feat(web): cbz reader — virtual scroll with height correction, prefetch, progress restore

This commit is contained in:
2026-09-07 15:58:01 +08:00
parent 052b94bb6a
commit 654e4febf1
4 changed files with 242 additions and 2 deletions
+63
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@@ -0,0 +1,63 @@
// CBZ 竖滚虚拟列表的高度模型:估高起步,页图加载完用真实高校正,
// 前缀和 + 二分定位。纯逻辑,无 DOM,vitest 全量覆盖。
export class PageHeights {
private actual: (number | undefined)[];
private cum: number[]; // cum[i] = 第 i 页顶部偏移;cum[n] = total
constructor(
private n: number,
private est: number,
) {
this.actual = new Array(n).fill(undefined);
this.cum = new Array(n + 1);
this.rebuild(0);
}
private rebuild(from: number): void {
if (from === 0) this.cum[0] = 0;
for (let i = from; i < this.n; i++) this.cum[i + 1] = this.cum[i] + (this.actual[i] ?? this.est);
}
/** 返回高度增量(相对旧值)。同值幂等返 0;越界/非法高度忽略。 */
set(i: number, h: number): number {
if (i < 0 || i >= this.n || !Number.isFinite(h) || h <= 0) return 0;
const old = this.actual[i];
if (old === h) return 0;
this.actual[i] = h;
this.rebuild(i);
return h - (old ?? this.est);
}
offset(i: number): number {
if (this.n === 0) return 0;
return this.cum[Math.max(0, Math.min(i, this.n))];
}
total(): number {
return this.cum[this.n];
}
/** 覆盖 y 的那一页。 */
pageAt(y: number): number {
if (this.n === 0) return 0;
let lo = 0;
let hi = this.n - 1;
let ans = 0;
const v = Math.max(0, y);
while (lo <= hi) {
const mid = (lo + hi) >> 1;
if (this.cum[mid] <= v) {
ans = mid;
lo = mid + 1;
} else hi = mid - 1;
}
return ans;
}
range(scrollTop: number, viewport: number, overscan: number): [number, number] {
if (this.n === 0) return [0, 0];
const a = Math.max(0, this.pageAt(scrollTop) - overscan);
const b = Math.min(this.n, this.pageAt(scrollTop + viewport) + overscan);
return [a, b];
}
}
+4 -2
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@@ -1,5 +1,5 @@
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { Suspense, type ComponentType, type LazyExoticComponent } from "react";
import { Suspense, lazy, type ComponentType, type LazyExoticComponent } from "react";
import { Link, useNavigate, useParams } from "react-router-dom";
import { api } from "../api/client";
import type { Format } from "../api/types";
@@ -9,7 +9,9 @@ import { btn } from "../components/ui";
import type { ReaderProps } from "../lib/useProgress";
// reader 任务逐个往里加:Task 7 cbz → Task 8 txt/md → Task 9 pdf → Task 10 epub
const READERS: Partial<Record<Format, LazyExoticComponent<ComponentType<ReaderProps>>>> = {};
const READERS: Partial<Record<Format, LazyExoticComponent<ComponentType<ReaderProps>>>> = {
cbz: lazy(() => import("../readers/CbzReader")),
};
export default function Reader() {
const { id: idStr } = useParams();
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import { useQuery } from "@tanstack/react-query";
import { useEffect, useMemo, useRef, useState } from "react";
import { api, formatPageUrl } from "../api/client";
import { btn } from "../components/ui";
import { fetchObjectUrl } from "../lib/authImage";
import { useProgressSaver, type ReaderProps } from "../lib/useProgress";
import { PageHeights } from "../lib/virt";
const MAX_W = 720;
const EST_RATIO = 1.4; // 估高:宽 × 1.4(漫画常见竖幅)
function PageImg({ url, width, onLoaded }: { url: string; width: number; onLoaded: (h: number) => void }) {
const [src, setSrc] = useState("");
const [failed, setFailed] = useState(false);
const [nonce, setNonce] = useState(0);
useEffect(() => {
let dead = false;
setSrc("");
setFailed(false);
fetchObjectUrl(url)
.then((s) => !dead && setSrc(s))
.catch(() => !dead && setFailed(true));
return () => {
dead = true;
};
}, [url, nonce]);
if (failed)
return (
<div className="grid place-items-center gap-2 bg-zinc-900 py-8 text-sm text-zinc-500" style={{ width }}>
本页加载失败
<button className={btn} onClick={() => setNonce((n) => n + 1)}>
重试
</button>
</div>
);
if (!src)
return <div className="animate-pulse bg-zinc-800" style={{ width, height: width * EST_RATIO }} />;
return (
<img
src={src}
alt=""
style={{ width }}
className="block"
onLoad={(e) => {
const el = e.currentTarget;
if (el.naturalWidth > 0) onLoaded((el.naturalHeight / el.naturalWidth) * width);
}}
/>
);
}
export default function CbzReader({ book, initialLocator }: ReaderProps) {
const countQ = useQuery({
queryKey: ["pages", book.id],
queryFn: () => api.pageCount(book.pages_url ?? ""),
enabled: !!book.pages_url,
retry: 0,
});
const count = countQ.data?.count ?? 0;
const saver = useProgressSaver(book.id);
const boxRef = useRef<HTMLDivElement>(null);
const [width, setWidth] = useState(480);
const [vh, setVh] = useState(600);
const [top, setTop] = useState(0);
const [, bump] = useState(0);
const restored = useRef(false);
const ph = useMemo(() => new PageHeights(count, width * EST_RATIO), [count, width]);
// 容器尺寸自适应(尺寸变化后重建 PageHeights,阅读位置以当前滚动值为准)
useEffect(() => {
const el = boxRef.current;
if (!el) return;
const ro = new ResizeObserver(() => {
setWidth(Math.min(el.clientWidth, MAX_W));
setVh(el.clientHeight);
});
ro.observe(el);
return () => ro.disconnect();
}, []);
// 首次拿到 count 后恢复进度页
useEffect(() => {
if (restored.current || !count || !boxRef.current) return;
restored.current = true;
const p = Number(initialLocator?.page);
if (Number.isInteger(p) && p > 0 && p < count) boxRef.current.scrollTop = ph.offset(p);
}, [count, initialLocator, ph]);
function onScroll() {
const el = boxRef.current;
if (!el) return;
const t = el.scrollTop;
setTop(t);
if (count) {
const cur = ph.pageAt(t + vh / 2);
saver.report({ page: cur }, (cur + 1) / count);
for (let j = cur + 1; j <= Math.min(count - 1, cur + 5); j++)
fetchObjectUrl(formatPageUrl(book.page_url_fmt ?? "", j)).catch(() => {}); // 预取下方 5 页
}
}
if (countQ.isPending) return <div className="grid h-full place-items-center text-zinc-500">页索引加载中…</div>;
if (countQ.isError || !book.page_url_fmt)
return (
<div className="grid h-full place-items-center p-8 text-center text-zinc-500">
无法解析页索引:{countQ.error instanceof Error ? countQ.error.message : "缺 page_url_fmt"}
</div>
);
const fmt: string = book.page_url_fmt;
const [a, b] = ph.range(top, vh, 2);
const cur = ph.pageAt(top + vh / 2);
return (
<div className="relative h-full">
<div ref={boxRef} onScroll={onScroll} className="h-full overflow-y-auto">
<div className="relative mx-auto" style={{ height: ph.total(), maxWidth: MAX_W }}>
{Array.from({ length: b - a }, (_, k) => {
const i = a + k;
return (
<div key={i} className="absolute left-0 w-full" style={{ top: ph.offset(i) }}>
<PageImg
url={formatPageUrl(fmt, i)}
width={width}
onLoaded={(h) => {
const el = boxRef.current;
const topOfI = ph.offset(i);
const d = ph.set(i, h);
if (el && d !== 0 && topOfI < el.scrollTop) el.scrollTop += d; // 视口上方页高变化 → 补偿滚动
bump((x) => x + 1);
}}
/>
</div>
);
})}
</div>
</div>
<div className="pointer-events-none absolute bottom-3 right-3 rounded bg-zinc-900/80 px-2 py-1 text-xs text-zinc-300">
{cur + 1}/{count}
</div>
</div>
);
}
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import { expect, it } from "vitest";
import { PageHeights } from "../src/lib/virt";
it("估算高度:offset/total/pageAt/range(带 overscan、夹边)", () => {
const ph = new PageHeights(10, 100);
expect(ph.offset(3)).toBe(300);
expect(ph.total()).toBe(1000);
expect(ph.pageAt(350)).toBe(3);
expect(ph.pageAt(-10)).toBe(0);
expect(ph.pageAt(99_999)).toBe(9);
expect(ph.range(0, 100, 2)).toEqual([0, 3]);
expect(ph.range(950, 100, 2)).toEqual([7, 10]);
});
it("set 修正高度并平移后续 offset;返回增量;幂等", () => {
const ph = new PageHeights(10, 100);
expect(ph.set(2, 150)).toBe(50);
expect(ph.offset(2)).toBe(200); // 自身 offset 不受自己影响
expect(ph.offset(3)).toBe(350); // 后续整体 +50
expect(ph.total()).toBe(1050);
expect(ph.pageAt(349)).toBe(2);
expect(ph.pageAt(351)).toBe(3);
expect(ph.set(2, 150)).toBe(0);
});
it("n=0 时一切归空", () => {
const ph = new PageHeights(0, 100);
expect(ph.total()).toBe(0);
expect(ph.range(0, 100, 2)).toEqual([0, 0]);
expect(ph.set(0, 50)).toBe(0);
});