pdfjs-dist/lib/display/font_loader.js

/**
 * @licstart The following is the entire license notice for the
 * JavaScript code in this page
 *
 * Copyright 2022 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.
 *
 * @licend The above is the entire license notice for the
 * JavaScript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.FontLoader = exports.FontFaceObject = void 0;
var _util = require("../shared/util.js");
class FontLoader {
  constructor({
    onUnsupportedFeature,
    ownerDocument = globalThis.document,
    styleElement = null
  }) {
    this._onUnsupportedFeature = onUnsupportedFeature;
    this._document = ownerDocument;
    this.nativeFontFaces = [];
    this.styleElement = null;
    this.loadingRequests = [];
    this.loadTestFontId = 0;
  }
  addNativeFontFace(nativeFontFace) {
    this.nativeFontFaces.push(nativeFontFace);
    this._document.fonts.add(nativeFontFace);
  }
  insertRule(rule) {
    if (!this.styleElement) {
      this.styleElement = this._document.createElement("style");
      this._document.documentElement.getElementsByTagName("head")[0].append(this.styleElement);
    }
    const styleSheet = this.styleElement.sheet;
    styleSheet.insertRule(rule, styleSheet.cssRules.length);
  }
  clear() {
    for (const nativeFontFace of this.nativeFontFaces) {
      this._document.fonts.delete(nativeFontFace);
    }
    this.nativeFontFaces.length = 0;
    if (this.styleElement) {
      this.styleElement.remove();
      this.styleElement = null;
    }
  }
  async bind(font) {
    if (font.attached || font.missingFile) {
      return;
    }
    font.attached = true;
    if (this.isFontLoadingAPISupported) {
      const nativeFontFace = font.createNativeFontFace();
      if (nativeFontFace) {
        this.addNativeFontFace(nativeFontFace);
        try {
          await nativeFontFace.loaded;
        } catch (ex) {
          this._onUnsupportedFeature({
            featureId: _util.UNSUPPORTED_FEATURES.errorFontLoadNative
          });
          (0, _util.warn)(`Failed to load font '${nativeFontFace.family}': '${ex}'.`);
          font.disableFontFace = true;
          throw ex;
        }
      }
      return;
    }
    const rule = font.createFontFaceRule();
    if (rule) {
      this.insertRule(rule);
      if (this.isSyncFontLoadingSupported) {
        return;
      }
      await new Promise(resolve => {
        const request = this._queueLoadingCallback(resolve);
        this._prepareFontLoadEvent(font, request);
      });
    }
  }
  get isFontLoadingAPISupported() {
    const hasFonts = !!this._document?.fonts;
    return (0, _util.shadow)(this, "isFontLoadingAPISupported", hasFonts);
  }
  get isSyncFontLoadingSupported() {
    let supported = false;
    if (typeof navigator === "undefined") {
      supported = true;
    } else {
      const m = /Mozilla\/5.0.*?rv:(\d+).*? Gecko/.exec(navigator.userAgent);
      if (m?.[1] >= 14) {
        supported = true;
      }
    }
    return (0, _util.shadow)(this, "isSyncFontLoadingSupported", supported);
  }
  _queueLoadingCallback(callback) {
    function completeRequest() {
      (0, _util.assert)(!request.done, "completeRequest() cannot be called twice.");
      request.done = true;
      while (loadingRequests.length > 0 && loadingRequests[0].done) {
        const otherRequest = loadingRequests.shift();
        setTimeout(otherRequest.callback, 0);
      }
    }
    const {
      loadingRequests
    } = this;
    const request = {
      done: false,
      complete: completeRequest,
      callback
    };
    loadingRequests.push(request);
    return request;
  }
  get _loadTestFont() {
    const testFont = atob("T1RUTwALAIAAAwAwQ0ZGIDHtZg4AAAOYAAAAgUZGVE1lkzZwAAAEHAAAABxHREVGABQA" + "FQAABDgAAAAeT1MvMlYNYwkAAAEgAAAAYGNtYXABDQLUAAACNAAAAUJoZWFk/xVFDQAA" + "ALwAAAA2aGhlYQdkA+oAAAD0AAAAJGhtdHgD6AAAAAAEWAAAAAZtYXhwAAJQAAAAARgA" + "AAAGbmFtZVjmdH4AAAGAAAAAsXBvc3T/hgAzAAADeAAAACAAAQAAAAEAALZRFsRfDzz1" + "AAsD6AAAAADOBOTLAAAAAM4KHDwAAAAAA+gDIQAAAAgAAgAAAAAAAAABAAADIQAAAFoD" + "6AAAAAAD6AABAAAAAAAAAAAAAAAAAAAAAQAAUAAAAgAAAAQD6AH0AAUAAAKKArwAAACM" + "AooCvAAAAeAAMQECAAACAAYJAAAAAAAAAAAAAQAAAAAAAAAAAAAAAFBmRWQAwAAuAC4D" + "IP84AFoDIQAAAAAAAQAAAAAAAAAAACAAIAABAAAADgCuAAEAAAAAAAAAAQAAAAEAAAAA" + "AAEAAQAAAAEAAAAAAAIAAQAAAAEAAAAAAAMAAQAAAAEAAAAAAAQAAQAAAAEAAAAAAAUA" + "AQAAAAEAAAAAAAYAAQAAAAMAAQQJAAAAAgABAAMAAQQJAAEAAgABAAMAAQQJAAIAAgAB" + "AAMAAQQJAAMAAgABAAMAAQQJAAQAAgABAAMAAQQJAAUAAgABAAMAAQQJAAYAAgABWABY" + "AAAAAAAAAwAAAAMAAAAcAAEAAAAAADwAAwABAAAAHAAEACAAAAAEAAQAAQAAAC7//wAA" + "AC7////TAAEAAAAAAAABBgAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" + "AAAAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" + "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" + "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" + "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" + "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMAAAAAAAD/gwAyAAAAAQAAAAAAAAAAAAAAAAAA" + "AAABAAQEAAEBAQJYAAEBASH4DwD4GwHEAvgcA/gXBIwMAYuL+nz5tQXkD5j3CBLnEQAC" + "AQEBIVhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYAAABAQAADwACAQEEE/t3" + "Dov6fAH6fAT+fPp8+nwHDosMCvm1Cvm1DAz6fBQAAAAAAAABAAAAAMmJbzEAAAAAzgTj" + "FQAAAADOBOQpAAEAAAAAAAAADAAUAAQAAAABAAAAAgABAAAAAAAAAAAD6AAAAAAAAA==");
    return (0, _util.shadow)(this, "_loadTestFont", testFont);
  }
  _prepareFontLoadEvent(font, request) {
    function int32(data, offset) {
      return data.charCodeAt(offset) << 24 | data.charCodeAt(offset + 1) << 16 | data.charCodeAt(offset + 2) << 8 | data.charCodeAt(offset + 3) & 0xff;
    }
    function spliceString(s, offset, remove, insert) {
      const chunk1 = s.substring(0, offset);
      const chunk2 = s.substring(offset + remove);
      return chunk1 + insert + chunk2;
    }
    let i, ii;
    const canvas = this._document.createElement("canvas");
    canvas.width = 1;
    canvas.height = 1;
    const ctx = canvas.getContext("2d");
    let called = 0;
    function isFontReady(name, callback) {
      if (++called > 30) {
        (0, _util.warn)("Load test font never loaded.");
        callback();
        return;
      }
      ctx.font = "30px " + name;
      ctx.fillText(".", 0, 20);
      const imageData = ctx.getImageData(0, 0, 1, 1);
      if (imageData.data[3] > 0) {
        callback();
        return;
      }
      setTimeout(isFontReady.bind(null, name, callback));
    }
    const loadTestFontId = `lt${Date.now()}${this.loadTestFontId++}`;
    let data = this._loadTestFont;
    const COMMENT_OFFSET = 976;
    data = spliceString(data, COMMENT_OFFSET, loadTestFontId.length, loadTestFontId);
    const CFF_CHECKSUM_OFFSET = 16;
    const XXXX_VALUE = 0x58585858;
    let checksum = int32(data, CFF_CHECKSUM_OFFSET);
    for (i = 0, ii = loadTestFontId.length - 3; i < ii; i += 4) {
      checksum = checksum - XXXX_VALUE + int32(loadTestFontId, i) | 0;
    }
    if (i < loadTestFontId.length) {
      checksum = checksum - XXXX_VALUE + int32(loadTestFontId + "XXX", i) | 0;
    }
    data = spliceString(data, CFF_CHECKSUM_OFFSET, 4, (0, _util.string32)(checksum));
    const url = `url(data:font/opentype;base64,${btoa(data)});`;
    const rule = `@font-face {font-family:"${loadTestFontId}";src:${url}}`;
    this.insertRule(rule);
    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 (const name of [font.loadedName, loadTestFontId]) {
      const span = this._document.createElement("span");
      span.textContent = "Hi";
      span.style.fontFamily = name;
      div.append(span);
    }
    this._document.body.append(div);
    isFontReady(loadTestFontId, () => {
      div.remove();
      request.complete();
    });
  }
}
exports.FontLoader = FontLoader;
class FontFaceObject {
  constructor(translatedData, {
    isEvalSupported = true,
    disableFontFace = false,
    ignoreErrors = false,
    onUnsupportedFeature,
    fontRegistry = null
  }) {
    this.compiledGlyphs = Object.create(null);
    for (const i in translatedData) {
      this[i] = translatedData[i];
    }
    this.isEvalSupported = isEvalSupported !== false;
    this.disableFontFace = disableFontFace === true;
    this.ignoreErrors = ignoreErrors === true;
    this._onUnsupportedFeature = onUnsupportedFeature;
    this.fontRegistry = fontRegistry;
  }
  createNativeFontFace() {
    if (!this.data || this.disableFontFace) {
      return null;
    }
    let nativeFontFace;
    if (!this.cssFontInfo) {
      nativeFontFace = new FontFace(this.loadedName, this.data, {});
    } else {
      const css = {
        weight: this.cssFontInfo.fontWeight
      };
      if (this.cssFontInfo.italicAngle) {
        css.style = `oblique ${this.cssFontInfo.italicAngle}deg`;
      }
      nativeFontFace = new FontFace(this.cssFontInfo.fontFamily, this.data, css);
    }
    this.fontRegistry?.registerFont(this);
    return nativeFontFace;
  }
  createFontFaceRule() {
    if (!this.data || this.disableFontFace) {
      return null;
    }
    const data = (0, _util.bytesToString)(this.data);
    const url = `url(data:${this.mimetype};base64,${btoa(data)});`;
    let rule;
    if (!this.cssFontInfo) {
      rule = `@font-face {font-family:"${this.loadedName}";src:${url}}`;
    } else {
      let css = `font-weight: ${this.cssFontInfo.fontWeight};`;
      if (this.cssFontInfo.italicAngle) {
        css += `font-style: oblique ${this.cssFontInfo.italicAngle}deg;`;
      }
      rule = `@font-face {font-family:"${this.cssFontInfo.fontFamily}";${css}src:${url}}`;
    }
    this.fontRegistry?.registerFont(this, url);
    return rule;
  }
  getPathGenerator(objs, character) {
    if (this.compiledGlyphs[character] !== undefined) {
      return this.compiledGlyphs[character];
    }
    let cmds;
    try {
      cmds = objs.get(this.loadedName + "_path_" + character);
    } catch (ex) {
      if (!this.ignoreErrors) {
        throw ex;
      }
      this._onUnsupportedFeature({
        featureId: _util.UNSUPPORTED_FEATURES.errorFontGetPath
      });
      (0, _util.warn)(`getPathGenerator - ignoring character: "${ex}".`);
      return this.compiledGlyphs[character] = function (c, size) {};
    }
    if (this.isEvalSupported && _util.FeatureTest.isEvalSupported) {
      const jsBuf = [];
      for (const current of cmds) {
        const args = current.args !== undefined ? current.args.join(",") : "";
        jsBuf.push("c.", current.cmd, "(", args, ");\n");
      }
      return this.compiledGlyphs[character] = new Function("c", "size", jsBuf.join(""));
    }
    return this.compiledGlyphs[character] = function (c, size) {
      for (const current of cmds) {
        if (current.cmd === "scale") {
          current.args = [size, -size];
        }
        c[current.cmd].apply(c, current.args);
      }
    };
  }
}
exports.FontFaceObject = FontFaceObject;