[api-minor] Add support for toggling of Optional Content in the viewer (issue 12096)

*Besides, obviously, adding viewer support:* This patch attempts to improve the general API for Optional Content Groups slightly, by adding a couple of new methods for interacting with the (more complex) data structures of `OptionalContentConfig`-instances. (Thus allowing us to mark some of the data as "private", given that it probably shouldn't be manipulated directly.) By utilizing not just the "raw" Optional Content Groups, but the data from the `/Order` array when available, we can thus display the Layers in a proper tree-structure with collapsible headings for PDF documents that utilizes that feature. Note that it's possible to reset all Optional Content Groups to their default visibility state, simply by double-clicking on the Layers-button in the sidebar. (Currently that's indicated in the Layers-button tooltip, which is obviously easy to overlook, however it's probably the best we can do for now without adding more buttons, or even a dropdown-toolbar, to the sidebar.) Also, the current Layers-button icons are a little rough around the edges, quite literally, but given that the viewer will soon have its UI modernized anyway they hopefully suffice in the meantime. To give users *full* control of the visibility of the various Optional Content Groups, even those which according to the `/Order` array should not (by default) be toggleable in the UI, this patch will place those under a *custom* heading which: - Is collapsed by default, and placed at the bottom of the Layers-tree, to be a bit less obtrusive. - Uses a slightly different formatting, compared to the "regular" headings. - Is localizable. Finally, note that the thumbnails are *purposely* always rendered with all Optional Content Groups at their default visibility state, since that seems the most useful and it's also consistent with other viewers. To ensure that this works as intended, we'll thus disable the `PDFThumbnailView.setImage` functionality when the Optional Content Groups have been changed in the viewer. (This obviously means that we'll re-render thumbnails instead of using the rendered pages. However, this situation ought to be rare enough for this to not really be a problem.)
2020-08-06 21:01:03 +02:00 · 2020-08-06 21:01:03 +02:00 · 66aabe3ec7
commit 66aabe3ec7
parent 2393443e73
17 changed files with 485 additions and 36 deletions
--- a/l10n/en-US/viewer.properties
+++ b/l10n/en-US/viewer.properties
@ -137,17 +137,20 @@ print_progress_close=Cancel
 # (the _label strings are alt text for the buttons, the .title strings are
 # tooltips)
 toggle_sidebar.title=Toggle Sidebar
-toggle_sidebar_notification.title=Toggle Sidebar (document contains outline/attachments)
+toggle_sidebar_notification2.title=Toggle Sidebar (document contains outline/attachments/layers)
 toggle_sidebar_label=Toggle Sidebar
 document_outline.title=Show Document Outline (double-click to expand/collapse all items)
 document_outline_label=Document Outline
 attachments.title=Show Attachments
 attachments_label=Attachments
+layers.title=Show Layers (double-click to reset all layers to the default state)
+layers_label=Layers
 thumbs.title=Show Thumbnails
 thumbs_label=Thumbnails
 findbar.title=Find in Document
 findbar_label=Find

+additional_layers=Additional Layers
 # LOCALIZATION NOTE (page_canvas): "{{page}}" will be replaced by the page number.
 page_canvas=Page {{page}}
 # Thumbnails panel item (tooltip and alt text for images)
--- a/l10n/sv-SE/viewer.properties
+++ b/l10n/sv-SE/viewer.properties
@ -137,17 +137,20 @@ print_progress_close=Avbryt
 # (the _label strings are alt text for the buttons, the .title strings are
 # tooltips)
 toggle_sidebar.title=Visa/dölj sidofält
-toggle_sidebar_notification.title=Visa/dölj sidofält (dokument innehåller översikt/bilagor)
+toggle_sidebar_notification2.title=Visa/dölj sidofält (dokument innehåller översikt/bilagor/lager)
 toggle_sidebar_label=Visa/dölj sidofält
 document_outline.title=Visa dokumentdisposition (dubbelklicka för att expandera/komprimera alla objekt)
 document_outline_label=Dokumentöversikt
 attachments.title=Visa Bilagor
 attachments_label=Bilagor
+layers.title=Visa lager (dubbelklicka för att återställa alla lager till ursrungligt läge)
+layers_label=Lager
 thumbs.title=Visa miniatyrer
 thumbs_label=Miniatyrer
 findbar.title=Sök i dokument
 findbar_label=Sök

+additional_layers=Ytterligare lager
 # LOCALIZATION NOTE (page_canvas): "{{page}}" will be replaced by the page number.
 page_canvas=Sida {{page}}
 # Thumbnails panel item (tooltip and alt text for images)
--- a/src/display/optional_content_config.js
+++ b/src/display/optional_content_config.js
@ -27,7 +27,7 @@ class OptionalContentConfig {
    this.name = null;
    this.creator = null;
    this._order = null;
-    this.groups = new Map();
+    this._groups = new Map();

    if (data === null) {
      return;
@ -36,34 +36,34 @@ class OptionalContentConfig {
    this.creator = data.creator;
    this._order = data.order;
    for (const group of data.groups) {
-      this.groups.set(
+      this._groups.set(
        group.id,
        new OptionalContentGroup(group.name, group.intent)
      );
    }

    if (data.baseState === "OFF") {
-      for (const group of this.groups) {
+      for (const group of this._groups) {
        group.visible = false;
      }
    }

    for (const on of data.on) {
-      this.groups.get(on).visible = true;
+      this._groups.get(on).visible = true;
    }

    for (const off of data.off) {
-      this.groups.get(off).visible = false;
+      this._groups.get(off).visible = false;
    }
  }

  isVisible(group) {
    if (group.type === "OCG") {
-      if (!this.groups.has(group.id)) {
+      if (!this._groups.has(group.id)) {
        warn(`Optional content group not found: ${group.id}`);
        return true;
      }
-      return this.groups.get(group.id).visible;
+      return this._groups.get(group.id).visible;
    } else if (group.type === "OCMD") {
      // Per the spec, the expression should be preferred if available. Until
      // we implement this, just fallback to using the group policy for now.
@ -73,44 +73,44 @@ class OptionalContentConfig {
      if (!group.policy || group.policy === "AnyOn") {
        // Default
        for (const id of group.ids) {
-          if (!this.groups.has(id)) {
+          if (!this._groups.has(id)) {
            warn(`Optional content group not found: ${id}`);
            return true;
          }
-          if (this.groups.get(id).visible) {
+          if (this._groups.get(id).visible) {
            return true;
          }
        }
        return false;
      } else if (group.policy === "AllOn") {
        for (const id of group.ids) {
-          if (!this.groups.has(id)) {
+          if (!this._groups.has(id)) {
            warn(`Optional content group not found: ${id}`);
            return true;
          }
-          if (!this.groups.get(id).visible) {
+          if (!this._groups.get(id).visible) {
            return false;
          }
        }
        return true;
      } else if (group.policy === "AnyOff") {
        for (const id of group.ids) {
-          if (!this.groups.has(id)) {
+          if (!this._groups.has(id)) {
            warn(`Optional content group not found: ${id}`);
            return true;
          }
-          if (!this.groups.get(id).visible) {
+          if (!this._groups.get(id).visible) {
            return true;
          }
        }
        return false;
      } else if (group.policy === "AllOff") {
        for (const id of group.ids) {
-          if (!this.groups.has(id)) {
+          if (!this._groups.has(id)) {
            warn(`Optional content group not found: ${id}`);
            return true;
          }
-          if (this.groups.get(id).visible) {
+          if (this._groups.get(id).visible) {
            return false;
          }
        }
@ -122,6 +122,35 @@ class OptionalContentConfig {
    warn(`Unknown group type ${group.type}.`);
    return true;
  }
+
+  setVisibility(id, visible = true) {
+    if (!this._groups.has(id)) {
+      warn(`Optional content group not found: ${id}`);
+      return;
+    }
+    this._groups.get(id).visible = !!visible;
+  }
+
+  getOrder() {
+    if (!this._groups.size) {
+      return null;
+    }
+    if (this._order) {
+      return this._order.slice();
+    }
+    return Array.from(this._groups.keys());
+  }
+
+  getGroups() {
+    if (!this._groups.size) {
+      return null;
+    }
+    return Object.fromEntries(this._groups);
+  }
+
+  getGroup(id) {
+    return this._groups.get(id) || null;
+  }
 }

 export { OptionalContentConfig };
--- a/web/app.js
+++ b/web/app.js
@ -64,6 +64,7 @@ import { PDFDocumentProperties } from "./pdf_document_properties.js";
 import { PDFFindBar } from "./pdf_find_bar.js";
 import { PDFFindController } from "./pdf_find_controller.js";
 import { PDFHistory } from "./pdf_history.js";
+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";
@ -209,6 +210,8 @@ const PDFViewerApplication = {
  pdfOutlineViewer: null,
  /** @type {PDFAttachmentViewer} */
  pdfAttachmentViewer: null,
+  /** @type {PDFLayerViewer} */
+  pdfLayerViewer: null,
  /** @type {PDFCursorTools} */
  pdfCursorTools: null,
  /** @type {ViewHistory} */
@ -445,6 +448,7 @@ const PDFViewerApplication = {

    this.pdfThumbnailViewer = new PDFThumbnailViewer({
      container: appConfig.sidebar.thumbnailView,
+      eventBus,
      renderingQueue: pdfRenderingQueue,
      linkService: pdfLinkService,
      l10n: this.l10n,
@ -509,6 +513,12 @@ const PDFViewerApplication = {
      downloadManager,
    });

+    this.pdfLayerViewer = new PDFLayerViewer({
+      container: appConfig.sidebar.layersView,
+      eventBus,
+      l10n: this.l10n,
+    });
+
    this.pdfSidebar = new PDFSidebar({
      elements: appConfig.sidebar,
      pdfViewer: this.pdfViewer,
@ -737,6 +747,7 @@ const PDFViewerApplication = {
    this.pdfSidebar.reset();
    this.pdfOutlineViewer.reset();
    this.pdfAttachmentViewer.reset();
+    this.pdfLayerViewer.reset();

    if (this.pdfHistory) {
      this.pdfHistory.reset();
@ -1318,6 +1329,11 @@ const PDFViewerApplication = {
      pdfDocument.getAttachments().then(attachments => {
        this.pdfAttachmentViewer.render({ attachments });
      });
+      // Ensure that the layers accurately reflects the current state in the
+      // viewer itself, rather than the default state provided by the API.
+      pdfViewer.optionalContentConfigPromise.then(optionalContentConfig => {
+        this.pdfLayerViewer.render({ optionalContentConfig, pdfDocument });
+      });
    });

    this._initializePageLabels(pdfDocument);
@ -1667,12 +1683,15 @@ const PDFViewerApplication = {
    const pagesOverview = this.pdfViewer.getPagesOverview();
    const printContainer = this.appConfig.printContainer;
    const printResolution = AppOptions.get("printResolution");
+    const optionalContentConfigPromise = this.pdfViewer
+      .optionalContentConfigPromise;

    const printService = PDFPrintServiceFactory.instance.createPrintService(
      this.pdfDocument,
      pagesOverview,
      printContainer,
      printResolution,
+      optionalContentConfigPromise,
      this.l10n
    );
    this.printService = printService;
@ -1748,6 +1767,7 @@ const PDFViewerApplication = {
    eventBus._on("scalechanged", webViewerScaleChanged);
    eventBus._on("rotatecw", webViewerRotateCw);
    eventBus._on("rotateccw", webViewerRotateCcw);
+    eventBus._on("optionalcontentconfig", webViewerOptionalContentConfig);
    eventBus._on("switchscrollmode", webViewerSwitchScrollMode);
    eventBus._on("scrollmodechanged", webViewerScrollModeChanged);
    eventBus._on("switchspreadmode", webViewerSwitchSpreadMode);
@ -1827,6 +1847,7 @@ const PDFViewerApplication = {
    eventBus._off("scalechanged", webViewerScaleChanged);
    eventBus._off("rotatecw", webViewerRotateCw);
    eventBus._off("rotateccw", webViewerRotateCcw);
+    eventBus._off("optionalcontentconfig", webViewerOptionalContentConfig);
    eventBus._off("switchscrollmode", webViewerSwitchScrollMode);
    eventBus._off("scrollmodechanged", webViewerScrollModeChanged);
    eventBus._off("switchspreadmode", webViewerSwitchSpreadMode);
@ -2169,12 +2190,15 @@ function webViewerPageMode({ mode }) {
      view = SidebarView.THUMBS;
      break;
    case "bookmarks":
-    case "outline":
+    case "outline": // non-standard
      view = SidebarView.OUTLINE;
      break;
-    case "attachments":
+    case "attachments": // non-standard
      view = SidebarView.ATTACHMENTS;
      break;
+    case "layers": // non-standard
+      view = SidebarView.LAYERS;
+      break;
    case "none":
      view = SidebarView.NONE;
      break;
@ -2420,6 +2444,9 @@ function webViewerRotateCw() {
 function webViewerRotateCcw() {
  PDFViewerApplication.rotatePages(-90);
 }
+function webViewerOptionalContentConfig(evt) {
+  PDFViewerApplication.pdfViewer.optionalContentConfigPromise = evt.promise;
+}
 function webViewerSwitchScrollMode(evt) {
  PDFViewerApplication.pdfViewer.scrollMode = evt.mode;
 }
@ -3013,7 +3040,7 @@ function apiPageModeToSidebarView(mode) {
    case "UseAttachments":
      return SidebarView.ATTACHMENTS;
    case "UseOC":
-    // Not implemented, since we don't support Optional Content Groups yet.
+      return SidebarView.LAYERS;
  }
  return SidebarView.NONE; // Default value.
 }
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@ -439,6 +439,7 @@ class BaseViewer {
    const firstPagePromise = pdfDocument.getPage(1);

    const annotationStorage = pdfDocument.annotationStorage;
+    const optionalContentConfigPromise = pdfDocument.getOptionalContentConfig();

    this._pagesCapability.promise.then(() => {
      this.eventBus.dispatch("pagesloaded", {
@ -474,6 +475,7 @@ class BaseViewer {
    firstPagePromise
      .then(firstPdfPage => {
        this._firstPageCapability.resolve(firstPdfPage);
+        this._optionalContentConfigPromise = optionalContentConfigPromise;

        const scale = this.currentScale;
        const viewport = firstPdfPage.getViewport({ scale: scale * CSS_UNITS });
@ -486,8 +488,9 @@ class BaseViewer {
            eventBus: this.eventBus,
            id: pageNum,
            scale,
-            annotationStorage,
            defaultViewport: viewport.clone(),
+            annotationStorage,
+            optionalContentConfigPromise,
            renderingQueue: this.renderingQueue,
            textLayerFactory,
            textLayerMode: this.textLayerMode,
@ -605,6 +608,7 @@ class BaseViewer {
    this._buffer = new PDFPageViewBuffer(DEFAULT_CACHE_SIZE);
    this._location = null;
    this._pagesRotation = 0;
+    this._optionalContentConfigPromise = null;
    this._pagesRequests = new WeakMap();
    this._firstPageCapability = createPromiseCapability();
    this._onePageRenderedCapability = createPromiseCapability();
@ -1222,6 +1226,50 @@ class BaseViewer {
    });
  }

+  /**
+   * @type {Promise<OptionalContentConfig | null>}
+   */
+  get optionalContentConfigPromise() {
+    if (!this.pdfDocument) {
+      return Promise.resolve(null);
+    }
+    if (!this._optionalContentConfigPromise) {
+      // Prevent issues if the getter is accessed *before* the `onePageRendered`
+      // promise has resolved; won't (normally) happen in the default viewer.
+      return this.pdfDocument.getOptionalContentConfig();
+    }
+    return this._optionalContentConfigPromise;
+  }
+
+  /**
+   * @param {Promise<OptionalContentConfig>} promise - A promise that is
+   *   resolved with an {@link OptionalContentConfig} instance.
+   */
+  set optionalContentConfigPromise(promise) {
+    if (!(promise instanceof Promise)) {
+      throw new Error(`Invalid optionalContentConfigPromise: ${promise}`);
+    }
+    if (!this.pdfDocument) {
+      return;
+    }
+    if (!this._optionalContentConfigPromise) {
+      // Ignore the setter *before* the `onePageRendered` promise has resolved,
+      // since it'll be overwritten anyway; won't happen in the default viewer.
+      return;
+    }
+    this._optionalContentConfigPromise = promise;
+
+    for (const pageView of this._pages) {
+      pageView.update(pageView.scale, pageView.rotation, promise);
+    }
+    this.update();
+
+    this.eventBus.dispatch("optionalcontentconfigchanged", {
+      source: this,
+      promise,
+    });
+  }
+
  /**
   * @type {number} One of the values in {ScrollMode}.
   */
--- a/web/firefox_print_service.js
+++ b/web/firefox_print_service.js
@ -23,7 +23,8 @@ function composePage(
  pageNumber,
  size,
  printContainer,
-  printResolution
+  printResolution,
+  optionalContentConfigPromise
 ) {
  const canvas = document.createElement("canvas");

@ -58,6 +59,7 @@ function composePage(
          viewport: pdfPage.getViewport({ scale: 1, rotation: size.rotation }),
          intent: "print",
          annotationStorage: pdfDocument.annotationStorage,
+          optionalContentConfigPromise,
        };
        return pdfPage.render(renderContext).promise;
      })
@ -84,12 +86,15 @@ function FirefoxPrintService(
  pdfDocument,
  pagesOverview,
  printContainer,
-  printResolution
+  printResolution,
+  optionalContentConfigPromise = null
 ) {
  this.pdfDocument = pdfDocument;
  this.pagesOverview = pagesOverview;
  this.printContainer = printContainer;
  this._printResolution = printResolution || 150;
+  this._optionalContentConfigPromise =
+    optionalContentConfigPromise || pdfDocument.getOptionalContentConfig();
 }

 FirefoxPrintService.prototype = {
@ -99,6 +104,7 @@ FirefoxPrintService.prototype = {
      pagesOverview,
      printContainer,
      _printResolution,
+      _optionalContentConfigPromise,
    } = this;

    const body = document.querySelector("body");
@ -110,7 +116,8 @@ FirefoxPrintService.prototype = {
        /* pageNumber = */ i + 1,
        pagesOverview[i],
        printContainer,
-        _printResolution
+        _printResolution,
+        _optionalContentConfigPromise
      );
    }
  },
@ -135,13 +142,15 @@ PDFPrintServiceFactory.instance = {
    pdfDocument,
    pagesOverview,
    printContainer,
-    printResolution
+    printResolution,
+    optionalContentConfigPromise
  ) {
    return new FirefoxPrintService(
      pdfDocument,
      pagesOverview,
      printContainer,
-      printResolution
+      printResolution,
+      optionalContentConfigPromise
    );
  },
 };
--- a/web/images/toolbarButton-viewLayers-dark.svg
+++ b/web/images/toolbarButton-viewLayers-dark.svg
@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 4.233 4.233" height="16" width="16" fill="rgba(255,255,255,1)"><path d="M.15 2.992c-.198.1-.2.266-.002.365l1.604.802a.93.93 0 00.729-.001l1.602-.801c.198-.1.197-.264 0-.364l-.695-.348c-1.306.595-2.542 0-2.542 0m-.264.53l.658-.329c.6.252 1.238.244 1.754 0l.659.329-1.536.768zM.15 1.935c-.198.1-.198.265 0 .364l1.604.802a.926.926 0 00.727 0l1.603-.802c.198-.099.198-.264 0-.363l-.694-.35c-1.14.56-2.546.001-2.546.001m-.264.53l.664-.332c.52.266 1.261.235 1.75.002l.659.33-1.537.768zM.15.877c-.198.099-.198.264 0 .363l1.604.802a.926.926 0 00.727 0l1.603-.802c.198-.099.198-.264 0-.363L2.481.075a.926.926 0 00-.727 0zm.43.182L2.117.29l1.538.769-1.538.768z"/></svg>
--- a/web/images/toolbarButton-viewLayers.svg
+++ b/web/images/toolbarButton-viewLayers.svg
@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 4.233 4.233" height="16" width="16"><path d="M.15 2.992c-.198.1-.2.266-.002.365l1.604.802a.93.93 0 00.729-.001l1.602-.801c.198-.1.197-.264 0-.364l-.695-.348c-1.306.595-2.542 0-2.542 0m-.264.53l.658-.329c.6.252 1.238.244 1.754 0l.659.329-1.536.768zM.15 1.935c-.198.1-.198.265 0 .364l1.604.802a.926.926 0 00.727 0l1.603-.802c.198-.099.198-.264 0-.363l-.694-.35c-1.14.56-2.546.001-2.546.001m-.264.53l.664-.332c.52.266 1.261.235 1.75.002l.659.33-1.537.768zM.15.877c-.198.099-.198.264 0 .363l1.604.802a.926.926 0 00.727 0l1.603-.802c.198-.099.198-.264 0-.363L2.481.075a.926.926 0 00-.727 0zm.43.182L2.117.29l1.538.769-1.538.768z"/></svg>
--- a/web/pdf_layer_viewer.js
+++ b/web/pdf_layer_viewer.js
@ -0,0 +1,212 @@
+/* Copyright 2020 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { BaseTreeViewer } from "./base_tree_viewer.js";
+
+/**
+ * @typedef {Object} PDFLayerViewerOptions
+ * @property {HTMLDivElement} container - The viewer element.
+ * @property {EventBus} eventBus - The application event bus.
+ * @property {IL10n} l10n - Localization service.
+ */
+
+/**
+ * @typedef {Object} PDFLayerViewerRenderParameters
+ * @property {OptionalContentConfig|null} optionalContentConfig - An
+ *   {OptionalContentConfig} instance.
+ * @property {PDFDocument} pdfDocument - A {PDFDocument} instance.
+ */
+
+class PDFLayerViewer extends BaseTreeViewer {
+  constructor(options) {
+    super(options);
+    this.l10n = options.l10n;
+
+    this.eventBus._on("resetlayers", this._resetLayers.bind(this));
+    this.eventBus._on("togglelayerstree", this._toggleAllTreeItems.bind(this));
+  }
+
+  reset() {
+    super.reset();
+    this._optionalContentConfig = null;
+    this._pdfDocument = null;
+  }
+
+  /**
+   * @private
+   */
+  _dispatchEvent(layersCount) {
+    this.eventBus.dispatch("layersloaded", {
+      source: this,
+      layersCount,
+    });
+  }
+
+  /**
+   * @private
+   */
+  _bindLink(element, { groupId, input }) {
+    const setVisibility = () => {
+      this._optionalContentConfig.setVisibility(groupId, input.checked);
+
+      this.eventBus.dispatch("optionalcontentconfig", {
+        source: this,
+        promise: Promise.resolve(this._optionalContentConfig),
+      });
+    };
+
+    element.onclick = evt => {
+      if (evt.target === input) {
+        setVisibility();
+        return true;
+      } else if (evt.target !== element) {
+        return true; // The target is the "label", which is handled above.
+      }
+      input.checked = !input.checked;
+      setVisibility();
+      return false;
+    };
+  }
+
+  /**
+   * @private
+   */
+  async _setNestedName(element, { name = null }) {
+    if (typeof name === "string") {
+      element.textContent = this._normalizeTextContent(name);
+      return;
+    }
+    element.textContent = await this.l10n.get(
+      "additional_layers",
+      null,
+      "Additional Layers"
+    );
+    element.style.fontStyle = "italic";
+  }
+
+  /**
+   * @private
+   */
+  _addToggleButton(div, { name = null }) {
+    super._addToggleButton(div, /* hidden = */ name === null);
+  }
+
+  /**
+   * @private
+   */
+  _toggleAllTreeItems() {
+    if (!this._optionalContentConfig) {
+      return;
+    }
+    super._toggleAllTreeItems();
+  }
+
+  /**
+   * @param {PDFLayerViewerRenderParameters} params
+   */
+  render({ optionalContentConfig, pdfDocument }) {
+    if (this._optionalContentConfig) {
+      this.reset();
+    }
+    this._optionalContentConfig = optionalContentConfig || null;
+    this._pdfDocument = pdfDocument || null;
+
+    const groups = optionalContentConfig && optionalContentConfig.getOrder();
+    if (!groups) {
+      this._dispatchEvent(/* layersCount = */ 0);
+      return;
+    }
+
+    const fragment = document.createDocumentFragment(),
+      queue = [{ parent: fragment, groups }];
+    let layersCount = 0,
+      hasAnyNesting = false;
+    while (queue.length > 0) {
+      const levelData = queue.shift();
+      for (const groupId of levelData.groups) {
+        const div = document.createElement("div");
+        div.className = "treeItem";
+
+        const element = document.createElement("a");
+        div.appendChild(element);
+
+        if (typeof groupId === "object") {
+          hasAnyNesting = true;
+          this._addToggleButton(div, groupId);
+          this._setNestedName(element, groupId);
+
+          const itemsDiv = document.createElement("div");
+          itemsDiv.className = "treeItems";
+          div.appendChild(itemsDiv);
+
+          queue.push({ parent: itemsDiv, groups: groupId.order });
+        } else {
+          const group = optionalContentConfig.getGroup(groupId);
+
+          const input = document.createElement("input");
+          this._bindLink(element, { groupId, input });
+          input.type = "checkbox";
+          input.id = groupId;
+          input.checked = group.visible;
+
+          const label = document.createElement("label");
+          label.setAttribute("for", groupId);
+          label.textContent = this._normalizeTextContent(group.name);
+
+          element.appendChild(input);
+          element.appendChild(label);
+
+          layersCount++;
+        }
+
+        levelData.parent.appendChild(div);
+      }
+    }
+    if (hasAnyNesting) {
+      this.container.classList.add("treeWithDeepNesting");
+
+      this._lastToggleIsShow =
+        fragment.querySelectorAll(".treeItemsHidden").length === 0;
+    }
+
+    this.container.appendChild(fragment);
+
+    this._dispatchEvent(layersCount);
+  }
+
+  /**
+   * @private
+   */
+  async _resetLayers() {
+    if (!this._optionalContentConfig) {
+      return;
+    }
+    // Fetch the default optional content configuration...
+    const optionalContentConfig = await this._pdfDocument.getOptionalContentConfig();
+
+    this.eventBus.dispatch("optionalcontentconfig", {
+      source: this,
+      promise: Promise.resolve(optionalContentConfig),
+    });
+
+    // ... and reset the sidebarView to the default state.
+    this.render({
+      optionalContentConfig,
+      pdfDocument: this._pdfDocument,
+    });
+  }
+}
+
+export { PDFLayerViewer };
--- a/web/pdf_page_view.js
+++ b/web/pdf_page_view.js
@ -40,6 +40,9 @@ import { viewerCompatibilityParams } from "./viewer_compatibility.js";
 * @property {PageViewport} defaultViewport - The page viewport.
 * @property {AnnotationStorage} [annotationStorage] - Storage for annotation
 *   data in forms. The default value is `null`.
+ * @property {Promise<OptionalContentConfig>} [optionalContentConfigPromise] -
+ *   A promise that is resolved with an {@link OptionalContentConfig} instance.
+ *   The default value is `null`.
 * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
 * @property {IPDFTextLayerFactory} textLayerFactory
 * @property {number} [textLayerMode] - Controls if the text layer used for
@ -83,8 +86,10 @@ class PDFPageView {
    this.rotation = 0;
    this.scale = options.scale || DEFAULT_SCALE;
    this.viewport = defaultViewport;
-    this._annotationStorage = options.annotationStorage || null;
    this.pdfPageRotate = defaultViewport.rotation;
+    this._annotationStorage = options.annotationStorage || null;
+    this._optionalContentConfigPromise =
+      options.optionalContentConfigPromise || null;
    this.hasRestrictedScaling = false;
    this.textLayerMode = Number.isInteger(options.textLayerMode)
      ? options.textLayerMode
@ -236,12 +241,15 @@ class PDFPageView {
    div.appendChild(this.loadingIconDiv);
  }

-  update(scale, rotation) {
+  update(scale, rotation, optionalContentConfigPromise = null) {
    this.scale = scale || this.scale;
    // The rotation may be zero.
    if (typeof rotation !== "undefined") {
      this.rotation = rotation;
    }
+    if (optionalContentConfigPromise instanceof Promise) {
+      this._optionalContentConfigPromise = optionalContentConfigPromise;
+    }

    const totalRotation = (this.rotation + this.pdfPageRotate) % 360;
    this.viewport = this.viewport.clone({
@ -660,6 +668,7 @@ class PDFPageView {
      viewport: this.viewport,
      enableWebGL: this.enableWebGL,
      renderInteractiveForms: this.renderInteractiveForms,
+      optionalContentConfigPromise: this._optionalContentConfigPromise,
    };
    const renderTask = this.pdfPage.render(renderContext);
    renderTask.onContinue = function (cont) {
--- a/web/pdf_print_service.js
+++ b/web/pdf_print_service.js
@ -27,7 +27,8 @@ function renderPage(
  pdfDocument,
  pageNumber,
  size,
-  printResolution
+  printResolution,
+  optionalContentConfigPromise
 ) {
  const scratchCanvas = activeService.scratchCanvas;

@ -55,6 +56,7 @@ function renderPage(
        viewport: pdfPage.getViewport({ scale: 1, rotation: size.rotation }),
        intent: "print",
        annotationStorage: pdfDocument.annotationStorage,
+        optionalContentConfigPromise,
      };
      return pdfPage.render(renderContext).promise;
    })
@ -71,12 +73,15 @@ function PDFPrintService(
  pagesOverview,
  printContainer,
  printResolution,
+  optionalContentConfigPromise = null,
  l10n
 ) {
  this.pdfDocument = pdfDocument;
  this.pagesOverview = pagesOverview;
  this.printContainer = printContainer;
  this._printResolution = printResolution || 150;
+  this._optionalContentConfigPromise =
+    optionalContentConfigPromise || pdfDocument.getOptionalContentConfig();
  this.l10n = l10n || NullL10n;
  this.currentPage = -1;
  // The temporary canvas where renderPage paints one page at a time.
@ -170,7 +175,8 @@ PDFPrintService.prototype = {
        this.pdfDocument,
        /* pageNumber = */ index + 1,
        this.pagesOverview[index],
-        this._printResolution
+        this._printResolution,
+        this._optionalContentConfigPromise
      )
        .then(this.useRenderedPage.bind(this))
        .then(function () {
@ -372,6 +378,7 @@ PDFPrintServiceFactory.instance = {
    pagesOverview,
    printContainer,
    printResolution,
+    optionalContentConfigPromise,
    l10n
  ) {
    if (activeService) {
@ -382,6 +389,7 @@ PDFPrintServiceFactory.instance = {
      pagesOverview,
      printContainer,
      printResolution,
+      optionalContentConfigPromise,
      l10n
    );
    return activeService;
--- a/web/pdf_sidebar.js
+++ b/web/pdf_sidebar.js
@ -52,12 +52,16 @@ const SidebarView = {
 *   the outline view.
 * @property {HTMLButtonElement} attachmentsButton - The button used to show
 *   the attachments view.
+ * @property {HTMLButtonElement} layersButton - The button used to show
+ *   the layers view.
 * @property {HTMLDivElement} thumbnailView - The container in which
 *   the thumbnails are placed.
 * @property {HTMLDivElement} outlineView - The container in which
 *   the outline is placed.
 * @property {HTMLDivElement} attachmentsView - The container in which
 *   the attachments are placed.
+ * @property {HTMLDivElement} layersView - The container in which
+ *   the layers are placed.
 */

 class PDFSidebar {
@ -92,10 +96,12 @@ class PDFSidebar {
    this.thumbnailButton = elements.thumbnailButton;
    this.outlineButton = elements.outlineButton;
    this.attachmentsButton = elements.attachmentsButton;
+    this.layersButton = elements.layersButton;

    this.thumbnailView = elements.thumbnailView;
    this.outlineView = elements.outlineView;
    this.attachmentsView = elements.attachmentsView;
+    this.layersView = elements.layersView;

    this.eventBus = eventBus;
    this.l10n = l10n;
@ -112,6 +118,7 @@ class PDFSidebar {

    this.outlineButton.disabled = false;
    this.attachmentsButton.disabled = false;
+    this.layersButton.disabled = false;
  }

  /**
@ -133,6 +140,10 @@ class PDFSidebar {
    return this.isOpen && this.active === SidebarView.ATTACHMENTS;
  }

+  get isLayersViewVisible() {
+    return this.isOpen && this.active === SidebarView.LAYERS;
+  }
+
  /**
   * @param {number} view - The sidebar view that should become visible,
   *                        must be one of the values in {SidebarView}.
@ -196,6 +207,11 @@ class PDFSidebar {
          return false;
        }
        break;
+      case SidebarView.LAYERS:
+        if (this.layersButton.disabled) {
+          return false;
+        }
+        break;
      default:
        console.error(`PDFSidebar._switchView: "${view}" is not a valid view.`);
        return false;
@ -217,6 +233,7 @@ class PDFSidebar {
      "toggled",
      view === SidebarView.ATTACHMENTS
    );
+    this.layersButton.classList.toggle("toggled", view === SidebarView.LAYERS);
    // ... and for all views.
    this.thumbnailView.classList.toggle("hidden", view !== SidebarView.THUMBS);
    this.outlineView.classList.toggle("hidden", view !== SidebarView.OUTLINE);
@ -224,6 +241,7 @@ class PDFSidebar {
      "hidden",
      view !== SidebarView.ATTACHMENTS
    );
+    this.layersView.classList.toggle("hidden", view !== SidebarView.LAYERS);

    if (forceOpen && !this.isOpen) {
      this.open();
@ -331,9 +349,9 @@ class PDFSidebar {

    this.l10n
      .get(
-        "toggle_sidebar_notification.title",
+        "toggle_sidebar_notification2.title",
        null,
-        "Toggle Sidebar (document contains outline/attachments)"
+        "Toggle Sidebar (document contains outline/attachments/layers)"
      )
      .then(msg => {
        this.toggleButton.title = msg;
@ -356,6 +374,9 @@ class PDFSidebar {
      case SidebarView.ATTACHMENTS:
        this.attachmentsButton.classList.add(UI_NOTIFICATION_CLASS);
        break;
+      case SidebarView.LAYERS:
+        this.layersButton.classList.add(UI_NOTIFICATION_CLASS);
+        break;
    }
  }

@ -375,6 +396,9 @@ class PDFSidebar {
        case SidebarView.ATTACHMENTS:
          this.attachmentsButton.classList.remove(UI_NOTIFICATION_CLASS);
          break;
+        case SidebarView.LAYERS:
+          this.layersButton.classList.remove(UI_NOTIFICATION_CLASS);
+          break;
      }
    };

@ -429,6 +453,13 @@ class PDFSidebar {
      this.switchView(SidebarView.ATTACHMENTS);
    });

+    this.layersButton.addEventListener("click", () => {
+      this.switchView(SidebarView.LAYERS);
+    });
+    this.layersButton.addEventListener("dblclick", () => {
+      this.eventBus.dispatch("resetlayers", { source: this });
+    });
+
    // Disable/enable views.
    const onTreeLoaded = (count, button, view) => {
      button.disabled = !count;
@ -454,6 +485,10 @@ class PDFSidebar {
      );
    });

+    this.eventBus._on("layersloaded", evt => {
+      onTreeLoaded(evt.layersCount, this.layersButton, SidebarView.LAYERS);
+    });
+
    // Update the thumbnailViewer, if visible, when exiting presentation mode.
    this.eventBus._on("presentationmodechanged", evt => {
      if (!evt.active && !evt.switchInProgress && this.isThumbnailViewVisible) {
--- a/web/pdf_thumbnail_view.js
+++ b/web/pdf_thumbnail_view.js
@ -29,8 +29,12 @@ const THUMBNAIL_WIDTH = 98; // px
 * @property {HTMLDivElement} container - The viewer element.
 * @property {number} id - The thumbnail's unique ID (normally its number).
 * @property {PageViewport} defaultViewport - The page viewport.
+ * @property {Promise<OptionalContentConfig>} [optionalContentConfigPromise] -
+ *   A promise that is resolved with an {@link OptionalContentConfig} instance.
+ *   The default value is `null`.
 * @property {IPDFLinkService} linkService - The navigation/linking service.
 * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
+ * @property {function} checkSetImageDisabled
 * @property {boolean} [disableCanvasToImageConversion] - Don't convert the
 *   canvas thumbnails to images. This prevents `toDataURL` calls, but
 *   increases the overall memory usage. The default value is `false`.
@ -91,8 +95,10 @@ class PDFThumbnailView {
    container,
    id,
    defaultViewport,
+    optionalContentConfigPromise,
    linkService,
    renderingQueue,
+    checkSetImageDisabled,
    disableCanvasToImageConversion = false,
    l10n = NullL10n,
  }) {
@ -104,6 +110,7 @@ class PDFThumbnailView {
    this.rotation = 0;
    this.viewport = defaultViewport;
    this.pdfPageRotate = defaultViewport.rotation;
+    this._optionalContentConfigPromise = optionalContentConfigPromise || null;

    this.linkService = linkService;
    this.renderingQueue = renderingQueue;
@ -111,6 +118,11 @@ class PDFThumbnailView {
    this.renderTask = null;
    this.renderingState = RenderingStates.INITIAL;
    this.resume = null;
+    this._checkSetImageDisabled =
+      checkSetImageDisabled ||
+      function () {
+        return false;
+      };
    this.disableCanvasToImageConversion = disableCanvasToImageConversion;

    this.pageWidth = this.viewport.width;
@ -345,6 +357,7 @@ class PDFThumbnailView {
    const renderContext = {
      canvasContext: ctx,
      viewport: drawViewport,
+      optionalContentConfigPromise: this._optionalContentConfigPromise,
    };
    const renderTask = (this.renderTask = pdfPage.render(renderContext));
    renderTask.onContinue = renderContinueCallback;
@ -361,6 +374,9 @@ class PDFThumbnailView {
  }

  setImage(pageView) {
+    if (this._checkSetImageDisabled()) {
+      return;
+    }
    if (this.renderingState !== RenderingStates.INITIAL) {
      return;
    }
--- a/web/pdf_thumbnail_viewer.js
+++ b/web/pdf_thumbnail_viewer.js
@ -29,6 +29,7 @@ const THUMBNAIL_SELECTED_CLASS = "selected";
 * @typedef {Object} PDFThumbnailViewerOptions
 * @property {HTMLDivElement} container - The container for the thumbnail
 *   elements.
+ * @property {EventBus} eventBus - The application event bus.
 * @property {IPDFLinkService} linkService - The navigation/linking service.
 * @property {PDFRenderingQueue} renderingQueue - The rendering queue object.
 * @property {IL10n} l10n - Localization service.
@ -43,7 +44,13 @@ class PDFThumbnailViewer {
  /**
   * @param {PDFThumbnailViewerOptions} options
   */
-  constructor({ container, linkService, renderingQueue, l10n = NullL10n }) {
+  constructor({
+    container,
+    eventBus,
+    linkService,
+    renderingQueue,
+    l10n = NullL10n,
+  }) {
    this.container = container;
    this.linkService = linkService;
    this.renderingQueue = renderingQueue;
@ -51,6 +58,12 @@ class PDFThumbnailViewer {

    this.scroll = watchScroll(this.container, this._scrollUpdated.bind(this));
    this._resetView();
+
+    eventBus._on("optionalcontentconfigchanged", () => {
+      // Ensure that the thumbnails always render with the *default* optional
+      // content configuration.
+      this._setImageDisabled = true;
+    });
  }

  /**
@ -151,7 +164,9 @@ class PDFThumbnailViewer {
    this._currentPageNumber = 1;
    this._pageLabels = null;
    this._pagesRotation = 0;
+    this._optionalContentConfigPromise = null;
    this._pagesRequests = new WeakMap();
+    this._setImageDisabled = false;

    // Remove the thumbnails from the DOM.
    this.container.textContent = "";
@ -167,19 +182,28 @@ class PDFThumbnailViewer {
    if (!pdfDocument) {
      return;
    }
+    const firstPagePromise = pdfDocument.getPage(1);
+    const optionalContentConfigPromise = pdfDocument.getOptionalContentConfig();

-    pdfDocument
-      .getPage(1)
+    firstPagePromise
      .then(firstPdfPage => {
+        this._optionalContentConfigPromise = optionalContentConfigPromise;
+
        const pagesCount = pdfDocument.numPages;
        const viewport = firstPdfPage.getViewport({ scale: 1 });
+        const checkSetImageDisabled = () => {
+          return this._setImageDisabled;
+        };
+
        for (let pageNum = 1; pageNum <= pagesCount; ++pageNum) {
          const thumbnail = new PDFThumbnailView({
            container: this.container,
            id: pageNum,
            defaultViewport: viewport.clone(),
+            optionalContentConfigPromise,
            linkService: this.linkService,
            renderingQueue: this.renderingQueue,
+            checkSetImageDisabled,
            disableCanvasToImageConversion: false,
            l10n: this.l10n,
          });
--- a/web/viewer.css
+++ b/web/viewer.css
@ -73,6 +73,7 @@
  --toolbarButton-viewThumbnail-icon: url(images/toolbarButton-viewThumbnail.svg);
  --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-search-icon: url(images/toolbarButton-search.svg);
  --findbarButton-previous-icon: url(images/findbarButton-previous.svg);
  --findbarButton-next-icon: url(images/findbarButton-next.svg);
@ -143,6 +144,7 @@
    --toolbarButton-viewThumbnail-icon: url(images/toolbarButton-viewThumbnail-dark.svg);
    --toolbarButton-viewOutline-icon: url(images/toolbarButton-viewOutline-dark.svg);
    --toolbarButton-viewAttachments-icon: url(images/toolbarButton-viewAttachments-dark.svg);
+    --toolbarButton-viewLayers-icon: url(images/toolbarButton-viewLayers-dark.svg);
    --toolbarButton-search-icon: url(images/toolbarButton-search-dark.svg);
    --findbarButton-previous-icon: url(images/findbarButton-previous-dark.svg);
    --findbarButton-next-icon: url(images/findbarButton-next-dark.svg);
@ -1066,6 +1068,10 @@ html[dir="rtl"] #viewOutline.toolbarButton::before {
  content: var(--toolbarButton-viewAttachments-icon);
 }

+#viewLayers.toolbarButton::before {
+  content: var(--toolbarButton-viewLayers-icon);
+}
+
 #viewFind.toolbarButton::before {
  content: var(--toolbarButton-search-icon);
 }
@ -1339,7 +1345,8 @@ a:focus > .thumbnail > .thumbnailSelectionRing,
 }

 #outlineView,
-#attachmentsView {
+#attachmentsView,
+#layersView {
  position: absolute;
  width: calc(100% - 8px);
  top: 0;
@ -1383,6 +1390,16 @@ html[dir='rtl'] .treeItem > a {
  padding: 2px 4px 5px 0;
 }

+#layersView .treeItem > a > * {
+  cursor: pointer;
+}
+html[dir='ltr'] #layersView .treeItem > a > label {
+  padding-left: 4px;
+}
+html[dir='rtl'] #layersView .treesItem > a > label {
+  padding-right: 4px;
+}
+
 .treeItemToggler {
  position: relative;
  height: 0;
--- a/web/viewer.html
+++ b/web/viewer.html
@ -86,6 +86,9 @@ See https://github.com/adobe-type-tools/cmap-resources
            <button id="viewAttachments" class="toolbarButton" title="Show Attachments" tabindex="4" data-l10n-id="attachments">
               <span data-l10n-id="attachments_label">Attachments</span>
            </button>
+            <button id="viewLayers" class="toolbarButton" title="Show Layers (double-click to reset all layers to the default state)" tabindex="5" data-l10n-id="layers">
+               <span data-l10n-id="layers_label">Layers</span>
+            </button>
          </div>
        </div>
        <div id="sidebarContent">
@ -95,6 +98,8 @@ See https://github.com/adobe-type-tools/cmap-resources
          </div>
          <div id="attachmentsView" class="hidden">
          </div>
+          <div id="layersView" class="hidden">
+          </div>
        </div>
        <div id="sidebarResizer" class="hidden"></div>
      </div>  <!-- sidebarContainer -->
--- a/web/viewer.js
+++ b/web/viewer.js
@ -121,10 +121,12 @@ function getViewerConfiguration() {
      thumbnailButton: document.getElementById("viewThumbnail"),
      outlineButton: document.getElementById("viewOutline"),
      attachmentsButton: document.getElementById("viewAttachments"),
+      layersButton: document.getElementById("viewLayers"),
      // Views
      thumbnailView: document.getElementById("thumbnailView"),
      outlineView: document.getElementById("outlineView"),
      attachmentsView: document.getElementById("attachmentsView"),
+      layersView: document.getElementById("layersView"),
    },
    sidebarResizer: {
      outerContainer: document.getElementById("outerContainer"),
				`@ -0,0 +1 @@`
				<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 4.233 4.233" height="16" width="16" fill="rgba(255,255,255,1)"><path d="M.15 2.992c-.198.1-.2.266-.002.365l1.604.802a.93.93 0 00.729-.001l1.602-.801c.198-.1.197-.264 0-.364l-.695-.348c-1.306.595-2.542 0-2.542 0m-.264.53l.658-.329c.6.252 1.238.244 1.754 0l.659.329-1.536.768zM.15 1.935c-.198.1-.198.265 0 .364l1.604.802a.926.926 0 00.727 0l1.603-.802c.198-.099.198-.264 0-.363l-.694-.35c-1.14.56-2.546.001-2.546.001m-.264.53l.664-.332c.52.266 1.261.235 1.75.002l.659.33-1.537.768zM.15.877c-.198.099-.198.264 0 .363l1.604.802a.926.926 0 00.727 0l1.603-.802c.198-.099.198-.264 0-.363L2.481.075a.926.926 0 00-.727 0zm.43.182L2.117.29l1.538.769-1.538.768z"/></svg>