[Editor] When editing mode is disabled, allow to double click on a added annotation to edit it

It's already possible but only when double clicking outside the the text layer.
This patach adds the possibility to click on the text layer.

src/display/editor/annotation_editor_layer.js

@@ -25,7 +25,11 @@
 // eslint-disable-next-line max-len
 /** @typedef {import("../src/display/struct_tree_layer_builder.js").StructTreeLayerBuilder} StructTreeLayerBuilder */
 
-import { AnnotationEditorType, FeatureTest } from "../../shared/util.js";
+import {
+  AnnotationEditorPrefix,
+  AnnotationEditorType,
+  FeatureTest,
+} from "../../shared/util.js";
 import { AnnotationEditor } from "./editor.js";
 import { FreeTextEditor } from "./freetext.js";
 import { HighlightEditor } from "./highlight.js";
@@ -85,6 +89,10 @@ class AnnotationEditorLayer {
 
   #textSelectionAC = null;
 
+  #textLayerDblClickAC = null;
+
+  #lastPointerDownTimestamp = -1;
+
   #uiManager;
 
   static _initialized = false;
@@ -238,6 +246,8 @@ class AnnotationEditorLayer {
     this.#isEnabling = true;
     this.div.tabIndex = 0;
     this.togglePointerEvents(true);
+    this.#textLayerDblClickAC?.abort();
+    this.#textLayerDblClickAC = null;
     const annotationElementIds = new Set();
     for (const editor of this.#editors.values()) {
       editor.enableEditing();
@@ -280,6 +290,52 @@ class AnnotationEditorLayer {
     this.#isDisabling = true;
     this.div.tabIndex = -1;
     this.togglePointerEvents(false);
+    if (this.#textLayer && !this.#textLayerDblClickAC) {
+      this.#textLayerDblClickAC = new AbortController();
+      const signal = this.#uiManager.combinedSignal(this.#textLayerDblClickAC);
+      this.#textLayer.div.addEventListener(
+        "pointerdown",
+        e => {
+          // It's the default value in Fenix:
+          // https://searchfox.org/mozilla-central/rev/beba5cde846f944c4d709e75cbe499d17af880a4/modules/libpref/init/StaticPrefList.yaml#19064
+          // and in Chrome and Windows:
+          // https://source.chromium.org/chromium/chromium/src/+/main:ui/events/event_constants.h;drc=f0f5f3ceebb00da9363ccc7a1e2c0f17b6b383ba;l=115
+          const DBL_CLICK_THRESHOLD = 500;
+          const { clientX, clientY, timeStamp } = e;
+          const lastPointerDownTimestamp = this.#lastPointerDownTimestamp;
+          if (timeStamp - lastPointerDownTimestamp > DBL_CLICK_THRESHOLD) {
+            this.#lastPointerDownTimestamp = timeStamp;
+            return;
+          }
+          this.#lastPointerDownTimestamp = -1;
+          const { classList } = this.div;
+          classList.toggle("getElements", true);
+          const elements = document.elementsFromPoint(clientX, clientY);
+          classList.toggle("getElements", false);
+          if (!this.div.contains(elements[0])) {
+            return;
+          }
+          let id;
+          const regex = new RegExp(`^${AnnotationEditorPrefix}[0-9]+$`);
+          for (const element of elements) {
+            if (regex.test(element.id)) {
+              id = element.id;
+              break;
+            }
+          }
+          if (!id) {
+            return;
+          }
+          const editor = this.#editors.get(id);
+          if (editor?.annotationElementId === null) {
+            e.stopPropagation();
+            e.preventDefault();
+            editor.dblclick();
+          }
+        },
+        { signal, capture: true }
+      );
+    }
     const changedAnnotations = new Map();
     const resetAnnotations = new Map();
     for (const editor of this.#editors.values()) {

test/integration/freetext_editor_spec.mjs

@@ -3357,4 +3357,56 @@ describe("FreeText Editor", () => {
       );
     });
   });
+
+  describe("Edit added Freetext annotation", () => {
+    let pages;
+
+    beforeEach(async () => {
+      pages = await loadAndWait("tracemonkey.pdf", ".annotationEditorLayer");
+    });
+
+    afterEach(async () => {
+      await closePages(pages);
+    });
+
+    it("must check that an added Freetext can be edited in double clicking on it", async () => {
+      await Promise.all(
+        pages.map(async ([browserName, page]) => {
+          await switchToFreeText(page);
+
+          const rect = await getRect(page, ".annotationEditorLayer");
+          const editorSelector = getEditorSelector(0);
+
+          const data = "Hello PDF.js World !!";
+          await page.mouse.click(
+            rect.x + rect.width / 2,
+            rect.y + rect.height / 2
+          );
+          await page.waitForSelector(editorSelector, { visible: true });
+          await page.type(`${editorSelector} .internal`, data);
+          await commit(page);
+          await waitForSerialized(page, 1);
+
+          await switchToFreeText(page, /* disable */ true);
+
+          const modeChangedHandle = await createPromise(page, resolve => {
+            window.PDFViewerApplication.eventBus.on(
+              "annotationeditormodechanged",
+              resolve,
+              { once: true }
+            );
+          });
+          const editorRect = await getRect(page, editorSelector);
+          await page.mouse.click(
+            editorRect.x + editorRect.width / 2,
+            editorRect.y + editorRect.height / 2,
+            { count: 2 }
+          );
+
+          await page.waitForSelector(".annotationEditorLayer.freetextEditing");
+          await awaitPromise(modeChangedHandle);
+        })
+      );
+    });
+  });
 });

web/annotation_editor_layer_builder.css

@@ -134,6 +134,13 @@
   &.drawing * {
     pointer-events: none !important;
   }
+
+  &.getElements {
+    pointer-events: auto !important;
+    > div {
+      pointer-events: auto !important;
+    }
+  }
 }
 
 .annotationEditorLayer.waiting {