Struct Tween 

pub struct Tween<T: Lerp> { /* private fields */ }

A finite eased interpolation between two values on a caller-supplied clock.

A tween never owns time: sampling and retargeting take now, so one value drives retained repaints and immediate-mode paints alike. Tween::retarget restarts from the current sample, so interrupting a running transition never jumps.

Example

use std::time::Duration;

use omp_tui::anim::{Easing, Tween};

let mut fade = Tween::settled(0.0f32);
fade.retarget(Duration::ZERO, 1.0, Duration::from_millis(100), Easing::Linear);
assert_eq!(fade.sample(Duration::from_millis(50)), 0.5);
assert!(fade.is_settled(Duration::from_millis(100)));

Implementations

impl<T: Lerp> Tween<T>

pub const fn settled(value: T) -> Self

A tween already settled at value.

Examples found in repository

examples/chat/welcome.rs (line 183)

	pub fn new(charset: Charset) -> Self {
		Self {
			charset,
			frame: Frame::new(Size::new(0, 0)),
			title: fmts!(" {} omp v{} ", charset.icon(Icon::Omp), env!("CARGO_PKG_VERSION")),
			camera: (0.0, 0.0),
			camera_target: (0.0, 0.0),
			last_elapsed: 0.0,
			logo_origin: (0, 0),
			logo: [[None; LOGO_COLS]; LOGO_ROWS],
			logo_at: None,
			backdrop_frame: Frame::new(Size::new(0, 0)),
			backdrop_at: None,
			backdrop: Eclipse::default(),
			surface: Surface::new(),
			pointer: None,
			hover: Tween::settled(0.0),
		}
	}

examples/chat/demo.rs (line 762)

	pub fn new(ctx: &UiContext) -> Self {
		let editor = Rc::new(RefCell::new({
			let mut editor = Editor::new(EditorOptions::default());
			editor.set_completion(Box::new(SlashCommands::new(demo_commands())));
			editor
		}));
		let edit_outcome = Rc::new(RefCell::new(None));
		let work = Rc::new(RefCell::new(WorkState {
			working: true,
			since:   Duration::ZERO,
			fade:    Tween::settled(GREEN),
		}));
		let model = Rc::new(RefCell::new(Str::new_static("Fable 5++")));
		let pane = EditorPane::new()
			.input(DemoInput::new(Rc::clone(&editor), Rc::clone(&edit_outcome)))
			.status(DemoStatus::new(Rc::clone(&work), Rc::clone(&model), ctx.charset));
		let attachments = pane.attachments();
		let editor_ui = Ui::from_root(pane, 0, ctx.clone());
		Self {
			started_at: Instant::now(),
			ctx: ctx.clone(),
			cancel_hint: ctx.charset.icon(Icon::Cancellable),
			editor_ui,
			editor,
			edit_outcome,
			work,
			last_working: true,
			model,
			attachments,
			transcript: vec![Entry::Command],
			drawn_entries: 0,
			transcript_rows: 0,
			appended_messages: 0,
			emitted_shards: 0,
			last_viewport: Size::new(0, 0),
			height_floor: 0,
			frame: Frame::new(Size::new(0, 0)),
			live_panel: None,
			live_rows: std::array::from_fn(|_| LiveRowCache::new()),
			live_label_scratch: StrMut::with_capacity(40),
			right_inset: 0,
			switch_requested: false,
		}
	}

pub fn sample(&self, now: Duration) -> T

The value at time now.

Examples found in repository

examples/chat/demo.rs (line 589)

	fn brand_segment(&self, now: Duration) -> Segment {
		let work = self.work.borrow();
		let brand = if work.working {
			fmts!(
				"{} {}",
				self.charset.spinner().at(now),
				elapsed_label(now.saturating_sub(work.since))
			)
		} else {
			fmts!("{} omp", self.charset.icon(Icon::Omp))
		};
		Segment::new()
			.label(brand)
			.with(Prop::Fg, work.fade.sample(now))
	}

examples/chat/welcome.rs (line 250)

	pub fn render(&mut self, viewport: Size, elapsed: Duration) -> &Frame {
		if self.frame.size() != viewport {
			self.frame = Frame::new(viewport);
			self.backdrop_frame = Frame::new(viewport);
			self.backdrop_at = None;
		}
		let clock = elapsed;
		let elapsed = elapsed.as_secs_f32();
		// Exponential pointer chase, frame-rate independent (~100ms lag).
		let delta = (elapsed - self.last_elapsed).max(0.0);
		self.last_elapsed = elapsed;
		let response = 1.0 - (-delta * 10.0).exp();
		self.camera.0 += (self.camera_target.0 - self.camera.0) * response;
		self.camera.1 += (self.camera_target.1 - self.camera.1) * response;
		self.draw_backdrop(viewport, clock, elapsed);

		let logo_interval = ambient_interval(clock, LOGO_IDLE_INTERVAL);
		if self
			.logo_at
			.is_none_or(|rendered_at| clock.saturating_sub(rendered_at) >= logo_interval)
		{
			self.logo = logo_cells(elapsed, self.camera);
			self.logo_at = Some(clock);
		}
		let cols = if viewport.width >= CARD_COLS && viewport.height >= CARD_ROWS {
			Some(CARD_COLS)
		} else if viewport.width >= SMOL_COLS && viewport.height >= CARD_ROWS {
			Some(SMOL_COLS)
		} else {
			None
		};
		let Some(cols) = cols else {
			let left = viewport.width.saturating_sub(LOGO_COLS as u16) / 2;
			let top = viewport.height.saturating_sub(LOGO_ROWS as u16) / 2;
			self.logo_origin = (left, top);
			blit_logo(&mut self.frame, &self.logo, left, top, PLATE);
			return &self.frame;
		};

		let left = (viewport.width - cols) / 2;
		let top = (viewport.height - CARD_ROWS) / 2;
		let hovered = self.pointer.is_some_and(|(x, y)| {
			(left..left + cols).contains(&x) && (top..top + CARD_ROWS).contains(&y)
		});
		self
			.hover
			.retarget(clock, if hovered { 1.0 } else { 0.0 }, HOVER_EASE, Easing::EaseOut);
		let hover = self.hover.sample(clock).clamp(0.0, 1.0);
		self.draw_card(cols, left, top, elapsed, hover);
		&self.frame
	}

pub const fn target(&self) -> T

The value the tween is heading toward.

pub fn is_settled(&self, now: Duration) -> bool

Whether the tween has reached its target at time now.

Examples found in repository

examples/chat/demo.rs (line 686)

	fn paint(&mut self, pc: &mut PaintCtx<'_>, rect: Rect) {
		let mut left = self.left_group(pc.now);
		let (_, left_width) = left.measure(pc.ctx);
		let (_, right_width) = self.right.measure(pc.ctx);
		if left_width.saturating_add(2).saturating_add(right_width) <= rect.width {
			left.paint(pc, Rect::new(rect.x, rect.y, left_width, 1));
			let dock = rect
				.x
				.saturating_add(rect.width)
				.saturating_sub(right_width);
			self
				.right
				.paint(pc, Rect::new(dock, rect.y, right_width, 1));
		} else {
			let mut combined = self.combined(pc.now);
			combined.paint(pc, rect);
		}
		let work = self.work.borrow();
		let fade_frame = work
			.fade
			.settles_at()
			.min(pc.now.saturating_add(FADE_FRAME));
		let deadline = match (work.working, work.fade.is_settled(pc.now)) {
			(true, true) => Some(pc.ctx.charset.spinner().next_change(pc.now)),
			(true, false) => Some(pc.ctx.charset.spinner().next_change(pc.now).min(fade_frame)),
			(false, false) => Some(fade_frame),
			(false, true) => None,
		};
		if let Some(at) = deadline {
			pc.wake(self.slot, at);
		}
	}

pub const fn settles_at(&self) -> Duration

When the tween reaches its target — the deadline for the final frame.

Examples found in repository

examples/chat/demo.rs (line 684)

	fn paint(&mut self, pc: &mut PaintCtx<'_>, rect: Rect) {
		let mut left = self.left_group(pc.now);
		let (_, left_width) = left.measure(pc.ctx);
		let (_, right_width) = self.right.measure(pc.ctx);
		if left_width.saturating_add(2).saturating_add(right_width) <= rect.width {
			left.paint(pc, Rect::new(rect.x, rect.y, left_width, 1));
			let dock = rect
				.x
				.saturating_add(rect.width)
				.saturating_sub(right_width);
			self
				.right
				.paint(pc, Rect::new(dock, rect.y, right_width, 1));
		} else {
			let mut combined = self.combined(pc.now);
			combined.paint(pc, rect);
		}
		let work = self.work.borrow();
		let fade_frame = work
			.fade
			.settles_at()
			.min(pc.now.saturating_add(FADE_FRAME));
		let deadline = match (work.working, work.fade.is_settled(pc.now)) {
			(true, true) => Some(pc.ctx.charset.spinner().next_change(pc.now)),
			(true, false) => Some(pc.ctx.charset.spinner().next_change(pc.now).min(fade_frame)),
			(false, false) => Some(fade_frame),
			(false, true) => None,
		};
		if let Some(at) = deadline {
			pc.wake(self.slot, at);
		}
	}

pub fn retarget( &mut self, now: Duration, to: T, duration: Duration, easing: Easing, )

where T: PartialEq,

Redirects the tween toward to over duration, starting from the value currently on screen. A matching target is a no-op, so callers may retarget unconditionally on every state change.

Examples found in repository

examples/chat/demo.rs (line 890)

	fn set_working(&mut self, working: bool, now: Duration) {
		{
			let mut work = self.work.borrow_mut();
			if work.working == working {
				return;
			}
			work.working = working;
			work.since = now;
			let target = if working { GREEN } else { MUTED };
			work
				.fade
				.retarget(now, target, BRAND_FADE, Easing::EaseInOut);
		}
		self.editor_ui.invalidate(STATUS_ID);
	}

examples/chat/welcome.rs (line 249)

	pub fn render(&mut self, viewport: Size, elapsed: Duration) -> &Frame {
		if self.frame.size() != viewport {
			self.frame = Frame::new(viewport);
			self.backdrop_frame = Frame::new(viewport);
			self.backdrop_at = None;
		}
		let clock = elapsed;
		let elapsed = elapsed.as_secs_f32();
		// Exponential pointer chase, frame-rate independent (~100ms lag).
		let delta = (elapsed - self.last_elapsed).max(0.0);
		self.last_elapsed = elapsed;
		let response = 1.0 - (-delta * 10.0).exp();
		self.camera.0 += (self.camera_target.0 - self.camera.0) * response;
		self.camera.1 += (self.camera_target.1 - self.camera.1) * response;
		self.draw_backdrop(viewport, clock, elapsed);

		let logo_interval = ambient_interval(clock, LOGO_IDLE_INTERVAL);
		if self
			.logo_at
			.is_none_or(|rendered_at| clock.saturating_sub(rendered_at) >= logo_interval)
		{
			self.logo = logo_cells(elapsed, self.camera);
			self.logo_at = Some(clock);
		}
		let cols = if viewport.width >= CARD_COLS && viewport.height >= CARD_ROWS {
			Some(CARD_COLS)
		} else if viewport.width >= SMOL_COLS && viewport.height >= CARD_ROWS {
			Some(SMOL_COLS)
		} else {
			None
		};
		let Some(cols) = cols else {
			let left = viewport.width.saturating_sub(LOGO_COLS as u16) / 2;
			let top = viewport.height.saturating_sub(LOGO_ROWS as u16) / 2;
			self.logo_origin = (left, top);
			blit_logo(&mut self.frame, &self.logo, left, top, PLATE);
			return &self.frame;
		};

		let left = (viewport.width - cols) / 2;
		let top = (viewport.height - CARD_ROWS) / 2;
		let hovered = self.pointer.is_some_and(|(x, y)| {
			(left..left + cols).contains(&x) && (top..top + CARD_ROWS).contains(&y)
		});
		self
			.hover
			.retarget(clock, if hovered { 1.0 } else { 0.0 }, HOVER_EASE, Easing::EaseOut);
		let hover = self.hover.sample(clock).clamp(0.0, 1.0);
		self.draw_card(cols, left, top, elapsed, hover);
		&self.frame
	}

Trait Implementations

impl<T: Clone + Lerp> Clone for Tween<T>

fn clone(&self) -> Tween<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Copy + Lerp> Copy for Tween<T>

impl<T: Debug + Lerp> Debug for Tween<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.