feat: add excessive animation when switching themes (#24)

package.json

@@ -54,7 +54,7 @@
   "homepage": "/~https://github.com/tolking/vitepress-theme-ououe#readme",
   "lint-staged": {
     "*.{ts,vue,js,tsx,jsx}": [
-      "prettier --write --no-verify ",
+      "prettier --write --no-verify",
       "eslint --fix"
     ],
     "*.{html,css,md,json}": "prettier --write"

src/components/VPAppearance.vue

@@ -0,0 +1,95 @@
+<script lang="ts" setup>
+import { computed, ref, nextTick } from 'vue'
+import { useData } from 'vitepress'
+import VPSwitch from 'vitepress/dist/client/theme-default/components/VPSwitch.vue'
+
+const { isDark, theme } = useData()
+const switchRef = ref()
+
+const switchTitle = computed(() => {
+  return isDark.value
+    ? theme.value.lightModeSwitchTitle || 'Switch to light theme'
+    : theme.value.darkModeSwitchTitle || 'Switch to dark theme'
+})
+
+function toggleAppearance() {
+  const isAppearanceTransition =
+    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+    // @ts-expect-error
+    document.startViewTransition &&
+    !window.matchMedia('(prefers-reduced-motion: reduce)').matches
+  if (!isAppearanceTransition) {
+    isDark.value = !isDark.value
+    return
+  }
+
+  const switchElement = switchRef.value?.$el
+  const rect = switchElement.getBoundingClientRect()
+  const x = rect.left + rect.width / 2
+  const y = rect.top + rect.height / 2
+
+  const endRadius = Math.hypot(
+    Math.max(x, innerWidth - x),
+    Math.max(y, innerHeight - y),
+  )
+  // @ts-expect-error: Transition API
+  const transition = document.startViewTransition(async () => {
+    isDark.value = !isDark.value
+    await nextTick()
+  })
+  transition.ready.then(() => {
+    const clipPath = [
+      `circle(0px at ${x}px ${y}px)`,
+      `circle(${endRadius}px at ${x}px ${y}px)`,
+    ]
+    document.documentElement.animate(
+      {
+        clipPath: isDark.value ? [...clipPath].reverse() : clipPath,
+      },
+      {
+        duration: 400,
+        easing: 'ease-in',
+        pseudoElement: isDark.value
+          ? '::view-transition-old(root)'
+          : '::view-transition-new(root)',
+      },
+    )
+  })
+}
+</script>
+
+<template>
+  <VPSwitch
+    ref="switchRef"
+    :title="switchTitle"
+    :aria-checked="isDark"
+    class="VPSwitchAppearance"
+    @click="toggleAppearance"
+  >
+    <span class="vpi-sun sun" />
+    <span class="vpi-moon moon" />
+  </VPSwitch>
+</template>
+
+<style scoped>
+.sun {
+  opacity: 1;
+}
+
+.moon {
+  opacity: 0;
+}
+
+.dark .sun {
+  opacity: 0;
+}
+
+.dark .moon {
+  opacity: 1;
+}
+
+.dark .VPSwitchAppearance :deep(.check) {
+  /*rtl:ignore*/
+  transform: translateX(18px);
+}
+</style>

src/components/VPHeader.vue

@@ -6,9 +6,9 @@ import VPImage from 'vitepress/dist/client/theme-default/components/VPImage.vue'
 import VPNavBarMenu from 'vitepress/dist/client/theme-default/components/VPNavBarMenu.vue'
 import VPNavBarSearch from 'vitepress/dist/client/theme-default/components/VPNavBarSearch.vue'
 import VPNavBarTranslations from 'vitepress/dist/client/theme-default/components/VPNavBarTranslations.vue'
-import VPNavBarAppearance from 'vitepress/dist/client/theme-default/components/VPNavBarAppearance.vue'
 import VPNavBarSocialLinks from 'vitepress/dist/client/theme-default/components/VPNavBarSocialLinks.vue'
 import VPNavBarHamburger from 'vitepress/dist/client/theme-default/components/VPNavBarHamburger.vue'
+import VPAppearance from './VPAppearance.vue'
 import type { HeaderSlots, Theme } from '../types/index'
 
 defineProps<{
@@ -51,7 +51,12 @@ const homeLink = computed(() => {
       <slot name="header-search-before" />
       <VPNavBarSearch class="search" />
       <VPNavBarTranslations class="translations" />
-      <VPNavBarAppearance class="appearance" />
+      <div
+        v-if="site.appearance && site.appearance !== 'force-dark'"
+        class="VPNavBarAppearance"
+      >
+        <VPAppearance />
+      </div>
       <VPNavBarSocialLinks class="social-links" />
       <VPNavBarHamburger
         :active="isScreenOpen"
@@ -109,10 +114,19 @@ const homeLink = computed(() => {
 .header .header-content .social-links {
   margin-left: var(--vp-size-space);
 }
+.VPNavBarAppearance {
+  display: none;
+  margin-left: var(--vp-size-space);
+}
 
 @media (min-width: 768px) {
   .header .header-content .header-logo {
     flex-grow: 0;
   }
+
+  .VPNavBarAppearance {
+    display: flex;
+    align-items: center;
+  }
 }
 </style>

src/styles/public.css

@@ -104,3 +104,17 @@
 .scale-leave-active {
   position: absolute;
 }
+
+::view-transition-old(root),
+::view-transition-new(root) {
+  animation: none;
+  mix-blend-mode: normal;
+}
+::view-transition-old(root),
+.dark::view-transition-new(root) {
+  z-index: 1;
+}
+::view-transition-new(root),
+.dark::view-transition-old(root) {
+  z-index: 999999999;
+}