From c0c312259291d364f7ce93519316b13a536d3a7a Mon Sep 17 00:00:00 2001
From: pengzhanbo <volodymyr@foxmail.com>
Date: Sun, 31 Dec 2023 00:12:29 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E6=96=B0=E5=A2=9E=20back-to-top?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 theme/src/client/components/BackToTop.vue     | 174 ++++++++++++++++++
 .../client/components/icons/IconBackToTop.vue |   3 +
 theme/src/client/layouts/Layout.vue           |   2 +
 theme/src/shared/frontmatter.ts               |   1 +
 4 files changed, 180 insertions(+)
 create mode 100644 theme/src/client/components/BackToTop.vue
 create mode 100644 theme/src/client/components/icons/IconBackToTop.vue

diff --git a/theme/src/client/components/BackToTop.vue b/theme/src/client/components/BackToTop.vue
new file mode 100644
index 000000000..e1a71c340
--- /dev/null
+++ b/theme/src/client/components/BackToTop.vue
@@ -0,0 +1,174 @@
+<script lang="ts" setup>
+import { useElementSize, useWindowScroll, useWindowSize } from '@vueuse/core'
+import { computed, onMounted, ref, shallowRef, watch } from 'vue'
+import { usePageData } from '@vuepress/client'
+import type { PlumeThemePageData } from '../../shared/index.js'
+import IconBackToTop from './icons/IconBackToTop.vue'
+
+const body = shallowRef<HTMLElement | null>()
+const { height: bodyHeight } = useElementSize(body)
+const { height: windowHeight } = useWindowSize()
+onMounted(() => {
+  body.value = document.body
+})
+
+const page = usePageData<PlumeThemePageData>()
+
+const { y } = useWindowScroll()
+const isScrolling = ref(false)
+
+const progress = computed(
+  () => (y.value / (bodyHeight.value - windowHeight.value)) * 100,
+)
+const percent = computed(() => `${Math.round(progress.value)}%`)
+
+const stroke = computed(() =>
+  `calc(${Math.PI * progress.value}% - ${4 * Math.PI}px) calc(${Math.PI * 100}% - ${4 * Math.PI}px)`,
+)
+
+const mustHidden = computed(() => {
+  return page.value.frontmatter.backToTop === false || page.value.frontmatter.home
+})
+
+const show = computed(() => {
+  if (bodyHeight.value < windowHeight.value)
+    return false
+
+  else
+    return y.value > windowHeight.value / 2
+})
+
+// eslint-disable-next-line no-undef
+let timer: NodeJS.Timeout | null = null
+function resetScrolling() {
+  timer && clearTimeout(timer)
+  timer = setTimeout(() => {
+    isScrolling.value = false
+  }, 1000)
+}
+watch(y, () => {
+  isScrolling.value = true
+  resetScrolling()
+})
+
+function handleClick() {
+  window.scrollTo({ top: 0, behavior: 'smooth' })
+}
+</script>
+
+<template>
+  <Transition name="fade">
+    <button
+      v-show="!mustHidden && (show || isScrolling)"
+      type="button"
+      class="back-to-top-button"
+      aria-label="back to top"
+      @click="handleClick"
+    >
+      <span class="percent" :class="{ show: isScrolling }">{{ percent }}</span>
+      <IconBackToTop class="icon" :class="{ show: !isScrolling }" />
+      <svg aria-hidden="true">
+        <circle cx="50%" cy="50%" :style="{ 'stroke-dasharray': stroke }" />
+      </svg>
+    </button>
+  </Transition>
+</template>
+
+<style scoped>
+.back-to-top-button {
+  position: fixed;
+  right: 20px;
+  bottom: 64px;
+  z-index: var(--vp-z-index-back-to-top);
+  width: 36px;
+  height: 36px;
+  border-radius: 100%;
+  box-shadow: var(--vp-shadow-2);
+  background-color: var(--vp-c-bg);
+  inset-inline-end: 1rem;
+  transition: background 0.25s ease, color 0.25s ease, box-shadow 0.25s ease;
+}
+
+.back-to-top-button .percent,
+.back-to-top-button .icon {
+  position: absolute;
+  top: 0;
+  left: 0;
+  transition: opacity 0.5s ease;
+  opacity: 0;
+}
+
+.back-to-top-button .percent.show,
+.back-to-top-button .icon.show {
+  opacity: 1;
+}
+
+.back-to-top-button .percent {
+  width: 100%;
+  height: 100%;
+  user-select: none;
+  line-height: 36px;
+  text-align: center;
+  font-size: 10px;
+}
+
+.back-to-top-button .icon {
+  width: 18px;
+  height: 18px;
+  top: 50%;
+  left: 50%;
+  transform: translate(-50%, -50%);
+  color: var(--vp-c-text-3);
+}
+
+.back-to-top-button svg {
+  width: 100%;
+  height: 100%;
+}
+
+.back-to-top-button svg circle {
+  fill: none;
+  stroke: var(--vp-c-brand-2);
+  transform: rotate(-90deg);
+  transform-origin: 50% 50%;
+  r: 16;
+  stroke-dasharray: 0% 314.1593%;
+  stroke-width: 4px;
+}
+
+@media (min-width: 768px) {
+  .back-to-top-button {
+    width: 48px;
+    height: 48px;
+  }
+
+  .back-to-top-button .percent {
+    line-height: 48px;
+    font-size: 14px;
+  }
+  .back-to-top-button .icon {
+    width: 24px;
+    height: 24px;
+  }
+
+  .back-to-top-button svg circle {
+    r: 22;
+  }
+}
+
+.fade-enter-active,
+.fade-leave-active {
+  transition: opacity 0.5s ease;
+}
+
+.fade-enter-from,
+.fade-leave-to {
+  opacity: 0;
+}
+
+@media print {
+  .back-to-top-button {
+    display: none;
+  }
+}
+</style>
diff --git a/theme/src/client/components/icons/IconBackToTop.vue b/theme/src/client/components/icons/IconBackToTop.vue
new file mode 100644
index 000000000..0151adb65
--- /dev/null
+++ b/theme/src/client/components/icons/IconBackToTop.vue
@@ -0,0 +1,3 @@
+<template>
+  <svg xmlns="http://www.w3.org/2000/svg" width="48" height="48" viewBox="0 0 48 48"><path fill="none" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round" stroke-width="4" d="M24.008 14.1V42M12 26l12-12l12 12M12 6h24" /></svg>
+</template>
diff --git a/theme/src/client/layouts/Layout.vue b/theme/src/client/layouts/Layout.vue
index 678068213..bc8413077 100644
--- a/theme/src/client/layouts/Layout.vue
+++ b/theme/src/client/layouts/Layout.vue
@@ -14,6 +14,7 @@ import Page from '../components/Page.vue'
 import Sidebar from '../components/Sidebar.vue'
 import SkipLink from '../components/SkipLink.vue'
 import VFooter from '../components/VFooter.vue'
+import BackToTop from '../components/BackToTop.vue'
 import {
   useCloseSidebarOnEscape,
   useSidebar,
@@ -56,6 +57,7 @@ provide('is-sidebar-open', isSidebarOpen)
       <Friends v-else-if="page.frontmatter.friends" />
       <Blog v-else-if="isBlogLayout" />
       <Page v-else />
+      <BackToTop />
       <VFooter />
     </LayoutContent>
   </div>
diff --git a/theme/src/shared/frontmatter.ts b/theme/src/shared/frontmatter.ts
index fed67553e..04c537b02 100644
--- a/theme/src/shared/frontmatter.ts
+++ b/theme/src/shared/frontmatter.ts
@@ -26,6 +26,7 @@ export interface PlumeThemePageFrontmatter {
   contributors?: boolean
   prev?: string | NavItemWithLink
   next?: string | NavItemWithLink
+  backToTop?: boolean
 }
 
 export interface PlumeThemePostFrontmatter extends PlumeThemePageFrontmatter {