Add an option to enable/disable hardware acceleration (bug 1902012)

extensions/chromium/preferences_schema.json

@@ -45,6 +45,11 @@
       "type": "boolean",
       "default": false
     },
+    "enableHWA": {
+      "description": "Whether to enable hardware acceleration.",
+      "type": "boolean",
+      "default": false
+    },
     "enableML": {
       "type": "boolean",
       "default": false

src/core/default_appearance.js

@@ -242,7 +242,7 @@ class FakeUnicodeFont {
     this.fontFamily = fontFamily;
 
     const canvas = new OffscreenCanvas(1, 1);
-    this.ctxMeasure = canvas.getContext("2d");
+    this.ctxMeasure = canvas.getContext("2d", { willReadFrequently: true });
 
     if (!FakeUnicodeFont._fontNameId) {
       FakeUnicodeFont._fontNameId = 1;

src/display/api.js

@@ -213,6 +213,8 @@ const DefaultStandardFontDataFactory =
  *   when creating canvases. The default value is {new DOMCanvasFactory()}.
  * @property {Object} [filterFactory] - A factory instance that will be used
  *   to create SVG filters when rendering some images on the main canvas.
+ * @property {boolean} [enableHWA] - Enables hardware acceleration for
+ *   rendering. The default value is `false`.
  */
 
 /**
@@ -297,6 +299,7 @@ function getDocument(src) {
   const disableStream = src.disableStream === true;
   const disableAutoFetch = src.disableAutoFetch === true;
   const pdfBug = src.pdfBug === true;
+  const enableHWA = src.enableHWA === true;
 
   // Parameters whose default values depend on other parameters.
   const length = rangeTransport ? rangeTransport.length : src.length ?? NaN;
@@ -315,7 +318,7 @@ function getDocument(src) {
           isValidFetchUrl(cMapUrl, document.baseURI) &&
           isValidFetchUrl(standardFontDataUrl, document.baseURI));
   const canvasFactory =
-    src.canvasFactory || new DefaultCanvasFactory({ ownerDocument });
+    src.canvasFactory || new DefaultCanvasFactory({ ownerDocument, enableHWA });
   const filterFactory =
     src.filterFactory || new DefaultFilterFactory({ docId, ownerDocument });
 

src/display/base_factory.js

@@ -46,10 +46,13 @@ class BaseFilterFactory {
 }
 
 class BaseCanvasFactory {
-  constructor() {
+  #enableHWA = false;
+
+  constructor({ enableHWA = false }) {
     if (this.constructor === BaseCanvasFactory) {
       unreachable("Cannot initialize BaseCanvasFactory.");
     }
+    this.#enableHWA = enableHWA;
   }
 
   create(width, height) {
@@ -59,7 +62,9 @@ class BaseCanvasFactory {
     const canvas = this._createCanvas(width, height);
     return {
       canvas,
-      context: canvas.getContext("2d"),
+      context: canvas.getContext("2d", {
+        willReadFrequently: !this.#enableHWA,
+      }),
     };
   }
 

src/display/display_utils.js

@@ -477,8 +477,8 @@ class DOMFilterFactory extends BaseFilterFactory {
 }
 
 class DOMCanvasFactory extends BaseCanvasFactory {
-  constructor({ ownerDocument = globalThis.document } = {}) {
-    super();
+  constructor({ ownerDocument = globalThis.document, enableHWA = false } = {}) {
+    super({ enableHWA });
     this._document = ownerDocument;
   }
 

src/display/editor/tools.js

@@ -98,7 +98,7 @@ class ImageManager {
     // behavior in Safari.
     const svg = `data:image/svg+xml;charset=UTF-8,<svg viewBox="0 0 1 1" width="1" height="1" xmlns="http://www.w3.org/2000/svg"><rect width="1" height="1" style="fill:red;"/></svg>`;
     const canvas = new OffscreenCanvas(1, 3);
-    const ctx = canvas.getContext("2d");
+    const ctx = canvas.getContext("2d", { willReadFrequently: true });
     const image = new Image();
     image.src = svg;
     const promise = image.decode().then(() => {

src/display/text_layer.js

@@ -447,7 +447,10 @@ class TextLayer {
       canvas.className = "hiddenCanvasElement";
       canvas.lang = lang;
       document.body.append(canvas);
-      canvasContext = canvas.getContext("2d", { alpha: false });
+      canvasContext = canvas.getContext("2d", {
+        alpha: false,
+        willReadFrequently: true,
+      });
       this.#canvasContexts.set(lang, canvasContext);
     }
     return canvasContext;

web/app.js

@@ -439,6 +439,7 @@ const PDFViewerApplication = {
         )
       : null;
 
+    const enableHWA = AppOptions.get("enableHWA");
     const pdfViewer = new PDFViewer({
       container,
       viewer,
@@ -465,6 +466,7 @@ const PDFViewerApplication = {
       pageColors,
       mlManager: this.mlManager,
       abortSignal: this._globalAbortController.signal,
+      enableHWA,
     });
     this.pdfViewer = pdfViewer;
 
@@ -480,6 +482,7 @@ const PDFViewerApplication = {
         linkService: pdfLinkService,
         pageColors,
         abortSignal: this._globalAbortController.signal,
+        enableHWA,
       });
       pdfRenderingQueue.setThumbnailViewer(this.pdfThumbnailViewer);
     }

web/app_options.js

@@ -310,6 +310,11 @@ const defaultOptions = {
     value: "",
     kind: OptionKind.API,
   },
+  enableHWA: {
+    /** @type {boolean} */
+    value: false,
+    kind: OptionKind.API + OptionKind.VIEWER + OptionKind.PREFERENCE,
+  },
   enableXfa: {
     /** @type {boolean} */
     value: true,

web/pdf_page_view.js

@@ -81,6 +81,8 @@ import { XfaLayerBuilder } from "./xfa_layer_builder.js";
  * @property {IL10n} [l10n] - Localization service.
  * @property {Object} [layerProperties] - The object that is used to lookup
  *   the necessary layer-properties.
+ * @property {boolean} [enableHWA] - Enables hardware acceleration for
+ *   rendering. The default value is `false`.
  */
 
 const DEFAULT_LAYER_PROPERTIES =
@@ -113,6 +115,8 @@ const LAYERS_ORDER = new Map([
 class PDFPageView {
   #annotationMode = AnnotationMode.ENABLE_FORMS;
 
+  #enableHWA = false;
+
   #hasRestrictedScaling = false;
 
   #layerProperties = null;
@@ -163,6 +167,7 @@ class PDFPageView {
     this.maxCanvasPixels =
       options.maxCanvasPixels ?? AppOptions.get("maxCanvasPixels");
     this.pageColors = options.pageColors || null;
+    this.#enableHWA = options.enableHWA || false;
 
     this.eventBus = options.eventBus;
     this.renderingQueue = options.renderingQueue;
@@ -981,7 +986,10 @@ class PDFPageView {
     canvasWrapper.append(canvas);
     this.canvas = canvas;
 
-    const ctx = canvas.getContext("2d", { alpha: false });
+    const ctx = canvas.getContext("2d", {
+      alpha: false,
+      willReadFrequently: !this.#enableHWA,
+    });
     const outputScale = (this.outputScale = new OutputScale());
 
     if (

web/pdf_thumbnail_view.js

@@ -44,6 +44,8 @@ const THUMBNAIL_WIDTH = 98; // px
  * @property {Object} [pageColors] - Overwrites background and foreground colors
  *   with user defined ones in order to improve readability in high contrast
  *   mode.
+ * @property {boolean} [enableHWA] - Enables hardware acceleration for
+ *   rendering. The default value is `false`.
  */
 
 class TempImageFactory {
@@ -92,6 +94,7 @@ class PDFThumbnailView {
     linkService,
     renderingQueue,
     pageColors,
+    enableHWA,
   }) {
     this.id = id;
     this.renderingId = "thumbnail" + id;
@@ -103,6 +106,7 @@ class PDFThumbnailView {
     this.pdfPageRotate = defaultViewport.rotation;
     this._optionalContentConfigPromise = optionalContentConfigPromise || null;
     this.pageColors = pageColors || null;
+    this.enableHWA = enableHWA || false;
 
     this.eventBus = eventBus;
     this.linkService = linkService;
@@ -196,11 +200,14 @@ class PDFThumbnailView {
     this.resume = null;
   }
 
-  #getPageDrawContext(upscaleFactor = 1) {
+  #getPageDrawContext(upscaleFactor = 1, enableHWA = this.enableHWA) {
     // Keep the no-thumbnail outline visible, i.e. `data-loaded === false`,
     // until rendering/image conversion is complete, to avoid display issues.
     const canvas = document.createElement("canvas");
-    const ctx = canvas.getContext("2d", { alpha: false });
+    const ctx = canvas.getContext("2d", {
+      alpha: false,
+      willReadFrequently: !enableHWA,
+    });
     const outputScale = new OutputScale();
 
     canvas.width = (upscaleFactor * this.canvasWidth * outputScale.sx) | 0;
@@ -340,7 +347,7 @@ class PDFThumbnailView {
   }
 
   #reduceImage(img) {
-    const { ctx, canvas } = this.#getPageDrawContext();
+    const { ctx, canvas } = this.#getPageDrawContext(1, true);
 
     if (img.width <= 2 * canvas.width) {
       ctx.drawImage(

web/pdf_thumbnail_viewer.js

@@ -44,6 +44,8 @@ const THUMBNAIL_SELECTED_CLASS = "selected";
  *   mode.
  * @property {AbortSignal} [abortSignal] - The AbortSignal for the window
  *   events.
+ * @property {boolean} [enableHWA] - Enables hardware acceleration for
+ *   rendering. The default value is `false`.
  */
 
 /**
@@ -60,12 +62,14 @@ class PDFThumbnailViewer {
     renderingQueue,
     pageColors,
     abortSignal,
+    enableHWA,
   }) {
     this.container = container;
     this.eventBus = eventBus;
     this.linkService = linkService;
     this.renderingQueue = renderingQueue;
     this.pageColors = pageColors || null;
+    this.enableHWA = enableHWA || false;
 
     this.scroll = watchScroll(
       this.container,
@@ -206,6 +210,7 @@ class PDFThumbnailViewer {
             linkService: this.linkService,
             renderingQueue: this.renderingQueue,
             pageColors: this.pageColors,
+            enableHWA: this.enableHWA,
           });
           this._thumbnails.push(thumbnail);
         }

web/pdf_viewer.js

@@ -123,6 +123,8 @@ function isValidAnnotationEditorMode(mode) {
  * @property {Object} [pageColors] - Overwrites background and foreground colors
  *   with user defined ones in order to improve readability in high contrast
  *   mode.
+ * @property {boolean} [enableHWA] - Enables hardware acceleration for
+ *   rendering. The default value is `false`.
  */
 
 class PDFPageViewBuffer {
@@ -211,6 +213,8 @@ class PDFViewer {
 
   #containerTopLeft = null;
 
+  #enableHWA = false;
+
   #enableHighlightFloatingButton = false;
 
   #enablePermissions = false;
@@ -296,6 +300,7 @@ class PDFViewer {
     this.#enablePermissions = options.enablePermissions || false;
     this.pageColors = options.pageColors || null;
     this.#mlManager = options.mlManager || null;
+    this.#enableHWA = options.enableHWA || false;
 
     this.defaultRenderingQueue = !options.renderingQueue;
     if (
@@ -943,6 +948,7 @@ class PDFViewer {
             pageColors,
             l10n: this.l10n,
             layerProperties: this._layerProperties,
+            enableHWA: this.#enableHWA,
           });
           this._pages.push(pageView);
         }