pdfjs-dist/lib/display/font_loader.js

/* Copyright 2017 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.
 */
'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.FontLoader = exports.FontFaceObject = undefined;

var _util = require('../shared/util');

function FontLoader(docId) {
  this.docId = docId;
  this.styleElement = null;
  this.nativeFontFaces = [];
  this.loadTestFontId = 0;
  this.loadingContext = {
    requests: [],
    nextRequestId: 0
  };
}
FontLoader.prototype = {
  insertRule: function fontLoaderInsertRule(rule) {
    var styleElement = this.styleElement;
    if (!styleElement) {
      styleElement = this.styleElement = document.createElement('style');
      styleElement.id = 'PDFJS_FONT_STYLE_TAG_' + this.docId;
      document.documentElement.getElementsByTagName('head')[0].appendChild(styleElement);
    }
    var styleSheet = styleElement.sheet;
    styleSheet.insertRule(rule, styleSheet.cssRules.length);
  },
  clear: function fontLoaderClear() {
    if (this.styleElement) {
      this.styleElement.remove();
      this.styleElement = null;
    }
    this.nativeFontFaces.forEach(function (nativeFontFace) {
      document.fonts.delete(nativeFontFace);
    });
    this.nativeFontFaces.length = 0;
  }
};
{
  var getLoadTestFont = function getLoadTestFont() {
    return atob('T1RUTwALAIAAAwAwQ0ZGIDHtZg4AAAOYAAAAgUZGVE1lkzZwAAAEHAAAABxHREVGABQAFQ' + 'AABDgAAAAeT1MvMlYNYwkAAAEgAAAAYGNtYXABDQLUAAACNAAAAUJoZWFk/xVFDQAAALwA' + 'AAA2aGhlYQdkA+oAAAD0AAAAJGhtdHgD6AAAAAAEWAAAAAZtYXhwAAJQAAAAARgAAAAGbm' + 'FtZVjmdH4AAAGAAAAAsXBvc3T/hgAzAAADeAAAACAAAQAAAAEAALZRFsRfDzz1AAsD6AAA' + 'AADOBOTLAAAAAM4KHDwAAAAAA+gDIQAAAAgAAgAAAAAAAAABAAADIQAAAFoD6AAAAAAD6A' + 'ABAAAAAAAAAAAAAAAAAAAAAQAAUAAAAgAAAAQD6AH0AAUAAAKKArwAAACMAooCvAAAAeAA' + 'MQECAAACAAYJAAAAAAAAAAAAAQAAAAAAAAAAAAAAAFBmRWQAwAAuAC4DIP84AFoDIQAAAA' + 'AAAQAAAAAAAAAAACAAIAABAAAADgCuAAEAAAAAAAAAAQAAAAEAAAAAAAEAAQAAAAEAAAAA' + 'AAIAAQAAAAEAAAAAAAMAAQAAAAEAAAAAAAQAAQAAAAEAAAAAAAUAAQAAAAEAAAAAAAYAAQ' + 'AAAAMAAQQJAAAAAgABAAMAAQQJAAEAAgABAAMAAQQJAAIAAgABAAMAAQQJAAMAAgABAAMA' + 'AQQJAAQAAgABAAMAAQQJAAUAAgABAAMAAQQJAAYAAgABWABYAAAAAAAAAwAAAAMAAAAcAA' + 'EAAAAAADwAAwABAAAAHAAEACAAAAAEAAQAAQAAAC7//wAAAC7////TAAEAAAAAAAABBgAA' + 'AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEAAAAAAA' + 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA' + 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA' + 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA' + 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMAAA' + 'AAAAD/gwAyAAAAAQAAAAAAAAAAAAAAAAAAAAABAAQEAAEBAQJYAAEBASH4DwD4GwHEAvgc' + 'A/gXBIwMAYuL+nz5tQXkD5j3CBLnEQACAQEBIVhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWF' + 'hYWFhYWFhYAAABAQAADwACAQEEE/t3Dov6fAH6fAT+fPp8+nwHDosMCvm1Cvm1DAz6fBQA' + 'AAAAAAABAAAAAMmJbzEAAAAAzgTjFQAAAADOBOQpAAEAAAAAAAAADAAUAAQAAAABAAAAAg' + 'ABAAAAAAAAAAAD6AAAAAAAAA==');
  };
  Object.defineProperty(FontLoader.prototype, 'loadTestFont', {
    get: function get() {
      return (0, _util.shadow)(this, 'loadTestFont', getLoadTestFont());
    },

    configurable: true
  });
  FontLoader.prototype.addNativeFontFace = function fontLoader_addNativeFontFace(nativeFontFace) {
    this.nativeFontFaces.push(nativeFontFace);
    document.fonts.add(nativeFontFace);
  };
  FontLoader.prototype.bind = function fontLoaderBind(fonts, callback) {
    var rules = [];
    var fontsToLoad = [];
    var fontLoadPromises = [];
    var getNativeFontPromise = function getNativeFontPromise(nativeFontFace) {
      return nativeFontFace.loaded.catch(function (e) {
        (0, _util.warn)('Failed to load font "' + nativeFontFace.family + '": ' + e);
      });
    };
    var isFontLoadingAPISupported = FontLoader.isFontLoadingAPISupported && !FontLoader.isSyncFontLoadingSupported;
    for (var i = 0, ii = fonts.length; i < ii; i++) {
      var font = fonts[i];
      if (font.attached || font.loading === false) {
        continue;
      }
      font.attached = true;
      if (isFontLoadingAPISupported) {
        var nativeFontFace = font.createNativeFontFace();
        if (nativeFontFace) {
          this.addNativeFontFace(nativeFontFace);
          fontLoadPromises.push(getNativeFontPromise(nativeFontFace));
        }
      } else {
        var rule = font.createFontFaceRule();
        if (rule) {
          this.insertRule(rule);
          rules.push(rule);
          fontsToLoad.push(font);
        }
      }
    }
    var request = this.queueLoadingCallback(callback);
    if (isFontLoadingAPISupported) {
      Promise.all(fontLoadPromises).then(function () {
        request.complete();
      });
    } else if (rules.length > 0 && !FontLoader.isSyncFontLoadingSupported) {
      this.prepareFontLoadEvent(rules, fontsToLoad, request);
    } else {
      request.complete();
    }
  };
  FontLoader.prototype.queueLoadingCallback = function FontLoader_queueLoadingCallback(callback) {
    function LoadLoader_completeRequest() {
      (0, _util.assert)(!request.end, 'completeRequest() cannot be called twice');
      request.end = Date.now();
      while (context.requests.length > 0 && context.requests[0].end) {
        var otherRequest = context.requests.shift();
        setTimeout(otherRequest.callback, 0);
      }
    }
    var context = this.loadingContext;
    var requestId = 'pdfjs-font-loading-' + context.nextRequestId++;
    var request = {
      id: requestId,
      complete: LoadLoader_completeRequest,
      callback: callback,
      started: Date.now()
    };
    context.requests.push(request);
    return request;
  };
  FontLoader.prototype.prepareFontLoadEvent = function fontLoaderPrepareFontLoadEvent(rules, fonts, 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) {
      var chunk1 = s.substr(0, offset);
      var chunk2 = s.substr(offset + remove);
      return chunk1 + insert + chunk2;
    }
    var i, ii;
    var canvas = document.createElement('canvas');
    canvas.width = 1;
    canvas.height = 1;
    var ctx = canvas.getContext('2d');
    var called = 0;
    function isFontReady(name, callback) {
      called++;
      if (called > 30) {
        (0, _util.warn)('Load test font never loaded.');
        callback();
        return;
      }
      ctx.font = '30px ' + name;
      ctx.fillText('.', 0, 20);
      var imageData = ctx.getImageData(0, 0, 1, 1);
      if (imageData.data[3] > 0) {
        callback();
        return;
      }
      setTimeout(isFontReady.bind(null, name, callback));
    }
    var loadTestFontId = 'lt' + Date.now() + this.loadTestFontId++;
    var data = this.loadTestFont;
    var COMMENT_OFFSET = 976;
    data = spliceString(data, COMMENT_OFFSET, loadTestFontId.length, loadTestFontId);
    var CFF_CHECKSUM_OFFSET = 16;
    var XXXX_VALUE = 0x58585858;
    var 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));
    var url = 'url(data:font/opentype;base64,' + btoa(data) + ');';
    var rule = '@font-face { font-family:"' + loadTestFontId + '";src:' + url + '}';
    this.insertRule(rule);
    var names = [];
    for (i = 0, ii = fonts.length; i < ii; i++) {
      names.push(fonts[i].loadedName);
    }
    names.push(loadTestFontId);
    var div = document.createElement('div');
    div.setAttribute('style', 'visibility: hidden;' + 'width: 10px; height: 10px;' + 'position: absolute; top: 0px; left: 0px;');
    for (i = 0, ii = names.length; i < ii; ++i) {
      var span = document.createElement('span');
      span.textContent = 'Hi';
      span.style.fontFamily = names[i];
      div.appendChild(span);
    }
    document.body.appendChild(div);
    isFontReady(loadTestFontId, function () {
      document.body.removeChild(div);
      request.complete();
    });
  };
}
{
  FontLoader.isFontLoadingAPISupported = typeof document !== 'undefined' && !!document.fonts;
}
{
  var isSyncFontLoadingSupported = function isSyncFontLoadingSupported() {
    if (typeof navigator === 'undefined') {
      return true;
    }
    var supported = false;
    var m = /Mozilla\/5.0.*?rv:(\d+).*? Gecko/.exec(navigator.userAgent);
    if (m && m[1] >= 14) {
      supported = true;
    }
    return supported;
  };
  Object.defineProperty(FontLoader, 'isSyncFontLoadingSupported', {
    get: function get() {
      return (0, _util.shadow)(FontLoader, 'isSyncFontLoadingSupported', isSyncFontLoadingSupported());
    },

    enumerable: true,
    configurable: true
  });
}
var IsEvalSupportedCached = {
  get value() {
    return (0, _util.shadow)(this, 'value', (0, _util.isEvalSupported)());
  }
};
var FontFaceObject = function FontFaceObjectClosure() {
  function FontFaceObject(translatedData, options) {
    this.compiledGlyphs = Object.create(null);
    for (var i in translatedData) {
      this[i] = translatedData[i];
    }
    this.options = options;
  }
  FontFaceObject.prototype = {
    createNativeFontFace: function FontFaceObject_createNativeFontFace() {
      if (!this.data) {
        return null;
      }
      if (this.options.disableFontFace) {
        this.disableFontFace = true;
        return null;
      }
      var nativeFontFace = new FontFace(this.loadedName, this.data, {});
      if (this.options.fontRegistry) {
        this.options.fontRegistry.registerFont(this);
      }
      return nativeFontFace;
    },
    createFontFaceRule: function FontFaceObject_createFontFaceRule() {
      if (!this.data) {
        return null;
      }
      if (this.options.disableFontFace) {
        this.disableFontFace = true;
        return null;
      }
      var data = (0, _util.bytesToString)(new Uint8Array(this.data));
      var fontName = this.loadedName;
      var url = 'url(data:' + this.mimetype + ';base64,' + btoa(data) + ');';
      var rule = '@font-face { font-family:"' + fontName + '";src:' + url + '}';
      if (this.options.fontRegistry) {
        this.options.fontRegistry.registerFont(this, url);
      }
      return rule;
    },
    getPathGenerator: function FontFaceObject_getPathGenerator(objs, character) {
      if (!(character in this.compiledGlyphs)) {
        var cmds = objs.get(this.loadedName + '_path_' + character);
        var current, i, len;
        if (this.options.isEvalSupported && IsEvalSupportedCached.value) {
          var args,
              js = '';
          for (i = 0, len = cmds.length; i < len; i++) {
            current = cmds[i];
            if (current.args !== undefined) {
              args = current.args.join(',');
            } else {
              args = '';
            }
            js += 'c.' + current.cmd + '(' + args + ');\n';
          }
          this.compiledGlyphs[character] = new Function('c', 'size', js);
        } else {
          this.compiledGlyphs[character] = function (c, size) {
            for (i = 0, len = cmds.length; i < len; i++) {
              current = cmds[i];
              if (current.cmd === 'scale') {
                current.args = [size, -size];
              }
              c[current.cmd].apply(c, current.args);
            }
          };
        }
      }
      return this.compiledGlyphs[character];
    }
  };
  return FontFaceObject;
}();
exports.FontFaceObject = FontFaceObject;
exports.FontLoader = FontLoader;