146 lines
4.0 KiB
JavaScript
146 lines
4.0 KiB
JavaScript
import * as React from 'react';
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import { useRef, useState } from 'react';
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const MIN_SWIPE_DISTANCE = 0.1;
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const STOP_SWIPE_DISTANCE = 0.01;
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const REFRESH_INTERVAL = 20;
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const SPEED_OFF_MULTIPLE = 0.995 ** REFRESH_INTERVAL;
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// ================================= Hook =================================
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export default function useTouchMove(ref, onOffset) {
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const [touchPosition, setTouchPosition] = useState();
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const [lastTimestamp, setLastTimestamp] = useState(0);
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const [lastTimeDiff, setLastTimeDiff] = useState(0);
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const [lastOffset, setLastOffset] = useState();
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const motionRef = useRef();
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// ========================= Events =========================
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// >>> Touch events
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function onTouchStart(e) {
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const {
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screenX,
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screenY
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} = e.touches[0];
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setTouchPosition({
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x: screenX,
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y: screenY
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});
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window.clearInterval(motionRef.current);
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}
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function onTouchMove(e) {
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if (!touchPosition) return;
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// e.preventDefault();
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const {
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screenX,
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screenY
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} = e.touches[0];
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setTouchPosition({
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x: screenX,
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y: screenY
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});
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const offsetX = screenX - touchPosition.x;
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const offsetY = screenY - touchPosition.y;
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onOffset(offsetX, offsetY);
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const now = Date.now();
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setLastTimestamp(now);
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setLastTimeDiff(now - lastTimestamp);
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setLastOffset({
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x: offsetX,
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y: offsetY
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});
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}
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function onTouchEnd() {
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if (!touchPosition) return;
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setTouchPosition(null);
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setLastOffset(null);
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// Swipe if needed
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if (lastOffset) {
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const distanceX = lastOffset.x / lastTimeDiff;
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const distanceY = lastOffset.y / lastTimeDiff;
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const absX = Math.abs(distanceX);
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const absY = Math.abs(distanceY);
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// Skip swipe if low distance
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if (Math.max(absX, absY) < MIN_SWIPE_DISTANCE) return;
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let currentX = distanceX;
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let currentY = distanceY;
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motionRef.current = window.setInterval(() => {
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if (Math.abs(currentX) < STOP_SWIPE_DISTANCE && Math.abs(currentY) < STOP_SWIPE_DISTANCE) {
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window.clearInterval(motionRef.current);
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return;
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}
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currentX *= SPEED_OFF_MULTIPLE;
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currentY *= SPEED_OFF_MULTIPLE;
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onOffset(currentX * REFRESH_INTERVAL, currentY * REFRESH_INTERVAL);
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}, REFRESH_INTERVAL);
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}
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}
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// >>> Wheel event
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const lastWheelDirectionRef = useRef();
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function onWheel(e) {
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const {
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deltaX,
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deltaY
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} = e;
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// Convert both to x & y since wheel only happened on PC
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let mixed = 0;
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const absX = Math.abs(deltaX);
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const absY = Math.abs(deltaY);
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if (absX === absY) {
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mixed = lastWheelDirectionRef.current === 'x' ? deltaX : deltaY;
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} else if (absX > absY) {
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mixed = deltaX;
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lastWheelDirectionRef.current = 'x';
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} else {
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mixed = deltaY;
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lastWheelDirectionRef.current = 'y';
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}
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if (onOffset(-mixed, -mixed)) {
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e.preventDefault();
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}
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}
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// ========================= Effect =========================
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const touchEventsRef = useRef(null);
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touchEventsRef.current = {
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onTouchStart,
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onTouchMove,
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onTouchEnd,
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onWheel
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};
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React.useEffect(() => {
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function onProxyTouchStart(e) {
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touchEventsRef.current.onTouchStart(e);
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}
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function onProxyTouchMove(e) {
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touchEventsRef.current.onTouchMove(e);
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}
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function onProxyTouchEnd(e) {
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touchEventsRef.current.onTouchEnd(e);
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}
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function onProxyWheel(e) {
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touchEventsRef.current.onWheel(e);
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}
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document.addEventListener('touchmove', onProxyTouchMove, {
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passive: false
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});
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document.addEventListener('touchend', onProxyTouchEnd, {
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passive: true
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});
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// No need to clean up since element removed
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ref.current.addEventListener('touchstart', onProxyTouchStart, {
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passive: true
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});
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ref.current.addEventListener('wheel', onProxyWheel, {
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passive: false
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});
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return () => {
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document.removeEventListener('touchmove', onProxyTouchMove);
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document.removeEventListener('touchend', onProxyTouchEnd);
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};
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}, []);
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} |