| 1 | //! Motion: the few things that move, and the promise that nothing else does. |
| 2 | //! |
| 3 | //! Motion is allowed for a change of state or for spatial continuity, and |
| 4 | //! nothing else: no sweeps, dissolves, glitches or bounces. This module is |
| 5 | //! that layer in a few hundred lines, instead of a dependency. |
| 6 | //! |
| 7 | //! - A [`MotionStep`] eases a value from where it is to a target in `0..=1`, |
| 8 | //! sampled at an instant the caller passes in. Nothing here reads a clock, |
| 9 | //! spawns a thread or waits. |
| 10 | //! - [`MotionPolicy`] says what may move. `Full` animates; `Reduced` and |
| 11 | //! `Still` jump straight to the end state, and every helper takes the |
| 12 | //! policy so a component cannot forget it. Color steps run at truecolor |
| 13 | //! only: at 256 and 16 colors the in-between values snap into visible |
| 14 | //! flicker, so the step is skipped (§4.3). |
| 15 | //! - [`MotionSet::next_frame_at`] is the whole scheduler: the next instant a |
| 16 | //! redraw is due, never sooner than the frame cap, and `None` once |
| 17 | //! everything has settled, so an idle screen asks for zero redraws. |
| 18 | //! |
| 19 | //! The host owns the loop. After each draw it calls `next_frame_at(now, |
| 20 | //! policy)` and sleeps until that instant, or until an event, whichever comes |
| 21 | //! first. `None` means sleep until an event. |
| 22 | |
| 23 | use std::borrow::Cow; |
| 24 | use std::time::{Duration, Instant}; |
| 25 | |
| 26 | use ratatui::{buffer::Buffer, layout::Rect, style::Style}; |
| 27 | |
| 28 | use crate::{ |
| 29 | MotionMode, Paint, Role, Theme, |
| 30 | color::{ColorDepth, blend}, |
| 31 | glyphs, text, tokens, |
| 32 | }; |
| 33 | |
| 34 | /// A redraw is never due sooner than this after it was asked for: 60 frames |
| 35 | /// a second. A step lasts 120 to 340 ms, so that is 7 to 20 frames. |
| 36 | pub const MOTION_FRAME_INTERVAL: Duration = Duration::from_micros(16_667); |
| 37 | |
| 38 | /// The fastest cap a [`MotionSet`] accepts (120 frames a second, the |
| 39 | /// engine's draw cap). A faster request is raised to this. |
| 40 | pub const MOTION_MIN_FRAME_INTERVAL: Duration = Duration::from_micros(8_333); |
| 41 | |
| 42 | /// How a step eases. Nothing overshoots: every curve stays inside `0..=1` |
| 43 | /// and never reverses. |
| 44 | #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash)] |
| 45 | pub enum MotionEasing { |
| 46 | Linear, |
| 47 | /// Fast, then settling: for things arriving. |
| 48 | #[default] |
| 49 | EaseOut, |
| 50 | /// Slow, then leaving: for things exiting. |
| 51 | EaseIn, |
| 52 | } |
| 53 | |
| 54 | impl MotionEasing { |
| 55 | /// The eased progress for `t` in `0..=1`. Outside the range clamps; a |
| 56 | /// NaN counts as finished. |
| 57 | #[must_use] |
| 58 | pub fn apply(self, t: f32) -> f32 { |
| 59 | let t = if t.is_nan() { 1.0 } else { t.clamp(0.0, 1.0) }; |
| 60 | match self { |
| 61 | Self::Linear => t, |
| 62 | Self::EaseOut => 1.0 - (1.0 - t).powi(3), |
| 63 | Self::EaseIn => t * t * t, |
| 64 | } |
| 65 | } |
| 66 | } |
| 67 | |
| 68 | /// What a step moves. A color step needs a concrete truecolor ground; a |
| 69 | /// spatial step moves cells and works at any depth. |
| 70 | #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)] |
| 71 | pub enum MotionChannel { |
| 72 | /// A column offset or a reveal width. |
| 73 | Space, |
| 74 | /// A role blend. |
| 75 | Tint, |
| 76 | } |
| 77 | |
| 78 | /// How long a step takes and how it eases. |
| 79 | #[derive(Clone, Copy, Debug, PartialEq, Eq)] |
| 80 | pub struct MotionTiming { |
| 81 | pub duration: Duration, |
| 82 | pub easing: MotionEasing, |
| 83 | pub channel: MotionChannel, |
| 84 | } |
| 85 | |
| 86 | impl MotionTiming { |
| 87 | /// A row's state changed (`duration_state`, 120 ms, ease out). |
| 88 | pub const STATE: Self = Self::tint( |
| 89 | Duration::from_millis(tokens::MOTION_DURATION_STATE_MS as u64), |
| 90 | MotionEasing::EaseOut, |
| 91 | ); |
| 92 | /// Something arrived (`duration_arrive`, 180 ms, ease out). |
| 93 | pub const ARRIVE: Self = Self::tint( |
| 94 | Duration::from_millis(tokens::MOTION_DURATION_ARRIVE_MS as u64), |
| 95 | MotionEasing::EaseOut, |
| 96 | ); |
| 97 | /// Something left (`duration_state`, 120 ms, ease in). |
| 98 | pub const EXIT: Self = Self::tint( |
| 99 | Duration::from_millis(tokens::MOTION_DURATION_STATE_MS as u64), |
| 100 | MotionEasing::EaseIn, |
| 101 | ); |
| 102 | /// A panel's width or position settles (`duration_panel`, 340 ms, ease |
| 103 | /// out). |
| 104 | pub const PANEL: Self = Self::space( |
| 105 | Duration::from_millis(tokens::MOTION_DURATION_PANEL_MS as u64), |
| 106 | MotionEasing::EaseOut, |
| 107 | ); |
| 108 | |
| 109 | /// A role blend. |
| 110 | #[must_use] |
| 111 | pub const fn tint(duration: Duration, easing: MotionEasing) -> Self { |
| 112 | Self { |
| 113 | duration, |
| 114 | easing, |
| 115 | channel: MotionChannel::Tint, |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | /// A column offset or reveal width. |
| 120 | #[must_use] |
| 121 | pub const fn space(duration: Duration, easing: MotionEasing) -> Self { |
| 122 | Self { |
| 123 | duration, |
| 124 | easing, |
| 125 | channel: MotionChannel::Space, |
| 126 | } |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | /// What may move, from the person's setting and what the terminal can show. |
| 131 | #[derive(Clone, Copy, Debug, PartialEq, Eq)] |
| 132 | pub struct MotionPolicy { |
| 133 | mode: MotionMode, |
| 134 | tints: bool, |
| 135 | } |
| 136 | |
| 137 | impl MotionPolicy { |
| 138 | /// `mode` on the terminal `theme` describes. |
| 139 | #[must_use] |
| 140 | pub fn new(mode: MotionMode, theme: &Theme) -> Self { |
| 141 | Self { |
| 142 | mode, |
| 143 | tints: can_blend(theme), |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | #[must_use] |
| 148 | pub const fn mode(self) -> MotionMode { |
| 149 | self.mode |
| 150 | } |
| 151 | |
| 152 | /// Whether anything moves at all: `Full` only. |
| 153 | #[must_use] |
| 154 | pub const fn animates(self) -> bool { |
| 155 | self.mode.animates() |
| 156 | } |
| 157 | |
| 158 | /// Whether a step on `channel` runs, or jumps to its end state. |
| 159 | #[must_use] |
| 160 | pub const fn allows(self, channel: MotionChannel) -> bool { |
| 161 | self.animates() |
| 162 | && match channel { |
| 163 | MotionChannel::Space => true, |
| 164 | MotionChannel::Tint => self.tints, |
| 165 | } |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | /// Colors blend only at truecolor on a known ground: the in-between values |
| 170 | /// of a 256-color blend are other roles, and an unknown ground has nothing |
| 171 | /// to blend with. |
| 172 | fn can_blend(theme: &Theme) -> bool { |
| 173 | theme.paints_grounds() && theme.depth() == ColorDepth::TrueColor |
| 174 | } |
| 175 | |
| 176 | /// One value easing from where it is to a target, both in `0..=1`. |
| 177 | /// |
| 178 | /// `0.0` is the start state (the `from` role, the home column, nothing |
| 179 | /// revealed) and `1.0` the end state. A new step starts at rest. |
| 180 | #[derive(Clone, Copy, Debug, PartialEq)] |
| 181 | pub struct MotionStep { |
| 182 | from: f32, |
| 183 | to: f32, |
| 184 | start: Option<Instant>, |
| 185 | duration: Duration, |
| 186 | easing: MotionEasing, |
| 187 | } |
| 188 | |
| 189 | impl Default for MotionStep { |
| 190 | fn default() -> Self { |
| 191 | Self::at_rest(0.0) |
| 192 | } |
| 193 | } |
| 194 | |
| 195 | impl MotionStep { |
| 196 | /// A step that is not moving, at `value` (clamped to `0..=1`). |
| 197 | #[must_use] |
| 198 | pub fn at_rest(value: f32) -> Self { |
| 199 | let value = unit(value); |
| 200 | Self { |
| 201 | from: value, |
| 202 | to: value, |
| 203 | start: None, |
| 204 | duration: Duration::ZERO, |
| 205 | easing: MotionEasing::Linear, |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | /// Where the step is going. |
| 210 | #[must_use] |
| 211 | pub const fn target(&self) -> f32 { |
| 212 | self.to |
| 213 | } |
| 214 | |
| 215 | /// The value at `now`, in `0..=1`. Before the start it is the start |
| 216 | /// value; at and after the end it is the target. |
| 217 | #[must_use] |
| 218 | pub fn at(&self, now: Instant) -> f32 { |
| 219 | let Some(start) = self.start else { |
| 220 | return self.to; |
| 221 | }; |
| 222 | let elapsed = now.saturating_duration_since(start); |
| 223 | if self.duration.is_zero() || elapsed >= self.duration { |
| 224 | return self.to; |
| 225 | } |
| 226 | let t = elapsed.as_secs_f32() / self.duration.as_secs_f32(); |
| 227 | unit(self.from + (self.to - self.from) * self.easing.apply(t)) |
| 228 | } |
| 229 | |
| 230 | /// Whether the step has reached its target at `now`. |
| 231 | #[must_use] |
| 232 | pub fn is_settled(&self, now: Instant) -> bool { |
| 233 | self.start.is_none_or(|start| { |
| 234 | self.duration.is_zero() || now.saturating_duration_since(start) >= self.duration |
| 235 | }) |
| 236 | } |
| 237 | |
| 238 | /// Whether this step still needs frames: it is moving, and `policy` |
| 239 | /// lets it move. |
| 240 | #[must_use] |
| 241 | pub fn is_live(&self, now: Instant, policy: MotionPolicy) -> bool { |
| 242 | policy.animates() && !self.is_settled(now) |
| 243 | } |
| 244 | |
| 245 | /// Head for `target` (clamped to `0..=1`). Mid-flight it starts from |
| 246 | /// where the step is now, so nothing jumps. Asking for the target the |
| 247 | /// step already has changes nothing and does not restart it, so a |
| 248 | /// component may call this on every event. Returns whether anything |
| 249 | /// changed. |
| 250 | /// |
| 251 | /// Where the policy does not let `timing.channel` move, the step jumps |
| 252 | /// to `target` and is settled. |
| 253 | pub fn go( |
| 254 | &mut self, |
| 255 | target: f32, |
| 256 | now: Instant, |
| 257 | timing: MotionTiming, |
| 258 | policy: MotionPolicy, |
| 259 | ) -> bool { |
| 260 | if !target.is_finite() { |
| 261 | return false; |
| 262 | } |
| 263 | let target = unit(target); |
| 264 | if target == self.to { |
| 265 | return false; |
| 266 | } |
| 267 | *self = if policy.allows(timing.channel) && !timing.duration.is_zero() { |
| 268 | Self { |
| 269 | from: self.at(now), |
| 270 | to: target, |
| 271 | start: Some(now), |
| 272 | duration: timing.duration, |
| 273 | easing: timing.easing, |
| 274 | } |
| 275 | } else { |
| 276 | Self::at_rest(target) |
| 277 | }; |
| 278 | true |
| 279 | } |
| 280 | |
| 281 | /// Stop where the step is going, at once. Input wins: a key press |
| 282 | /// settles every running step. |
| 283 | pub fn settle(&mut self) { |
| 284 | *self = Self::at_rest(self.to); |
| 285 | } |
| 286 | |
| 287 | /// The redraw this step wants after `now`, or `None` once it is settled |
| 288 | /// (or the policy does not animate). |
| 289 | #[must_use] |
| 290 | pub fn next_frame_at(&self, now: Instant, policy: MotionPolicy) -> Option<Instant> { |
| 291 | self.is_live(now, policy) |
| 292 | .then(|| now.checked_add(MOTION_FRAME_INTERVAL)) |
| 293 | .flatten() |
| 294 | } |
| 295 | |
| 296 | /// The value to show: eased where `policy` lets `channel` move, the |
| 297 | /// target where it does not. The one place the policy is applied at |
| 298 | /// paint time, so a mode changed mid-flight cannot leave a ghost. |
| 299 | fn shown(&self, now: Instant, policy: MotionPolicy, channel: MotionChannel) -> f32 { |
| 300 | if policy.allows(channel) { |
| 301 | self.at(now) |
| 302 | } else { |
| 303 | self.to |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | /// A column between `from` and `to`: slide a marker, nudge a panel. |
| 308 | #[must_use] |
| 309 | pub fn offset(&self, now: Instant, policy: MotionPolicy, from: u16, to: u16) -> u16 { |
| 310 | let v = self.shown(now, policy, MotionChannel::Space); |
| 311 | let (a, b) = (f32::from(from), f32::from(to)); |
| 312 | (a + (b - a) * v).round().clamp(0.0, f32::from(u16::MAX)) as u16 |
| 313 | } |
| 314 | |
| 315 | /// How many of `width` columns are shown: `0` before, `width` after. |
| 316 | #[must_use] |
| 317 | pub fn reveal(&self, now: Instant, policy: MotionPolicy, width: u16) -> u16 { |
| 318 | self.offset(now, policy, 0, width) |
| 319 | } |
| 320 | |
| 321 | /// Ink: [`Theme::fg`] blended from `from` toward `to`. At the ends it is |
| 322 | /// exactly `theme.fg(from)` and `theme.fg(to)`; between, a blend at |
| 323 | /// truecolor, and a jump to the nearer role anywhere else. |
| 324 | #[must_use] |
| 325 | pub fn fg( |
| 326 | &self, |
| 327 | now: Instant, |
| 328 | policy: MotionPolicy, |
| 329 | theme: &Theme, |
| 330 | from: Role, |
| 331 | to: Role, |
| 332 | ) -> Style { |
| 333 | let v = self.shown(now, policy, MotionChannel::Tint); |
| 334 | match ends(v, from, to) { |
| 335 | Some(role) => theme.fg(role), |
| 336 | None if !can_blend(theme) => theme.fg(nearer(v, from, to)), |
| 337 | None => match (theme.fg(from).fg, theme.fg(to).fg) { |
| 338 | (Some(a), Some(b)) => Style::default().fg(blend(b, a, v)), |
| 339 | _ => theme.fg(nearer(v, from, to)), |
| 340 | }, |
| 341 | } |
| 342 | } |
| 343 | |
| 344 | /// A ground: [`Theme::bg`] blended from `from` toward `to`. A ground the |
| 345 | /// terminal keeps (unpainted, or `NO_COLOR`) is not blended through: the |
| 346 | /// step jumps to the nearer role. |
| 347 | #[must_use] |
| 348 | pub fn bg( |
| 349 | &self, |
| 350 | now: Instant, |
| 351 | policy: MotionPolicy, |
| 352 | theme: &Theme, |
| 353 | from: Role, |
| 354 | to: Role, |
| 355 | ) -> Style { |
| 356 | let v = self.shown(now, policy, MotionChannel::Tint); |
| 357 | match ends(v, from, to) { |
| 358 | Some(role) => theme.bg(role), |
| 359 | None if !can_blend(theme) => theme.bg(nearer(v, from, to)), |
| 360 | None => match (theme.bg(from).bg, theme.bg(to).bg) { |
| 361 | (Some(a), Some(b)) => Style::default().bg(blend(b, a, v)), |
| 362 | _ => theme.bg(nearer(v, from, to)), |
| 363 | }, |
| 364 | } |
| 365 | } |
| 366 | } |
| 367 | |
| 368 | fn unit(v: f32) -> f32 { |
| 369 | if v.is_nan() { 0.0 } else { v.clamp(0.0, 1.0) } |
| 370 | } |
| 371 | |
| 372 | fn ends(v: f32, from: Role, to: Role) -> Option<Role> { |
| 373 | if v <= 0.0 { |
| 374 | Some(from) |
| 375 | } else if v >= 1.0 { |
| 376 | Some(to) |
| 377 | } else { |
| 378 | None |
| 379 | } |
| 380 | } |
| 381 | |
| 382 | fn nearer(v: f32, from: Role, to: Role) -> Role { |
| 383 | if v >= 0.5 { to } else { from } |
| 384 | } |
| 385 | |
| 386 | /// A component's few named motions, and the schedule for all of them. |
| 387 | #[derive(Clone, Debug)] |
| 388 | pub struct MotionSet { |
| 389 | steps: Vec<(&'static str, MotionStep)>, |
| 390 | interval: Duration, |
| 391 | } |
| 392 | |
| 393 | impl Default for MotionSet { |
| 394 | fn default() -> Self { |
| 395 | Self::new() |
| 396 | } |
| 397 | } |
| 398 | |
| 399 | impl MotionSet { |
| 400 | #[must_use] |
| 401 | pub fn new() -> Self { |
| 402 | Self { |
| 403 | steps: Vec::new(), |
| 404 | interval: MOTION_FRAME_INTERVAL, |
| 405 | } |
| 406 | } |
| 407 | |
| 408 | /// Cap redraws at one per `interval` (at least |
| 409 | /// [`MOTION_MIN_FRAME_INTERVAL`]): 33 ms holds a slow terminal to 30 |
| 410 | /// frames a second. |
| 411 | #[must_use] |
| 412 | pub fn with_frame_interval(mut self, interval: Duration) -> Self { |
| 413 | self.interval = interval.max(MOTION_MIN_FRAME_INTERVAL); |
| 414 | self |
| 415 | } |
| 416 | |
| 417 | /// Head the motion called `name` for `target`; see [`MotionStep::go`]. |
| 418 | /// A name seen for the first time starts at rest at `0.0`. |
| 419 | pub fn go( |
| 420 | &mut self, |
| 421 | name: &'static str, |
| 422 | target: f32, |
| 423 | now: Instant, |
| 424 | timing: MotionTiming, |
| 425 | policy: MotionPolicy, |
| 426 | ) -> bool { |
| 427 | let at = match self.steps.iter().position(|(n, _)| *n == name) { |
| 428 | Some(at) => at, |
| 429 | None => { |
| 430 | self.steps.push((name, MotionStep::default())); |
| 431 | self.steps.len() - 1 |
| 432 | } |
| 433 | }; |
| 434 | self.steps[at].1.go(target, now, timing, policy) |
| 435 | } |
| 436 | |
| 437 | /// The motion called `name`, or one at rest at `0.0`. |
| 438 | #[must_use] |
| 439 | pub fn step(&self, name: &str) -> MotionStep { |
| 440 | self.steps |
| 441 | .iter() |
| 442 | .find(|(n, _)| *n == name) |
| 443 | .map_or_else(MotionStep::default, |(_, step)| *step) |
| 444 | } |
| 445 | |
| 446 | /// Settle every motion at its target now. Input wins. |
| 447 | pub fn settle_all(&mut self) { |
| 448 | for (_, step) in &mut self.steps { |
| 449 | step.settle(); |
| 450 | } |
| 451 | } |
| 452 | |
| 453 | /// Whether every motion has reached its target at `now`. |
| 454 | #[must_use] |
| 455 | pub fn is_settled(&self, now: Instant) -> bool { |
| 456 | self.steps.iter().all(|(_, step)| step.is_settled(now)) |
| 457 | } |
| 458 | |
| 459 | /// When the next redraw is due: one frame interval after `now` while any |
| 460 | /// motion is live, and `None` once everything is settled or the policy |
| 461 | /// does not animate. Ask right after a draw, with the instant it was |
| 462 | /// drawn at, so the interval is the cap between draws. |
| 463 | #[must_use] |
| 464 | pub fn next_frame_at(&self, now: Instant, policy: MotionPolicy) -> Option<Instant> { |
| 465 | self.steps |
| 466 | .iter() |
| 467 | .any(|(_, step)| step.is_live(now, policy)) |
| 468 | .then(|| now.checked_add(self.interval)) |
| 469 | .flatten() |
| 470 | } |
| 471 | } |
| 472 | |
| 473 | /// The earliest of several components' [`MotionSet::next_frame_at`] |
| 474 | /// answers; `None` when none of them wants a frame. |
| 475 | #[must_use] |
| 476 | pub fn soonest_frame(due: impl IntoIterator<Item = Option<Instant>>) -> Option<Instant> { |
| 477 | due.into_iter().flatten().min() |
| 478 | } |
| 479 | |
| 480 | /// What one frame may spend, and the earliest redraw anyone asked for. |
| 481 | /// |
| 482 | /// Kept from the first draft of this package. The host makes one per frame, |
| 483 | /// each component claims what it draws, and the host reads |
| 484 | /// [`FrameBudget::next_frame_in`] after the draw. Only the first |
| 485 | /// [`claim_spinner`](Self::claim_spinner) and |
| 486 | /// [`claim_horizon`](Self::claim_horizon) return `true`: a second spinner is |
| 487 | /// drawn as the still `●` plus its word (hiding it would hide real work), and |
| 488 | /// a second horizon is not drawn. |
| 489 | #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)] |
| 490 | pub struct FrameBudget { |
| 491 | next: Option<Duration>, |
| 492 | spinners: usize, |
| 493 | horizons: usize, |
| 494 | } |
| 495 | |
| 496 | impl FrameBudget { |
| 497 | #[must_use] |
| 498 | pub fn new() -> Self { |
| 499 | Self::default() |
| 500 | } |
| 501 | |
| 502 | /// A redraw wanted `after` from now (`None` asks for nothing), as |
| 503 | /// [`spin::next_frame_in`](crate::spin::next_frame_in) answers. |
| 504 | pub fn request(&mut self, after: Option<Duration>) { |
| 505 | if let Some(after) = after { |
| 506 | self.next = Some(self.next.map_or(after, |current| current.min(after))); |
| 507 | } |
| 508 | } |
| 509 | |
| 510 | /// A redraw due at `at`, as [`MotionSet::next_frame_at`] answers. An |
| 511 | /// instant already past asks for a frame now. |
| 512 | pub fn request_at(&mut self, now: Instant, at: Option<Instant>) { |
| 513 | self.request(at.map(|at| at.saturating_duration_since(now))); |
| 514 | } |
| 515 | |
| 516 | /// The soonest redraw anyone asked for; `None` when nothing moves, so an |
| 517 | /// idle screen sleeps until an event. |
| 518 | #[must_use] |
| 519 | pub fn next_frame_in(&self) -> Option<Duration> { |
| 520 | self.next |
| 521 | } |
| 522 | |
| 523 | /// Whether this is the frame's first spinner. |
| 524 | pub fn claim_spinner(&mut self) -> bool { |
| 525 | self.spinners += 1; |
| 526 | self.spinners == 1 |
| 527 | } |
| 528 | |
| 529 | /// Whether this is the frame's first horizon rule. |
| 530 | pub fn claim_horizon(&mut self) -> bool { |
| 531 | self.horizons += 1; |
| 532 | self.horizons == 1 |
| 533 | } |
| 534 | } |
| 535 | |
| 536 | /// The words [`MotionDemo`] shows. |
| 537 | #[derive(Clone, Debug, PartialEq, Eq)] |
| 538 | pub struct MotionDemoWords { |
| 539 | pub working: Cow<'static, str>, |
| 540 | pub done: Cow<'static, str>, |
| 541 | pub slide: Cow<'static, str>, |
| 542 | pub detail: Cow<'static, str>, |
| 543 | } |
| 544 | |
| 545 | impl Default for MotionDemoWords { |
| 546 | fn default() -> Self { |
| 547 | Self { |
| 548 | working: Cow::Borrowed("Working"), |
| 549 | done: Cow::Borrowed("Done"), |
| 550 | slide: Cow::Borrowed("Selected"), |
| 551 | detail: Cow::Borrowed("patch applied to 3 files"), |
| 552 | } |
| 553 | } |
| 554 | } |
| 555 | |
| 556 | /// The reference component for this module: one state change, painted at |
| 557 | /// one instant. |
| 558 | /// |
| 559 | /// Three rows. The first is a state mark and word whose ink eases from |
| 560 | /// `Muted` to `Live` (a tint). The mark and the word always say the real |
| 561 | /// state, so a frame caught mid-step is never ambiguous. The second slides a |
| 562 | /// selection marker across, and the third reveals a line of detail. Where |
| 563 | /// the policy does not animate, every row is its end state. |
| 564 | #[derive(Clone, Debug)] |
| 565 | pub struct MotionDemo<'a> { |
| 566 | motions: &'a MotionSet, |
| 567 | now: Instant, |
| 568 | policy: MotionPolicy, |
| 569 | done: bool, |
| 570 | words: MotionDemoWords, |
| 571 | } |
| 572 | |
| 573 | impl<'a> MotionDemo<'a> { |
| 574 | #[must_use] |
| 575 | pub fn new(motions: &'a MotionSet, now: Instant, policy: MotionPolicy, done: bool) -> Self { |
| 576 | Self { |
| 577 | motions, |
| 578 | now, |
| 579 | policy, |
| 580 | done, |
| 581 | words: MotionDemoWords::default(), |
| 582 | } |
| 583 | } |
| 584 | |
| 585 | #[must_use] |
| 586 | pub fn with_words(mut self, words: MotionDemoWords) -> Self { |
| 587 | self.words = words; |
| 588 | self |
| 589 | } |
| 590 | |
| 591 | /// Start the three motions toward `done` (or back to working). |
| 592 | pub fn start(motions: &mut MotionSet, done: bool, now: Instant, policy: MotionPolicy) { |
| 593 | let target = if done { 1.0 } else { 0.0 }; |
| 594 | motions.go("ink", target, now, MotionTiming::ARRIVE, policy); |
| 595 | motions.go( |
| 596 | "slide", |
| 597 | target, |
| 598 | now, |
| 599 | MotionTiming::space(MotionTiming::ARRIVE.duration, MotionEasing::EaseOut), |
| 600 | policy, |
| 601 | ); |
| 602 | motions.go("reveal", target, now, MotionTiming::PANEL, policy); |
| 603 | } |
| 604 | } |
| 605 | |
| 606 | impl Paint for MotionDemo<'_> { |
| 607 | fn paint(&self, area: Rect, buf: &mut Buffer, theme: &Theme) { |
| 608 | let area = area.intersection(buf.area); |
| 609 | if area.is_empty() { |
| 610 | return; |
| 611 | } |
| 612 | let (now, policy) = (self.now, self.policy); |
| 613 | let row = |i: u16| (area.height > i).then_some(area.y + i); |
| 614 | let put = |buf: &mut Buffer, x: u16, y: u16, s: &str, style: Style, max: u16| { |
| 615 | if x < area.right() { |
| 616 | buf.set_stringn(x, y, s, usize::from(max.min(area.right() - x)), style); |
| 617 | } |
| 618 | }; |
| 619 | |
| 620 | if let Some(y) = row(0) { |
| 621 | let ink = self |
| 622 | .motions |
| 623 | .step("ink") |
| 624 | .fg(now, policy, theme, Role::Muted, Role::Live); |
| 625 | let (mark, word) = if self.done { |
| 626 | (glyphs::DONE, &self.words.done) |
| 627 | } else { |
| 628 | (glyphs::CURRENT, &self.words.working) |
| 629 | }; |
| 630 | let mark = glyphs::pick(mark, theme.ascii()); |
| 631 | put(buf, area.x, y, mark, ink, area.width); |
| 632 | let x = area.x.saturating_add(text::width(mark) as u16 + 1); |
| 633 | put( |
| 634 | buf, |
| 635 | x, |
| 636 | y, |
| 637 | &text::display_safe(word), |
| 638 | theme.fg(Role::Foreground), |
| 639 | area.width, |
| 640 | ); |
| 641 | } |
| 642 | |
| 643 | if let Some(y) = row(1) { |
| 644 | let marker = glyphs::pick(glyphs::SELECTION, theme.ascii()); |
| 645 | let label = text::display_safe(&self.words.slide); |
| 646 | let used = text::width(marker) + 1 + text::width(&label); |
| 647 | let span = area.width.saturating_sub(used as u16).min(24); |
| 648 | let x = area |
| 649 | .x |
| 650 | .saturating_add(self.motions.step("slide").offset(now, policy, 0, span)); |
| 651 | put(buf, x, y, marker, theme.fg(Role::Primary), area.width); |
| 652 | let lx = x.saturating_add(text::width(marker) as u16 + 1); |
| 653 | put(buf, lx, y, &label, theme.fg(Role::Foreground), area.width); |
| 654 | } |
| 655 | |
| 656 | if let Some(y) = row(2) { |
| 657 | let detail = text::display_safe(&self.words.detail); |
| 658 | let full = text::width(&detail).min(usize::from(area.width)) as u16; |
| 659 | let shown = self.motions.step("reveal").reveal(now, policy, full); |
| 660 | put(buf, area.x, y, &detail, theme.fg(Role::Muted), shown); |
| 661 | } |
| 662 | } |
| 663 | |
| 664 | fn height(&self, _width: u16, _theme: &Theme) -> u16 { |
| 665 | 3 |
| 666 | } |
| 667 | } |
| 668 |