feat: 添加主题切换扩散动画

assets/css/main.css

@@ -87,6 +87,27 @@ body {
   -moz-osx-font-smoothing: grayscale;
 }
 
+::view-transition-old(root),
+::view-transition-new(root) {
+  animation: none;
+  mix-blend-mode: normal;
+}
+
+::view-transition-new(root) {
+  z-index: 1;
+}
+
+::view-transition-old(root) {
+  z-index: 0;
+}
+
+@media (prefers-reduced-motion: reduce) {
+  ::view-transition-old(root),
+  ::view-transition-new(root) {
+    animation: none;
+  }
+}
+
 /* 入场动画 */
 @keyframes fade-in-up {
   from {

components/layout/ThemeToggle.vue

@@ -2,7 +2,20 @@
 import { Icon } from '@iconify/vue'
 
 const colorMode = useColorMode()
+const buttonRef = ref<HTMLButtonElement | null>(null)
+const isAnimating = ref(false)
+const isMounted = ref(false)
+
 type Mode = 'system' | 'dark' | 'light'
+type ViewTransition = {
+  ready: Promise<void>
+  finished: Promise<void>
+  updateCallbackDone: Promise<void>
+}
+
+type DocumentWithViewTransition = Document & {
+  startViewTransition?: (callback: () => void | Promise<void>) => ViewTransition
+}
 
 const iconMap: Record<Mode, string> = {
   system: 'mdi:monitor',
@@ -22,27 +35,191 @@ const cycleOrder = computed<Mode[]>(() => {
 })
 
 const currentMode = computed(() => colorMode.preference as Mode)
-const currentIcon = computed(() => iconMap[currentMode.value] || iconMap.system)
-const currentLabel = computed(() => labelMap[currentMode.value] || labelMap.system)
+const displayMode = computed<Mode>(() => isMounted.value ? currentMode.value : 'system')
+const currentIcon = computed(() => iconMap[displayMode.value] || iconMap.system)
+const currentLabel = computed(() => labelMap[displayMode.value] || labelMap.system)
+const resolvedMode = computed(() => colorMode.value)
+const displayResolvedMode = computed(() => isMounted.value ? resolvedMode.value : 'light')
 
-function cycle() {
+onMounted(() => {
+  isMounted.value = true
+})
+
+function getNextMode() {
   const order = cycleOrder.value
   const idx = order.indexOf(currentMode.value)
-  colorMode.preference = order[(idx + 1) % order.length]
+  return order[(idx + 1) % order.length]
+}
+
+function getTransitionOrigin() {
+  const rect = buttonRef.value?.getBoundingClientRect()
+  if (!rect) {
+    return {
+      x: window.innerWidth / 2,
+      y: window.innerHeight / 2,
+    }
+  }
+
+  return {
+    x: rect.left + rect.width / 2,
+    y: rect.top + rect.height / 2,
+  }
+}
+
+function getMaxRadius(x: number, y: number) {
+  return Math.hypot(
+    Math.max(x, window.innerWidth - x),
+    Math.max(y, window.innerHeight - y)
+  )
+}
+
+function wait(ms: number) {
+  return new Promise(resolve => window.setTimeout(resolve, ms))
+}
+
+async function cycle() {
+  if (isAnimating.value) return
+
+  const nextMode = getNextMode()
+
+  if (!import.meta.client) {
+    colorMode.preference = nextMode
+    return
+  }
+
+  const prefersReducedMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches
+  const documentWithTransition = document as DocumentWithViewTransition
+
+  if (prefersReducedMotion || !documentWithTransition.startViewTransition) {
+    colorMode.preference = nextMode
+    return
+  }
+
+  const { x, y } = getTransitionOrigin()
+  const endRadius = getMaxRadius(x, y)
+
+  isAnimating.value = true
+  const fallbackTimer = window.setTimeout(() => {
+    isAnimating.value = false
+  }, 900)
+
+  const applyMode = async () => {
+    colorMode.preference = nextMode
+    await nextTick()
+  }
+
+  let transition: ViewTransition
+
+  try {
+    transition = documentWithTransition.startViewTransition(applyMode)
+  } catch {
+    await applyMode()
+    window.clearTimeout(fallbackTimer)
+    isAnimating.value = false
+    return
+  }
+
+  try {
+    await transition.ready
+
+    const animation = document.documentElement.animate(
+      {
+        clipPath: [
+          `circle(0px at ${x}px ${y}px)`,
+          `circle(${endRadius}px at ${x}px ${y}px)`,
+        ],
+      },
+      {
+        duration: 620,
+        easing: 'cubic-bezier(0.22, 1, 0.36, 1)',
+        pseudoElement: '::view-transition-new(root)',
+      } as KeyframeAnimationOptions
+    )
+
+    await Promise.race([
+      animation.finished.catch(() => undefined),
+      wait(700),
+    ])
+    void transition.finished.catch(() => undefined)
+  } catch {
+    await transition.updateCallbackDone.catch(applyMode)
+  } finally {
+    window.clearTimeout(fallbackTimer)
+    isAnimating.value = false
+  }
 }
 </script>
 
 <template>
   <button
+    ref="buttonRef"
     @click="cycle"
-    class="inline-flex items-center justify-center rounded-md w-8 h-8 transition-colors"
+    class="theme-toggle inline-flex items-center justify-center rounded-md w-8 h-8 transition-colors"
     style="color: var(--color-text-secondary)"
     :class="[
       'hover:bg-[var(--color-bg-hover)] hover:text-[var(--color-text)]',
     ]"
+    :disabled="isAnimating"
     :aria-label="currentLabel"
+    :aria-pressed="displayResolvedMode === 'dark'"
     :title="currentLabel"
   >
-    <Icon :icon="currentIcon" class="w-5 h-5" />
+    <span
+      class="theme-toggle-icon"
+      :class="{ 'is-dark': displayResolvedMode === 'dark' }"
+    >
+      <Icon
+        :key="currentIcon"
+        :icon="currentIcon"
+        class="w-5 h-5"
+      />
+    </span>
   </button>
 </template>
+
+<style scoped>
+.theme-toggle {
+  overflow: hidden;
+  isolation: isolate;
+}
+
+.theme-toggle:disabled {
+  cursor: wait;
+}
+
+.theme-toggle-icon {
+  display: grid;
+  place-items: center;
+  transition:
+    transform 0.28s ease,
+    opacity 0.2s ease;
+}
+
+.theme-toggle-icon.is-dark {
+  transform: rotate(-18deg) scale(0.96);
+}
+
+.theme-toggle-icon :deep(svg) {
+  animation: theme-icon-pop 0.28s ease;
+}
+
+@keyframes theme-icon-pop {
+  from {
+    opacity: 0;
+    transform: rotate(-45deg) scale(0.72);
+  }
+
+  to {
+    opacity: 1;
+    transform: rotate(0deg) scale(1);
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .theme-toggle-icon,
+  .theme-toggle-icon :deep(svg) {
+    animation: none;
+    transition: none;
+  }
+}
+</style>