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';
var sharedUtil = require('../shared/util.js');
var assert = sharedUtil.assert;
var bytesToString = sharedUtil.bytesToString;
var string32 = sharedUtil.string32;
var shadow = sharedUtil.shadow;
var warn = sharedUtil.warn;
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 () {
 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 () {
  return 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 (nativeFontFace) {
  return nativeFontFace.loaded.catch(function (e) {
   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() {
  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) {
   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, 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 () {
  return shadow(FontLoader, 'isSyncFontLoadingSupported', isSyncFontLoadingSupported());
 },
 enumerable: true,
 configurable: true
});
var IsEvalSupportedCached = {
 get value() {
  return shadow(this, 'value', sharedUtil.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 = 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;