Enable automatic URL linking

Automatically detect links in the text content of a file and automatically
generate link annotations at the appropriate locations to achieve
automatic link detection and hyperlinking.

web/annotation_layer_builder.js

@@ -27,7 +27,12 @@
 // eslint-disable-next-line max-len
 /** @typedef {import("../src/display/editor/tools.js").AnnotationEditorUIManager} AnnotationEditorUIManager */
 
-import { AnnotationLayer } from "pdfjs-lib";
+import {
+  AnnotationLayer,
+  AnnotationType,
+  setLayerDimensions,
+  Util,
+} from "pdfjs-lib";
 import { PresentationModeState } from "./ui_utils.js";
 
 /**
@@ -56,7 +61,18 @@ import { PresentationModeState } from "./ui_utils.js";
  * @property {StructTreeLayerBuilder} [structTreeLayer]
  */
 
+/**
+ * @typedef {Object} InjectLinkAnnotationsOptions
+ * @property {Array<Object>} inferredLinks
+ * @property {PageViewport} viewport
+ * @property {StructTreeLayerBuilder} [structTreeLayer]
+ */
+
 class AnnotationLayerBuilder {
+  #annotations = null;
+
+  #externalHide = false;
+
   #onAppend = null;
 
   #eventAbortController = null;
@@ -133,19 +149,13 @@ class AnnotationLayerBuilder {
     this.#onAppend?.(div);
 
     if (annotations.length === 0) {
-      this.hide();
+      this.#annotations = annotations;
+
+      this.hide(/* internal = */ true);
       return;
     }
 
-    this.annotationLayer = new AnnotationLayer({
-      div,
-      accessibilityManager: this._accessibilityManager,
-      annotationCanvasMap: this._annotationCanvasMap,
-      annotationEditorUIManager: this._annotationEditorUIManager,
-      page: this.pdfPage,
-      viewport: viewport.clone({ dontFlip: true }),
-      structTreeLayer,
-    });
+    this.#initAnnotationLayer(viewport, structTreeLayer);
 
     await this.annotationLayer.render({
       annotations,
@@ -159,6 +169,8 @@ class AnnotationLayerBuilder {
       fieldObjects,
     });
 
+    this.#annotations = annotations;
+
     // Ensure that interactive form elements in the annotationLayer are
     // disabled while PresentationMode is active (see issue 12232).
     if (this.linkService.isInPresentationMode) {
@@ -177,6 +189,18 @@ class AnnotationLayerBuilder {
     }
   }
 
+  #initAnnotationLayer(viewport, structTreeLayer) {
+    this.annotationLayer = new AnnotationLayer({
+      div: this.div,
+      accessibilityManager: this._accessibilityManager,
+      annotationCanvasMap: this._annotationCanvasMap,
+      annotationEditorUIManager: this._annotationEditorUIManager,
+      page: this.pdfPage,
+      viewport: viewport.clone({ dontFlip: true }),
+      structTreeLayer,
+    });
+  }
+
   cancel() {
     this._cancelled = true;
 
@@ -184,7 +208,8 @@ class AnnotationLayerBuilder {
     this.#eventAbortController = null;
   }
 
-  hide() {
+  hide(internal = false) {
+    this.#externalHide = !internal;
     if (!this.div) {
       return;
     }
@@ -195,6 +220,45 @@ class AnnotationLayerBuilder {
     return !!this.annotationLayer?.hasEditableAnnotations();
   }
 
+  /**
+   * @param {InjectLinkAnnotationsOptions} options
+   * @returns {Promise<void>} A promise that is resolved when the inferred links
+   *   are added to the annotation layer.
+   */
+  async injectLinkAnnotations({
+    inferredLinks,
+    viewport,
+    structTreeLayer = null,
+  }) {
+    if (this.#annotations === null) {
+      throw new Error(
+        "`render` method must be called before `injectLinkAnnotations`."
+      );
+    }
+    if (this._cancelled) {
+      return;
+    }
+
+    const newLinks = this.#annotations.length
+      ? this.#checkInferredLinks(inferredLinks)
+      : inferredLinks;
+
+    if (!newLinks.length) {
+      return;
+    }
+
+    if (!this.annotationLayer) {
+      this.#initAnnotationLayer(viewport, structTreeLayer);
+      setLayerDimensions(this.div, viewport);
+    }
+
+    await this.annotationLayer.addLinkAnnotations(newLinks, this.linkService);
+    // Don't show the annotation layer if it was explicitly hidden previously.
+    if (!this.#externalHide) {
+      this.div.hidden = false;
+    }
+  }
+
   #updatePresentationModeState(state) {
     if (!this.div) {
       return;
@@ -217,6 +281,75 @@ class AnnotationLayerBuilder {
       section.inert = disableFormElements;
     }
   }
+
+  #checkInferredLinks(inferredLinks) {
+    function annotationRects(annot) {
+      if (!annot.quadPoints) {
+        return [annot.rect];
+      }
+      const rects = [];
+      for (let i = 2, ii = annot.quadPoints.length; i < ii; i += 8) {
+        const trX = annot.quadPoints[i];
+        const trY = annot.quadPoints[i + 1];
+        const blX = annot.quadPoints[i + 2];
+        const blY = annot.quadPoints[i + 3];
+        rects.push([blX, blY, trX, trY]);
+      }
+      return rects;
+    }
+
+    function intersectAnnotations(annot1, annot2) {
+      const intersections = [];
+      const annot1Rects = annotationRects(annot1);
+      const annot2Rects = annotationRects(annot2);
+      for (const rect1 of annot1Rects) {
+        for (const rect2 of annot2Rects) {
+          const intersection = Util.intersect(rect1, rect2);
+          if (intersection) {
+            intersections.push(intersection);
+          }
+        }
+      }
+      return intersections;
+    }
+
+    function areaRects(rects) {
+      let totalArea = 0;
+      for (const rect of rects) {
+        totalArea += Math.abs((rect[2] - rect[0]) * (rect[3] - rect[1]));
+      }
+      return totalArea;
+    }
+
+    return inferredLinks.filter(link => {
+      let linkAreaRects;
+
+      for (const annotation of this.#annotations) {
+        if (
+          annotation.annotationType !== AnnotationType.LINK ||
+          annotation.url !== link.url
+        ) {
+          continue;
+        }
+        // TODO: Add a test case to verify that we can find the intersection
+        //       between two annotations with quadPoints properly.
+        const intersections = intersectAnnotations(annotation, link);
+
+        if (intersections.length === 0) {
+          continue;
+        }
+        linkAreaRects ??= areaRects(annotationRects(link));
+
+        if (
+          areaRects(intersections) / linkAreaRects >
+          0.5 /* If the overlap is more than 50%. */
+        ) {
+          return false;
+        }
+      }
+      return true;
+    });
+  }
 }
 
 export { AnnotationLayerBuilder };

web/app.js

@@ -353,6 +353,7 @@ const PDFViewerApplication = {
     if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("TESTING")) {
       Object.assign(opts, {
         enableAltText: x => x === "true",
+        enableAutoLinking: x => x === "true",
         enableFakeMLManager: x => x === "true",
         enableGuessAltText: x => x === "true",
         enableUpdatedAddImage: x => x === "true",
@@ -492,6 +493,7 @@ const PDFViewerApplication = {
       abortSignal: this._globalAbortController.signal,
       enableHWA,
       supportsPinchToZoom: this.supportsPinchToZoom,
+      enableAutoLinking: AppOptions.get("enableAutoLinking"),
     });
     this.pdfViewer = pdfViewer;
 

web/app_options.js

@@ -195,6 +195,11 @@ const defaultOptions = {
     value: true,
     kind: OptionKind.VIEWER + OptionKind.PREFERENCE + OptionKind.EVENT_DISPATCH,
   },
+  enableAutoLinking: {
+    /** @type {boolean} */
+    value: false,
+    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
+  },
   enableGuessAltText: {
     /** @type {boolean} */
     value: true,

web/autolinker.js

@@ -0,0 +1,147 @@
+/* Copyright 2025 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 {
+  AnnotationBorderStyleType,
+  AnnotationType,
+  createValidAbsoluteUrl,
+  Util,
+} from "pdfjs-lib";
+import { getOriginalIndex, normalize } from "./pdf_find_controller.js";
+
+function DOMRectToPDF({ width, height, left, top }, pdfPageView) {
+  if (width === 0 || height === 0) {
+    return null;
+  }
+
+  const pageBox = pdfPageView.textLayer.div.getBoundingClientRect();
+  const bottomLeft = pdfPageView.getPagePoint(
+    left - pageBox.left,
+    top - pageBox.top
+  );
+  const topRight = pdfPageView.getPagePoint(
+    left - pageBox.left + width,
+    top - pageBox.top + height
+  );
+
+  return Util.normalizeRect([
+    bottomLeft[0],
+    bottomLeft[1],
+    topRight[0],
+    topRight[1],
+  ]);
+}
+
+function calculateLinkPosition(range, pdfPageView) {
+  const rangeRects = range.getClientRects();
+  if (rangeRects.length === 1) {
+    return { rect: DOMRectToPDF(rangeRects[0], pdfPageView) };
+  }
+
+  const rect = [Infinity, Infinity, -Infinity, -Infinity];
+  const quadPoints = [];
+  let i = 0;
+  for (const domRect of rangeRects) {
+    const normalized = DOMRectToPDF(domRect, pdfPageView);
+    if (normalized === null) {
+      continue;
+    }
+
+    quadPoints[i] = quadPoints[i + 4] = normalized[0];
+    quadPoints[i + 1] = quadPoints[i + 3] = normalized[3];
+    quadPoints[i + 2] = quadPoints[i + 6] = normalized[2];
+    quadPoints[i + 5] = quadPoints[i + 7] = normalized[1];
+
+    rect[0] = Math.min(rect[0], normalized[0]);
+    rect[1] = Math.min(rect[1], normalized[1]);
+    rect[2] = Math.max(rect[2], normalized[2]);
+    rect[3] = Math.max(rect[3], normalized[3]);
+
+    i += 8;
+  }
+  return { quadPoints, rect };
+}
+
+function createLinkAnnotation({ url, index, length }, pdfPageView, id) {
+  const highlighter = pdfPageView._textHighlighter;
+  const [{ begin, end }] = highlighter._convertMatches([index], [length]);
+
+  const range = new Range();
+  range.setStart(highlighter.textDivs[begin.divIdx].firstChild, begin.offset);
+  range.setEnd(highlighter.textDivs[end.divIdx].firstChild, end.offset);
+
+  return {
+    id: `inferred_link_${id}`,
+    unsafeUrl: url,
+    url,
+    annotationType: AnnotationType.LINK,
+    rotation: 0,
+    ...calculateLinkPosition(range, pdfPageView),
+    // This is just the default for AnnotationBorderStyle.
+    borderStyle: {
+      width: 1,
+      rawWidth: 1,
+      style: AnnotationBorderStyleType.SOLID,
+      dashArray: [3],
+      horizontalCornerRadius: 0,
+      verticalCornerRadius: 0,
+    },
+  };
+}
+
+class Autolinker {
+  static #index = 0;
+
+  static #regex;
+
+  static findLinks(text) {
+    // Regex can be tested and verified at https://regex101.com/r/zgDwPE/1.
+    this.#regex ??=
+      /\b(?:https?:\/\/|mailto:|www\.)(?:[[\S--\[]--\p{P}]|\/|[\p{P}--\[]+[[\S--\[]--\p{P}])+|\b[[\S--@]--\{]+@[\S--.]+\.[[\S--\[]--\p{P}]{2,}/gmv;
+
+    const [normalizedText, diffs] = normalize(text);
+    const matches = normalizedText.matchAll(this.#regex);
+    const links = [];
+    for (const match of matches) {
+      const raw =
+        match[0].startsWith("www.") ||
+        match[0].startsWith("mailto:") ||
+        match[0].startsWith("http://") ||
+        match[0].startsWith("https://")
+          ? match[0]
+          : `mailto:${match[0]}`;
+      const url = createValidAbsoluteUrl(raw, null, {
+        addDefaultProtocol: true,
+      });
+      if (url) {
+        const [index, length] = getOriginalIndex(
+          diffs,
+          match.index,
+          match[0].length
+        );
+        links.push({ url: url.href, index, length });
+      }
+    }
+    return links;
+  }
+
+  static processLinks(pdfPageView) {
+    return this.findLinks(
+      pdfPageView._textHighlighter.textContentItemsStr.join("\n")
+    ).map(link => createLinkAnnotation(link, pdfPageView, this.#index++));
+  }
+}
+
+export { Autolinker };

web/pdf_find_controller.js

@@ -1185,4 +1185,4 @@ class PDFFindController {
   }
 }
 
-export { FindState, PDFFindController };
+export { FindState, getOriginalIndex, normalize, PDFFindController };

web/pdf_page_view.js

@@ -43,6 +43,7 @@ import {
 import { AnnotationEditorLayerBuilder } from "./annotation_editor_layer_builder.js";
 import { AnnotationLayerBuilder } from "./annotation_layer_builder.js";
 import { AppOptions } from "./app_options.js";
+import { Autolinker } from "./autolinker.js";
 import { DrawLayerBuilder } from "./draw_layer_builder.js";
 import { GenericL10n } from "web-null_l10n";
 import { SimpleLinkService } from "./pdf_link_service.js";
@@ -84,6 +85,8 @@ import { XfaLayerBuilder } from "./xfa_layer_builder.js";
  *   the necessary layer-properties.
  * @property {boolean} [enableHWA] - Enables hardware acceleration for
  *   rendering. The default value is `false`.
+ * @property {boolean} [enableAutoLinking] - Enable creation of hyperlinks from
+ *   text that look like URLs. The default value is `false`.
  */
 
 const DEFAULT_LAYER_PROPERTIES =
@@ -120,6 +123,8 @@ class PDFPageView {
 
   #enableHWA = false;
 
+  #enableAutoLinking = false;
+
   #hasRestrictedScaling = false;
 
   #isEditing = false;
@@ -177,6 +182,7 @@ class PDFPageView {
       options.maxCanvasPixels ?? AppOptions.get("maxCanvasPixels");
     this.pageColors = options.pageColors || null;
     this.#enableHWA = options.enableHWA || false;
+    this.#enableAutoLinking = options.enableAutoLinking || false;
 
     this.eventBus = options.eventBus;
     this.renderingQueue = options.renderingQueue;
@@ -1100,10 +1106,19 @@ class PDFPageView {
           viewport.rawDims
         );
 
-        this.#renderTextLayer();
+        const textLayerPromise = this.#renderTextLayer();
 
         if (this.annotationLayer) {
           await this.#renderAnnotationLayer();
+
+          if (this.#enableAutoLinking) {
+            await textLayerPromise;
+            this.annotationLayer.injectLinkAnnotations({
+              inferredLinks: Autolinker.processLinks(this),
+              viewport: this.viewport,
+              structTreeLayer: this.structTreeLayer,
+            });
+          }
         }
 
         const { annotationEditorUIManager } = this.#layerProperties;

web/pdf_viewer.js

@@ -128,6 +128,8 @@ function isValidAnnotationEditorMode(mode) {
  *   rendering. The default value is `false`.
  * @property {boolean} [supportsPinchToZoom] - Enable zooming on pinch gesture.
  *   The default value is `true`.
+ * @property {boolean} [enableAutoLinking] - Enable creation of hyperlinks from
+ *   text that look like URLs. The default value is `false`.
  */
 
 class PDFPageViewBuffer {
@@ -228,6 +230,8 @@ class PDFViewer {
 
   #enableNewAltTextWhenAddingImage = false;
 
+  #enableAutoLinking = false;
+
   #eventAbortController = null;
 
   #mlManager = null;
@@ -321,6 +325,7 @@ class PDFViewer {
     this.#mlManager = options.mlManager || null;
     this.#enableHWA = options.enableHWA || false;
     this.#supportsPinchToZoom = options.supportsPinchToZoom !== false;
+    this.#enableAutoLinking = options.enableAutoLinking || false;
 
     this.defaultRenderingQueue = !options.renderingQueue;
     if (
@@ -990,6 +995,7 @@ class PDFViewer {
             l10n: this.l10n,
             layerProperties: this._layerProperties,
             enableHWA: this.#enableHWA,
+            enableAutoLinking: this.#enableAutoLinking,
           });
           this._pages.push(pageView);
         }

web/pdfjs.js

@@ -15,12 +15,14 @@
 
 const {
   AbortException,
+  AnnotationBorderStyleType,
   AnnotationEditorLayer,
   AnnotationEditorParamsType,
   AnnotationEditorType,
   AnnotationEditorUIManager,
   AnnotationLayer,
   AnnotationMode,
+  AnnotationType,
   build,
   ColorPicker,
   createValidAbsoluteUrl,
@@ -63,12 +65,14 @@ const {
 
 export {
   AbortException,
+  AnnotationBorderStyleType,
   AnnotationEditorLayer,
   AnnotationEditorParamsType,
   AnnotationEditorType,
   AnnotationEditorUIManager,
   AnnotationLayer,
   AnnotationMode,
+  AnnotationType,
   build,
   ColorPicker,
   createValidAbsoluteUrl,