enhance(frontend): 投稿フォームのヒントを追加 (#16712)

* wip

* wip

* Update MkSpot.vue

* Update MkPostForm.vue

* wip

* wip

* Update CHANGELOG.md

packages/frontend/src/components/MkSpot.vue

@@ -0,0 +1,161 @@
+<!--
+SPDX-FileCopyrightText: syuilo and misskey-project
+SPDX-License-Identifier: AGPL-3.0-only
+-->
+
+<template>
+<div ref="rootEl" :class="$style.root" :style="{ zIndex }">
+	<div :class="[$style.bg]"></div>
+	<div ref="spotEl" :class="$style.spot"></div>
+	<div ref="bodyEl" :class="$style.body" class="_panel _shadow">
+		<div class="_gaps_s">
+			<div><b>{{ title }}</b></div>
+			<div>{{ description }}</div>
+			<div class="_buttons">
+				<MkButton v-if="hasPrev" small @click="prev"><i class="ti ti-arrow-left"></i> {{ i18n.ts.goBack }}</MkButton>
+				<MkButton v-if="hasNext" small primary @click="next">{{ i18n.ts.next }} <i class="ti ti-arrow-right"></i></MkButton>
+				<MkButton v-else small primary @click="next">{{ i18n.ts.done }} <i class="ti ti-check"></i></MkButton>
+			</div>
+		</div>
+	</div>
+</div>
+</template>
+
+<script lang="ts" setup>
+import { nextTick, onMounted, onUnmounted, ref, useTemplateRef } from 'vue';
+import { calcPopupPosition } from '@/utility/popup-position.js';
+import * as os from '@/os.js';
+import MkButton from '@/components/MkButton.vue';
+import { i18n } from '@/i18n.js';
+
+const props = withDefaults(defineProps<{
+	title: string;
+	description: string;
+	anchorElement?: HTMLElement;
+	x?: number;
+	y?: number;
+	direction?: 'top' | 'bottom' | 'right' | 'left';
+	hasPrev: boolean;
+	hasNext: boolean;
+}>(), {
+	direction: 'top',
+});
+
+const emit = defineEmits<{
+	(prev: 'prev'): void;
+	(next: 'next'): void;
+}>();
+
+function prev() {
+	emit('prev');
+}
+
+function next() {
+	emit('next');
+}
+
+const rootEl = useTemplateRef('rootEl');
+const bodyEl = useTemplateRef('bodyEl');
+const spotEl = useTemplateRef('spotEl');
+const zIndex = os.claimZIndex('high');
+const spotX = ref(0);
+const spotY = ref(0);
+const spotWidth = ref(0);
+const spotHeight = ref(0);
+
+function setPosition() {
+	if (spotEl.value == null) return;
+	if (bodyEl.value == null) return;
+	if (props.anchorElement == null) return;
+
+	const rect = props.anchorElement.getBoundingClientRect();
+	spotX.value = rect.left;
+	spotY.value = rect.top;
+	spotWidth.value = rect.width;
+	spotHeight.value = rect.height;
+
+	const data = calcPopupPosition(bodyEl.value, {
+		anchorElement: props.anchorElement,
+		direction: props.direction,
+		align: 'center',
+		innerMargin: 16,
+		x: props.x,
+		y: props.y,
+	});
+
+	bodyEl.value.style.transformOrigin = data.transformOrigin;
+	bodyEl.value.style.left = data.left + 'px';
+	bodyEl.value.style.top = data.top + 'px';
+}
+
+let loopHandler;
+
+onMounted(() => {
+	nextTick(() => {
+		setPosition();
+
+		const loop = () => {
+			setPosition();
+			loopHandler = window.requestAnimationFrame(loop);
+		};
+
+		loop();
+	});
+});
+
+onUnmounted(() => {
+	window.cancelAnimationFrame(loopHandler);
+});
+</script>
+
+<style lang="scss" module>
+.root {
+	position: absolute;
+}
+
+.bg {
+	position: fixed;
+	top: 0;
+	left: 0;
+	width: 100%;
+	height: 100%;
+}
+
+.spot {
+	--x: v-bind("spotX + 'px'");
+	--y: v-bind("spotY + 'px'");
+	--width: v-bind("spotWidth + 'px'");
+	--height: v-bind("spotHeight + 'px'");
+	--padding: 8px;
+	position: absolute;
+	left: calc(var(--x) - var(--padding));
+	top: calc(var(--y) - var(--padding));
+	width: calc(var(--width) + var(--padding) * 2);
+	height: calc(var(--height) + var(--padding) * 2);
+	box-sizing: border-box;
+	border: 1px solid transparent;
+	border-radius: 8px;
+	box-shadow: 0 0 0 9999px #000a;
+	transition: left 0.2s ease-out, top 0.2s ease-out, width 0.2s ease-out, height 0.2s ease-out;
+	animation: blink 1s infinite;
+}
+
+.body {
+	position: absolute;
+	padding: 16px 20px;
+	box-sizing: border-box;
+	width: max-content;
+	max-width: min(500px, 100vw);
+}
+
+@keyframes blink {
+	0%, 100% {
+		background: color(from var(--MI_THEME-accent) srgb r g b / 0.1);
+		border: 1px solid color(from var(--MI_THEME-accent) srgb r g b / 0.75);
+	}
+	50% {
+		background: transparent;
+		border: 1px solid transparent;
+	}
+}
+</style>