perf: refine the fallback of the avatar component (#649)

#### What type of PR is this?

/kind improvement
/milestone 2.0

#### What this PR does / why we need it:

优化 Avatar 组件在图片加载失败的状态，以及添加加载状态的动画。目前的策略为，如果图片加载异常，那么会取 `alt` 属性生成占位样式。如果没有设置 `alt`，会显示失败的图标。

#### Screenshots:

<img width="421" alt="image" src="https://user-images.githubusercontent.com/21301288/196194978-229cf58d-19e1-4492-b77a-8b1a6b41e3a0.png">

#### Special notes for your reviewer:

/cc @halo-dev/sig-halo-console 

测试方式：

1. 需要 `pnpm build:packages`
2. 测试修改个人资料的头像，观测不同效果。
3. 访问 https://halo-admin-ui-git-fork-ruibaby-perf-avatar-fallback-halo-dev.vercel.app/story/src-components-avatar-avatar-story-vue?variantId=_default 测试不同参数的效果。

#### Does this PR introduce a user-facing change?

```release-note
优化 Avatar 组件在图片加载失败的状态
```

packages/components/src/components/avatar/Avatar.story.vue

@@ -1,8 +1,49 @@
 <script lang="ts" setup>
 import { VAvatar } from "./index";
+import { VSpace } from "../space";
 </script>
 <template>
   <Story title="Avatar">
-    <VAvatar src="https://ryanc.cc/avatar" size="lg" />
+    <VSpace direction="column">
+      <VSpace>
+        <VAvatar size="md" alt="Halo" src="https://halo.run/logo" />
+        <VAvatar size="md" alt="Ryan Wang" src="https://ryanc.cc/avatar" />
+        <VAvatar size="md" alt="John Niang" src="https://johnniang.me/avatar" />
+        <VAvatar size="md" alt="guqing" src="https://guqing.xyz/avatar" />
+      </VSpace>
+      <VSpace>
+        <VAvatar size="md" alt="Halo" />
+        <VAvatar size="md" alt="Ryan Wang" />
+        <VAvatar size="md" alt="John Niang" />
+        <VAvatar size="md" alt="guqing" />
+      </VSpace>
+      <VSpace>
+        <VAvatar size="md" circle alt="Halo" />
+        <VAvatar size="md" circle alt="Ryan Wang" />
+        <VAvatar size="md" circle alt="John Niang" />
+        <VAvatar size="md" circle alt="guqing" />
+      </VSpace>
+      <VSpace>
+        <VAvatar size="xs" circle alt="Halo" src="https://halo.run/logo" />
+        <VAvatar
+          size="sm"
+          circle
+          alt="Ryan Wang"
+          src="https://ryanc.cc/avatar"
+        />
+        <VAvatar
+          size="md"
+          circle
+          alt="John Niang"
+          src="https://johnniang.me/avatar"
+        />
+        <VAvatar
+          size="lg"
+          circle
+          alt="guqing"
+          src="https://guqing.xyz/avatar"
+        />
+      </VSpace>
+    </VSpace>
   </Story>
 </template>

packages/components/src/components/avatar/Avatar.vue

@@ -1,8 +1,7 @@
 <script lang="ts" setup>
-import { computed } from "vue";
+import { computed, onMounted, ref } from "vue";
+import { IconErrorWarning } from "../../icons/icons";
 import type { Size } from "./interface";
-import { useImage } from "@vueuse/core";
-import { IconUserLine } from "@/icons/icons";
 
 const props = withDefaults(
   defineProps<{
@@ -16,13 +15,41 @@ const props = withDefaults(
   {
     src: undefined,
     alt: undefined,
-    size: undefined,
+    size: "md",
     width: undefined,
     height: undefined,
     circle: false,
   }
 );
 
+const isLoading = ref(false);
+const error = ref(false);
+
+const loadImage = async () => {
+  const image = new Image();
+  image.src = props.src;
+  return new Promise((resolve, reject) => {
+    image.onload = () => resolve(image);
+    image.onerror = (err) => reject(err);
+  });
+};
+
+onMounted(async () => {
+  if (!props.src) {
+    error.value = true;
+    return;
+  }
+
+  isLoading.value = true;
+  try {
+    await loadImage();
+  } catch (e) {
+    error.value = true;
+  } finally {
+    isLoading.value = false;
+  }
+});
+
 const classes = computed(() => {
   const result = [`avatar-${props.circle ? "circle" : "square"}`];
   if (props.size) {
@@ -42,13 +69,49 @@ const styles = computed(() => {
   return result;
 });
 
-const { isLoading, error } = useImage({ src: props.src });
+const placeholderText = computed(() => {
+  if (!props.alt) {
+    return undefined;
+  }
+  const words = props.alt.split(" ");
+  if (words.length === 1) {
+    return words[0].charAt(0).toUpperCase();
+  }
+  if (words.length > 1) {
+    return words[0].charAt(0).toUpperCase() + words[1].charAt(0).toUpperCase();
+  }
+  return undefined;
+});
 </script>
 
 <template>
   <div class="avatar-wrapper" :class="classes" :style="styles">
-    <div v-if="isLoading || error" class="w-full h-full">
-      <IconUserLine class="w-full h-full" />
+    <div v-if="isLoading || error" class="avatar-fallback">
+      <svg
+        v-if="isLoading"
+        class="avatar-loading"
+        fill="none"
+        viewBox="0 0 24 24"
+        xmlns="http://www.w3.org/2000/svg"
+      >
+        <circle
+          class="opacity-25"
+          cx="12"
+          cy="12"
+          r="10"
+          stroke="currentColor"
+          stroke-width="4"
+        ></circle>
+        <path
+          class="opacity-75"
+          d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"
+          fill="currentColor"
+        ></path>
+      </svg>
+      <span v-else-if="placeholderText" class="avatar-placeholder">
+        {{ placeholderText }}
+      </span>
+      <IconErrorWarning v-else class="avatar-error" />
     </div>
     <img v-else :src="src" :alt="alt" />
   </div>
@@ -56,12 +119,28 @@ const { isLoading, error } = useImage({ src: props.src });
 
 <style lang="scss">
 .avatar-wrapper {
-  @apply inline-flex items-center justify-center overflow-hidden bg-white;
+  @apply inline-flex items-center justify-center overflow-hidden bg-gray-100;
 
   img {
     @apply w-full h-full object-cover;
   }
 
+  .avatar-fallback {
+    @apply w-full h-full flex items-center justify-center;
+  }
+
+  .avatar-loading {
+    @apply animate-spin w-5 h-5;
+  }
+
+  .avatar-placeholder {
+    @apply text-sm text-gray-800 font-medium;
+  }
+
+  .avatar-error {
+    @apply w-5 h-5 text-red-500;
+  }
+
   &.avatar-circle {
     @apply rounded-full;
   }
@@ -72,10 +151,18 @@ const { isLoading, error } = useImage({ src: props.src });
 
   &.avatar-xs {
     @apply w-6 h-6;
+
+    .avatar-placeholder {
+      @apply text-xs;
+    }
   }
 
   &.avatar-sm {
     @apply w-8 h-8;
+
+    .avatar-placeholder {
+      @apply text-xs;
+    }
   }
 
   &.avatar-md {

src/modules/contents/comments/components/CommentListItem.vue

@@ -259,7 +259,12 @@ const subjectRefResult = computed(() => {
     <template #start>
       <VEntityField>
         <template #description>
-          <VAvatar circle :src="comment?.owner.avatar" size="md"></VAvatar>
+          <VAvatar
+            circle
+            :src="comment?.owner.avatar"
+            :alt="comment?.owner.displayName"
+            size="md"
+          ></VAvatar>
         </template>
       </VEntityField>
       <VEntityField

src/modules/contents/comments/components/ReplyListItem.vue

@@ -104,7 +104,12 @@ const isHoveredReply = computed(() => {
     <template #start>
       <VEntityField>
         <template #description>
-          <VAvatar circle :src="reply?.owner.avatar" size="md"></VAvatar>
+          <VAvatar
+            circle
+            :src="reply?.owner.avatar"
+            :alt="reply?.owner.displayName"
+            size="md"
+          ></VAvatar>
         </template>
       </VEntityField>
       <VEntityField

src/modules/system/users/layouts/UserProfileLayout.vue

@@ -93,6 +93,7 @@ const handleTabChange = (id: string) => {
             <div class="h-24 w-24 sm:h-32 sm:w-32">
               <VAvatar
                 :src="user?.spec?.avatar"
+                :alt="user?.spec?.displayName"
                 circle
                 width="100%"
                 height="100%"