fix(reader): 修正章节内页码换算，去掉不存在的首尾 padding 假设 (#745)

packages/app-expo/assets/reader/reader.template.html

@@ -1604,10 +1604,12 @@
           const rendererPages = view && view.renderer && typeof view.renderer.pages === 'number'
             ? view.renderer.pages
             : null;
-          const actualPage = rendererPage != null && rendererPages != null && rendererPages > 2
+          // renderer.page is 0-based and renderer.pages is the real page count:
+          // the renderer adds no padding pages around a section.
+          const actualPage = rendererPage != null && rendererPages != null && rendererPages > 0
             ? {
-                current: Math.max(1, Math.min(rendererPage, rendererPages - 2)),
-                total: Math.max(1, rendererPages - 2),
+                current: Math.min(Math.max(rendererPage + 1, 1), rendererPages),
+                total: rendererPages,
               }
             : null;
           postToRN('relocate', {

packages/app-expo/src/screens/reader/chapter-page-numbering-contract.test.ts

@@ -0,0 +1,45 @@
+import { readFileSync } from "node:fs";
+import { dirname, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+import { describe, expect, it } from "vitest";
+
+const repositoryRoot = resolve(dirname(fileURLToPath(import.meta.url)), "../../../../..");
+
+function readSource(relativePath: string): string {
+  return readFileSync(resolve(repositoryRoot, relativePath), "utf8");
+}
+
+describe("chapter page numbering", () => {
+  it("maps the 0-based renderer page onto a 1-based page number on both platforms", () => {
+    const desktopViewer = readSource("packages/app/src/components/reader/FoliateViewer.tsx");
+    const template = readSource("packages/app-expo/assets/reader/reader.template.html");
+
+    for (const source of [desktopViewer, template]) {
+      expect(source).toMatch(
+        /current: Math\.min\(Math\.max\(rendererPage \+ 1, 1\), rendererPages\)/,
+      );
+      expect(source).toMatch(/total: rendererPages,/);
+    }
+  });
+
+  it("no longer assumes padding pages around a section", () => {
+    const desktopViewer = readSource("packages/app/src/components/reader/FoliateViewer.tsx");
+    const template = readSource("packages/app-expo/assets/reader/reader.template.html");
+
+    // renderer.pages is the real page count, so the old "minus one padding page on
+    // each side" conversion clamped the first and last page of every section.
+    for (const source of [desktopViewer, template]) {
+      expect(source).not.toContain("rendererPages - 2");
+      expect(source).toMatch(/rendererPages != null && rendererPages > 0/);
+    }
+  });
+
+  it("keeps the built reader in sync with the template", () => {
+    const builtReader = readSource("packages/app-expo/assets/reader/reader.html");
+
+    expect(builtReader).toMatch(
+      /current: Math\.min\(Math\.max\(rendererPage \+ 1, 1\), rendererPages\)/,
+    );
+    expect(builtReader).not.toContain("rendererPages - 2");
+  });
+});

packages/app/src/components/reader/FoliateViewer.tsx

@@ -2060,13 +2060,15 @@ export const FoliateViewer = forwardRef<FoliateViewerHandle, FoliateViewerProps>
           viewRef.current?.renderer && typeof viewRef.current.renderer.pages === "number"
             ? viewRef.current.renderer.pages
             : null;
+        // renderer.page is 0-based and renderer.pages is the real page count:
+        // the renderer adds no padding pages around a section.
         const detail: RelocateDetail =
-          rendererPage != null && rendererPages != null && rendererPages > 2
+          rendererPage != null && rendererPages != null && rendererPages > 0
             ? {
                 ...rawDetail,
                 page: {
-                  current: Math.max(1, Math.min(rendererPage, rendererPages - 2)),
-                  total: Math.max(1, rendererPages - 2),
+                  current: Math.min(Math.max(rendererPage + 1, 1), rendererPages),
+                  total: rendererPages,
                 },
               }
             : rawDetail;