e4758beaaa
Rather than duplicating the lookup and caching in multiple files, it seems easier to simply move all of this functionality into `src/shared/util.js` instead. This will also help avoid a bunch of ESLint errors once the `no-shadow` rule is eventually enabled.
445 lines
15 KiB
JavaScript
445 lines
15 KiB
JavaScript
/* Copyright 2012 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import {
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assert,
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bytesToString,
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IsEvalSupportedCached,
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shadow,
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string32,
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unreachable,
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UNSUPPORTED_FEATURES,
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warn,
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} from "../shared/util.js";
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class BaseFontLoader {
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constructor({ docId, onUnsupportedFeature }) {
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if (this.constructor === BaseFontLoader) {
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unreachable("Cannot initialize BaseFontLoader.");
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}
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this.docId = docId;
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this._onUnsupportedFeature = onUnsupportedFeature;
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this.nativeFontFaces = [];
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this.styleElement = null;
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}
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addNativeFontFace(nativeFontFace) {
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this.nativeFontFaces.push(nativeFontFace);
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document.fonts.add(nativeFontFace);
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}
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insertRule(rule) {
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let styleElement = this.styleElement;
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if (!styleElement) {
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styleElement = this.styleElement = document.createElement("style");
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styleElement.id = `PDFJS_FONT_STYLE_TAG_${this.docId}`;
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document.documentElement
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.getElementsByTagName("head")[0]
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.appendChild(styleElement);
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}
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const styleSheet = styleElement.sheet;
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styleSheet.insertRule(rule, styleSheet.cssRules.length);
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}
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clear() {
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this.nativeFontFaces.forEach(function(nativeFontFace) {
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document.fonts.delete(nativeFontFace);
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});
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this.nativeFontFaces.length = 0;
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if (this.styleElement) {
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// Note: ChildNode.remove doesn't throw if the parentNode is undefined.
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this.styleElement.remove();
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this.styleElement = null;
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}
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}
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async bind(font) {
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// Add the font to the DOM only once; skip if the font is already loaded.
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if (font.attached || font.missingFile) {
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return;
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}
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font.attached = true;
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if (this.isFontLoadingAPISupported) {
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const nativeFontFace = font.createNativeFontFace();
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if (nativeFontFace) {
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this.addNativeFontFace(nativeFontFace);
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try {
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await nativeFontFace.loaded;
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} catch (ex) {
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this._onUnsupportedFeature({ featureId: UNSUPPORTED_FEATURES.font });
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warn(`Failed to load font '${nativeFontFace.family}': '${ex}'.`);
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// When font loading failed, fall back to the built-in font renderer.
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font.disableFontFace = true;
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throw ex;
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}
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}
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return; // The font was, asynchronously, loaded.
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}
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// !this.isFontLoadingAPISupported
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const rule = font.createFontFaceRule();
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if (rule) {
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this.insertRule(rule);
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if (this.isSyncFontLoadingSupported) {
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return; // The font was, synchronously, loaded.
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}
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await new Promise(resolve => {
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const request = this._queueLoadingCallback(resolve);
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this._prepareFontLoadEvent([rule], [font], request);
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});
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// The font was, asynchronously, loaded.
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}
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}
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_queueLoadingCallback(callback) {
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unreachable("Abstract method `_queueLoadingCallback`.");
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}
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get isFontLoadingAPISupported() {
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const supported = typeof document !== "undefined" && !!document.fonts;
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return shadow(this, "isFontLoadingAPISupported", supported);
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}
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// eslint-disable-next-line getter-return
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get isSyncFontLoadingSupported() {
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unreachable("Abstract method `isSyncFontLoadingSupported`.");
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}
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// eslint-disable-next-line getter-return
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get _loadTestFont() {
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unreachable("Abstract method `_loadTestFont`.");
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}
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_prepareFontLoadEvent(rules, fontsToLoad, request) {
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unreachable("Abstract method `_prepareFontLoadEvent`.");
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}
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}
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let FontLoader;
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if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
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FontLoader = class MozcentralFontLoader extends BaseFontLoader {
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get isSyncFontLoadingSupported() {
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return shadow(this, "isSyncFontLoadingSupported", true);
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}
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};
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} else {
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// PDFJSDev.test('CHROME || GENERIC')
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FontLoader = class GenericFontLoader extends BaseFontLoader {
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constructor(docId) {
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super(docId);
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this.loadingContext = {
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requests: [],
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nextRequestId: 0,
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};
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this.loadTestFontId = 0;
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}
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get isSyncFontLoadingSupported() {
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let supported = false;
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if (typeof PDFJSDev === "undefined" || !PDFJSDev.test("CHROME")) {
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if (typeof navigator === "undefined") {
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// Node.js - we can pretend that sync font loading is supported.
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supported = true;
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} else {
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// User agent string sniffing is bad, but there is no reliable way to
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// tell if the font is fully loaded and ready to be used with canvas.
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const m = /Mozilla\/5.0.*?rv:(\d+).*? Gecko/.exec(
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navigator.userAgent
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);
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if (m && m[1] >= 14) {
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supported = true;
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}
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// TODO - other browsers...
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}
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}
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return shadow(this, "isSyncFontLoadingSupported", supported);
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}
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_queueLoadingCallback(callback) {
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function completeRequest() {
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assert(!request.done, "completeRequest() cannot be called twice.");
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request.done = true;
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// Sending all completed requests in order of how they were queued.
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while (context.requests.length > 0 && context.requests[0].done) {
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const otherRequest = context.requests.shift();
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setTimeout(otherRequest.callback, 0);
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}
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}
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const context = this.loadingContext;
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const request = {
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id: `pdfjs-font-loading-${context.nextRequestId++}`,
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done: false,
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complete: completeRequest,
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callback,
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};
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context.requests.push(request);
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return request;
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}
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get _loadTestFont() {
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const getLoadTestFont = function() {
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// This is a CFF font with 1 glyph for '.' that fills its entire width
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// and height.
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return atob(
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"T1RUTwALAIAAAwAwQ0ZGIDHtZg4AAAOYAAAAgUZGVE1lkzZwAAAEHAAAABxHREVGABQA" +
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"FQAABDgAAAAeT1MvMlYNYwkAAAEgAAAAYGNtYXABDQLUAAACNAAAAUJoZWFk/xVFDQAA" +
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"ALwAAAA2aGhlYQdkA+oAAAD0AAAAJGhtdHgD6AAAAAAEWAAAAAZtYXhwAAJQAAAAARgA" +
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"AAAGbmFtZVjmdH4AAAGAAAAAsXBvc3T/hgAzAAADeAAAACAAAQAAAAEAALZRFsRfDzz1" +
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"AAsD6AAAAADOBOTLAAAAAM4KHDwAAAAAA+gDIQAAAAgAAgAAAAAAAAABAAADIQAAAFoD" +
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"6AAAAAAD6AABAAAAAAAAAAAAAAAAAAAAAQAAUAAAAgAAAAQD6AH0AAUAAAKKArwAAACM" +
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"AooCvAAAAeAAMQECAAACAAYJAAAAAAAAAAAAAQAAAAAAAAAAAAAAAFBmRWQAwAAuAC4D" +
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"IP84AFoDIQAAAAAAAQAAAAAAAAAAACAAIAABAAAADgCuAAEAAAAAAAAAAQAAAAEAAAAA" +
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"AAEAAQAAAAEAAAAAAAIAAQAAAAEAAAAAAAMAAQAAAAEAAAAAAAQAAQAAAAEAAAAAAAUA" +
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"AQAAAAEAAAAAAAYAAQAAAAMAAQQJAAAAAgABAAMAAQQJAAEAAgABAAMAAQQJAAIAAgAB" +
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"AAMAAQQJAAMAAgABAAMAAQQJAAQAAgABAAMAAQQJAAUAAgABAAMAAQQJAAYAAgABWABY" +
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"AAAAAAAAAwAAAAMAAAAcAAEAAAAAADwAAwABAAAAHAAEACAAAAAEAAQAAQAAAC7//wAA" +
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"AC7////TAAEAAAAAAAABBgAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" +
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"AAAAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" +
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"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" +
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"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" +
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"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" +
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"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMAAAAAAAD/gwAyAAAAAQAAAAAAAAAAAAAAAAAA" +
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"AAABAAQEAAEBAQJYAAEBASH4DwD4GwHEAvgcA/gXBIwMAYuL+nz5tQXkD5j3CBLnEQAC" +
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"AQEBIVhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYAAABAQAADwACAQEEE/t3" +
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"Dov6fAH6fAT+fPp8+nwHDosMCvm1Cvm1DAz6fBQAAAAAAAABAAAAAMmJbzEAAAAAzgTj" +
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"FQAAAADOBOQpAAEAAAAAAAAADAAUAAQAAAABAAAAAgABAAAAAAAAAAAD6AAAAAAAAA=="
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);
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};
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return shadow(this, "_loadTestFont", getLoadTestFont());
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}
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_prepareFontLoadEvent(rules, fonts, request) {
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/** Hack begin */
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// There's currently no event when a font has finished downloading so the
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// following code is a dirty hack to 'guess' when a font is ready.
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// It's assumed fonts are loaded in order, so add a known test font after
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// the desired fonts and then test for the loading of that test font.
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function int32(data, offset) {
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return (
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(data.charCodeAt(offset) << 24) |
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(data.charCodeAt(offset + 1) << 16) |
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(data.charCodeAt(offset + 2) << 8) |
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(data.charCodeAt(offset + 3) & 0xff)
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);
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}
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function spliceString(s, offset, remove, insert) {
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const chunk1 = s.substring(0, offset);
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const chunk2 = s.substring(offset + remove);
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return chunk1 + insert + chunk2;
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}
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let i, ii;
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// The temporary canvas is used to determine if fonts are loaded.
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const canvas = document.createElement("canvas");
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canvas.width = 1;
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canvas.height = 1;
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const ctx = canvas.getContext("2d");
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let called = 0;
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function isFontReady(name, callback) {
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called++;
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// With setTimeout clamping this gives the font ~100ms to load.
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if (called > 30) {
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warn("Load test font never loaded.");
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callback();
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return;
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}
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ctx.font = "30px " + name;
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ctx.fillText(".", 0, 20);
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const imageData = ctx.getImageData(0, 0, 1, 1);
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if (imageData.data[3] > 0) {
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callback();
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return;
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}
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setTimeout(isFontReady.bind(null, name, callback));
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}
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const loadTestFontId = `lt${Date.now()}${this.loadTestFontId++}`;
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// Chromium seems to cache fonts based on a hash of the actual font data,
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// so the font must be modified for each load test else it will appear to
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// be loaded already.
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// TODO: This could maybe be made faster by avoiding the btoa of the full
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// font by splitting it in chunks before hand and padding the font id.
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let data = this._loadTestFont;
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const COMMENT_OFFSET = 976; // has to be on 4 byte boundary (for checksum)
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data = spliceString(
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data,
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COMMENT_OFFSET,
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loadTestFontId.length,
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loadTestFontId
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);
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// CFF checksum is important for IE, adjusting it
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const CFF_CHECKSUM_OFFSET = 16;
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const XXXX_VALUE = 0x58585858; // the "comment" filled with 'X'
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let checksum = int32(data, CFF_CHECKSUM_OFFSET);
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for (i = 0, ii = loadTestFontId.length - 3; i < ii; i += 4) {
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checksum = (checksum - XXXX_VALUE + int32(loadTestFontId, i)) | 0;
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}
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if (i < loadTestFontId.length) {
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// align to 4 bytes boundary
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checksum =
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(checksum - XXXX_VALUE + int32(loadTestFontId + "XXX", i)) | 0;
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}
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data = spliceString(data, CFF_CHECKSUM_OFFSET, 4, string32(checksum));
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const url = `url(data:font/opentype;base64,${btoa(data)});`;
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const rule = `@font-face {font-family:"${loadTestFontId}";src:${url}}`;
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this.insertRule(rule);
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const names = [];
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for (i = 0, ii = fonts.length; i < ii; i++) {
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names.push(fonts[i].loadedName);
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}
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names.push(loadTestFontId);
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const div = document.createElement("div");
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div.style.visibility = "hidden";
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div.style.width = div.style.height = "10px";
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div.style.position = "absolute";
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div.style.top = div.style.left = "0px";
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for (i = 0, ii = names.length; i < ii; ++i) {
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const span = document.createElement("span");
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span.textContent = "Hi";
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span.style.fontFamily = names[i];
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div.appendChild(span);
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}
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document.body.appendChild(div);
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isFontReady(loadTestFontId, function() {
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document.body.removeChild(div);
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request.complete();
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});
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/** Hack end */
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}
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};
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} // End of PDFJSDev.test('CHROME || GENERIC')
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class FontFaceObject {
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constructor(
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translatedData,
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{
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isEvalSupported = true,
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disableFontFace = false,
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ignoreErrors = false,
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onUnsupportedFeature = null,
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fontRegistry = null,
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}
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) {
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this.compiledGlyphs = Object.create(null);
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// importing translated data
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for (const i in translatedData) {
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this[i] = translatedData[i];
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}
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this.isEvalSupported = isEvalSupported !== false;
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this.disableFontFace = disableFontFace === true;
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this.ignoreErrors = ignoreErrors === true;
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this._onUnsupportedFeature = onUnsupportedFeature;
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this.fontRegistry = fontRegistry;
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}
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createNativeFontFace() {
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if (!this.data || this.disableFontFace) {
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return null;
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}
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const nativeFontFace = new FontFace(this.loadedName, this.data, {});
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if (this.fontRegistry) {
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this.fontRegistry.registerFont(this);
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}
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return nativeFontFace;
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}
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createFontFaceRule() {
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if (!this.data || this.disableFontFace) {
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return null;
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}
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const data = bytesToString(new Uint8Array(this.data));
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// Add the @font-face rule to the document.
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const url = `url(data:${this.mimetype};base64,${btoa(data)});`;
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const rule = `@font-face {font-family:"${this.loadedName}";src:${url}}`;
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if (this.fontRegistry) {
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this.fontRegistry.registerFont(this, url);
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}
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return rule;
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}
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getPathGenerator(objs, character) {
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if (this.compiledGlyphs[character] !== undefined) {
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return this.compiledGlyphs[character];
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}
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let cmds, current;
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try {
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cmds = objs.get(this.loadedName + "_path_" + character);
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} catch (ex) {
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if (!this.ignoreErrors) {
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throw ex;
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}
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if (this._onUnsupportedFeature) {
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this._onUnsupportedFeature({ featureId: UNSUPPORTED_FEATURES.font });
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}
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warn(`getPathGenerator - ignoring character: "${ex}".`);
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return (this.compiledGlyphs[character] = function(c, size) {
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// No-op function, to allow rendering to continue.
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});
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}
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// If we can, compile cmds into JS for MAXIMUM SPEED...
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if (this.isEvalSupported && IsEvalSupportedCached.value) {
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let args,
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js = "";
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for (let i = 0, ii = cmds.length; i < ii; i++) {
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current = cmds[i];
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if (current.args !== undefined) {
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args = current.args.join(",");
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} else {
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args = "";
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}
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js += "c." + current.cmd + "(" + args + ");\n";
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}
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// eslint-disable-next-line no-new-func
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return (this.compiledGlyphs[character] = new Function("c", "size", js));
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}
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// ... but fall back on using Function.prototype.apply() if we're
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// blocked from using eval() for whatever reason (like CSP policies).
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return (this.compiledGlyphs[character] = function(c, size) {
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for (let i = 0, ii = cmds.length; i < ii; i++) {
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current = cmds[i];
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if (current.cmd === "scale") {
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current.args = [size, -size];
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}
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c[current.cmd].apply(c, current.args);
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}
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});
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}
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}
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export { FontFaceObject, FontLoader };
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