18 lines
538 B
TypeScript
18 lines
538 B
TypeScript
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import { Pointer } from "./types";
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import { normalizeScroll } from "./scene/data";
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export function getCenter(pointers: readonly Pointer[]) {
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return {
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x: normalizeScroll(sum(pointers, p => p.x) / pointers.length),
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y: normalizeScroll(sum(pointers, p => p.y) / pointers.length),
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};
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}
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export function getDistance([a, b]: readonly Pointer[]) {
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return Math.hypot(a.x - b.x, a.y - b.y);
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}
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function sum<T>(array: readonly T[], mapper: (item: T) => number): number {
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return array.reduce((acc, item) => acc + mapper(item), 0);
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}
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