[Editor] Don't try to use an non-existing canvas when rendering an in…

…visible existing stamp editor

It fixes mozilla#19239.

When the canvas isn't existing the editor has no image: it's fine because the editor is invisible.
Once it's made visible, the canvas is set when the annotation layer has been rendered.

src/display/annotation_layer.js

@@ -3301,6 +3301,22 @@ class AnnotationLayer {
       } else {
         firstChild.after(canvas);
       }
+
+      const editableAnnotation = this.#editableAnnotations.get(id);
+      if (!editableAnnotation) {
+        continue;
+      }
+      if (editableAnnotation._hasNoCanvas) {
+        // The canvas wasn't available when the annotation was created.
+        this._annotationEditorUIManager?.setMissingCanvas(
+          id,
+          element.id,
+          canvas
+        );
+        editableAnnotation._hasNoCanvas = false;
+      } else {
+        editableAnnotation.canvas = canvas;
+      }
     }
     this.#annotationCanvasMap.clear();
   }

src/display/editor/stamp.js

@@ -40,6 +40,8 @@ class StampEditor extends AnnotationEditor {
 
   #canvas = null;
 
+  #missingCanvas = false;
+
   #resizeTimeoutId = null;
 
   #isSvg = false;
@@ -352,7 +354,8 @@ class StampEditor extends AnnotationEditor {
       this.#bitmap ||
       this.#bitmapUrl ||
       this.#bitmapFile ||
-      this.#bitmapId
+      this.#bitmapId ||
+      this.#missingCanvas
     );
   }
 
@@ -379,10 +382,12 @@ class StampEditor extends AnnotationEditor {
 
     this.addAltTextButton();
 
-    if (this.#bitmap) {
-      this.#createCanvas();
-    } else {
-      this.#getBitmap();
+    if (!this.#missingCanvas) {
+      if (this.#bitmap) {
+        this.#createCanvas();
+      } else {
+        this.#getBitmap();
+      }
     }
 
     if (this.width && !this.annotationElementId) {
@@ -401,6 +406,22 @@ class StampEditor extends AnnotationEditor {
     return this.div;
   }
 
+  setCanvas(annotationElementId, canvas) {
+    const { id: bitmapId, bitmap } = this._uiManager.imageManager.getFromCanvas(
+      annotationElementId,
+      canvas
+    );
+    canvas.remove();
+    if (bitmapId && this._uiManager.imageManager.isValidId(bitmapId)) {
+      this.#bitmapId = bitmapId;
+      if (bitmap) {
+        this.#bitmap = bitmap;
+      }
+      this.#missingCanvas = false;
+      this.#createCanvas();
+    }
+  }
+
   /** @inheritdoc */
   _onResized() {
     // We used a CSS-zoom during the resizing, but now it's resized we can
@@ -752,20 +773,28 @@ class StampEditor extends AnnotationEditor {
   /** @inheritdoc */
   static async deserialize(data, parent, uiManager) {
     let initialData = null;
+    let missingCanvas = false;
     if (data instanceof StampAnnotationElement) {
       const {
         data: { rect, rotation, id, structParent, popupRef },
         container,
         parent: {
           page: { pageNumber },
         },
+        canvas,
       } = data;
-      const canvas = container.querySelector("canvas");
-      const imageData = uiManager.imageManager.getFromCanvas(
-        container.id,
-        canvas
-      );
-      canvas.remove();
+      let bitmapId, bitmap;
+      if (canvas) {
+        delete data.canvas;
+        ({ id: bitmapId, bitmap } = uiManager.imageManager.getFromCanvas(
+          container.id,
+          canvas
+        ));
+        canvas.remove();
+      } else {
+        missingCanvas = true;
+        data._hasNoCanvas = true;
+      }
 
       // When switching to edit mode, we wait for the structure tree to be
       // ready (see pdf_viewer.js), so it's fine to use getAriaAttributesSync.
@@ -776,8 +805,8 @@ class StampEditor extends AnnotationEditor {
 
       initialData = data = {
         annotationType: AnnotationEditorType.STAMP,
-        bitmapId: imageData.id,
-        bitmap: imageData.bitmap,
+        bitmapId,
+        bitmap,
         pageIndex: pageNumber - 1,
         rect: rect.slice(0),
         rotation,
@@ -795,7 +824,10 @@ class StampEditor extends AnnotationEditor {
     const editor = await super.deserialize(data, parent, uiManager);
     const { rect, bitmap, bitmapUrl, bitmapId, isSvg, accessibilityData } =
       data;
-    if (bitmapId && uiManager.imageManager.isValidId(bitmapId)) {
+    if (missingCanvas) {
+      uiManager.addMissingCanvas(data.id, editor);
+      editor.#missingCanvas = true;
+    } else if (bitmapId && uiManager.imageManager.isValidId(bitmapId)) {
       editor.#bitmapId = bitmapId;
       if (bitmap) {
         editor.#bitmap = bitmap;

src/display/editor/tools.js

@@ -654,6 +654,8 @@ class AnnotationEditorUIManager {
 
   #mainHighlightColorPicker = null;
 
+  #missingCanvases = null;
+
   #mlManager = null;
 
   #mode = AnnotationEditorType.NONE;
@@ -898,6 +900,7 @@ class AnnotationEditorUIManager {
     this.#allLayers.clear();
     this.#allEditors.clear();
     this.#editorsToRescale.clear();
+    this.#missingCanvases?.clear();
     this.#activeEditor = null;
     this.#selectedEditors.clear();
     this.#commandManager.destroy();
@@ -1711,6 +1714,10 @@ class AnnotationEditorUIManager {
     this.#updateModeCapability.resolve();
   }
 
+  isInEditingMode() {
+    return this.#mode !== AnnotationEditorType.NONE;
+  }
+
   addNewEditorFromKeyboard() {
     if (this.currentLayer.canCreateNewEmptyEditor()) {
       this.currentLayer.addNewEditor();
@@ -2514,6 +2521,19 @@ class AnnotationEditorUIManager {
     }
     editor.renderAnnotationElement(annotation);
   }
+
+  setMissingCanvas(annotationId, annotationElementId, canvas) {
+    const editor = this.#missingCanvases?.get(annotationId);
+    if (!editor) {
+      return;
+    }
+    editor.setCanvas(annotationElementId, canvas);
+    this.#missingCanvases.delete(annotationId);
+  }
+
+  addMissingCanvas(annotationId, editor) {
+    (this.#missingCanvases ||= new Map()).set(annotationId, editor);
+  }
 }
 
 export {

test/integration/stamp_editor_spec.mjs

@@ -1745,4 +1745,73 @@ describe("Stamp Editor", () => {
       );
     });
   });
+
+  describe("Switch to edit mode a pdf with an existing stamp annotation on an invisible and rendered page", () => {
+    let pages;
+
+    beforeAll(async () => {
+      pages = await loadAndWait("issue19239.pdf", ".annotationEditorLayer");
+    });
+
+    afterAll(async () => {
+      await closePages(pages);
+    });
+
+    it("must move on the second page", async () => {
+      await Promise.all(
+        pages.map(async ([, page]) => {
+          const pageOneSelector = `.page[data-page-number = "1"]`;
+          const pageTwoSelector = `.page[data-page-number = "2"]`;
+          await scrollIntoView(page, pageTwoSelector);
+          await page.waitForSelector(pageOneSelector, {
+            visible: false,
+          });
+
+          await switchToStamp(page);
+          await scrollIntoView(page, pageOneSelector);
+          await page.waitForSelector(
+            `${pageOneSelector} .annotationEditorLayer canvas`,
+            { visible: true }
+          );
+        })
+      );
+    });
+  });
+
+  describe("Switch to edit mode a pdf with an existing stamp annotation on an invisible and unrendered page", () => {
+    let pages;
+
+    beforeAll(async () => {
+      pages = await loadAndWait("issue19239.pdf", ".annotationEditorLayer");
+    });
+
+    afterAll(async () => {
+      await closePages(pages);
+    });
+
+    it("must move on the last page", async () => {
+      await Promise.all(
+        pages.map(async ([, page]) => {
+          const twoToFourteen = Array.from(new Array(13).keys(), n => n + 2);
+          for (const pageNumber of twoToFourteen) {
+            const pageSelector = `.page[data-page-number = "${pageNumber}"]`;
+            await scrollIntoView(page, pageSelector);
+          }
+
+          await switchToStamp(page);
+
+          const thirteenToOne = Array.from(new Array(13).keys(), n => 13 - n);
+          for (const pageNumber of thirteenToOne) {
+            const pageSelector = `.page[data-page-number = "${pageNumber}"]`;
+            await scrollIntoView(page, pageSelector);
+          }
+
+          await page.waitForSelector(
+            `.page[data-page-number = "1"] .annotationEditorLayer canvas`,
+            { visible: true }
+          );
+        })
+      );
+    });
+  });
 });

test/pdfs/.gitignore

@@ -693,3 +693,4 @@
 !issue19182.pdf
 !issue18911.pdf
 !issue19207.pdf
+!issue19239.pdf

web/pdf_page_view.js

@@ -588,10 +588,14 @@ class PDFPageView {
   }
 
   toggleEditingMode(isEditing) {
+    // The page can be invisible, consequently there's no annotation layer and
+    // we can't know if there are editable annotations.
+    // So to avoid any issue when the page is rendered the #isEditing flag must
+    // be set.
+    this.#isEditing = isEditing;
     if (!this.hasEditableAnnotations()) {
       return;
     }
-    this.#isEditing = isEditing;
     this.reset({
       keepAnnotationLayer: true,
       keepAnnotationEditorLayer: true,