Merge pull request #14874 from calixteman/colors

[api-minor] Improve pdf reading in high contrast mode

web/app.js

@@ -525,6 +525,10 @@ const PDFViewerApplication = {
       useOnlyCssZoom: AppOptions.get("useOnlyCssZoom"),
       maxCanvasPixels: AppOptions.get("maxCanvasPixels"),
       enablePermissions: AppOptions.get("enablePermissions"),
+      pageColors: {
+        background: AppOptions.get("pageBackgroundColor"),
+        foreground: AppOptions.get("pageForegroundColor"),
+      },
     });
     pdfRenderingQueue.setViewer(this.pdfViewer);
     pdfLinkService.setViewer(this.pdfViewer);

web/app_options.js

@@ -129,6 +129,16 @@ const defaultOptions = {
     compatibility: compatibilityParams.maxCanvasPixels,
     kind: OptionKind.VIEWER,
   },
+  pageBackgroundColor: {
+    /** @type {string} */
+    value: "Canvas",
+    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
+  },
+  pageForegroundColor: {
+    /** @type {string} */
+    value: "CanvasText",
+    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
+  },
   pdfBugEnabled: {
     /** @type {boolean} */
     value: typeof PDFJSDev === "undefined" || !PDFJSDev.test("PRODUCTION"),

web/base_viewer.js

@@ -116,6 +116,9 @@ const PagesCountLimit = {
  * @property {IL10n} l10n - Localization service.
  * @property {boolean} [enablePermissions] - Enables PDF document permissions,
  *   when they exist. The default value is `false`.
+ * @property {Object} [pageColors] - Overwrites background and foreground colors
+ *   with user defined ones in order to improve readability in high contrast
+ *   mode.
  */
 
 class PDFPageViewBuffer {
@@ -262,6 +265,22 @@ class BaseViewer {
     this.maxCanvasPixels = options.maxCanvasPixels;
     this.l10n = options.l10n || NullL10n;
     this.#enablePermissions = options.enablePermissions || false;
+    this.pageColors = options.pageColors || null;
+
+    if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("MOZCENTRAL")) {
+      if (
+        options.pageColors &&
+        (!CSS.supports("color", options.pageColors.background) ||
+          !CSS.supports("color", options.pageColors.foreground))
+      ) {
+        if (options.pageColors.background || options.pageColors.foreground) {
+          console.warn(
+            "Ignoring `pageColors`-option, since the browser doesn't support the values used."
+          );
+        }
+        this.pageColors = null;
+      }
+    }
 
     this.defaultRenderingQueue = !options.renderingQueue;
     if (this.defaultRenderingQueue) {
@@ -698,6 +717,7 @@ class BaseViewer {
             renderer: this.renderer,
             useOnlyCssZoom: this.useOnlyCssZoom,
             maxCanvasPixels: this.maxCanvasPixels,
+            pageColors: this.pageColors,
             l10n: this.l10n,
           });
           this._pages.push(pageView);

web/pdf_page_view.js

@@ -82,6 +82,9 @@ import { NullL10n } from "./l10n_utils.js";
  * @property {number} [maxCanvasPixels] - The maximum supported canvas size in
  *   total pixels, i.e. width * height. Use -1 for no limit. The default value
  *   is 4096 * 4096 (16 mega-pixels).
+ * @property {Object} [pageColors] - Overwrites background and foreground colors
+ *   with user defined ones in order to improve readability in high contrast
+ *   mode.
  * @property {IL10n} l10n - Localization service.
  */
 
@@ -118,6 +121,7 @@ class PDFPageView {
     this.imageResourcesPath = options.imageResourcesPath || "";
     this.useOnlyCssZoom = options.useOnlyCssZoom || false;
     this.maxCanvasPixels = options.maxCanvasPixels || MAX_CANVAS_PIXELS;
+    this.pageColors = options.pageColors || null;
 
     this.eventBus = options.eventBus;
     this.renderingQueue = options.renderingQueue;
@@ -832,6 +836,7 @@ class PDFPageView {
       annotationMode: this.#annotationMode,
       optionalContentConfigPromise: this._optionalContentConfigPromise,
       annotationCanvasMap: this._annotationCanvasMap,
+      pageColors: this.pageColors,
     };
     const renderTask = this.pdfPage.render(renderContext);
     renderTask.onContinue = function (cont) {