[api-minor] Allow loading pdf fonts into another document.

src/display/api.js

@@ -152,6 +152,9 @@ function setPDFNetworkStreamFactory(pdfNetworkStreamFactory) {
  *   parsed font data from the worker-thread. This may be useful for debugging
  *   purposes (and backwards compatibility), but note that it will lead to
  *   increased memory usage. The default value is `false`.
+ * @property {HTMLDocument} [ownerDocument] - Specify an explicit document
+ *   context to create elements with and to load resources, such as fonts,
+ *   into. Defaults to the current document.
  * @property {boolean} [disableRange] - Disable range request loading
  *   of PDF files. When enabled, and if the server supports partial content
  *   requests, then the PDF will be fetched in chunks.
@@ -268,6 +271,9 @@ function getDocument(src) {
   if (typeof params.disableFontFace !== "boolean") {
     params.disableFontFace = apiCompatibilityParams.disableFontFace || false;
   }
+  if (typeof params.ownerDocument === "undefined") {
+    params.ownerDocument = globalThis.document;
+  }
 
   if (typeof params.disableRange !== "boolean") {
     params.disableRange = false;
@@ -907,9 +913,10 @@ class PDFDocumentProxy {
  * @alias PDFPageProxy
  */
 class PDFPageProxy {
-  constructor(pageIndex, pageInfo, transport, pdfBug = false) {
+  constructor(pageIndex, pageInfo, transport, ownerDocument, pdfBug = false) {
     this._pageIndex = pageIndex;
     this._pageInfo = pageInfo;
+    this._ownerDocument = ownerDocument;
     this._transport = transport;
     this._stats = pdfBug ? new StatTimer() : null;
     this._pdfBug = pdfBug;
@@ -1036,7 +1043,9 @@ class PDFPageProxy {
       intentState.streamReaderCancelTimeout = null;
     }
 
-    const canvasFactoryInstance = canvasFactory || new DefaultCanvasFactory();
+    const canvasFactoryInstance =
+      canvasFactory ||
+      new DefaultCanvasFactory({ ownerDocument: this._ownerDocument });
     const webGLContext = new WebGLContext({
       enable: enableWebGL,
     });
@@ -1944,6 +1953,7 @@ class WorkerTransport {
     this.fontLoader = new FontLoader({
       docId: loadingTask.docId,
       onUnsupportedFeature: this._onUnsupportedFeature.bind(this),
+      ownerDocument: params.ownerDocument,
     });
     this._params = params;
     this.CMapReaderFactory = new params.CMapReaderFactory({
@@ -2387,6 +2397,7 @@ class WorkerTransport {
           pageIndex,
           pageInfo,
           this,
+          this._params.ownerDocument,
           this._params.pdfBug
         );
         this.pageCache[pageIndex] = page;

src/display/display_utils.js

@@ -65,11 +65,16 @@ class BaseCanvasFactory {
 }
 
 class DOMCanvasFactory extends BaseCanvasFactory {
+  constructor({ ownerDocument = globalThis.document } = {}) {
+    super();
+    this._document = ownerDocument;
+  }
+
   create(width, height) {
     if (width <= 0 || height <= 0) {
       throw new Error("Invalid canvas size");
     }
-    const canvas = document.createElement("canvas");
+    const canvas = this._document.createElement("canvas");
     const context = canvas.getContext("2d");
     canvas.width = width;
     canvas.height = height;

src/display/font_loader.js

@@ -25,28 +25,33 @@ import {
 } from "../shared/util.js";
 
 class BaseFontLoader {
-  constructor({ docId, onUnsupportedFeature }) {
+  constructor({
+    docId,
+    onUnsupportedFeature,
+    ownerDocument = globalThis.document,
+  }) {
     if (this.constructor === BaseFontLoader) {
       unreachable("Cannot initialize BaseFontLoader.");
     }
     this.docId = docId;
     this._onUnsupportedFeature = onUnsupportedFeature;
+    this._document = ownerDocument;
 
     this.nativeFontFaces = [];
     this.styleElement = null;
   }
 
   addNativeFontFace(nativeFontFace) {
     this.nativeFontFaces.push(nativeFontFace);
-    document.fonts.add(nativeFontFace);
+    this._document.fonts.add(nativeFontFace);
   }
 
   insertRule(rule) {
     let styleElement = this.styleElement;
     if (!styleElement) {
-      styleElement = this.styleElement = document.createElement("style");
+      styleElement = this.styleElement = this._document.createElement("style");
       styleElement.id = `PDFJS_FONT_STYLE_TAG_${this.docId}`;
-      document.documentElement
+      this._document.documentElement
         .getElementsByTagName("head")[0]
         .appendChild(styleElement);
     }
@@ -56,8 +61,8 @@ class BaseFontLoader {
   }
 
   clear() {
-    this.nativeFontFaces.forEach(function (nativeFontFace) {
-      document.fonts.delete(nativeFontFace);
+    this.nativeFontFaces.forEach(nativeFontFace => {
+      this._document.fonts.delete(nativeFontFace);
     });
     this.nativeFontFaces.length = 0;
 
@@ -116,7 +121,8 @@ class BaseFontLoader {
   }
 
   get isFontLoadingAPISupported() {
-    const supported = typeof document !== "undefined" && !!document.fonts;
+    const supported =
+      typeof this._document !== "undefined" && !!this._document.fonts;
     return shadow(this, "isFontLoadingAPISupported", supported);
   }
 
@@ -146,8 +152,8 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
   // PDFJSDev.test('CHROME || GENERIC')
 
   FontLoader = class GenericFontLoader extends BaseFontLoader {
-    constructor(docId) {
-      super(docId);
+    constructor(params) {
+      super(params);
       this.loadingContext = {
         requests: [],
         nextRequestId: 0,
@@ -254,7 +260,7 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
       let i, ii;
 
       // The temporary canvas is used to determine if fonts are loaded.
-      const canvas = document.createElement("canvas");
+      const canvas = this._document.createElement("canvas");
       canvas.width = 1;
       canvas.height = 1;
       const ctx = canvas.getContext("2d");
@@ -316,22 +322,22 @@ if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
       }
       names.push(loadTestFontId);
 
-      const div = document.createElement("div");
+      const div = this._document.createElement("div");
       div.style.visibility = "hidden";
       div.style.width = div.style.height = "10px";
       div.style.position = "absolute";
       div.style.top = div.style.left = "0px";
 
       for (i = 0, ii = names.length; i < ii; ++i) {
-        const span = document.createElement("span");
+        const span = this._document.createElement("span");
         span.textContent = "Hi";
         span.style.fontFamily = names[i];
         div.appendChild(span);
       }
-      document.body.appendChild(div);
+      this._document.body.appendChild(div);
 
-      isFontReady(loadTestFontId, function () {
-        document.body.removeChild(div);
+      isFontReady(loadTestFontId, () => {
+        this._document.body.removeChild(div);
         request.complete();
       });
       /** Hack end */

src/display/text_layer.js

@@ -510,6 +510,7 @@ var renderTextLayer = (function renderTextLayerClosure() {
     this._textContent = textContent;
     this._textContentStream = textContentStream;
     this._container = container;
+    this._document = container.ownerDocument;
     this._viewport = viewport;
     this._textDivs = textDivs || [];
     this._textContentItemsStr = textContentItemsStr || [];
@@ -614,7 +615,7 @@ var renderTextLayer = (function renderTextLayerClosure() {
       let styleCache = Object.create(null);
 
       // The temporary canvas is used to measure text length in the DOM.
-      const canvas = document.createElement("canvas");
+      const canvas = this._document.createElement("canvas");
       if (
         typeof PDFJSDev === "undefined" ||
         PDFJSDev.test("MOZCENTRAL || GENERIC")

test/unit/custom_spec.js

@@ -107,3 +107,119 @@ describe("custom canvas rendering", function () {
       .catch(done.fail);
   });
 });
+
+describe("alternate document context", function () {
+  const FontFace = global.FontFace;
+
+  let altDocument;
+  let CanvasFactory;
+  let elements;
+
+  beforeEach(() => {
+    global.FontFace = function MockFontFace(name) {
+      this.family = name;
+    };
+
+    elements = [];
+    const createElement = name => {
+      const element = {
+        tagName: name,
+        remove() {
+          this.remove.called = true;
+        },
+      };
+      if (name === "style") {
+        element.sheet = {
+          cssRules: [],
+          insertRule(rule) {
+            this.cssRules.push(rule);
+          },
+        };
+      }
+      elements.push(element);
+      return element;
+    };
+    altDocument = {
+      fonts: new Set(),
+      createElement,
+      documentElement: {
+        getElementsByTagName: () => [{ appendChild: () => {} }],
+      },
+    };
+
+    CanvasFactory = isNodeJS
+      ? new NodeCanvasFactory()
+      : new DOMCanvasFactory({ ownerDocument: altDocument });
+  });
+
+  afterEach(() => {
+    global.FontFace = FontFace;
+    CanvasFactory = null;
+    elements = null;
+  });
+
+  it("should use given document for loading fonts (with Font Loading API)", async function () {
+    const getDocumentParams = buildGetDocumentParams(
+      "TrueType_without_cmap.pdf",
+      {
+        disableFontFace: false,
+        ownerDocument: altDocument,
+      }
+    );
+
+    const loadingTask = getDocument(getDocumentParams);
+    const doc = await loadingTask.promise;
+    const page = await doc.getPage(1);
+
+    const viewport = page.getViewport({ scale: 1 });
+    const canvasAndCtx = CanvasFactory.create(viewport.width, viewport.height);
+
+    await page.render({
+      canvasContext: canvasAndCtx.context,
+      viewport,
+    }).promise;
+
+    expect(elements).toEqual([]);
+    expect(altDocument.fonts.size).toBe(1);
+    const [font] = Array.from(altDocument.fonts);
+    expect(font.family).toMatch(/g_d\d+_f1/);
+
+    await doc.destroy();
+    await loadingTask.destroy();
+    CanvasFactory.destroy(canvasAndCtx);
+    expect(altDocument.fonts.size).toBe(0);
+  });
+
+  it("should use given document for loading fonts (with CSS rules)", async function () {
+    altDocument.fonts = null;
+    const getDocumentParams = buildGetDocumentParams(
+      "TrueType_without_cmap.pdf",
+      {
+        disableFontFace: false,
+        ownerDocument: altDocument,
+      }
+    );
+
+    const loadingTask = getDocument(getDocumentParams);
+    const doc = await loadingTask.promise;
+    const page = await doc.getPage(1);
+
+    const viewport = page.getViewport({ scale: 1 });
+    const canvasAndCtx = CanvasFactory.create(viewport.width, viewport.height);
+
+    await page.render({
+      canvasContext: canvasAndCtx.context,
+      viewport,
+    }).promise;
+
+    const style = elements.find(element => element.tagName === "style");
+    expect(style.sheet.cssRules.length).toBe(1);
+    expect(style.sheet.cssRules[0]).toMatch(
+      /^@font-face {font-family:"g_d\d+_f1";src:/
+    );
+    await doc.destroy();
+    await loadingTask.destroy();
+    CanvasFactory.destroy(canvasAndCtx);
+    expect(style.remove.called).toBe(true);
+  });
+});