kui_core/runtime/cause.rs
1//! Why a frame was drawn: two readings a view can take of
2//! the frame it is building, for an app that keeps a ledger of its frames
3//! and wants to know why one ran with nothing on screen moving.
4//!
5//! - [`FrameCause`], the set of reasons that reached the window since the
6//! last frame began. The core records the input it was handed
7//! ([`Core::handle_input`]) and whether the last frame left one owed;
8//! the driver adds what only it sees ([`Core::note_frame_cause`]) — a
9//! wake, a resize, the caret's blink, a surface retry, the OS events
10//! that never become input. Always kept: it is a few ORs a frame.
11//! - [`OwedBy`], *who* holds a frame the last one left owed: the nodes
12//! whose transition is mid-flight, the cycles running, the departures
13//! playing, the containers easing a scroll, the held drag's scroller,
14//! the `animate` nodes, and where `request_frame` was called from.
15//! [`Core::owed`] with names. Off unless [`Core::set_frame_trace`] asked
16//! for it, and taken at the start of `begin_frame` — the only moment the
17//! last frame's tree, which names the holders, and the stores' state,
18//! which says who they are, are both still there.
19//!
20//! The same switch keeps a digest of every finished frame's display list,
21//! so [`Core::frame_unchanged`] says whether a frame drew exactly what the
22//! one before it drew: a frame that changed nothing on screen.
23
24use std::panic::Location;
25
26use rustc_hash::FxHashMap;
27
28use super::*;
29use crate::input::InputEvent;
30
31/// Why a frame was drawn: every reason that reached the window between
32/// the start of the last frame and the start of this one.
33/// Read from a view as [`Core::frame_cause`]. A set, because a frame
34/// answers everything that asked since the last one — a keystroke and the
35/// caret's blink, a wheel and the transition it started.
36///
37/// Empty is a frame nobody here asked for: the platform's own redraw (an
38/// expose, a live resize the OS paints through), or a driver that notes
39/// nothing.
40#[derive(Clone, Copy, Default, PartialEq, Eq, Hash)]
41pub struct FrameCause(u32);
42
43impl FrameCause {
44 /// Nothing recorded.
45 pub const NONE: FrameCause = FrameCause(0);
46
47 // The input the core was handed (`Core::handle_input`), by kind —
48 // every driver's, recorded by the core itself.
49 /// The pointer moved over the window.
50 pub const POINTER_MOVE: FrameCause = FrameCause(1 << 0);
51 /// The pointer left the window.
52 pub const POINTER_LEAVE: FrameCause = FrameCause(1 << 1);
53 /// A mouse button went down or up, or a force click.
54 pub const BUTTON: FrameCause = FrameCause(1 << 2);
55 /// A wheel or a trackpad scroll — a swipe's momentum included, which
56 /// the platform sends as scrolls after the hand has left.
57 pub const WHEEL: FrameCause = FrameCause(1 << 3);
58 /// A key went down or up.
59 pub const KEY: FrameCause = FrameCause(1 << 4);
60 /// The modifier keys changed.
61 pub const MODIFIERS: FrameCause = FrameCause(1 << 5);
62 /// Text arrived: typed, committed by an input method, or pasted.
63 pub const TEXT: FrameCause = FrameCause(1 << 6);
64 /// An input method's composition changed.
65 pub const PREEDIT: FrameCause = FrameCause(1 << 7);
66 /// Assistive technology asked for an action.
67 pub const ACCESS: FrameCause = FrameCause(1 << 8);
68 /// Files dragged over the window, dropped on it, or taken away.
69 pub const FILE_DRAG: FrameCause = FrameCause(1 << 9);
70 /// A file dialog answered, or the OS handed the app documents to open
71 /// (`InputEvent::Open`, backlog F124).
72 pub const FILES: FrameCause = FrameCause(1 << 10);
73
74 // What the driver saw (`Core::note_frame_cause`).
75 /// The window's first frame.
76 pub const FIRST: FrameCause = FrameCause(1 << 11);
77 /// The app woke the loop from another thread (a `Waker`).
78 pub const WAKE: FrameCause = FrameCause(1 << 12);
79 /// The host asked for a frame: a pumped runner's `request_redraw`,
80 /// a new view handed over.
81 pub const HOST: FrameCause = FrameCause(1 << 13);
82 /// The window changed size.
83 pub const RESIZE: FrameCause = FrameCause(1 << 14);
84 /// The window moved to a display of another scale.
85 pub const SCALE: FrameCause = FrameCause(1 << 15);
86 /// The window gained or lost the keyboard.
87 pub const FOCUS: FrameCause = FrameCause(1 << 16);
88 /// The window was uncovered, or came back from minimized. The runner
89 /// leaves out of that frame what it noted while the window could not
90 /// draw and no frame took — another window's input, an appearance
91 /// change — so a restore does not report reasons from long before;
92 /// `resize` is the same edge on Windows, where
93 /// restoring is a resize.
94 pub const OCCLUSION: FrameCause = FrameCause(1 << 17);
95 /// The system's appearance or settings changed: light or dark, the
96 /// accent, reduced motion, assistive technology coming or going, a
97 /// font installed or removed.
98 pub const APPEARANCE: FrameCause = FrameCause(1 << 18);
99 /// The caret's blink changed phase.
100 pub const CARET: FrameCause = FrameCause(1 << 19);
101 /// The last frame's surface refused it (skipped, out of date,
102 /// misconfigured) and the frame is tried again.
103 pub const RETRY: FrameCause = FrameCause(1 << 20);
104 /// A frame held for the display waited too long and is drawn anyway.
105 pub const OVERDUE: FrameCause = FrameCause(1 << 21);
106 /// The graphics device was reopened.
107 pub const DEVICE: FrameCause = FrameCause(1 << 22);
108 /// The last frame's own events — a resize, what a new layout put
109 /// under a still pointer — were routed after it, and answered.
110 pub const AFTER_FRAME: FrameCause = FrameCause(1 << 23);
111 /// Something that reached the app in another window, which can change
112 /// what this one shows.
113 pub const ELSEWHERE: FrameCause = FrameCause(1 << 24);
114 /// A menu (the platform's context menu or menu bar) was answered.
115 pub const MENU: FrameCause = FrameCause(1 << 25);
116 /// A sound finished or was refused, and its event was routed.
117 pub const AUDIO: FrameCause = FrameCause(1 << 26);
118 /// A smoke run's frame counter asked for the next frame.
119 pub const SMOKE: FrameCause = FrameCause(1 << 27);
120
121 // The core's own.
122 /// The last frame left one owed ([`Core::owed`]); [`Core::owed_by`]
123 /// says who, when traced.
124 pub const OWED: FrameCause = FrameCause(1 << 28);
125
126 /// Each reason and its name, in bit order.
127 pub const ALL: [(FrameCause, &'static str); 29] = [
128 (Self::POINTER_MOVE, "pointerMove"),
129 (Self::POINTER_LEAVE, "pointerLeave"),
130 (Self::BUTTON, "button"),
131 (Self::WHEEL, "wheel"),
132 (Self::KEY, "key"),
133 (Self::MODIFIERS, "modifiers"),
134 (Self::TEXT, "text"),
135 (Self::PREEDIT, "preedit"),
136 (Self::ACCESS, "access"),
137 (Self::FILE_DRAG, "fileDrag"),
138 (Self::FILES, "files"),
139 (Self::FIRST, "first"),
140 (Self::WAKE, "wake"),
141 (Self::HOST, "host"),
142 (Self::RESIZE, "resize"),
143 (Self::SCALE, "scale"),
144 (Self::FOCUS, "focus"),
145 (Self::OCCLUSION, "occlusion"),
146 (Self::APPEARANCE, "appearance"),
147 (Self::CARET, "caret"),
148 (Self::RETRY, "retry"),
149 (Self::OVERDUE, "overdue"),
150 (Self::DEVICE, "device"),
151 (Self::AFTER_FRAME, "afterFrame"),
152 (Self::ELSEWHERE, "elsewhere"),
153 (Self::MENU, "menu"),
154 (Self::AUDIO, "audio"),
155 (Self::SMOKE, "smoke"),
156 (Self::OWED, "owed"),
157 ];
158
159 /// The bits, for a binding or a log.
160 pub const fn bits(self) -> u32 {
161 self.0
162 }
163
164 /// The set these bits spell; bits no reason has are dropped.
165 pub const fn from_bits(bits: u32) -> FrameCause {
166 FrameCause(bits & ((1 << Self::ALL.len()) - 1))
167 }
168
169 pub const fn is_empty(self) -> bool {
170 self.0 == 0
171 }
172
173 /// Whether every reason in `other` is in this set.
174 pub const fn contains(self, other: FrameCause) -> bool {
175 self.0 & other.0 == other.0
176 }
177
178 /// Whether any reason in `other` is in this set.
179 pub const fn intersects(self, other: FrameCause) -> bool {
180 self.0 & other.0 != 0
181 }
182
183 pub const fn union(self, other: FrameCause) -> FrameCause {
184 FrameCause(self.0 | other.0)
185 }
186
187 /// The names of the reasons in the set, in bit order.
188 pub fn names(self) -> impl Iterator<Item = &'static str> {
189 Self::ALL
190 .into_iter()
191 .filter(move |(c, _)| self.contains(*c))
192 .map(|(_, name)| name)
193 }
194
195 /// The reason one input is: what [`Core::handle_input`] records, and
196 /// what a driver that screens input before the core sees it can note
197 /// for an event it keeps.
198 pub fn of_input(ev: &InputEvent) -> FrameCause {
199 match ev {
200 InputEvent::CursorMoved(_) => Self::POINTER_MOVE,
201 InputEvent::CursorLeft => Self::POINTER_LEAVE,
202 InputEvent::MouseDown { .. } | InputEvent::MouseUp { .. } => Self::BUTTON,
203 InputEvent::ForceClick(_) => Self::BUTTON,
204 InputEvent::Scroll(_) | InputEvent::ScrollGesture { .. } => Self::WHEEL,
205 InputEvent::Key(..) | InputEvent::KeyDown(_) | InputEvent::KeyUp(_) => Self::KEY,
206 InputEvent::Modifiers(_) => Self::MODIFIERS,
207 InputEvent::Text(_) | InputEvent::Commit(_) | InputEvent::Paste { .. } => Self::TEXT,
208 InputEvent::Preedit(..) => Self::PREEDIT,
209 InputEvent::Access(_) => Self::ACCESS,
210 InputEvent::DragFiles { .. }
211 | InputEvent::DropFiles { .. }
212 | InputEvent::DragCancel => Self::FILE_DRAG,
213 InputEvent::Files(_) | InputEvent::Open(_) => Self::FILES,
214 }
215 }
216}
217
218impl std::ops::BitOr for FrameCause {
219 type Output = FrameCause;
220 fn bitor(self, rhs: FrameCause) -> FrameCause {
221 self.union(rhs)
222 }
223}
224
225impl std::ops::BitOrAssign for FrameCause {
226 fn bitor_assign(&mut self, rhs: FrameCause) {
227 self.0 |= rhs.0;
228 }
229}
230
231impl std::fmt::Debug for FrameCause {
232 /// `FrameCause(key|caret)`, `FrameCause()` when empty.
233 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
234 write!(f, "FrameCause(")?;
235 for (i, name) in self.names().enumerate() {
236 if i > 0 {
237 write!(f, "|")?;
238 }
239 write!(f, "{name}")?;
240 }
241 write!(f, ")")
242 }
243}
244
245/// One thing that holds an owed frame, named for a person: see
246/// [`OwedBy`].
247#[derive(Clone, Debug, PartialEq, Eq)]
248pub struct FrameHolder {
249 pub key: Key,
250 /// The node's labels from the root, `/`-joined — the ones it and its
251 /// ancestors were opened under (`open_keyed`, a `key` prop), which is
252 /// the name the devtools' tree shows a node by. A node opened without
253 /// one ends in its accessible name in quotes, or `#` and the low
254 /// eight hex digits of its key, as the devtools' event stream writes
255 /// an unlabelled node. A departure's node is in no tree, so it is its
256 /// own label alone, when a frame still knows it.
257 pub name: String,
258 /// A transition's slots still mid-flight — `width`, `height`, `bg`,
259 /// `borderColor`, `radius`, `position`, `opacity`, `shadow`,
260 /// `shadowColor` — in that order. Empty for every other holder.
261 pub slots: Vec<&'static str>,
262}
263
264/// Where a frame was asked for: a [`Core::request_frame`] call, or one the
265/// core makes for itself.
266#[derive(Clone, Copy, Debug, PartialEq, Eq)]
267pub struct FrameRequest {
268 /// `"request_frame"` for a call to [`Core::request_frame`] or
269 /// `Ui::request_frame` — the app's or a binding's, which `at` tells
270 /// apart. A door that asks for the frame that lands it is named for
271 /// itself, `at` its caller's line: `"reveal"`,
272 /// `"reveal_label"`, `"set_scroll"`, `"set_scroll_label"`,
273 /// `"focus_region"`, `"focus_region_by_label"`,
274 /// `"request_focus_step"` (`Ui::focus_next`, `Ui::focus_prev`),
275 /// `"request_files"`. The core's and its widgets' own asks say what
276 /// they are for: `"scrollbar fade"`, `"atlas full"`,
277 /// `"long line rows"`, `"resliced"`, `"devtools"`,
278 /// `"list first frame"`.
279 pub why: &'static str,
280 /// The source line that asked (`#[track_caller]`): the app's own for
281 /// its calls, a binding's for a guest's, kui's for its own asks.
282 pub at: &'static Location<'static>,
283}
284
285/// Who holds the frame the last one left owed: [`Core::owed`], named.
286/// Each list is empty when its kind in [`crate::Owed`] is
287/// false, and names what made it true when it is.
288///
289/// Read with [`Core::owed_by`] from inside a view, where it describes the
290/// frame before — the reason the frame being built exists — or between
291/// frames, where it still does. Empty unless [`Core::set_frame_trace`]
292/// turned the record on before that frame began.
293#[derive(Clone, Debug, Default, PartialEq, Eq)]
294pub struct OwedBy {
295 /// Nodes with a transition mid-flight, each with its slots
296 /// (`Owed::transition`).
297 pub transitions: Vec<FrameHolder>,
298 /// Nodes with a keyframe cycle running (`Owed::cycle`).
299 pub cycles: Vec<FrameHolder>,
300 /// Subtrees still playing their exit (`Owed::depart`).
301 pub departures: Vec<FrameHolder>,
302 /// Scroll containers easing a programmatic offset change
303 /// (`Owed::scroll`).
304 pub scrolls: Vec<FrameHolder>,
305 /// The container a held drag is scrolling (`Owed::autoscroll`).
306 pub autoscroll: Option<FrameHolder>,
307 /// Nodes declaring `animate` (half of `Owed::requested`).
308 pub animate: Vec<FrameHolder>,
309 /// Where the frame was asked for (the other half of
310 /// `Owed::requested`), one per calling line, in the order first
311 /// asked, at most [`OwedBy::REQUESTS`] of them.
312 pub requests: Vec<FrameRequest>,
313}
314
315impl OwedBy {
316 /// How many distinct asking lines a frame keeps.
317 pub const REQUESTS: usize = 32;
318
319 /// Nothing held.
320 pub fn is_empty(&self) -> bool {
321 self.transitions.is_empty()
322 && self.cycles.is_empty()
323 && self.departures.is_empty()
324 && self.scrolls.is_empty()
325 && self.autoscroll.is_none()
326 && self.animate.is_empty()
327 && self.requests.is_empty()
328 }
329
330 fn clear(&mut self) {
331 self.transitions.clear();
332 self.cycles.clear();
333 self.departures.clear();
334 self.scrolls.clear();
335 self.autoscroll = None;
336 self.animate.clear();
337 self.requests.clear();
338 }
339}
340
341/// The core's side of the trace: what [`Core::frame_cause`] and
342/// [`Core::owed_by`] read, and what fills them.
343#[derive(Default)]
344pub(crate) struct Trace {
345 /// `set_frame_trace`: the holders and the digest are kept.
346 on: bool,
347 /// The frame being built's reasons (the last frame's, between frames).
348 cause: FrameCause,
349 /// What has reached the window since this frame began: the next
350 /// frame's reasons so far.
351 since: FrameCause,
352 /// Who held the frame being built, as its `begin_frame` found them.
353 owed_by: OwedBy,
354 /// The lines that asked for a frame since the last one began.
355 requests: Vec<FrameRequest>,
356 /// The last finished frame's display-list digest, and whether it
357 /// matched the one before.
358 digest: Option<u64>,
359 unchanged: Option<bool>,
360 /// The departures' names, taken by the exit diff from the frame that
361 /// still had them: a ghost's node is in no tree after that frame.
362 gone: FxHashMap<Key, String>,
363 /// [`Core::begin_frame_cause`] took the next frame's reasons ahead of
364 /// its `begin_frame`, which keeps them.
365 begun: bool,
366}
367
368impl Trace {
369 fn ask(&mut self, why: &'static str, at: &'static Location<'static>) {
370 if self.requests.len() < OwedBy::REQUESTS
371 && !self.requests.iter().any(|r| r.at == at && r.why == why)
372 {
373 self.requests.push(FrameRequest { why, at });
374 }
375 }
376}
377
378impl Core {
379 /// Turns the trace of why frames run on or off: who
380 /// holds each owed frame ([`Self::owed_by`]) and whether each frame
381 /// changed what is drawn ([`Self::frame_unchanged`]). Off by default,
382 /// where neither costs anything; on, the holders are taken at the
383 /// start of every frame the last one owed — a walk of what is owed
384 /// and one of the last frame's tree to name it — and the display
385 /// list is hashed at the end of every frame. [`Self::frame_cause`]
386 /// is kept either way.
387 pub fn set_frame_trace(&mut self, on: bool) {
388 let t = &mut self.trace;
389 t.on = on;
390 if !on {
391 t.owed_by.clear();
392 t.requests.clear();
393 t.digest = None;
394 t.unchanged = None;
395 t.gone.clear();
396 }
397 }
398
399 /// Whether [`Self::set_frame_trace`] turned the trace on.
400 pub fn frame_trace(&self) -> bool {
401 self.trace.on
402 }
403
404 /// Why the frame being built runs: every reason that reached the
405 /// window between the start of the last frame and the start of this
406 /// one. Between frames, the last frame's — or, after
407 /// [`Self::begin_frame_cause`], the next one's. See [`FrameCause`].
408 pub fn frame_cause(&self) -> FrameCause {
409 self.trace.cause
410 }
411
412 /// Starts the next frame's record now rather than at its
413 /// `begin_frame`: its reasons ([`Self::frame_cause`]) and, traced,
414 /// who holds it ([`Self::owed_by`]) — for a driver whose view runs
415 /// before the frame it is for begins. Node's loop runs
416 /// `view` to a tree and only then hands the tree to a frame, so a
417 /// view reading either would read the frame before; the loop calls
418 /// this first, and the view reads the frame it is building. The
419 /// `begin_frame` that follows keeps what this took, and a second
420 /// call before it is nothing. What reaches the window in between —
421 /// input, a note — is the frame after's, as it is during a build.
422 pub fn begin_frame_cause(&mut self) {
423 if !self.trace.begun {
424 self.take_frame_cause();
425 self.trace.begun = true;
426 }
427 }
428
429 /// Adds to the next frame's reasons — the driver's door, for what it
430 /// saw and the core never will: a wake, a resize, a blink, a retry,
431 /// an OS event it kept. The input it hands [`Self::handle_input`] is
432 /// recorded without this.
433 pub fn note_frame_cause(&mut self, cause: FrameCause) {
434 self.trace.since |= cause;
435 }
436
437 /// Who held the frame the last one left owed, as the frame being
438 /// built found them (see [`OwedBy`]) — or, after
439 /// [`Self::begin_frame_cause`], as the next one will. Empty when the
440 /// trace is off.
441 pub fn owed_by(&self) -> &OwedBy {
442 &self.trace.owed_by
443 }
444
445 /// Whether the last finished frame drew exactly what the one before
446 /// it drew — the same quads, clips, fragments and textures at the
447 /// same size and scale — so it changed nothing on screen. `None`
448 /// while the trace is off and for the first frame after it came on.
449 /// A frame that draws a fragment is never unchanged: the shader reads
450 /// the clock. What the glyph atlas holds is not compared, only where
451 /// the quads sample it.
452 pub fn frame_unchanged(&self) -> Option<bool> {
453 self.trace.unchanged
454 }
455
456 /// Asks for the next frame on the core's own behalf — `why` says
457 /// what for, in a trace.
458 #[track_caller]
459 pub(crate) fn owe_frame(&mut self, why: &'static str) {
460 self.taint_kept("a widget in it owes a frame");
461 self.frame_requested = true;
462 if self.trace.on {
463 self.trace.ask(why, Location::caller());
464 }
465 }
466
467 /// `request_frame`'s half of the trace.
468 #[track_caller]
469 pub(super) fn trace_request(&mut self) {
470 if self.trace.on {
471 self.trace.ask("request_frame", Location::caller());
472 }
473 }
474
475 /// `begin_frame`'s reset of `frame_requested`, mirrored.
476 pub(super) fn trace_forget_requests(&mut self) {
477 self.trace.requests.clear();
478 }
479
480 /// One input's reason, from [`Self::handle_input`].
481 pub(super) fn trace_input(&mut self, ev: &InputEvent) {
482 self.trace.since |= FrameCause::of_input(ev);
483 }
484
485 /// The start of `begin_frame`, before anything there moves: the
486 /// reasons gathered since the last frame began become this frame's,
487 /// and — traced — the holders of what the last frame owed are named
488 /// against its tree, which `begin_frame` is about to clear.
489 pub(super) fn trace_begin_frame(&mut self) {
490 // Taken already, ahead of a view that ran before this frame did.
491 if std::mem::take(&mut self.trace.begun) {
492 return;
493 }
494 self.take_frame_cause();
495 }
496
497 /// The record itself: [`Self::trace_begin_frame`]'s, or
498 /// [`Self::begin_frame_cause`]'s ahead of it.
499 fn take_frame_cause(&mut self) {
500 let owed = self.owed();
501 let mut cause = std::mem::take(&mut self.trace.since);
502 if owed.any() {
503 cause |= FrameCause::OWED;
504 }
505 self.trace.cause = cause;
506 if !self.trace.on {
507 return;
508 }
509 let mut by = std::mem::take(&mut self.trace.owed_by);
510 by.clear();
511 std::mem::swap(&mut by.requests, &mut self.trace.requests);
512 self.trace.requests.clear();
513 if owed.any() {
514 self.name_holders(owed, &mut by);
515 } else {
516 by.requests.clear();
517 }
518 self.trace.owed_by = by;
519 if !self.trace.gone.is_empty() {
520 let held: rustc_hash::FxHashSet<Key> = self.depart.keys().collect();
521 self.trace.gone.retain(|k, _| held.contains(k));
522 }
523 }
524
525 /// The exit diff's roots, as indices of `prev_tree` — the frame that
526 /// declared them — named against that frame, traced.
527 pub(super) fn trace_departures(&mut self, roots: &[usize]) {
528 if !self.trace.on {
529 return;
530 }
531 let names = Names::new(&self.prev_tree, &self.key_labels_last);
532 for &i in roots {
533 let key = self.prev_tree.keys[i];
534 let name = names.holder(key, None).name;
535 self.trace.gone.insert(key, name);
536 }
537 }
538
539 fn name_holders(&self, owed: crate::Owed, by: &mut OwedBy) {
540 let names = Names::new(&self.tree, &self.key_labels);
541 if owed.transition {
542 let mut slots: FxHashMap<Key, u16> = FxHashMap::default();
543 self.anim.owing(|key, slot| {
544 *slots.entry(key).or_default() |= 1 << slot as u16;
545 });
546 let mut held: Vec<(usize, FrameHolder)> = slots
547 .into_iter()
548 .map(|(key, mask)| {
549 let mut h = names.holder(key, None);
550 h.slots = crate::anim::Slot::names(mask);
551 (names.order(key), h)
552 })
553 .collect();
554 held.sort_by_key(|(at, _)| *at);
555 by.transitions = held.into_iter().map(|(_, h)| h).collect();
556 }
557 if owed.cycle && self.anim.time().is_some() {
558 for i in 0..self.tree.len() {
559 let spec = &self.tree.specs[i];
560 // A finite cycle that is over holds no frame (F133).
561 if let Some(t) = spec.transition
562 && t.duration_ms > 0.0
563 && !spec.anim().keyframes.is_empty()
564 && self
565 .anim
566 .cycle_running(self.tree.keys[i], t, spec.anim().iterations)
567 {
568 by.cycles.push(names.holder(self.tree.keys[i], None));
569 }
570 }
571 }
572 if owed.depart {
573 for (key, spec) in self.depart.roots() {
574 let mut h = names.holder(key, Some(spec));
575 if let Some(name) = self.trace.gone.get(&key) {
576 h.name.clone_from(name);
577 }
578 by.departures.push(h);
579 }
580 }
581 if owed.scroll {
582 let mut keys: Vec<Key> = self.scroll.easing().collect();
583 keys.sort_by_key(|k| names.order(*k));
584 by.scrolls = keys.into_iter().map(|k| names.holder(k, None)).collect();
585 }
586 if owed.autoscroll {
587 by.autoscroll = self.autoscroller().map(|k| names.holder(k, None));
588 }
589 if self.tree.any_animate {
590 for i in 0..self.tree.len() {
591 if self.tree.specs[i].animate {
592 by.animate.push(names.holder(self.tree.keys[i], None));
593 }
594 }
595 }
596 if !owed.requested {
597 by.requests.clear();
598 }
599 }
600
601 /// The end of `finish_frame`, traced: this frame's display list
602 /// against the last one's.
603 pub(super) fn trace_finish_frame(&mut self) {
604 if !self.trace.on {
605 return;
606 }
607 let digest = digest(&self.display);
608 self.trace.unchanged = self.trace.digest.map(|d| d == digest);
609 self.trace.digest = Some(digest);
610 }
611}
612
613/// The last frame's tree and labels, indexed once for naming holders.
614struct Names<'a> {
615 tree: &'a Tree,
616 at: FxHashMap<Key, u32>,
617 labels: FxHashMap<Key, &'a str>,
618}
619
620impl<'a> Names<'a> {
621 fn new(tree: &'a Tree, labels: &'a crate::key::LabelIndex) -> Self {
622 Names {
623 tree,
624 at: tree
625 .keys
626 .iter()
627 .enumerate()
628 .map(|(i, k)| (*k, i as u32))
629 .collect(),
630 labels: labels.iter().collect(),
631 }
632 }
633
634 /// Where `key` sits in tree order, for sorting; past the end when it
635 /// is in no tree.
636 fn order(&self, key: Key) -> usize {
637 self.at.get(&key).map_or(usize::MAX, |i| *i as usize)
638 }
639
640 fn holder(&self, key: Key, gone: Option<&NodeSpec>) -> FrameHolder {
641 let mut parts: Vec<&str> = Vec::new();
642 let spec = match self.at.get(&key) {
643 Some(&i) => {
644 let mut p = self.tree.parent[i as usize];
645 while p != NIL {
646 if let Some(l) = self.labels.get(&self.tree.keys[p as usize]) {
647 parts.push(l);
648 }
649 p = self.tree.parent[p as usize];
650 }
651 parts.reverse();
652 Some(&self.tree.specs[i as usize])
653 }
654 None => gone,
655 };
656 let own = match self.labels.get(&key) {
657 Some(l) => l.to_string(),
658 None => match spec.and_then(|s| s.access().label.as_deref()) {
659 Some(l) => format!("\"{l}\""),
660 None => format!("#{:08x}", key.0 as u32),
661 },
662 };
663 let mut name = String::new();
664 for p in parts {
665 name.push_str(p);
666 name.push('/');
667 }
668 name.push_str(&own);
669 FrameHolder {
670 key,
671 name,
672 slots: Vec::new(),
673 }
674 }
675}
676
677/// A digest of what a display list draws: every quad, clip, fragment and
678/// texture draw, at its viewport and scale. Not the dropped handles (a
679/// backend's bookkeeping) and not the pixels behind a texture beyond its
680/// revision.
681fn digest(dl: &crate::display::DisplayList) -> u64 {
682 use std::hash::{Hash, Hasher};
683 let mut h = rustc_hash::FxHasher::default();
684 let f = |h: &mut rustc_hash::FxHasher, v: f32| h.write_u32(v.to_bits());
685 f(&mut h, dl.viewport.w);
686 f(&mut h, dl.viewport.h);
687 f(&mut h, dl.scale);
688 h.write_usize(dl.quads.len());
689 for q in &dl.quads {
690 for v in [q.rect.x, q.rect.y, q.rect.w, q.rect.h] {
691 f(&mut h, v);
692 }
693 for c in [q.color, q.border_color] {
694 for v in [c.r, c.g, c.b, c.a] {
695 f(&mut h, v);
696 }
697 }
698 for v in q.radius {
699 f(&mut h, v);
700 }
701 f(&mut h, q.border_w);
702 f(&mut h, q.blur);
703 h.write_u32(q.kind as u32);
704 h.write_u32(q.clip);
705 for w in q.uv {
706 h.write_u32(w);
707 }
708 }
709 h.write_usize(dl.clips.len());
710 for c in &dl.clips {
711 for v in [c.rect.x, c.rect.y, c.rect.w, c.rect.h] {
712 f(&mut h, v);
713 }
714 for v in c.radius {
715 f(&mut h, v);
716 }
717 }
718 h.write_usize(dl.fragments.len());
719 if !dl.fragments.is_empty() {
720 // A fragment reads the clock, so its frame is its own.
721 f(&mut h, dl.time);
722 for fr in &dl.fragments {
723 fr.id.hash(&mut h);
724 for v in fr.params {
725 f(&mut h, v);
726 }
727 fr.image.hash(&mut h);
728 }
729 }
730 h.write_usize(dl.textures.len());
731 for (t, px) in dl.textures.iter().zip(&dl.texture_pixels) {
732 t.id.hash(&mut h);
733 for w in t.uv {
734 h.write_u32(w);
735 }
736 h.write_u32(px.rev);
737 }
738 h.finish()
739}