feat: add tabbar component horizontal-scroll-indicator (#4979)

#### What type of PR is this?

/area console
/kind improvement

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

在 Tabbar 组件内容可滚动时，添加内容超出时的水平方向滚动指示器；解决由  #4582 指出的体验问题

#### Which issue(s) this PR fixes:

Fixes #4582

#### Special notes for your reviewer:

注意观察各处使用 Tabbar 组件且内容可滚动时的情况（浏览器宽度变化也可生效）

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


```release-note
添加 Tabbar 组件内容超出时的水平方向滚动指示器
```

console/packages/components/src/components/tabs/Tabbar.vue

@@ -1,6 +1,9 @@
 <script lang="ts" setup>
-import { computed, onMounted, onUnmounted, ref } from "vue";
-import type { Direction, Type } from "./interface";
+import { computed, onMounted, onUnmounted, ref, watch } from "vue";
+import type { ArrowShow, Direction, Type } from "./interface";
+import type { ComputedRef } from "vue";
+import { useElementSize, useThrottleFn } from "@vueuse/core";
+import { IconArrowLeft, IconArrowRight } from "../../icons/icons";
 
 const props = withDefaults(
   defineProps<{
@@ -30,12 +33,35 @@ const classes = computed(() => {
   return [`tabbar-${props.type}`, `tabbar-direction-${props.direction}`];
 });
 
-const handleChange = (id: number | string) => {
+const handleChange = (id: number | string, index: number) => {
+  handleClickTabItem(index);
   emit("update:activeId", id);
   emit("change", id);
 };
 
 const tabbarItemsRef = ref<HTMLElement | undefined>();
+const tabItemRefs = ref<HTMLElement[] | undefined>();
+const itemWidthArr = ref<number[]>([]);
+const indicatorRef = ref<HTMLElement | undefined>();
+const arrowFlag = ref(false);
+const { width: tabbarWidth } = useElementSize(tabbarItemsRef);
+
+const arrowShow: ComputedRef<ArrowShow> = computed(() => {
+  const show: ArrowShow = { left: false, right: false };
+  if (!tabbarItemsRef.value) return show;
+  void arrowFlag.value;
+  void tabbarWidth.value;
+  const { scrollWidth, scrollLeft, clientWidth } = tabbarItemsRef.value;
+  if (scrollWidth > clientWidth) {
+    if (scrollLeft < scrollWidth - clientWidth) {
+      show.right = true;
+    }
+    if (scrollLeft > 20) {
+      show.left = true;
+    }
+  }
+  return show;
+});
 
 function handleHorizontalWheel(event: WheelEvent) {
   if (!tabbarItemsRef.value) {
@@ -52,23 +78,138 @@ function handleHorizontalWheel(event: WheelEvent) {
   }
 }
 
+function saveItemsWidth() {
+  if (!tabbarItemsRef.value || !tabItemRefs.value) return;
+  itemWidthArr.value = [];
+  for (const item of tabItemRefs.value) {
+    itemWidthArr.value.push(item.offsetWidth);
+  }
+  arrowFlag.value = !arrowFlag.value;
+}
+
+function handleClickTabItem(index: number) {
+  if (!tabbarItemsRef.value || !indicatorRef.value) return;
+  const { scrollWidth, clientWidth } = tabbarItemsRef.value;
+  if (scrollWidth <= clientWidth) return;
+  if (index === 0) {
+    tabbarItemsRef.value.scrollTo({ left: 0, behavior: "smooth" });
+    return;
+  }
+  if (index === itemWidthArr.value.length - 1) {
+    tabbarItemsRef.value.scrollTo({
+      left: scrollWidth - clientWidth,
+      behavior: "smooth",
+    });
+    return;
+  }
+}
+
+function handleClickArrow(prev: boolean) {
+  if (!tabbarItemsRef.value || !indicatorRef.value || !tabItemRefs.value)
+    return;
+  const { scrollWidth, scrollLeft, clientWidth } = tabbarItemsRef.value;
+  if (scrollWidth <= clientWidth) return;
+  if (!itemWidthArr.value[0]) {
+    itemWidthArr.value = [];
+    for (const item of tabItemRefs.value) {
+      itemWidthArr.value.push(item.offsetWidth);
+    }
+  }
+  let hiddenNum = 0;
+  let totalWith = 0;
+  let scrollByX = 0;
+  const lastItemWidth = itemWidthArr.value[itemWidthArr.value.length - 1];
+  if (prev) {
+    for (let i = 0; i < itemWidthArr.value.length; i++) {
+      const w = itemWidthArr.value[i];
+      totalWith += w;
+      if (totalWith >= scrollLeft) {
+        hiddenNum = i;
+        break;
+      }
+    }
+    if (hiddenNum === 0) {
+      scrollByX = -itemWidthArr.value[0];
+    } else {
+      scrollByX = -(
+        itemWidthArr.value[hiddenNum] -
+        totalWith +
+        scrollLeft +
+        itemWidthArr.value[hiddenNum - 1]
+      );
+    }
+  } else {
+    const overWidth = scrollWidth - scrollLeft - clientWidth;
+    for (let i = itemWidthArr.value.length - 1; i >= 0; i--) {
+      const w = itemWidthArr.value[i];
+      totalWith += w;
+      if (totalWith >= overWidth) {
+        hiddenNum = i;
+        break;
+      }
+    }
+
+    if (hiddenNum === itemWidthArr.value.length - 1) {
+      scrollByX =
+        lastItemWidth + itemWidthArr.value[itemWidthArr.value.length - 1];
+    } else {
+      scrollByX =
+        itemWidthArr.value[hiddenNum] -
+        (totalWith - overWidth) +
+        itemWidthArr.value[hiddenNum + 1];
+    }
+  }
+  tabbarItemsRef.value.scrollBy({
+    left: scrollByX,
+    behavior: "smooth",
+  });
+}
+
+const handleScroll = useThrottleFn(
+  () => {
+    arrowFlag.value = !arrowFlag.value;
+  },
+  100,
+  true
+);
+
+watch(() => tabItemRefs.value?.length, saveItemsWidth);
+
 onMounted(() => {
   tabbarItemsRef.value?.addEventListener("wheel", handleHorizontalWheel);
+  tabbarItemsRef.value?.addEventListener("scroll", handleScroll);
 });
 
 onUnmounted(() => {
   tabbarItemsRef.value?.removeEventListener("wheel", handleHorizontalWheel);
+  tabbarItemsRef.value?.removeEventListener("scroll", handleScroll);
 });
 </script>
 <template>
   <div :class="classes" class="tabbar-wrapper">
+    <div
+      ref="indicatorRef"
+      :class="['indicator', 'left', arrowShow.left ? 'visible' : 'invisible']"
+    >
+      <div title="向前" class="arrow-left" @click="handleClickArrow(true)">
+        <IconArrowLeft />
+      </div>
+    </div>
+    <div
+      :class="['indicator', 'right', arrowShow.right ? 'visible' : 'invisible']"
+    >
+      <div title="向后" class="arrow-right" @click="handleClickArrow(false)">
+        <IconArrowRight />
+      </div>
+    </div>
     <div ref="tabbarItemsRef" class="tabbar-items">
       <div
         v-for="(item, index) in items"
         :key="index"
+        ref="tabItemRefs"
         :class="{ 'tabbar-item-active': item[idKey] === activeId }"
         class="tabbar-item"
-        @click="handleChange(item[idKey])"
+        @click="handleChange(item[idKey], index)"
       >
         <div v-if="item.icon" class="tabbar-item-icon">
           <component :is="item.icon" />
@@ -82,6 +223,51 @@ onUnmounted(() => {
 </template>
 <style lang="scss">
 .tabbar-wrapper {
+  @apply relative;
+  .indicator {
+    @apply absolute
+    top-0
+    z-10
+    w-20
+    h-full
+    flex
+    items-center
+    from-transparent
+    from-10%
+    via-white/80
+    via-30%
+    to-white
+    to-70%
+    pt-1
+    pointer-events-none
+    pb-1.5;
+
+    &.left {
+      @apply left-0
+      justify-start
+      bg-gradient-to-l;
+    }
+    &.right {
+      @apply right-0
+      justify-end
+      bg-gradient-to-r;
+    }
+    .arrow-left,
+    .arrow-right {
+      @apply w-10
+      h-9
+      flex
+      justify-center
+      items-center
+      pointer-events-auto
+      cursor-pointer
+      select-none;
+      svg {
+        font-size: 1.5em;
+      }
+    }
+  }
+
   .tabbar-items {
     @apply flex
     items-center

console/packages/components/src/components/tabs/interface.ts

@@ -1,2 +1,6 @@
 export type Type = "default" | "pills" | "outline";
 export type Direction = "row" | "column";
+export type ArrowShow = {
+  left: boolean;
+  right: boolean;
+};