feat(theme): support themeable images for logo and hero (#745)

Co-authored-by: Divyansh Singh <40380293+brc-dd@users.noreply.github.com>

src/client/theme-default/components/VPHero.vue

@@ -1,22 +1,19 @@
 <script setup lang="ts">
+import type { DefaultTheme } from 'vitepress/theme'
 import VPButton from './VPButton.vue'
+import VPImage from './VPImage.vue'
 
 export interface HeroAction {
   theme?: 'brand' | 'alt'
   text: string
   link: string
 }
 
-export interface Image {
-  src: string
-  alt?: string
-}
-
 defineProps<{
   name?: string
   text: string
   tagline?: string
-  image?: Image
+  image?: DefaultTheme.ThemeableImage
   actions?: HeroAction[]
 }>()
 </script>
@@ -25,7 +22,9 @@ defineProps<{
   <div class="VPHero" :class="{ 'has-image': image }">
     <div class="container">
       <div class="main">
-        <h1 v-if="name" class="name"><span class="clip">{{ name }}</span></h1>
+        <h1 v-if="name" class="name">
+          <span class="clip">{{ name }}</span>
+        </h1>
         <p v-if="text" class="text">{{ text }}</p>
         <p v-if="tagline" class="tagline">{{ tagline }}</p>
 
@@ -45,7 +44,7 @@ defineProps<{
       <div v-if="image" class="image">
         <div class="image-container">
           <div class="image-bg" />
-          <img class="image-src" :src="image.src" :alt="image.alt">
+          <VPImage class="image-src" :image="image" />
         </div>
       </div>
     </div>
@@ -293,7 +292,7 @@ defineProps<{
   }
 }
 
-.image-src {
+:deep(.image-src) {
   position: absolute;
   top: 50%;
   left: 50%;

src/client/theme-default/components/VPImage.vue

@@ -0,0 +1,38 @@
+<script setup lang="ts">
+import { withBase } from 'vitepress'
+import type { DefaultTheme } from 'vitepress/theme'
+
+defineProps<{
+  image: DefaultTheme.ThemeableImage
+}>()
+</script>
+
+<script lang="ts">
+export default {
+  inheritAttrs: false
+}
+</script>
+
+<template>
+  <template v-if="image">
+    <img
+      v-if="typeof image === 'string' || 'src' in image"
+      class="VPImage"
+      v-bind="typeof image === 'string' ? $attrs : { ...image, ...$attrs }"
+      :src="withBase(typeof image === 'string' ? image : image.src)"
+    />
+    <template v-else>
+      <VPImage class="dark" :image="image.dark" v-bind="$attrs" />
+      <VPImage class="light" :image="image.light" v-bind="$attrs" />
+    </template>
+  </template>
+</template>
+
+<style scoped>
+html:not(.dark) .VPImage.dark {
+  display: none;
+}
+.dark .VPImage.light {
+  display: none;
+}
+</style>

src/client/theme-default/components/VPNavBarTitle.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import { useData } from 'vitepress'
 import { useSidebar } from '../composables/sidebar'
+import VPImage from './VPImage.vue'
 
 const { site, theme } = useData()
 const { hasSidebar } = useSidebar()
@@ -9,7 +10,7 @@ const { hasSidebar } = useSidebar()
 <template>
   <div class="VPNavBarTitle" :class="{ 'has-sidebar': hasSidebar }">
     <a class="title" :href="site.base">
-      <img v-if="theme.logo" class="logo" :src="theme.logo">
+      <VPImage class="logo" :image="theme.logo" />
       <template v-if="theme.siteTitle">{{ theme.siteTitle }}</template>
       <template v-else-if="theme.siteTitle === undefined">{{ site.title }}</template>
     </a>
@@ -52,7 +53,7 @@ const { hasSidebar } = useSidebar()
   }
 }
 
-.logo {
+:deep(.logo) {
   margin-right: 8px;
   height: 24px;
 }

src/client/tsconfig.json

@@ -12,7 +12,8 @@
     "types": ["vite/client"],
     "paths": {
       "/@theme/*": ["theme-default/*"],
-      "vitepress": ["index.ts"]
+      "vitepress": ["index.ts"],
+      "vitepress/theme": ["../../types/default-theme.d"]
     }
   },
   "include": ["."]

types/default-theme.d.ts

@@ -5,7 +5,7 @@ export namespace DefaultTheme {
      *
      * @example '/logo.svg'
      */
-    logo?: string
+    logo?: ThemeableImage
 
     /**
      * Custom site title in navbar. If the value is undefined,
@@ -96,6 +96,11 @@ export namespace DefaultTheme {
     items: (NavItemChildren | NavItemWithLink)[]
   }
 
+  // image -----------------------------------------------------------------------
+
+  export type ThemeableImage = Image | { light: Image; dark: Image }
+  export type Image = string | { src: string; alt?: string }
+
   // sidebar -------------------------------------------------------------------
 
   export type Sidebar = SidebarGroup[] | SidebarMulti