122 lines
3.0 KiB
JavaScript
122 lines
3.0 KiB
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow strict-local
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* @format
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*/
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import type {PlatformConfig} from '../AnimatedPlatformConfig';
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import type AnimatedValue from '../nodes/AnimatedValue';
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import type {AnimationConfig, EndCallback} from './Animation';
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import Animation from './Animation';
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export type DecayAnimationConfig = $ReadOnly<{
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...AnimationConfig,
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velocity:
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| number
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| $ReadOnly<{
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x: number,
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y: number,
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...
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}>,
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deceleration?: number,
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...
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}>;
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export type DecayAnimationConfigSingle = $ReadOnly<{
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...AnimationConfig,
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velocity: number,
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deceleration?: number,
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...
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}>;
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export default class DecayAnimation extends Animation {
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_startTime: number;
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_lastValue: number;
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_fromValue: number;
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_deceleration: number;
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_velocity: number;
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_onUpdate: (value: number) => void;
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_animationFrame: ?AnimationFrameID;
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_platformConfig: ?PlatformConfig;
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constructor(config: DecayAnimationConfigSingle) {
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super(config);
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this._deceleration = config.deceleration ?? 0.998;
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this._velocity = config.velocity;
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this._platformConfig = config.platformConfig;
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}
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__getNativeAnimationConfig(): $ReadOnly<{
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deceleration: number,
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iterations: number,
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platformConfig: ?PlatformConfig,
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type: 'decay',
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velocity: number,
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...
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}> {
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return {
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type: 'decay',
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deceleration: this._deceleration,
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velocity: this._velocity,
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iterations: this.__iterations,
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platformConfig: this._platformConfig,
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};
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}
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start(
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fromValue: number,
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onUpdate: (value: number) => void,
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onEnd: ?EndCallback,
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previousAnimation: ?Animation,
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animatedValue: AnimatedValue,
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): void {
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super.start(fromValue, onUpdate, onEnd, previousAnimation, animatedValue);
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this._lastValue = fromValue;
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this._fromValue = fromValue;
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this._onUpdate = onUpdate;
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this._startTime = Date.now();
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const useNativeDriver = this.__startAnimationIfNative(animatedValue);
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if (!useNativeDriver) {
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this._animationFrame = requestAnimationFrame(() => this.onUpdate());
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}
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}
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onUpdate(): void {
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const now = Date.now();
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const value =
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this._fromValue +
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(this._velocity / (1 - this._deceleration)) *
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(1 - Math.exp(-(1 - this._deceleration) * (now - this._startTime)));
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this._onUpdate(value);
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if (Math.abs(this._lastValue - value) < 0.1) {
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this.__notifyAnimationEnd({finished: true});
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return;
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}
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this._lastValue = value;
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if (this.__active) {
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// $FlowFixMe[method-unbinding] added when improving typing for this parameters
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this._animationFrame = requestAnimationFrame(this.onUpdate.bind(this));
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}
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}
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stop(): void {
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super.stop();
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if (this._animationFrame != null) {
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global.cancelAnimationFrame(this._animationFrame);
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}
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this.__notifyAnimationEnd({finished: false});
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}
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}
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