2581 }
2582
2583 #[test]
2584 fn a_figures_tone_lands_on_the_delta_when_there_is_one() {
2585 // 0.13.0. The delta is the part that reads as good or bad; the number
2586 // itself is an ordinary fact. A figure with no delta has nowhere else to
2587 // put the colour, so the value takes it, and `:has` is what lets one
2588 // attribute mean both without the emitter choosing an element.
2589 let css = stylesheet(&Emit::default());
2590
2591 assert!(
2592 css.contains(".figure[data-tone=\"success\"] > .figure-change"),
2593 "{css}"
2594 );
2595 assert!(
2596 css.contains(
2597 ".figure[data-tone=\"success\"]:not(:has(> .figure-change)) > .figure-value"
2598 ),
2599 "{css}"
2600 );
2601 // The caption is the noun and never takes the tone.
2602 assert!(
2603 !css.contains("[data-tone=\"success\"] > .figure-caption"),
2604 "{css}"
2605 );
2606 }
2607
2608 #[test]
2609 fn the_three_text_parts_take_their_intents_and_actions_inherits() {
2610 let css = row_rules(&Emit::default());
2611 assert!(css.contains(".row-primary {\n color: var(--content);"));
2612 assert!(css.contains(".row-secondary {\n color: var(--content-secondary);"));
2613 assert!(css.contains(".row-meta {\n color: var(--content-muted);"));
2614 // Actions carry controls, not text. Pinning the colour it would inherit
2615 // anyway is louder than saying nothing.
2616 assert!(!css.contains(".row-actions {\n color:"));
2617 }
2618
2619 #[test]
2620 fn the_token_strip_takes_no_colour_of_its_own() {
2621 // makeover-layout 0.9.0. A token carries its own tone, so a colour on
2622 // the strip would be a rule fighting the things sitting in it -- the
2623 // same reasoning as actions, reached for a different reason.
2624 let css = row_rules(&Emit::default());
2625 assert!(!css.contains(".row-tokens {\n color:"));
2626 }
2627
2628 #[test]
2629 fn an_unknown_row_part_renders_plainly_rather_than_failing_to_build() {
2630 // What `#[non_exhaustive]` bought and what it cost. `part_class` can no
2631 // longer be exhaustive, so a member added upstream lands as a bare
2632 // class with no rule instead of stopping the build. Asserting the
2633 // fallback exists is what keeps it from being written as `unreachable!`
2634 // by someone who reads the match as closed.
2635 assert_eq!(part_class(RowPart::Tokens), "row-tokens");
2636 assert_eq!(part_class(RowPart::Meta), "row-meta");
2637 }
2638
2639 #[test]
2640 fn a_link_takes_the_action_colour_the_theme_actually_defines() {
2641 // `--action-primary` shipped here for months and no theme has ever
2642 // defined it, so every `.link` dropped its colour declaration outright
2643 // and fell back to inherited text. Nothing caught it because the sheet
2644 // is valid CSS either way; MNW's no-undefined-token lint is what found
2645 // it, 2026-08-14. The hover arm two lines below was always `--action-hover`,
2646 // which is what makes the typo legible in hindsight.
2647 let css = link_rules(&Emit::default());
2648 assert!(css.contains("color: var(--action);"));
2649 assert!(!css.contains("--action-primary"));
2650 assert!(css.contains("color: var(--action-hover);"));
2651 }
2652
2653 #[test]
2654 fn the_progress_trough_is_a_well() {
2655 let css = progress_rules(&Emit::default());
2656 assert!(css.contains(".progress {"));
2657 assert!(css.contains("box-shadow: var(--bevel-inset)"));
2658 assert!(css.contains(".progress > .progress-fill {"));
2659 assert!(css.contains("background: var(--action)"));
2660 // A bare `.fill` would catch things that have nothing to do with
2661 // progress once the sheet lands unprefixed.
2662 assert!(!css.contains("> .fill "));
2663 }
2664
2665 #[test]
2666 fn a_progress_bar_can_carry_a_tone_and_defaults_to_action() {
2667 let css = progress_rules(&Emit::default());
2668 // Untoned is --action, not Tone::Neutral's content-muted: a bar with no
2669 // status is still reporting progress, and muted would read as disabled.
2670 assert!(css.contains(".progress > .progress-fill {\n background: var(--action);"));
2671 assert!(!css.contains("progress-fill {\n color: var(--content-muted)"));
2672 for tone in ["info", "success", "warning", "danger"] {
2673 assert!(
2674 css.contains(&format!(".progress > .progress-fill[data-tone=\"{tone}\"]")),
2675 "missing progress tone {tone}"
2676 );
2677 }
2678 // goingson's two live cases, which is why the tones are emitted at all.
2679 assert!(css.contains("[data-tone=\"success\"] {\n background: var(--success);"));
2680 assert!(css.contains("[data-tone=\"danger\"] {\n background: var(--danger);"));
2681 }
2682
2683 #[test]
2684 fn no_scrollbar_track_is_emitted() {
2685 // Decision 3's negative half. It was on the phase A list and came off;
2686 // this is what stops it drifting back in.
2687 let css = stylesheet(&Emit::default());
2688 assert!(!css.contains("scrollbar"));
2689 assert!(!css.contains("::-webkit"));
2690 }
2691
2692 #[test]
2693 fn an_invalid_field_is_ringed_without_being_lit() {
2694 let css = surface_rules(&Emit::default());
2695 assert!(css.contains(".field {"));
2696 // The ARIA attribute, not a class: one fact, read by both the visual
2697 // and the accessible state, so they cannot drift.
2698 assert!(css.contains(".field[aria-invalid=\"true\"] {"));
2699 assert!(!css.contains(".field.invalid"));
2700 // A flat ring: this edge says "wrong", and a two-tone bevel would have
2701 // it say "raised" at the same time.
2702 assert!(css.contains("0 0 0 1px var(--danger)"));
2703 }
2704
2705 #[test]
2706 fn an_invalid_field_keeps_the_well_underneath_it() {
2707 // box-shadow is not additive. A lone ring replaces the bevel and drops
2708 // the well out from under the field, which is what this emitted before
2709 // 0.5.0 and is the whole reason the rule composes.
2710 let css = surface_rules(&Emit::default());
2711 let invalid = css
2712 .lines()
2713 .skip_while(|l| !l.starts_with(".field[aria-invalid"))
2714 .take_while(|l| !l.starts_with('}'))
2715 .collect::<Vec<_>>()
2716 .join("\n");
2717 assert!(
2718 invalid.contains("var(--bevel-inset)"),
2719 "the well was dropped: {invalid}"
2720 );
2721 assert!(invalid.contains("var(--danger)"));
2722 }
2723
2724 #[test]
2725 fn button_and_card_come_out_identical_by_construction() {
2726 // The duplication phase A deletes. They are the same composition, so
2727 // the only honest way to emit both is from one call.
2728 let opts = Emit::default();
2729 let css = surface_rules(&opts);
2730 assert_eq!(
2731 depth_declarations(Depth::Raised),
2732 depth_declarations(Depth::Raised)
2733 );
2734 assert!(css.contains(".button {"));
2735 assert!(css.contains(".card {"));
2736 assert_eq!(
2737 interactive_rules("button", Depth::Raised, &Emit::default()).replace("button", "card"),
2738 interactive_rules("card", Depth::Raised, &Emit::default())
2739 );
2740 }
2741
2742 #[test]
2743 fn a_prefix_reaches_the_component_classes_too() {
2744 let opts = Emit {
2745 class_prefix: "mo-",
2746 ..Emit::default()
2747 };
2748 let css = stylesheet(&opts);
2749 for name in [
2750 "mo-button",
2751 "mo-card",
2752 "mo-field",
2753 "mo-badge",
2754 "mo-chip",
2755 "mo-tab",
2756 "mo-row-primary",
2757 "mo-progress",
2758 "mo-progress-fill",
2759 ] {
2760 assert!(css.contains(&format!(".{name}")), "unprefixed: {name}");
2761 }
2762 // The bare names must be gone entirely, or a prefixed build still
2763 // collides with the app's own stylesheet.
2764 assert!(!css.contains(".button {"));
2765 assert!(!css.contains(".card {"));
2766 assert!(!css.contains(".badge {"));
2767 }
2768
2769 #[test]
2770 fn the_class_a_renderer_puts_on_an_option_is_the_one_the_rules_key_off() {
2771 // `option_class` is the contract a screen renderer writes markup
2772 // against, and the rules below are the other half of it. They come off
2773 // one mapping now, so this asserts the mapping is the one that reaches
2774 // the stylesheet rather than that two lists still agree.
2775 let css = stylesheet(&Emit::default());
2776 for selector in [Selector::Tabs, Selector::Segmented, Selector::Toggle] {
2777 let name = option_class(selector);
2778 assert!(css.contains(&format!(".{name} {{")), "{name}: {css}");
2779 assert!(css.contains(&format!(".{name}.chosen {{")), "{name}: {css}");
2780 }
2781 assert_eq!(option_class(Selector::Tabs), "tab");
2782 }
2783
2784 #[test]
2785 fn the_caret_brings_its_own_gap_and_is_the_glyph_the_description_names() {
2786 let css = stylesheet(&Emit::default());
2787
2788 // The space is inside the glyph, which is what the other two renderers
2789 // write. Emitted bare, every consumer has to add it back, and the
2790 // obvious way to add it -- `content` in an app stylesheet, which is
2791 // unlayered and so outranks this sheet -- deletes the caret instead.
2792 assert!(css.contains("content: \" \\25B2\";"), "{css}");
2793 assert!(css.contains("content: \" \\25BC\";"), "{css}");
2794 assert!(!css.contains("content: \"\\2"), "{css}");
2795
2796 // The arrows this renderer used to draw alone are gone. Composition
2797 // rather than agreement: the glyph comes from `Sort::glyph`, so a
2798 // fourth spelling cannot appear here without appearing everywhere.
2799 assert!(!css.contains("2191") && !css.contains("2193"), "{css}");
2800 assert!(css.contains(&css_escape(Sort::Ascending.glyph())), "{css}");
2801
2802 // Three states, three tones. An idle sortable heading draws its caret
2803 // now rather than reserving a hidden box for it, so there is no
2804 // visibility to order and no reflow left to guard against; what
2805 // separates the states is the colour, and the sorted arms come after
2806 // the idle one because the specificity is the same.
2807 let idle = css
2808 .find(".table-heading[data-sortable]::after")
2809 .expect("the idle caret is emitted");
2810 let sorted = css
2811 .find(".table-heading[aria-sort=\"ascending\"]::after")
2812 .expect("the ascending caret is emitted");
2813 assert!(idle < sorted, "{css}");
2814 assert!(
2815 css[idle..sorted].contains("color: var(--content-secondary);"),
2816 "{css}"
2817 );
2818 assert!(css[sorted..].contains("color: var(--content);"), "{css}");
2819 assert!(!css.contains("visibility: hidden;"), "{css}");
2820 }
2821
2822 #[test]
2823 fn a_destructive_button_has_somewhere_for_its_tone_to_land() {
2824 let css = component_rules(&Emit::default());
2825
2826 for tone in [Tone::Info, Tone::Success, Tone::Warning, Tone::Danger] {
2827 assert!(
2828 css.contains(&format!(".button[data-tone=\"{}\"]", tone.token())),
2829 "{css}"
2830 );
2831 }
2832 // Colour, not a fill. A red surface is an app's decision about emphasis.
2833 assert!(!css.contains(".button[data-tone=\"danger\"] {\n background"));
2834 }
2835
2836 #[test]
2837 fn the_table_model_is_scoped_to_the_table_but_the_caret_is_not() {
2838 // goingson's task headings are `.table-heading` inside a CSS grid.
2839 // They want the sort caret and the sortable cursor; they do not want
2840 // `display: table-cell`, which a grid item blockifies away anyway.
2841 // Scoping the one and not the other is what separates them.
2842 let css = component_rules(&Emit::default());
2843
2844 assert!(
2845 css.contains(".table .table-heading,\n.table .cell {\n display: table-cell;"),
2846 "{css}"
2847 );
2848 assert!(
2849 !css.contains(".table-heading,\n.cell {\n display: table-cell;"),
2850 "the table model is still unscoped: {css}"
2851 );
2852
2853 let states = state_rules(&Emit::default());
2854 assert!(
2855 states.contains(".table-heading[aria-sort"),
2856 "the caret got scoped along with the model: {states}"
2857 );
2858 }
2859
2860 #[test]
2861 fn a_figure_value_is_the_thing_itself_and_a_badge_is_quiet() {
2862 // Both used to read `Tone::Neutral.token()`, which answered
2863 // `content-muted`, so the headline number sat at the colour of its own
2864 // caption. Neutral answers `content` now; each site states its own
2865 // claim rather than borrowing one from the status axis.
2866 let css = component_rules(&Emit::default());
2867
2868 assert!(
2869 css.contains(".figure > .figure-value {\n color: var(--content);"),
2870 "{css}"
2871 );
2872 assert!(
2873 css.contains(".figure > .figure-caption {\n color: var(--content-muted);"),
2874 "{css}"
2875 );
2876 assert!(
2877 css.contains(".badge {\n color: var(--content-muted);"),
2878 "{css}"
2879 );
2880 }
2881
2882 #[test]
2883 fn a_described_list_is_not_a_bulleted_list() {
2884 let css = component_rules(&Emit::default());
2885 assert!(css.contains(".list {\n list-style: none;"), "{css}");
2886 }
2887
2888 #[test]
2889 fn a_table_lays_itself_out_without_being_told_its_columns() {
2890 // The whole point of the CSS table. A described table's columns are
2891 // known at render time, so anything the stylesheet has to be told about
2892 // them would have to travel with the markup.
2893 let css = component_rules(&Emit::default());
2894
2895 assert!(css.contains(".table {\n display: table;"), "{css}");
2896 assert!(css.contains("display: table-row;"), "{css}");
2897 assert!(css.contains("display: table-cell;"), "{css}");
2898 assert!(!css.contains("grid-template-columns"), "{css}");
2899 }
2900
2901 #[test]
2902 fn a_control_in_a_cell_is_not_painted_as_text() {
2903 // The point of makeover-layout 0.14.0's CellPart, and the table-side
2904 // twin of `the_three_text_parts_take_their_intents_and_actions_inherits`
2905 // above. One `.cell` and one content colour meant a button in a cell
2906 // inherited it.
2907 let css = table_rules(&Emit::default());
2908
2909 assert!(
2910 css.contains(".cell-value {\n color: var(--content);"),
2911 "{css}"
2912 );
2913 assert!(!css.contains(".cell-actions {\n color:"), "{css}");
2914 assert!(!css.contains(".cell-tokens {\n color:"), "{css}");
2915 assert!(!css.contains(".cell-link {\n color:"), "{css}");
2916
2917 // The colour is on the part that is text, never on the container. On
2918 // `.cell` it would cascade into the three parts that are not text,
2919 // which is the bug written as one rule.
2920 assert!(!css.contains(".cell {\n color:"), "{css}");
2921 }
2922
2923 #[test]
2924 fn an_unknown_cell_part_renders_plainly_rather_than_failing_to_build() {
2925 // `part_class`'s obligation, taken on for the table side too. CellPart
2926 // is `#[non_exhaustive]`, so a member added upstream must land as a
2927 // bare class rather than as a build that stops.
2928 assert_eq!(cell_part_class(CellPart::Value), "cell-value");
2929 assert_eq!(cell_part_class(CellPart::Actions), "cell-actions");
2930 }
2931
2932 #[test]
2933 fn a_column_drops_by_its_priority_and_never_by_its_position() {
2934 let css = component_rules(&Emit::default());
2935
2936 // Optional goes at the narrowest class and secondary goes with it,
2937 // which is `kept_at`'s cutoff walk said as two queries.
2938 let compact = css
2939 .find(&format!("@media {}", SizeClass::Compact.media_condition()))
2940 .expect("a compact query");
2941 let medium = css
2942 .find(&format!("@media {}", SizeClass::Medium.media_condition()))
2943 .expect("a medium query");
2944 assert!(css[compact..].contains(".cell-drops-next"), "{css}");
2945 assert!(!css[medium..].contains(".cell-drops-next"), "{css}");
2946
2947 // Essential columns are never mentioned, because not being mentioned is
2948 // already what never dropping means.
2949 assert!(!css.contains(".cell-keeps"), "{css}");
2950
2951 // And nothing counts. `nth-child` is the bug the priority vocabulary
2952 // exists to end.
2953 assert!(!css.contains("nth-child"), "{css}");
2954 }
2955
2956 #[test]
2957 fn a_track_places_by_custom_property_and_never_by_a_size() {
2958 let css = track_rules(&Emit::default());
2959
2960 // Placement arrives from the caller, computed once by Track::fraction.
2961 // If either of these becomes a literal, three renderers have started
2962 // disagreeing about where 09:30 is.
2963 assert!(css.contains("top: var(--track-at"), "{css}");
2964 assert!(css.contains("height: var(--track-for"), "{css}");
2965
2966 // Overlap lanes default so an entry naming neither is full width.
2967 assert!(css.contains("--track-lane, 0"), "{css}");
2968 assert!(css.contains("--track-lanes, 1"), "{css}");
2969
2970 // The refusal that matters. A slot height here would be this crate
2971 // deciding how tall a quarter of an hour is, which is the thing
2972 // makeover-geometry owns and the reason `.track` gets no height at all.
2973 assert!(!css.contains("height: var(--track-slot"), "{css}");
2974 for size in ["px", "rem", "em", "vh"] {
2975 let bare = css
2976 .lines()
2977 .filter(|l| !l.contains("var(--"))
2978 .any(|l| l.contains(size));
2979 assert!(!bare, "track_rules named a {size} outside a var(): {css}");
2980 }
2981 }
2982
2983 #[test]
2984 fn a_relaxed_part_clamps_and_a_tight_one_says_nothing() {
2985 let css = stylesheet(&Emit::default());
2986 assert!(css.contains(".row-relaxed {"));
2987 }
2988
2989 /// The done condition: a row carrying a level indents in a browser with no
2990 /// app-authored CSS.
2991 ///
2992 /// quasi-webview emits `row-nested` with `--row-depth` on every described
2993 /// hierarchy. Without a rule reading it, a described outline is a flat list
2994 /// with chevrons in it.
2995 #[test]
2996 fn a_nested_row_indents_by_its_level_and_an_app_can_say_what_a_level_is_worth() {
2997 let css = stylesheet(&Emit::default());
2998
2999 assert!(css.contains(".row-nested {"), "{css}");
3000 assert!(
3001 css.contains(
3002 "padding-inline-start: calc(var(--row-depth, 0) * var(--row-indent, 1.5ch));"
3003 ),
3004 "{css}"
3005 );
3006 // The magnitude is a custom property with a fallback, which is
3007 // `--awaiting-gap`'s shape: what a level IS stays the description's and
3008 // what it is WORTH is this renderer's, overridable by an app. Padding
3009 // rather than margin, so the indent is inside the box a selection
3010 // shades.
3011 assert!(
3012 !css.contains("margin-inline-start: calc(var(--row-depth"),
3013 "{css}"
3014 );
3015
3016 // The branch and its chevron, emitted and unstyled for the same reason.
3017 assert!(css.contains(".row-branch {"), "{css}");
3018 assert!(css.contains(".row-disclose {"), "{css}");
3019
3020 for name in ["row-nested", "row-branch", "row-disclose"] {
3021 assert!(
3022 crate::vocabulary::names(&Emit::default()).contains(name),
3023 "{name} is declared"
3024 );
3025 }
3026 assert!(css.contains("-webkit-line-clamp: 2;"));
3027 // The count is `Flow`'s, not this crate's. If the tier ever means three
3028 // lines, this fails here rather than in an app.
3029 assert!(css.contains(&format!("line-clamp: {};", Flow::Relaxed.lines())));
3030 // Tight gets no rule at all: one line is what a run already does, and a
3031 // class per part saying so is a declaration that changes nothing.
3032 assert!(!css.contains("row-tight"));
3033 assert_eq!(crate::list::flow_class(Flow::Relaxed), Some("row-relaxed"));
3034 assert_eq!(crate::list::flow_class(Flow::Tight), None);
3035 // Emitted, therefore checkable: an app's dead-vocabulary seal and the
3036 // overlap check both read `vocabulary::names`, so a class the renderer
3037 // can write and that list does not carry is invisible to both.
3038 assert!(crate::vocabulary::names(&Emit::default()).contains("row-relaxed"));
3039 }
3040
3041 #[test]
3042 fn the_two_kinds_of_wait_stop_rendering_identically() {
3043 // The state `d43ea1c5` fixes: the emitter had been writing
3044 // `data-awaiting` for months and nothing styled either value, so a
3045 // measured wait and an unmeasured one drew the same nothing.
3046 let css = stylesheet(&Emit::default());
3047 assert!(css.contains("[data-awaiting]::after"), "{css}");
3048 assert!(
3049 css.contains("[data-awaiting][aria-busy=\"true\"]::after"),
3050 "the mark is drawn only while something is actually waiting"
3051 );
3052 assert!(
3053 css.contains("[data-awaiting=\"determinate\"][aria-busy=\"true\"]::after"),
3054 "the measured half is its own drawing"
3055 );
3056 }
3057
3058 #[test]
3059 fn the_blink_takes_its_cadence_and_never_names_one() {
3060 // Three renderers draw this mark. A number written here would be a
3061 // second heartbeat for one wait.
3062 let css = stylesheet(&Emit::default());
3063 assert!(
3064 css.contains("calc(var(--cadence-activity) * 2)"),
3065 "a half-period doubled, not a literal"
3066 );
3067 assert!(!css.contains("500ms"), "{css}");
3068 }
3069
3070 #[test]
3071 fn a_bar_nobody_is_counting_is_empty_rather_than_full() {
3072 // Rule 1. The share defaults to zero, so a determinate control with no
3073 // binder watching bytes draws a trough. A default of 1 would be the
3074 // confidently-wrong drawing the rule exists to forbid.
3075 let css = stylesheet(&Emit::default());
3076 assert!(css.contains("var(--awaiting-share, 0)"), "{css}");
3077 }
3078
3079 #[test]
3080 fn motion_off_leaves_the_mark_lit_because_the_keyframes_do_the_dimming() {
3081 // `makeover_timing::reduced_motion_css` sets `--cadence-activity: 0ms`,
3082 // and a zero-length animation leaves the element in its base style
3083 // rather than at its last keyframe. So the base has to be the lit one.
3084 // The inverted spelling would blank the mark for a reader who asked for
3085 // less motion, which answers a request nobody made.
3086 let css = stylesheet(&Emit::default());
3087 let busy = css
3088 .split("[data-awaiting][aria-busy=\"true\"]::after {")
3089 .nth(1)
3090 .expect("the busy rule");
3091 let busy = busy.split('}').next().expect("its body");
3092 assert!(
3093 busy.contains("background: var(--action);"),
3094 "the base state is lit: {busy}"
3095 );
3096 }
3097
3098 #[test]
3099 fn the_whole_sheet_still_names_every_colour() {
3100 // The crate's founding property, asserted over the component layer and
3101 // not only the primitives.
3102 let css = stylesheet(&Emit::default());
3103 assert!(!css.contains('#'));
3104 assert!(!css.contains("rgb"));
3105 for line in css.lines() {
3106 // Declarations only: a selector or an at-rule can carry a colon of
3107 // its own (`:root`, `:hover`, `@media (hover: hover)`) and declares
3108 // nothing. Keyed on the trailing semicolon rather than on leading
3109 // indentation, which only ever worked as a proxy for nesting depth
3110 // and stopped when the sheet gained a cascade layer around it.
3111 let trimmed = line.trim();
3112 if !trimmed.ends_with(';') {
3113 continue;
3114 }
3115 let Some((_, value)) = trimmed.split_once(": ") else {
3116 continue;
3117 };
3118 if value.contains("var(--") {
3119 continue;
3120 }
3121 // Everything left has to be a keyword, a number or a
3122 // caller-supplied length, never a colour.
3123 //
3124 // The length arm is what the comment above always claimed and the
3125 // list never covered: `border_width` arrives from `Emit` and lands
3126 // bare in the focus ring's offset, where the bevel had only ever
3127 // used it inside an `inset` shadow.
3128 let opts = Emit::default();
3129 assert!(
3130 value.contains("inset")
3131 || value.contains(opts.border_width)
3132 || value.contains(opts.focus_width)
3133 // 0.12.0's two: a sortable header is a control and says so
3134 // with the pointer, and the caret is this renderer's own
3135 // expression of `aria-sort`. Neither is a colour, which is
3136 // what this test is actually about, and neither is a size,
3137 // which is the other thing this crate must not name. The
3138 // leading space inside the glyph is the same thing the other
3139 // two renderers write into theirs, so it is part of the
3140 // caret rather than spacing this crate decided on.
3141 || value
3142 .trim_start_matches('"')
3143 .trim_start()
3144 .starts_with("\\2")
3145 || matches!(
3146 value.trim_end_matches(';'),
3147 "0" | "1"
3148 // The wait's mark and bar, 0.60.0. An empty
3149 // `content` is what brings a pseudo-element into
3150 // existence with nothing in it, and `step-end`
3151 // is an easing: the blink is two states, not a
3152 // slide between them. Neither is a colour, and
3153 // neither is a magnitude.
3154 | "\"\""
3155 // Where the mark sits on the line it joins.
3156 // Alignment is structure, the same way `display`
3157 // is, and `baseline` is the initial value said out
3158 // loud so a host stylesheet cannot leave it
3159 // wherever an earlier rule put it.
3160 | "baseline"
3161 | "inline-block"
3162 | "none"
3163 | "auto"
3164 | "not-allowed"
3165 | "pointer"
3166 // The caret's reserved box. Visibility is presence,
3167 // not magnitude and not colour.
3168 | "hidden"
3169 | "visible"
3170 // The link's two signals. `underline` is a line and
3171 // `inherit` defers to whatever the app set, so
3172 // neither names a colour or a magnitude.
3173 | "underline"
3174 | "inherit"
3175 // The table frame. `display` is structure and not a
3176 // size; `nowrap` is what makes a content column
3177 // content. The two widths are the awkward pair and
3178 // they are still not sizes: `100%` is "all of
3179 // whatever you were given" and `1%` is the CSS
3180 // table idiom for "shrink to fit", which is a
3181 // behaviour spelled as a number because CSS has no
3182 // keyword for it. Neither names a magnitude, which
3183 // is the thing this crate leaves to
3184 // makeover-geometry.
3185 | "table"
3186 | "table-row"
3187 | "table-cell"
3188 | "nowrap"
3189 | "100%"
3190 | "1%"
3191 // The time axis, 0.42.0. `position` is the one
3192 // property whose whole job is where a thing sits,
3193 // which is exactly what this crate spent its life
3194 // refusing to say -- so it is worth being exact
3195 // about why these two are not that refusal
3196 // breaking.
3197 //
3198 // Neither names a magnitude. `relative` says the
3199 // track is what its entries resolve against, and
3200 // `absolute` says an entry is placed rather than
3201 // flowed. *Where* each entry lands is
3202 // `--track-at` and `--track-for`, custom
3203 // properties the caller sets from
3204 // `Track::fraction`, and they are skipped by the
3205 // `var(--` arm above like every other value this
3206 // crate refuses to decide.
3207 //
3208 // The rule that would break the refusal is a slot
3209 // height, and there is none: the track's height is
3210 // the app's, so the percentages have something to
3211 // resolve against and this crate still never says
3212 // how tall a day is.
3213 | "relative"
3214 | "absolute"
3215 // A run's five, 0.49.0. `flex`, `wrap` and
3216 // `center` are structure and alignment, the same
3217 // reading `table` gets: which way members are laid
3218 // out and how they line up, never how much of
3219 // anything.
3220 //
3221 // The two intrinsic keywords are the interesting
3222 // pair and they are the opposite of a size. A
3223 // magnitude is a number somebody chose;
3224 // `min-content` and `max-content` are the browser
3225 // being asked what the members themselves come to,
3226 // which is the derived minimum the room ruling
3227 // requires and the reason no breakpoint appears
3228 // anywhere in these rules. `1 1 max-content` is
3229 // grow, shrink and that basis, so its two digits
3230 // are ratios rather than lengths.
3231 | "flex"
3232 | "wrap"
3233 | "center"
3234 | "min-content"
3235 | "1 1 max-content"
3236 // A menu run's overflow control, 0.64.0.
3237 // `column` and `stretch` are the same reading
3238 // `flex` and `center` get one line up: which way
3239 // the shed members stack inside the panel and how
3240 // they line up across it. Neither is a magnitude.
3241 //
3242 // `100%` is already above and reused here as the
3243 // panel's `inset-block-start`, which is "the whole
3244 // of the control it hangs from" rather than a
3245 // distance anybody picked.
3246 | "column"
3247 | "stretch"
3248 // A picture's three, 0.36.0. `block` is structure
3249 // for the reason `table` is: an inline image sits
3250 // on the baseline and carries a descender's worth
3251 // of space under it, which is a fact about
3252 // replaced elements rather than a size this crate
3253 // chose. `cover` and `contain` are `Fit`'s two
3254 // named members reaching CSS unchanged, which is
3255 // an intent arriving rather than a value being
3256 // picked.
3257 | "block"
3258 | "cover"
3259 | "contain"
3260 // A relaxed part's three, and the third is the
3261 // awkward one. `-webkit-box` and `vertical` are
3262 // structure: they say the part is a box of lines
3263 // stacked downward, which is the only way CSS lets
3264 // anyone ask for a clamp at all.
3265 //
3266 // `2` is a count of lines, not a length. The
3267 // distinction this crate holds is between naming a
3268 // magnitude -- a padding, a height, a font size,
3269 // all of which belong to makeover-geometry -- and
3270 // naming how many of something there are. A line's
3271 // height is still the app's, so two lines is
3272 // whatever two of the app's lines come to, and
3273 // nothing here decides how tall that is. It is also
3274 // not a value picked here: it is `Flow::Relaxed`'s
3275 // own answer arriving unchanged, the same way
3276 // `cover` and `contain` are `Fit`'s.
3277 | "-webkit-box"
3278 | "vertical"
3279 | "2"
3280 ),
3281 "unrecognised literal value: {line}"
3282 );
3283 }
3284 }
3285
3286 #[test]
3287 fn flat_emits_nothing_at_all() {
3288 assert_eq!(depth_class(Depth::Flat, &Emit::default()), None);
3289 assert!(!depth_rules(&Emit::default()).contains("flat"));
3290 }
3291
3292 #[test]
3293 fn a_prefix_namespaces_every_class() {
3294 let opts = Emit {
3295 class_prefix: "mo-",
3296 ..Emit::default()
3297 };
3298 let css = depth_rules(&opts);
3299 assert!(css.contains(".mo-raised {"));
3300 assert!(css.contains(".mo-well {"));
3301 assert!(!css.contains(".raised {"));
3302 }
3303
3304 #[test]
3305 fn the_border_width_is_the_callers() {
3306 let opts = Emit {
3307 border_width: "2px",
3308 ..Emit::default()
3309 };
3310 assert!(bevel_shadow(Bevel::Raised, &opts).contains("inset 2px 2px 0"));
3311 }
3312
3313 #[test]
3314 fn edges_agree_with_the_description() {
3315 // Not a tautology: it is the guard that a CSS-shaped convenience never
3316 // quietly reverses which side is lit.
3317 let (tl, br) = Bevel::Raised.edges();
3318 assert_eq!(tl.token(), Edge::Light.token());
3319 assert_eq!(br.token(), Edge::Dark.token());
3320 }
3321 }
3322