Struct SpringAnimation 

pub struct SpringAnimation<T = ()> { /* private fields */ }

A spring animation for an element: a SpringConfig, a target and a starting value.

Build one with SpringAnimation::new and SpringAnimation::to, then pass it to AnimationExt::with_spring. The element keeps the spring’s position and velocity across frames, so a retargeted spring bends toward the new target instead of jumping. Under App::reduce_motion, the spring jumps straight to its target.

Examples

use std::{cell::Cell, rc::Rc};

use gpui::{
    AnimationExt, Context, IntoElement, Render, SpringAnimation, TestApp, Window, div,
    prelude::*, spring,
};

struct Knob {
    last: Rc<Cell<f32>>,
}

impl Render for Knob {
    fn render(&mut self, _window: &mut Window, _cx: &mut Context<Self>) -> impl IntoElement {
        let last = self.last.clone();
        div().child("knob").with_spring(
            "knob",
            SpringAnimation::new(spring(320., 24., 1.)).to(1.0_f32),
            move |el, position| {
                last.set(position);
                el.opacity(position)
            },
        )
    }
}

let last = Rc::new(Cell::new(0.0));
let mut app = TestApp::new();
app.update(|cx| cx.set_reduce_motion(true));
let mut window = app.open_window(|_, _| Knob { last: last.clone() });
window.draw();
assert_eq!(last.get(), 1.0);

Implementations

impl SpringAnimation<()>

pub fn new(config: SpringConfig) -> Self

Creates a spring animation with config, which has no target yet.

Call to to set the target before passing the animation to an element.

pub fn to<T: SpringTarget>(self, target: T) -> SpringAnimation<T>

Sets the target of this spring.

An f32 targets a number, a Pixels or Rems targets a length, a bool targets 0.0 or 1.0, and an AnimationPhase targets a phase. The animator receives the target’s SpringTarget::Output.

impl<T> SpringAnimation<T>

pub fn with_epsilon(self, epsilon: f32) -> Self

Sets how close the spring must be to its target before it counts as settled.

The tolerance is in the target’s scalar coordinate. For a Pixels target, it is in pixels. See Motion::with_epsilon.

pub fn playback(self, playback: SpringPlayback) -> Self

Sets how the spring advances, and where it rests, when its animation changes state.

See SpringPlayback.

impl<T: SpringTarget> SpringAnimation<T>

pub fn from(self, initial: T) -> Self

Sets the value a newly mounted spring starts from.

Without this, a new spring starts at its target and doesn’t animate on mount. The value is converted with SpringTarget::target, so it must be the same kind of value as the target.

Trait Implementations

impl<T: Clone> Clone for SpringAnimation<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for SpringAnimation<T>

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

Formats the value using the given formatter.