50 lines
1.8 KiB
JavaScript
50 lines
1.8 KiB
JavaScript
import { easeInOut, isEasingArray, easingDefinitionToFunction } from 'motion-utils';
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import { interpolate } from '../../utils/interpolate.mjs';
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import { defaultOffset } from '../keyframes/offsets/default.mjs';
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import { convertOffsetToTimes } from '../keyframes/offsets/time.mjs';
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function defaultEasing(values, easing) {
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return values.map(() => easing || easeInOut).splice(0, values.length - 1);
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}
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function keyframes({ duration = 300, keyframes: keyframeValues, times, ease = "easeInOut", }) {
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/**
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* Easing functions can be externally defined as strings. Here we convert them
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* into actual functions.
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*/
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const easingFunctions = isEasingArray(ease)
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? ease.map(easingDefinitionToFunction)
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: easingDefinitionToFunction(ease);
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/**
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* This is the Iterator-spec return value. We ensure it's mutable rather than using a generator
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* to reduce GC during animation.
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*/
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const state = {
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done: false,
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value: keyframeValues[0],
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};
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/**
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* Create a times array based on the provided 0-1 offsets
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*/
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const absoluteTimes = convertOffsetToTimes(
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// Only use the provided offsets if they're the correct length
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// TODO Maybe we should warn here if there's a length mismatch
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times && times.length === keyframeValues.length
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? times
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: defaultOffset(keyframeValues), duration);
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const mapTimeToKeyframe = interpolate(absoluteTimes, keyframeValues, {
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ease: Array.isArray(easingFunctions)
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? easingFunctions
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: defaultEasing(keyframeValues, easingFunctions),
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});
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return {
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calculatedDuration: duration,
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next: (t) => {
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state.value = mapTimeToKeyframe(t);
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state.done = t >= duration;
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return state;
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},
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};
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}
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export { defaultEasing, keyframes };
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