feat(frontend): 横スワイプでタブを切り替える機能 (#13011)

* (add) 横スワイプでタブを切り替える機能

* Change Changelog

* y方向の移動が一定量を超えたらスワイプを中断するように

* Update swipe distance thresholds

* Remove console.log

* adjust threshold

* rename, use v-model

* fix

* Update MkHorizontalSwipe.vue

Co-authored-by: syuilo <Syuilotan@yahoo.co.jp>

* use css module

---------

Co-authored-by: syuilo <Syuilotan@yahoo.co.jp>

packages/frontend/src/components/MkHorizontalSwipe.vue

@@ -0,0 +1,209 @@
+<!--
+SPDX-FileCopyrightText: syuilo and other misskey contributors
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
+<template>
+<div
+	ref="rootEl"
+	:class="[$style.transitionRoot, (defaultStore.state.animation && $style.enableAnimation)]"
+	@touchstart="touchStart"
+	@touchmove="touchMove"
+	@touchend="touchEnd"
+>
+	<Transition
+		:class="[$style.transitionChildren, { [$style.swiping]: isSwipingForClass }]"
+		:enterActiveClass="$style.swipeAnimation_enterActive"
+		:leaveActiveClass="$style.swipeAnimation_leaveActive"
+		:enterFromClass="transitionName === 'swipeAnimationLeft' ? $style.swipeAnimationLeft_enterFrom : $style.swipeAnimationRight_enterFrom"
+		:leaveToClass="transitionName === 'swipeAnimationLeft' ? $style.swipeAnimationLeft_leaveTo : $style.swipeAnimationRight_leaveTo"
+		:style="`--swipe: ${pullDistance}px;`"
+	>
+		<!-- 【注意】slot内の最上位要素に動的にkeyを設定すること -->
+		<!-- 各最上位要素にユニークなkeyの指定がないとTransitionがうまく動きません -->
+		<slot></slot>
+	</Transition>
+</div>
+</template>
+<script lang="ts" setup>
+import { ref, shallowRef, computed, nextTick, watch } from 'vue';
+import type { Tab } from '@/components/global/MkPageHeader.tabs.vue';
+import { defaultStore } from '@/store.js';
+
+const rootEl = shallowRef<HTMLDivElement>();
+
+// eslint-disable-next-line no-undef
+const tabModel = defineModel<string>('tab');
+
+const props = defineProps<{
+	tabs: Tab[];
+}>();
+
+const emit = defineEmits<{
+	(ev: 'swiped', newKey: string, direction: 'left' | 'right'): void;
+}>();
+
+// ▼ しきい値 ▼ //
+
+// スワイプと判定される最小の距離
+const MIN_SWIPE_DISTANCE = 50;
+
+// スワイプ時の動作を発火する最小の距離
+const SWIPE_DISTANCE_THRESHOLD = 125;
+
+// スワイプを中断するY方向の移動距離
+const SWIPE_ABORT_Y_THRESHOLD = 75;
+
+// スワイプできる最大の距離
+const MAX_SWIPE_DISTANCE = 150;
+
+// ▲ しきい値 ▲ //
+
+let startScreenX: number | null = null;
+let startScreenY: number | null = null;
+
+const currentTabIndex = computed(() => props.tabs.findIndex(tab => tab.key === tabModel.value));
+
+const pullDistance = ref(0);
+const isSwiping = ref(false);
+const isSwipingForClass = ref(false);
+let swipeAborted = false;
+
+function touchStart(event: TouchEvent) {
+	if (!defaultStore.reactiveState.enableHorizontalSwipe.value) return;
+
+	if (event.touches.length !== 1) return;
+
+	startScreenX = event.touches[0].screenX;
+	startScreenY = event.touches[0].screenY;
+}
+
+function touchMove(event: TouchEvent) {
+	if (!defaultStore.reactiveState.enableHorizontalSwipe.value) return;
+
+	if (event.touches.length !== 1) return;
+
+	if (startScreenX == null || startScreenY == null) return;
+
+	if (swipeAborted) return;
+
+	let distanceX = event.touches[0].screenX - startScreenX;
+	let distanceY = event.touches[0].screenY - startScreenY;
+
+	if (Math.abs(distanceY) > SWIPE_ABORT_Y_THRESHOLD) {
+		swipeAborted = true;
+
+		pullDistance.value = 0;
+		isSwiping.value = false;
+		setTimeout(() => {
+			isSwipingForClass.value = false;
+		}, 400);
+
+		return;
+	}
+
+	if (Math.abs(distanceX) < MIN_SWIPE_DISTANCE) return;
+	if (Math.abs(distanceX) > MAX_SWIPE_DISTANCE) return;
+
+	if (currentTabIndex.value === 0 || props.tabs[currentTabIndex.value - 1].onClick) {
+		distanceX = Math.min(distanceX, 0);
+	}
+	if (currentTabIndex.value === props.tabs.length - 1 || props.tabs[currentTabIndex.value + 1].onClick) {
+		distanceX = Math.max(distanceX, 0);
+	}
+	if (distanceX === 0) return;
+
+	isSwiping.value = true;
+	isSwipingForClass.value = true;
+	nextTick(() => {
+		// グリッチを控えるため、1.5px以上の差がないと更新しない
+		if (Math.abs(distanceX - pullDistance.value) < 1.5) return;
+		pullDistance.value = distanceX;
+	});
+}
+
+function touchEnd(event: TouchEvent) {
+	if (swipeAborted) {
+		swipeAborted = false;
+		return;
+	}
+
+	if (!defaultStore.reactiveState.enableHorizontalSwipe.value) return;
+
+	if (event.touches.length !== 0) return;
+
+	if (startScreenX == null) return;
+
+	if (!isSwiping.value) return;
+
+	const distance = event.changedTouches[0].screenX - startScreenX;
+
+	if (Math.abs(distance) > SWIPE_DISTANCE_THRESHOLD) {
+		if (distance > 0) {
+			if (props.tabs[currentTabIndex.value - 1] && !props.tabs[currentTabIndex.value - 1].onClick) {
+				tabModel.value = props.tabs[currentTabIndex.value - 1].key;
+				emit('swiped', props.tabs[currentTabIndex.value - 1].key, 'right');
+			}
+		} else {
+			if (props.tabs[currentTabIndex.value + 1] && !props.tabs[currentTabIndex.value + 1].onClick) {
+				tabModel.value = props.tabs[currentTabIndex.value + 1].key;
+				emit('swiped', props.tabs[currentTabIndex.value + 1].key, 'left');
+			}
+		}
+	}
+
+	pullDistance.value = 0;
+	isSwiping.value = false;
+	setTimeout(() => {
+		isSwipingForClass.value = false;
+	}, 400);
+}
+
+const transitionName = ref<'swipeAnimationLeft' | 'swipeAnimationRight' | undefined>(undefined);
+
+watch(tabModel, (newTab, oldTab) => {
+	const newIndex = props.tabs.findIndex(tab => tab.key === newTab);
+	const oldIndex = props.tabs.findIndex(tab => tab.key === oldTab);
+
+	if (oldIndex >= 0 && newIndex && oldIndex < newIndex) {
+		transitionName.value = 'swipeAnimationLeft';
+	} else {
+		transitionName.value = 'swipeAnimationRight';
+	}
+
+	window.setTimeout(() => {
+		transitionName.value = undefined;
+	}, 400);
+});
+</script>
+
+<style lang="scss" module>
+.transitionRoot.enableAnimation {
+	display: grid;
+	overflow: clip;
+
+	.transitionChildren {
+		grid-area: 1 / 1 / 2 / 2;
+		transform: translateX(var(--swipe));
+
+		&.swipeAnimation_enterActive,
+		&.swipeAnimation_leaveActive {
+			transition: transform .3s cubic-bezier(0.65, 0.05, 0.36, 1);
+		}
+
+		&.swipeAnimationRight_leaveTo,
+		&.swipeAnimationLeft_enterFrom {
+			transform: translateX(calc(100% + 24px));
+		}
+
+		&.swipeAnimationRight_enterFrom,
+		&.swipeAnimationLeft_leaveTo {
+			transform: translateX(calc(-100% - 24px));
+		}
+	}
+}
+
+.swiping {
+	transition: transform .2s ease-out;
+}
+</style>