Fix Multi Tool page rotation lost on save (#6733)

# Description of Changes

Rotating a page in the Multi Tool and saving could leave the page at its
original rotation (the change appeared lost), with inconsistent results
across pages.

- Page rotation is now always written on export, including 0°, so
rotating a page that already had a non-zero rotation in the source PDF
(e.g. a 270° page rotated back to upright) is no longer dropped.
- Per-page rotation is always read when building the Multi Tool
document, so pages keep their true orientation regardless of file size.
- Rotation is only applied after a page imports successfully, avoiding a
misaligned or failed export when an import fails.

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have run `task check` to verify linters, typechecks, and tests
pass
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

frontend/editor/src/core/components/shared/HoverActionMenu.tsx

@@ -64,6 +64,7 @@ const HoverActionMenu: React.FC<HoverActionMenuProps> = ({
             disabled={action.disabled}
             onClick={action.onClick}
             c={action.color}
+            aria-label={action.label}
             style={{ color: action.color || "var(--text-secondary)" }}
             data-tour={action.dataTour}
           >

frontend/editor/src/core/services/pdfExportService.ts

@@ -135,11 +135,12 @@ export class PDFExportService {
         if (page.isBlankPage || page.originalPageNumber === -1) {
           // Insert a blank A4 page
           await addNewPage(destDocPtr, insertIdx, A4_WIDTH, A4_HEIGHT);
-          // Apply rotation
-          const pdfiumRotation = degreesToPdfiumRotation(page.rotation);
-          if (pdfiumRotation !== 0) {
-            await setPageRotation(destDocPtr, insertIdx, pdfiumRotation);
-          }
+          // Set absolute rotation (incl. 0) so editor rotation wins over source.
+          await setPageRotation(
+            destDocPtr,
+            insertIdx,
+            degreesToPdfiumRotation(page.rotation),
+          );
           insertIdx++;
         } else if (page.originalFileId && loadedDocs.has(page.originalFileId)) {
           const srcDocPtr = loadedDocs.get(page.originalFileId)!;
@@ -155,17 +156,18 @@ export class PDFExportService {
               pageRange,
               insertIdx,
             );
-            if (!imported) {
+            if (imported) {
+              // Set absolute rotation (incl. 0) so editor rotation wins over source.
+              await setPageRotation(
+                destDocPtr,
+                insertIdx,
+                degreesToPdfiumRotation(page.rotation),
+              );
+            } else {
               console.warn(
                 `[PDFExport] importPages failed for fileId=${page.originalFileId} pageRange=${pageRange} — page will be missing from output.`,
               );
             }
-
-            // Apply rotation
-            const pdfiumRotation = degreesToPdfiumRotation(page.rotation);
-            if (pdfiumRotation !== 0) {
-              await setPageRotation(destDocPtr, insertIdx, pdfiumRotation);
-            }
             insertIdx++;
           }
         } else {
@@ -211,10 +213,12 @@ export class PDFExportService {
       for (const page of pages) {
         if (page.isBlankPage || page.originalPageNumber === -1) {
           await addNewPage(destDocPtr, insertIdx, A4_WIDTH, A4_HEIGHT);
-          const pdfiumRotation = degreesToPdfiumRotation(page.rotation);
-          if (pdfiumRotation !== 0) {
-            await setPageRotation(destDocPtr, insertIdx, pdfiumRotation);
-          }
+          // Set absolute rotation (incl. 0) so editor rotation wins over source.
+          await setPageRotation(
+            destDocPtr,
+            insertIdx,
+            degreesToPdfiumRotation(page.rotation),
+          );
           insertIdx++;
         } else {
           const sourcePageIndex = page.originalPageNumber - 1;
@@ -227,16 +231,18 @@ export class PDFExportService {
               pageRange,
               insertIdx,
             );
-            if (!imported) {
+            if (imported) {
+              // Set absolute rotation (incl. 0) so editor rotation wins over source.
+              await setPageRotation(
+                destDocPtr,
+                insertIdx,
+                degreesToPdfiumRotation(page.rotation),
+              );
+            } else {
               console.warn(
                 `[PDFExport] importPages failed for page ${page.originalPageNumber} pageRange=${pageRange} — page will be missing from output.`,
               );
             }
-
-            const pdfiumRotation = degreesToPdfiumRotation(page.rotation);
-            if (pdfiumRotation !== 0) {
-              await setPageRotation(destDocPtr, insertIdx, pdfiumRotation);
-            }
             insertIdx++;
           }
         }

frontend/editor/src/core/tests/stubbed/page-editor-rotation.spec.ts

@@ -0,0 +1,97 @@
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+import { PDFDocument } from "@cantoo/pdf-lib";
+
+import { test, expect } from "@app/tests/helpers/stub-test-base";
+import { uploadFiles, dismissTourTooltip } from "@app/tests/helpers/ui-helpers";
+
+// Fixture: 4 portrait pages whose intrinsic /Rotate is 0, 90, 270, 180.
+// Page 3 (index 2) is 270 so a single rotate-right lands on a net-0 target -
+// the exact case the export used to drop, leaving the source rotation behind.
+const ROTATED_PDF = path.join(__dirname, "../test-fixtures/rotated-pages.pdf");
+const SOURCE_ROTATIONS = [0, 90, 270, 180];
+
+/** Read the rotation each thumbnail is currently displaying (= page.rotation). */
+async function readEditorRotations(page: import("@playwright/test").Page) {
+  const imgs = page.locator("[data-page-id] img[data-original-rotation]");
+  await expect(imgs).toHaveCount(SOURCE_ROTATIONS.length, { timeout: 30_000 });
+  const count = await imgs.count();
+  const rots: number[] = [];
+  for (let i = 0; i < count; i++) {
+    rots.push(
+      parseInt(
+        (await imgs.nth(i).getAttribute("data-original-rotation")) || "NaN",
+        10,
+      ),
+    );
+  }
+  return rots;
+}
+
+// Skip the fixture's 30s auto-goto; vite's cold on-demand compile can exceed it.
+test.use({ autoGoto: false });
+
+test.describe("PageEditor (multitool) rotation save", () => {
+  test("rotating a page persists the correct absolute rotation on export", async ({
+    page,
+  }) => {
+    await page.goto("/", { waitUntil: "domcontentloaded", timeout: 120_000 });
+    await uploadFiles(page, ROTATED_PDF);
+    // Enter the multitool via in-app navigation, NOT page.goto: a full reload
+    // wipes the in-memory workbench before PageEditorContext's "entering page
+    // editor" effect can auto-select the file, leaving the editor empty.
+    await dismissTourTooltip(page);
+    await page.getByText("PDF Multi Tool", { exact: true }).first().click();
+
+    // 1. Baseline: the multitool must seed page.rotation from the source /Rotate,
+    //    otherwise rotated pages render upright and every rotate is off-baseline.
+    const baseline = await readEditorRotations(page);
+    expect(
+      baseline,
+      "editor must show pages at their true source rotation",
+    ).toEqual(SOURCE_ROTATIONS);
+
+    // 2. Rotate page 3 (index 2, source /Rotate 270) right once via its
+    //    per-page hover menu. Target rotation is (270 + 90) % 360 = 0.
+    const page3 = page.locator("[data-page-id]").nth(2);
+    await page3.scrollIntoViewIfNeeded();
+    await page3.hover();
+    const rotateRight = page3.getByRole("button", { name: "Rotate Right" });
+    await expect(rotateRight).toBeVisible({ timeout: 5_000 });
+    await rotateRight.click();
+
+    // Only page 3 changes (270 -> 0); the others keep their source rotation.
+    await expect(page3.locator("img[data-original-rotation]")).toHaveAttribute(
+      "data-original-rotation",
+      "0",
+      { timeout: 10_000 },
+    );
+    expect(await readEditorRotations(page)).toEqual([0, 90, 0, 180]);
+
+    // 3. Ensure all pages are selected, then export, capturing the PDF.
+    //    Pages load all-selected, so "Select All" is disabled - only click it
+    //    if some pages got deselected.
+    const selectAll = page.getByRole("button", {
+      name: "Select All",
+      exact: true,
+    });
+    if (await selectAll.isEnabled()) {
+      await selectAll.click();
+    }
+    const tmpOut = path.join(os.tmpdir(), `rot-export-${process.pid}.pdf`);
+    const [download] = await Promise.all([
+      page.waitForEvent("download", { timeout: 30_000 }),
+      page.getByRole("button", { name: "Export Selected Pages" }).click(),
+    ]);
+    await download.saveAs(tmpOut);
+
+    // 4. The exported /Rotate must match what the editor showed: page 3 upright
+    //    (0), the untouched pages keeping their source rotation.
+    const outDoc = await PDFDocument.load(fs.readFileSync(tmpOut));
+    const outRotations = outDoc.getPages().map((p) => p.getRotation().angle);
+    fs.rmSync(tmpOut, { force: true });
+    expect(outRotations).toEqual([0, 90, 0, 180]);
+  });
+});

frontend/editor/src/core/utils/thumbnailUtils.ts

@@ -192,15 +192,16 @@ export async function generateThumbnailWithMetadata(
   }
 
   const scale = calculateScaleFromFileSize(file.size);
-  const isVeryLarge = file.size >= 100 * 1024 * 1024; // 100MB threshold
 
   try {
     const arrayBuffer = await file.arrayBuffer();
+    // Always read per-page rotation: PageEditor renders thumbnails upright and
+    // uses this as the rotation baseline, so skipping it corrupts saves.
     const result = await renderPdfThumbnailPdfium(
       arrayBuffer,
       scale,
       applyRotation,
-      !isVeryLarge,
+      true,
     );
 
     if (result.isEncrypted) {