Merge pull request #14765 from Snuffleupagus/requestFullscreen-Promise

Simplify handling of `requestFullscreen` errors in `PDFPresentationMode`

web/pdf_presentation_mode.js

@@ -20,7 +20,6 @@ import {
   SpreadMode,
 } from "./ui_utils.js";
 
-const DELAY_BEFORE_RESETTING_SWITCH_IN_PROGRESS = 1500; // in ms
 const DELAY_BEFORE_HIDING_CONTROLS = 3000; // in ms
 const ACTIVE_SELECTOR = "pdfPresentationMode";
 const CONTROLS_SELECTOR = "pdfPresentationModeControls";
@@ -42,6 +41,10 @@ const SWIPE_ANGLE_THRESHOLD = Math.PI / 6;
  */
 
 class PDFPresentationMode {
+  #state = PresentationModeState.UNKNOWN;
+
+  #args = null;
+
   /**
    * @param {PDFPresentationModeOptions} options
    */
@@ -50,8 +53,6 @@ class PDFPresentationMode {
     this.pdfViewer = pdfViewer;
     this.eventBus = eventBus;
 
-    this.active = false;
-    this.args = null;
     this.contextMenuOpen = false;
     this.mouseScrollTimeStamp = 0;
     this.mouseScrollDelta = 0;
@@ -60,37 +61,47 @@ class PDFPresentationMode {
 
   /**
    * Request the browser to enter fullscreen mode.
-   * @returns {boolean} Indicating if the request was successful.
+   * @returns {Promise<boolean>} Indicating if the request was successful.
    */
-  request() {
+  async request() {
-    if (
+    const { container, pdfViewer } = this;
-      this.switchInProgress ||
+
-      this.active ||
+    if (this.active || !pdfViewer.pagesCount || !container.requestFullscreen) {
-      !this.pdfViewer.pagesCount ||
-      !this.container.requestFullscreen
-    ) {
       return false;
     }
     this.#addFullscreenChangeListeners();
-    this.#setSwitchInProgress();
+    this.#notifyStateChange(PresentationModeState.CHANGING);
-    this.#notifyStateChange();
 
-    this.container.requestFullscreen();
+    const promise = container.requestFullscreen();
 
-    this.args = {
+    this.#args = {
-      pageNumber: this.pdfViewer.currentPageNumber,
+      pageNumber: pdfViewer.currentPageNumber,
-      scaleValue: this.pdfViewer.currentScaleValue,
+      scaleValue: pdfViewer.currentScaleValue,
-      scrollMode: this.pdfViewer.scrollMode,
+      scrollMode: pdfViewer.scrollMode,
-      spreadMode: this.pdfViewer.spreadMode,
+      spreadMode: pdfViewer.spreadMode,
     };
-    return true;
+
+    try {
+      await promise;
+      return true;
+    } catch (reason) {
+      this.#removeFullscreenChangeListeners();
+      this.#notifyStateChange(PresentationModeState.NORMAL);
+    }
+    return false;
+  }
+
+  get active() {
+    return (
+      this.#state === PresentationModeState.CHANGING ||
+      this.#state === PresentationModeState.FULLSCREEN
+    );
   }
 
   #mouseWheel(evt) {
     if (!this.active) {
       return;
     }
-
     evt.preventDefault();
 
     const delta = normalizeWheelEventDelta(evt);
@@ -126,48 +137,14 @@ class PDFPresentationMode {
     }
   }
 
-  #notifyStateChange() {
+  #notifyStateChange(state) {
-    let state = PresentationModeState.NORMAL;
+    this.#state = state;
-    if (this.switchInProgress) {
-      state = PresentationModeState.CHANGING;
-    } else if (this.active) {
-      state = PresentationModeState.FULLSCREEN;
-    }
-    this.eventBus.dispatch("presentationmodechanged", {
-      source: this,
-      state,
-    });
-  }
 
-  /**
+    this.eventBus.dispatch("presentationmodechanged", { source: this, state });
-   * Used to initialize a timeout when requesting Presentation Mode,
-   * i.e. when the browser is requested to enter fullscreen mode.
-   * This timeout is used to prevent the current page from being scrolled
-   * partially, or completely, out of view when entering Presentation Mode.
-   * NOTE: This issue seems limited to certain zoom levels (e.g. page-width).
-   */
-  #setSwitchInProgress() {
-    if (this.switchInProgress) {
-      clearTimeout(this.switchInProgress);
-    }
-    this.switchInProgress = setTimeout(() => {
-      this.#removeFullscreenChangeListeners();
-      delete this.switchInProgress;
-      this.#notifyStateChange();
-    }, DELAY_BEFORE_RESETTING_SWITCH_IN_PROGRESS);
-  }
-
-  #resetSwitchInProgress() {
-    if (this.switchInProgress) {
-      clearTimeout(this.switchInProgress);
-      delete this.switchInProgress;
-    }
   }
 
   #enter() {
-    this.active = true;
+    this.#notifyStateChange(PresentationModeState.FULLSCREEN);
-    this.#resetSwitchInProgress();
-    this.#notifyStateChange();
     this.container.classList.add(ACTIVE_SELECTOR);
 
     // Ensure that the correct page is scrolled into view when entering
@@ -175,7 +152,7 @@ class PDFPresentationMode {
     setTimeout(() => {
       this.pdfViewer.scrollMode = ScrollMode.PAGE;
       this.pdfViewer.spreadMode = SpreadMode.NONE;
-      this.pdfViewer.currentPageNumber = this.args.pageNumber;
+      this.pdfViewer.currentPageNumber = this.#args.pageNumber;
       this.pdfViewer.currentScaleValue = "page-fit";
     }, 0);
 
@@ -196,15 +173,14 @@ class PDFPresentationMode {
     // Ensure that the correct page is scrolled into view when exiting
     // Presentation Mode, by waiting until fullscreen mode is disabled.
     setTimeout(() => {
-      this.active = false;
       this.#removeFullscreenChangeListeners();
-      this.#notifyStateChange();
+      this.#notifyStateChange(PresentationModeState.NORMAL);
 
-      this.pdfViewer.scrollMode = this.args.scrollMode;
+      this.pdfViewer.scrollMode = this.#args.scrollMode;
-      this.pdfViewer.spreadMode = this.args.spreadMode;
+      this.pdfViewer.spreadMode = this.#args.spreadMode;
-      this.pdfViewer.currentScaleValue = this.args.scaleValue;
+      this.pdfViewer.currentScaleValue = this.#args.scaleValue;
       this.pdfViewer.currentPageNumber = pageNumber;
-      this.args = null;
+      this.#args = null;
     }, 0);
 
     this.#removeWindowListeners();