Merge pull request #12777 from Snuffleupagus/currentOutlineItem

Add support for finding/highlighting the outlineItem, corresponding to the currently visible page, in the sidebar (issue 7557, bug 1253820, bug 1499050)

l10n/en-US/viewer.properties

@@ -147,6 +147,8 @@ layers.title=Show Layers (double-click to reset all layers to the default state)
 layers_label=Layers
 thumbs.title=Show Thumbnails
 thumbs_label=Thumbnails
+current_outline_item.title=Find Current Outline Item
+current_outline_item_label=Current Outline Item
 findbar.title=Find in Document
 findbar_label=Find
 

l10n/nl/viewer.properties

@@ -148,6 +148,8 @@ layers.title=Lagen tonen (dubbelklik om alle lagen naar de standaardstatus terug
 layers_label=Lagen
 thumbs.title=Miniaturen tonen
 thumbs_label=Miniaturen
+current_outline_item.title=Huidige positie in documentoverzicht selecteren
+current_outline_item_label=Huidige positie in documentoverzicht
 findbar.title=Zoeken in document
 findbar_label=Zoeken
 

l10n/sv-SE/viewer.properties

@@ -148,6 +148,8 @@ layers.title=Visa lager (dubbelklicka för att återställa alla lager till stan
 layers_label=Lager
 thumbs.title=Visa miniatyrer
 thumbs_label=Miniatyrer
+current_outline_item.title=Hitta aktuell position i dokumentdispositionen
+current_outline_item_label=Aktuell position i dokumentdisposition
 findbar.title=Sök i dokument
 findbar_label=Sök
 

web/app.js

@@ -32,6 +32,7 @@ import {
   ProgressBar,
   RendererType,
   ScrollMode,
+  SidebarView,
   SpreadMode,
   TextLayerMode,
 } from "./ui_utils.js";
@@ -56,7 +57,6 @@ import {
 } from "pdfjs-lib";
 import { CursorTool, PDFCursorTools } from "./pdf_cursor_tools.js";
 import { PDFRenderingQueue, RenderingStates } from "./pdf_rendering_queue.js";
-import { PDFSidebar, SidebarView } from "./pdf_sidebar.js";
 import { OverlayManager } from "./overlay_manager.js";
 import { PasswordPrompt } from "./password_prompt.js";
 import { PDFAttachmentViewer } from "./pdf_attachment_viewer.js";
@@ -68,6 +68,7 @@ import { PDFLayerViewer } from "./pdf_layer_viewer.js";
 import { PDFLinkService } from "./pdf_link_service.js";
 import { PDFOutlineViewer } from "./pdf_outline_viewer.js";
 import { PDFPresentationMode } from "./pdf_presentation_mode.js";
+import { PDFSidebar } from "./pdf_sidebar.js";
 import { PDFSidebarResizer } from "./pdf_sidebar_resizer.js";
 import { PDFThumbnailViewer } from "./pdf_thumbnail_viewer.js";
 import { PDFViewer } from "./pdf_viewer.js";
@@ -1419,7 +1420,7 @@ const PDFViewerApplication = {
 
     onePageRendered.then(() => {
       pdfDocument.getOutline().then(outline => {
-        this.pdfOutlineViewer.render({ outline });
+        this.pdfOutlineViewer.render({ outline, pdfDocument });
       });
       pdfDocument.getAttachments().then(attachments => {
         this.pdfAttachmentViewer.render({ attachments });

web/base_tree_viewer.js

@@ -15,6 +15,9 @@
 
 import { removeNullCharacters } from "pdfjs-lib";
 
+const TREEITEM_OFFSET_TOP = -100; // px
+const TREEITEM_SELECTED_CLASS = "selected";
+
 class BaseTreeViewer {
   constructor(options) {
     if (this.constructor === BaseTreeViewer) {
@@ -27,7 +30,9 @@ class BaseTreeViewer {
   }
 
   reset() {
+    this._pdfDocument = null;
     this._lastToggleIsShow = true;
+    this._currentTreeItem = null;
 
     // Remove the tree from the DOM.
     this.container.textContent = "";
@@ -120,6 +125,46 @@ class BaseTreeViewer {
   render(params) {
     throw new Error("Not implemented: render");
   }
+
+  /**
+   * @private
+   */
+  _updateCurrentTreeItem(treeItem = null) {
+    if (this._currentTreeItem) {
+      // Ensure that the current treeItem-selection is always removed.
+      this._currentTreeItem.classList.remove(TREEITEM_SELECTED_CLASS);
+      this._currentTreeItem = null;
+    }
+    if (treeItem) {
+      treeItem.classList.add(TREEITEM_SELECTED_CLASS);
+      this._currentTreeItem = treeItem;
+    }
+  }
+
+  /**
+   * @private
+   */
+  _scrollToCurrentTreeItem(treeItem) {
+    if (!treeItem) {
+      return;
+    }
+    // Ensure that the treeItem is *fully* expanded, such that it will first of
+    // all be visible and secondly that scrolling it into view works correctly.
+    let currentNode = treeItem.parentNode;
+    while (currentNode && currentNode !== this.container) {
+      if (currentNode.classList.contains("treeItem")) {
+        const toggler = currentNode.firstElementChild;
+        toggler?.classList.remove("treeItemsHidden");
+      }
+      currentNode = currentNode.parentNode;
+    }
+    this._updateCurrentTreeItem(treeItem);
+
+    this.container.scrollTo(
+      treeItem.offsetLeft,
+      treeItem.offsetTop + TREEITEM_OFFSET_TOP
+    );
+  }
 }
 
 export { BaseTreeViewer };

web/images/toolbarButton-currentOutlineItem.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="16" width="16"><path d="m14 9h-6c-1.3 0-1.3 2 0 2h6c1.3 0 1.3-2 0-2zm-5.2-8h-3.8c-1.3 0-1.3 2 0 2h1.7zm-6.8 0c-1 0-1.3 1-0.7 1.7 0.7 0.6 1.7 0.3 1.7-0.7 0-0.5-0.4-1-1-1zm3 8c-1 0-1.3 1-0.7 1.7 0.6 0.6 1.7 0.2 1.7-0.7 0-0.5-0.4-1-1-1zm0.3-4h-0.3c-1.4 0-1.4 2 0 2h2.3zm-3.3 0c-0.9 0-1.4 1-0.7 1.7 0.7 0.6 1.7 0.2 1.7-0.7 0-0.6-0.5-1-1-1zm12 8h-9c-1.3 0-1.3 2 0 2h9c1.3 0 1.3-2 0-2zm-12 0c-1 0-1.3 1-0.7 1.7 0.7 0.6 1.7 0.2 1.7-0.712 0-0.5-0.4-1-1-1z"/><path d="m7.37 4.838 3.93-3.911v2.138h3.629v3.546h-3.629v2.138l-3.93-3.911"/></svg>

web/pdf_layer_viewer.js

@@ -41,7 +41,6 @@ class PDFLayerViewer extends BaseTreeViewer {
   reset() {
     super.reset();
     this._optionalContentConfig = null;
-    this._pdfDocument = null;
   }
 
   /**

web/pdf_outline_viewer.js

@@ -13,8 +13,13 @@
  * limitations under the License.
  */
 
-import { addLinkAttributes, LinkTarget } from "pdfjs-lib";
+import {
+  addLinkAttributes,
+  createPromiseCapability,
+  LinkTarget,
+} from "pdfjs-lib";
 import { BaseTreeViewer } from "./base_tree_viewer.js";
+import { SidebarView } from "./ui_utils.js";
 
 /**
  * @typedef {Object} PDFOutlineViewerOptions
@@ -26,6 +31,7 @@ import { BaseTreeViewer } from "./base_tree_viewer.js";
 /**
  * @typedef {Object} PDFOutlineViewerRenderParameters
  * @property {Array|null} outline - An array of outline objects.
+ * @property {PDFDocument} pdfDocument - A {PDFDocument} instance.
  */
 
 class PDFOutlineViewer extends BaseTreeViewer {
@@ -37,11 +43,29 @@ class PDFOutlineViewer extends BaseTreeViewer {
     this.linkService = options.linkService;
 
     this.eventBus._on("toggleoutlinetree", this._toggleAllTreeItems.bind(this));
+    this.eventBus._on(
+      "currentoutlineitem",
+      this._currentOutlineItem.bind(this)
+    );
+
+    this.eventBus._on("pagechanging", evt => {
+      this._currentPageNumber = evt.pageNumber;
+    });
+    this.eventBus._on("pagesloaded", evt => {
+      this._isPagesLoaded = !!evt.pagesCount;
+    });
+    this.eventBus._on("sidebarviewchanged", evt => {
+      this._sidebarView = evt.view;
+    });
   }
 
   reset() {
     super.reset();
     this._outline = null;
+
+    this._pageNumberToDestHashCapability = null;
+    this._currentPageNumber = 1;
+    this._isPagesLoaded = false;
   }
 
   /**
@@ -51,6 +75,8 @@ class PDFOutlineViewer extends BaseTreeViewer {
     this.eventBus.dispatch("outlineloaded", {
       source: this,
       outlineCount,
+      enableCurrentOutlineItemButton:
+        outlineCount > 0 && !this._pdfDocument?.loadingParams.disableAutoFetch,
     });
   }
 
@@ -71,7 +97,9 @@ class PDFOutlineViewer extends BaseTreeViewer {
     }
 
     element.href = linkService.getDestinationHash(dest);
-    element.onclick = () => {
+    element.onclick = evt => {
+      this._updateCurrentTreeItem(evt.target.parentNode);
+
       if (dest) {
         linkService.goToDestination(dest);
       }
@@ -128,11 +156,12 @@ class PDFOutlineViewer extends BaseTreeViewer {
   /**
    * @param {PDFOutlineViewerRenderParameters} params
    */
-  render({ outline }) {
+  render({ outline, pdfDocument }) {
     if (this._outline) {
       this.reset();
     }
     this._outline = outline || null;
+    this._pdfDocument = pdfDocument || null;
 
     if (!outline) {
       this._dispatchEvent(/* outlineCount = */ 0);
@@ -174,6 +203,120 @@ class PDFOutlineViewer extends BaseTreeViewer {
 
     this._finishRendering(fragment, outlineCount, hasAnyNesting);
   }
+
+  /**
+   * Find/highlight the current outline item, corresponding to the active page.
+   * @private
+   */
+  async _currentOutlineItem() {
+    if (!this._isPagesLoaded) {
+      throw new Error("_currentOutlineItem: All pages have not been loaded.");
+    }
+    if (!this._outline || !this._pdfDocument) {
+      return;
+    }
+
+    const pageNumberToDestHash = await this._getPageNumberToDestHash(
+      this._pdfDocument
+    );
+    if (!pageNumberToDestHash) {
+      return;
+    }
+    this._updateCurrentTreeItem(/* treeItem = */ null);
+
+    if (this._sidebarView !== SidebarView.OUTLINE) {
+      return; // The outline view is no longer visible, hence do nothing.
+    }
+    // When there is no destination on the current page, always check the
+    // previous ones in (reverse) order.
+    for (let i = this._currentPageNumber; i > 0; i--) {
+      const destHash = pageNumberToDestHash.get(i);
+      if (!destHash) {
+        continue;
+      }
+      const linkElement = this.container.querySelector(`a[href="${destHash}"]`);
+      if (!linkElement) {
+        continue;
+      }
+      this._scrollToCurrentTreeItem(linkElement.parentNode);
+      break;
+    }
+  }
+
+  /**
+   * To (significantly) simplify the overall implementation, we will only
+   * consider *one* destination per page when finding/highlighting the current
+   * outline item (similar to e.g. Adobe Reader); more specifically, we choose
+   * the *first* outline item at the *lowest* level of the outline tree.
+   * @private
+   */
+  async _getPageNumberToDestHash(pdfDocument) {
+    if (this._pageNumberToDestHashCapability) {
+      return this._pageNumberToDestHashCapability.promise;
+    }
+    this._pageNumberToDestHashCapability = createPromiseCapability();
+
+    const pageNumberToDestHash = new Map(),
+      pageNumberNesting = new Map();
+    const queue = [{ nesting: 0, items: this._outline }];
+    while (queue.length > 0) {
+      const levelData = queue.shift(),
+        currentNesting = levelData.nesting;
+      for (const { dest, items } of levelData.items) {
+        let explicitDest, pageNumber;
+        if (typeof dest === "string") {
+          explicitDest = await pdfDocument.getDestination(dest);
+
+          if (pdfDocument !== this._pdfDocument) {
+            return null; // The document was closed while the data resolved.
+          }
+        } else {
+          explicitDest = dest;
+        }
+        if (Array.isArray(explicitDest)) {
+          const [destRef] = explicitDest;
+
+          if (typeof destRef === "object") {
+            pageNumber = this.linkService._cachedPageNumber(destRef);
+
+            if (!pageNumber) {
+              try {
+                pageNumber = (await pdfDocument.getPageIndex(destRef)) + 1;
+
+                if (pdfDocument !== this._pdfDocument) {
+                  return null; // The document was closed while the data resolved.
+                }
+                this.linkService.cachePageRef(pageNumber, destRef);
+              } catch (ex) {
+                // Invalid page reference, ignore it and continue parsing.
+              }
+            }
+          } else if (Number.isInteger(destRef)) {
+            pageNumber = destRef + 1;
+          }
+
+          if (
+            Number.isInteger(pageNumber) &&
+            (!pageNumberToDestHash.has(pageNumber) ||
+              currentNesting > pageNumberNesting.get(pageNumber))
+          ) {
+            const destHash = this.linkService.getDestinationHash(dest);
+            pageNumberToDestHash.set(pageNumber, destHash);
+            pageNumberNesting.set(pageNumber, currentNesting);
+          }
+        }
+
+        if (items.length > 0) {
+          queue.push({ nesting: currentNesting + 1, items });
+        }
+      }
+    }
+
+    this._pageNumberToDestHashCapability.resolve(
+      pageNumberToDestHash.size > 0 ? pageNumberToDestHash : null
+    );
+    return this._pageNumberToDestHashCapability.promise;
+  }
 }
 
 export { PDFOutlineViewer };

web/pdf_sidebar.js

@@ -13,20 +13,11 @@
  * limitations under the License.
  */
 
-import { NullL10n, PresentationModeState } from "./ui_utils.js";
+import { NullL10n, PresentationModeState, SidebarView } from "./ui_utils.js";
 import { RenderingStates } from "./pdf_rendering_queue.js";
 
 const UI_NOTIFICATION_CLASS = "pdfSidebarNotification";
 
-const SidebarView = {
-  UNKNOWN: -1,
-  NONE: 0,
-  THUMBS: 1, // Default value.
-  OUTLINE: 2,
-  ATTACHMENTS: 3,
-  LAYERS: 4,
-};
-
 /**
  * @typedef {Object} PDFSidebarOptions
  * @property {PDFSidebarElements} elements - The DOM elements.
@@ -62,6 +53,10 @@ const SidebarView = {
  *   the attachments are placed.
  * @property {HTMLDivElement} layersView - The container in which
  *   the layers are placed.
+ * @property {HTMLDivElement} outlineOptionsContainer - The container in which
+ *   the outline view-specific option button(s) are placed.
+ * @property {HTMLButtonElement} currentOutlineItemButton - The button used to
+ *   find the current outline item.
  */
 
 class PDFSidebar {
@@ -103,6 +98,9 @@ class PDFSidebar {
     this.attachmentsView = elements.attachmentsView;
     this.layersView = elements.layersView;
 
+    this._outlineOptionsContainer = elements.outlineOptionsContainer;
+    this._currentOutlineItemButton = elements.currentOutlineItemButton;
+
     this.eventBus = eventBus;
     this.l10n = l10n;
     this._disableNotification = disableNotification;
@@ -119,6 +117,7 @@ class PDFSidebar {
     this.outlineButton.disabled = false;
     this.attachmentsButton.disabled = false;
     this.layersButton.disabled = false;
+    this._currentOutlineItemButton.disabled = true;
   }
 
   /**
@@ -243,6 +242,12 @@ class PDFSidebar {
     );
     this.layersView.classList.toggle("hidden", view !== SidebarView.LAYERS);
 
+    // Finally, update view-specific CSS classes.
+    this._outlineOptionsContainer.classList.toggle(
+      "hidden",
+      view !== SidebarView.OUTLINE
+    );
+
     if (forceOpen && !this.isOpen) {
       this.open();
       return true; // Opening will trigger rendering and dispatch the event.
@@ -460,6 +465,11 @@ class PDFSidebar {
       this.eventBus.dispatch("resetlayers", { source: this });
     });
 
+    // Buttons for view-specific options.
+    this._currentOutlineItemButton.addEventListener("click", () => {
+      this.eventBus.dispatch("currentoutlineitem", { source: this });
+    });
+
     // Disable/enable views.
     const onTreeLoaded = (count, button, view) => {
       button.disabled = !count;
@@ -475,6 +485,12 @@ class PDFSidebar {
 
     this.eventBus._on("outlineloaded", evt => {
       onTreeLoaded(evt.outlineCount, this.outlineButton, SidebarView.OUTLINE);
+
+      if (evt.enableCurrentOutlineItemButton) {
+        this.pdfViewer.pagesPromise.then(() => {
+          this._currentOutlineItemButton.disabled = !this.isInitialViewSet;
+        });
+      }
     });
 
     this.eventBus._on("attachmentsloaded", evt => {

web/ui_utils.js

@@ -32,6 +32,15 @@ const PresentationModeState = {
   FULLSCREEN: 3,
 };
 
+const SidebarView = {
+  UNKNOWN: -1,
+  NONE: 0,
+  THUMBS: 1, // Default value.
+  OUTLINE: 2,
+  ATTACHMENTS: 3,
+  LAYERS: 4,
+};
+
 const RendererType = {
   CANVAS: "canvas",
   SVG: "svg",
@@ -1037,6 +1046,7 @@ export {
   isValidSpreadMode,
   isPortraitOrientation,
   PresentationModeState,
+  SidebarView,
   RendererType,
   TextLayerMode,
   ScrollMode,

web/viewer.css

@@ -48,8 +48,8 @@
   --findbar-nextprevious-btn-bg-color: rgba(227, 228, 230, 1);
   --treeitem-color: rgba(0, 0, 0, 0.8);
   --treeitem-hover-color: rgba(0, 0, 0, 0.9);
-  --treeitem-active-color: rgba(0, 0, 0, 0.08);
+  --treeitem-selected-color: rgba(0, 0, 0, 0.9);
-  --treeitem-active-bg-color: rgba(0, 0, 0, 1);
+  --treeitem-selected-bg-color: rgba(0, 0, 0, 0.25);
   --sidebaritem-bg-color: rgba(0, 0, 0, 0.15);
   --doorhanger-bg-color: rgba(255, 255, 255, 1);
   --doorhanger-border-color: rgba(12, 12, 13, 0.2);
@@ -77,6 +77,7 @@
   --toolbarButton-viewOutline-icon: url(images/toolbarButton-viewOutline.svg);
   --toolbarButton-viewAttachments-icon: url(images/toolbarButton-viewAttachments.svg);
   --toolbarButton-viewLayers-icon: url(images/toolbarButton-viewLayers.svg);
+  --toolbarButton-currentOutlineItem-icon: url(images/toolbarButton-currentOutlineItem.svg);
   --toolbarButton-search-icon: url(images/toolbarButton-search.svg);
   --findbarButton-previous-icon: url(images/findbarButton-previous.svg);
   --findbarButton-next-icon: url(images/findbarButton-next.svg);
@@ -121,8 +122,8 @@
     --findbar-nextprevious-btn-bg-color: rgba(89, 89, 89, 1);
     --treeitem-color: rgba(255, 255, 255, 0.8);
     --treeitem-hover-color: rgba(255, 255, 255, 0.9);
-    --treeitem-active-color: rgba(255, 255, 255, 0.08);
+    --treeitem-selected-color: rgba(255, 255, 255, 0.9);
-    --treeitem-active-bg-color: rgba(255, 255, 255, 1);
+    --treeitem-selected-bg-color: rgba(255, 255, 255, 0.25);
     --sidebaritem-bg-color: rgba(255, 255, 255, 0.15);
     --doorhanger-bg-color: rgba(74, 74, 79, 1);
     --doorhanger-border-color: rgba(39, 39, 43, 1);
@@ -338,6 +339,13 @@ html[dir="rtl"] #toolbarSidebar .toolbarButton {
   margin-left: 2px !important;
 }
 
+html[dir="ltr"] #toolbarSidebarRight .toolbarButton {
+  margin-right: 3px !important;
+}
+html[dir="rtl"] #toolbarSidebarRight .toolbarButton {
+  margin-left: 3px !important;
+}
+
 #sidebarResizer {
   position: absolute;
   top: 0;
@@ -694,16 +702,22 @@ html[dir="ltr"] .doorHangerRight:before {
 }
 
 html[dir="ltr"] #toolbarViewerLeft,
-html[dir="rtl"] #toolbarViewerRight {
+html[dir="rtl"] #toolbarViewerRight,
+html[dir="ltr"] #toolbarSidebarLeft,
+html[dir="rtl"] #toolbarSidebarRight {
   float: left;
 }
 html[dir="ltr"] #toolbarViewerRight,
-html[dir="rtl"] #toolbarViewerLeft {
+html[dir="rtl"] #toolbarViewerLeft,
+html[dir="ltr"] #toolbarSidebarRight,
+html[dir="rtl"] #toolbarSidebarLeft {
   float: right;
 }
 html[dir="ltr"] #toolbarViewerLeft > *,
 html[dir="ltr"] #toolbarViewerMiddle > *,
 html[dir="ltr"] #toolbarViewerRight > *,
+html[dir="ltr"] #toolbarSidebarLeft *,
+html[dir="ltr"] #toolbarSidebarRight *,
 html[dir="ltr"] .findbar * {
   position: relative;
   float: left;
@@ -711,6 +725,8 @@ html[dir="ltr"] .findbar * {
 html[dir="rtl"] #toolbarViewerLeft > *,
 html[dir="rtl"] #toolbarViewerMiddle > *,
 html[dir="rtl"] #toolbarViewerRight > *,
+html[dir="rtl"] #toolbarSidebarLeft *,
+html[dir="rtl"] #toolbarSidebarRight *,
 html[dir="rtl"] .findbar * {
   position: relative;
   float: right;
@@ -1073,6 +1089,14 @@ html[dir="rtl"] #viewOutline.toolbarButton::before {
   mask-image: var(--toolbarButton-viewLayers-icon);
 }
 
+#currentOutlineItem.toolbarButton::before {
+  -webkit-mask-image: var(--toolbarButton-currentOutlineItem-icon);
+  mask-image: var(--toolbarButton-currentOutlineItem-icon);
+}
+html[dir="rtl"] #currentOutlineItem.toolbarButton::before {
+  transform: scaleX(-1);
+}
+
 #viewFind.toolbarButton::before {
   -webkit-mask-image: var(--toolbarButton-search-icon);
   mask-image: var(--toolbarButton-search-icon);
@@ -1448,6 +1472,11 @@ html[dir="rtl"] .treeItemToggler::before {
   left: 4px;
 }
 
+.treeItem.selected > a {
+  background-color: var(--treeitem-selected-bg-color);
+  color: var(--treeitem-selected-color);
+}
+
 .treeItemToggler:hover,
 .treeItemToggler:hover + a,
 .treeItemToggler:hover ~ .treeItems,
@@ -1458,12 +1487,6 @@ html[dir="rtl"] .treeItemToggler::before {
   color: var(--treeitem-hover-color);
 }
 
-.treeItem.selected {
-  background-color: var(--treeitem-active-bg-color);
-  background-clip: padding-box;
-  color: var(--treeitem-active-color);
-}
-
 /* TODO: file FF bug to support ::-moz-selection:window-inactive
    so we can override the opaque grey background when the window is inactive;
    see https://bugzilla.mozilla.org/show_bug.cgi?id=706209 */

web/viewer.html

@@ -76,6 +76,7 @@ See https://github.com/adobe-type-tools/cmap-resources
 
       <div id="sidebarContainer">
         <div id="toolbarSidebar">
+          <div id="toolbarSidebarLeft">
             <div class="splitToolbarButton toggled">
               <button id="viewThumbnail" class="toolbarButton toggled" title="Show Thumbnails" tabindex="2" data-l10n-id="thumbs">
                  <span data-l10n-id="thumbs_label">Thumbnails</span>
@@ -91,6 +92,17 @@ See https://github.com/adobe-type-tools/cmap-resources
               </button>
             </div>
           </div>
+
+          <div id="toolbarSidebarRight">
+            <div id="outlineOptionsContainer" class="hidden">
+              <div class="verticalToolbarSeparator"></div>
+
+              <button id="currentOutlineItem" class="toolbarButton" disabled="disabled" title="Find Current Outline Item" tabindex="6" data-l10n-id="current_outline_item">
+                <span data-l10n-id="current_outline_item_label">Current Outline Item</span>
+              </button>
+            </div>
+          </div>
+        </div>
         <div id="sidebarContent">
           <div id="thumbnailView">
           </div>

web/viewer.js

@@ -132,6 +132,11 @@ function getViewerConfiguration() {
       outlineView: document.getElementById("outlineView"),
       attachmentsView: document.getElementById("attachmentsView"),
       layersView: document.getElementById("layersView"),
+      // View-specific options
+      outlineOptionsContainer: document.getElementById(
+        "outlineOptionsContainer"
+      ),
+      currentOutlineItemButton: document.getElementById("currentOutlineItem"),
     },
     sidebarResizer: {
       outerContainer: document.getElementById("outerContainer"),