pdfjs-dist/lib/core/font_renderer.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 coreStream = require('./stream.js');
var coreGlyphList = require('./glyphlist.js');
var coreEncodings = require('./encodings.js');
var coreCFFParser = require('./cff_parser.js');
var Util = sharedUtil.Util;
var bytesToString = sharedUtil.bytesToString;
var error = sharedUtil.error;
var Stream = coreStream.Stream;
var getGlyphsUnicode = coreGlyphList.getGlyphsUnicode;
var StandardEncoding = coreEncodings.StandardEncoding;
var CFFParser = coreCFFParser.CFFParser;
var FontRendererFactory = function FontRendererFactoryClosure() {
 function getLong(data, offset) {
  return data[offset] << 24 | data[offset + 1] << 16 | data[offset + 2] << 8 | data[offset + 3];
 }
 function getUshort(data, offset) {
  return data[offset] << 8 | data[offset + 1];
 }
 function parseCmap(data, start, end) {
  var offset = getUshort(data, start + 2) === 1 ? getLong(data, start + 8) : getLong(data, start + 16);
  var format = getUshort(data, start + offset);
  var ranges, p, i;
  if (format === 4) {
   getUshort(data, start + offset + 2);
   var segCount = getUshort(data, start + offset + 6) >> 1;
   p = start + offset + 14;
   ranges = [];
   for (i = 0; i < segCount; i++, p += 2) {
    ranges[i] = { end: getUshort(data, p) };
   }
   p += 2;
   for (i = 0; i < segCount; i++, p += 2) {
    ranges[i].start = getUshort(data, p);
   }
   for (i = 0; i < segCount; i++, p += 2) {
    ranges[i].idDelta = getUshort(data, p);
   }
   for (i = 0; i < segCount; i++, p += 2) {
    var idOffset = getUshort(data, p);
    if (idOffset === 0) {
     continue;
    }
    ranges[i].ids = [];
    for (var j = 0, jj = ranges[i].end - ranges[i].start + 1; j < jj; j++) {
     ranges[i].ids[j] = getUshort(data, p + idOffset);
     idOffset += 2;
    }
   }
   return ranges;
  } else if (format === 12) {
   getLong(data, start + offset + 4);
   var groups = getLong(data, start + offset + 12);
   p = start + offset + 16;
   ranges = [];
   for (i = 0; i < groups; i++) {
    ranges.push({
     start: getLong(data, p),
     end: getLong(data, p + 4),
     idDelta: getLong(data, p + 8) - getLong(data, p)
    });
    p += 12;
   }
   return ranges;
  }
  error('not supported cmap: ' + format);
 }
 function parseCff(data, start, end, seacAnalysisEnabled) {
  var properties = {};
  var parser = new CFFParser(new Stream(data, start, end - start), properties, seacAnalysisEnabled);
  var cff = parser.parse();
  return {
   glyphs: cff.charStrings.objects,
   subrs: cff.topDict.privateDict && cff.topDict.privateDict.subrsIndex && cff.topDict.privateDict.subrsIndex.objects,
   gsubrs: cff.globalSubrIndex && cff.globalSubrIndex.objects
  };
 }
 function parseGlyfTable(glyf, loca, isGlyphLocationsLong) {
  var itemSize, itemDecode;
  if (isGlyphLocationsLong) {
   itemSize = 4;
   itemDecode = function fontItemDecodeLong(data, offset) {
    return data[offset] << 24 | data[offset + 1] << 16 | data[offset + 2] << 8 | data[offset + 3];
   };
  } else {
   itemSize = 2;
   itemDecode = function fontItemDecode(data, offset) {
    return data[offset] << 9 | data[offset + 1] << 1;
   };
  }
  var glyphs = [];
  var startOffset = itemDecode(loca, 0);
  for (var j = itemSize; j < loca.length; j += itemSize) {
   var endOffset = itemDecode(loca, j);
   glyphs.push(glyf.subarray(startOffset, endOffset));
   startOffset = endOffset;
  }
  return glyphs;
 }
 function lookupCmap(ranges, unicode) {
  var code = unicode.charCodeAt(0), gid = 0;
  var l = 0, r = ranges.length - 1;
  while (l < r) {
   var c = l + r + 1 >> 1;
   if (code < ranges[c].start) {
    r = c - 1;
   } else {
    l = c;
   }
  }
  if (ranges[l].start <= code && code <= ranges[l].end) {
   gid = ranges[l].idDelta + (ranges[l].ids ? ranges[l].ids[code - ranges[l].start] : code) & 0xFFFF;
  }
  return {
   charCode: code,
   glyphId: gid
  };
 }
 function compileGlyf(code, cmds, font) {
  function moveTo(x, y) {
   cmds.push({
    cmd: 'moveTo',
    args: [
     x,
     y
    ]
   });
  }
  function lineTo(x, y) {
   cmds.push({
    cmd: 'lineTo',
    args: [
     x,
     y
    ]
   });
  }
  function quadraticCurveTo(xa, ya, x, y) {
   cmds.push({
    cmd: 'quadraticCurveTo',
    args: [
     xa,
     ya,
     x,
     y
    ]
   });
  }
  var i = 0;
  var numberOfContours = (code[i] << 24 | code[i + 1] << 16) >> 16;
  var flags;
  var x = 0, y = 0;
  i += 10;
  if (numberOfContours < 0) {
   do {
    flags = code[i] << 8 | code[i + 1];
    var glyphIndex = code[i + 2] << 8 | code[i + 3];
    i += 4;
    var arg1, arg2;
    if (flags & 0x01) {
     arg1 = (code[i] << 24 | code[i + 1] << 16) >> 16;
     arg2 = (code[i + 2] << 24 | code[i + 3] << 16) >> 16;
     i += 4;
    } else {
     arg1 = code[i++];
     arg2 = code[i++];
    }
    if (flags & 0x02) {
     x = arg1;
     y = arg2;
    } else {
     x = 0;
     y = 0;
    }
    var scaleX = 1, scaleY = 1, scale01 = 0, scale10 = 0;
    if (flags & 0x08) {
     scaleX = scaleY = (code[i] << 24 | code[i + 1] << 16) / 1073741824;
     i += 2;
    } else if (flags & 0x40) {
     scaleX = (code[i] << 24 | code[i + 1] << 16) / 1073741824;
     scaleY = (code[i + 2] << 24 | code[i + 3] << 16) / 1073741824;
     i += 4;
    } else if (flags & 0x80) {
     scaleX = (code[i] << 24 | code[i + 1] << 16) / 1073741824;
     scale01 = (code[i + 2] << 24 | code[i + 3] << 16) / 1073741824;
     scale10 = (code[i + 4] << 24 | code[i + 5] << 16) / 1073741824;
     scaleY = (code[i + 6] << 24 | code[i + 7] << 16) / 1073741824;
     i += 8;
    }
    var subglyph = font.glyphs[glyphIndex];
    if (subglyph) {
     cmds.push({ cmd: 'save' });
     cmds.push({
      cmd: 'transform',
      args: [
       scaleX,
       scale01,
       scale10,
       scaleY,
       x,
       y
      ]
     });
     compileGlyf(subglyph, cmds, font);
     cmds.push({ cmd: 'restore' });
    }
   } while (flags & 0x20);
  } else {
   var endPtsOfContours = [];
   var j, jj;
   for (j = 0; j < numberOfContours; j++) {
    endPtsOfContours.push(code[i] << 8 | code[i + 1]);
    i += 2;
   }
   var instructionLength = code[i] << 8 | code[i + 1];
   i += 2 + instructionLength;
   var numberOfPoints = endPtsOfContours[endPtsOfContours.length - 1] + 1;
   var points = [];
   while (points.length < numberOfPoints) {
    flags = code[i++];
    var repeat = 1;
    if (flags & 0x08) {
     repeat += code[i++];
    }
    while (repeat-- > 0) {
     points.push({ flags: flags });
    }
   }
   for (j = 0; j < numberOfPoints; j++) {
    switch (points[j].flags & 0x12) {
    case 0x00:
     x += (code[i] << 24 | code[i + 1] << 16) >> 16;
     i += 2;
     break;
    case 0x02:
     x -= code[i++];
     break;
    case 0x12:
     x += code[i++];
     break;
    }
    points[j].x = x;
   }
   for (j = 0; j < numberOfPoints; j++) {
    switch (points[j].flags & 0x24) {
    case 0x00:
     y += (code[i] << 24 | code[i + 1] << 16) >> 16;
     i += 2;
     break;
    case 0x04:
     y -= code[i++];
     break;
    case 0x24:
     y += code[i++];
     break;
    }
    points[j].y = y;
   }
   var startPoint = 0;
   for (i = 0; i < numberOfContours; i++) {
    var endPoint = endPtsOfContours[i];
    var contour = points.slice(startPoint, endPoint + 1);
    if (contour[0].flags & 1) {
     contour.push(contour[0]);
    } else if (contour[contour.length - 1].flags & 1) {
     contour.unshift(contour[contour.length - 1]);
    } else {
     var p = {
      flags: 1,
      x: (contour[0].x + contour[contour.length - 1].x) / 2,
      y: (contour[0].y + contour[contour.length - 1].y) / 2
     };
     contour.unshift(p);
     contour.push(p);
    }
    moveTo(contour[0].x, contour[0].y);
    for (j = 1, jj = contour.length; j < jj; j++) {
     if (contour[j].flags & 1) {
      lineTo(contour[j].x, contour[j].y);
     } else if (contour[j + 1].flags & 1) {
      quadraticCurveTo(contour[j].x, contour[j].y, contour[j + 1].x, contour[j + 1].y);
      j++;
     } else {
      quadraticCurveTo(contour[j].x, contour[j].y, (contour[j].x + contour[j + 1].x) / 2, (contour[j].y + contour[j + 1].y) / 2);
     }
    }
    startPoint = endPoint + 1;
   }
  }
 }
 function compileCharString(code, cmds, font) {
  var stack = [];
  var x = 0, y = 0;
  var stems = 0;
  function moveTo(x, y) {
   cmds.push({
    cmd: 'moveTo',
    args: [
     x,
     y
    ]
   });
  }
  function lineTo(x, y) {
   cmds.push({
    cmd: 'lineTo',
    args: [
     x,
     y
    ]
   });
  }
  function bezierCurveTo(x1, y1, x2, y2, x, y) {
   cmds.push({
    cmd: 'bezierCurveTo',
    args: [
     x1,
     y1,
     x2,
     y2,
     x,
     y
    ]
   });
  }
  function parse(code) {
   var i = 0;
   while (i < code.length) {
    var stackClean = false;
    var v = code[i++];
    var xa, xb, ya, yb, y1, y2, y3, n, subrCode;
    switch (v) {
    case 1:
     stems += stack.length >> 1;
     stackClean = true;
     break;
    case 3:
     stems += stack.length >> 1;
     stackClean = true;
     break;
    case 4:
     y += stack.pop();
     moveTo(x, y);
     stackClean = true;
     break;
    case 5:
     while (stack.length > 0) {
      x += stack.shift();
      y += stack.shift();
      lineTo(x, y);
     }
     break;
    case 6:
     while (stack.length > 0) {
      x += stack.shift();
      lineTo(x, y);
      if (stack.length === 0) {
       break;
      }
      y += stack.shift();
      lineTo(x, y);
     }
     break;
    case 7:
     while (stack.length > 0) {
      y += stack.shift();
      lineTo(x, y);
      if (stack.length === 0) {
       break;
      }
      x += stack.shift();
      lineTo(x, y);
     }
     break;
    case 8:
     while (stack.length > 0) {
      xa = x + stack.shift();
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb + stack.shift();
      bezierCurveTo(xa, ya, xb, yb, x, y);
     }
     break;
    case 10:
     n = stack.pop() + font.subrsBias;
     subrCode = font.subrs[n];
     if (subrCode) {
      parse(subrCode);
     }
     break;
    case 11:
     return;
    case 12:
     v = code[i++];
     switch (v) {
     case 34:
      xa = x + stack.shift();
      xb = xa + stack.shift();
      y1 = y + stack.shift();
      x = xb + stack.shift();
      bezierCurveTo(xa, y, xb, y1, x, y1);
      xa = x + stack.shift();
      xb = xa + stack.shift();
      x = xb + stack.shift();
      bezierCurveTo(xa, y1, xb, y, x, y);
      break;
     case 35:
      xa = x + stack.shift();
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb + stack.shift();
      bezierCurveTo(xa, ya, xb, yb, x, y);
      xa = x + stack.shift();
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb + stack.shift();
      bezierCurveTo(xa, ya, xb, yb, x, y);
      stack.pop();
      break;
     case 36:
      xa = x + stack.shift();
      y1 = y + stack.shift();
      xb = xa + stack.shift();
      y2 = y1 + stack.shift();
      x = xb + stack.shift();
      bezierCurveTo(xa, y1, xb, y2, x, y2);
      xa = x + stack.shift();
      xb = xa + stack.shift();
      y3 = y2 + stack.shift();
      x = xb + stack.shift();
      bezierCurveTo(xa, y2, xb, y3, x, y);
      break;
     case 37:
      var x0 = x, y0 = y;
      xa = x + stack.shift();
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb + stack.shift();
      bezierCurveTo(xa, ya, xb, yb, x, y);
      xa = x + stack.shift();
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb;
      y = yb;
      if (Math.abs(x - x0) > Math.abs(y - y0)) {
       x += stack.shift();
      } else {
       y += stack.shift();
      }
      bezierCurveTo(xa, ya, xb, yb, x, y);
      break;
     default:
      error('unknown operator: 12 ' + v);
     }
     break;
    case 14:
     if (stack.length >= 4) {
      var achar = stack.pop();
      var bchar = stack.pop();
      y = stack.pop();
      x = stack.pop();
      cmds.push({ cmd: 'save' });
      cmds.push({
       cmd: 'translate',
       args: [
        x,
        y
       ]
      });
      var cmap = lookupCmap(font.cmap, String.fromCharCode(font.glyphNameMap[StandardEncoding[achar]]));
      compileCharString(font.glyphs[cmap.glyphId], cmds, font);
      cmds.push({ cmd: 'restore' });
      cmap = lookupCmap(font.cmap, String.fromCharCode(font.glyphNameMap[StandardEncoding[bchar]]));
      compileCharString(font.glyphs[cmap.glyphId], cmds, font);
     }
     return;
    case 18:
     stems += stack.length >> 1;
     stackClean = true;
     break;
    case 19:
     stems += stack.length >> 1;
     i += stems + 7 >> 3;
     stackClean = true;
     break;
    case 20:
     stems += stack.length >> 1;
     i += stems + 7 >> 3;
     stackClean = true;
     break;
    case 21:
     y += stack.pop();
     x += stack.pop();
     moveTo(x, y);
     stackClean = true;
     break;
    case 22:
     x += stack.pop();
     moveTo(x, y);
     stackClean = true;
     break;
    case 23:
     stems += stack.length >> 1;
     stackClean = true;
     break;
    case 24:
     while (stack.length > 2) {
      xa = x + stack.shift();
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb + stack.shift();
      bezierCurveTo(xa, ya, xb, yb, x, y);
     }
     x += stack.shift();
     y += stack.shift();
     lineTo(x, y);
     break;
    case 25:
     while (stack.length > 6) {
      x += stack.shift();
      y += stack.shift();
      lineTo(x, y);
     }
     xa = x + stack.shift();
     ya = y + stack.shift();
     xb = xa + stack.shift();
     yb = ya + stack.shift();
     x = xb + stack.shift();
     y = yb + stack.shift();
     bezierCurveTo(xa, ya, xb, yb, x, y);
     break;
    case 26:
     if (stack.length % 2) {
      x += stack.shift();
     }
     while (stack.length > 0) {
      xa = x;
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb;
      y = yb + stack.shift();
      bezierCurveTo(xa, ya, xb, yb, x, y);
     }
     break;
    case 27:
     if (stack.length % 2) {
      y += stack.shift();
     }
     while (stack.length > 0) {
      xa = x + stack.shift();
      ya = y;
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb;
      bezierCurveTo(xa, ya, xb, yb, x, y);
     }
     break;
    case 28:
     stack.push((code[i] << 24 | code[i + 1] << 16) >> 16);
     i += 2;
     break;
    case 29:
     n = stack.pop() + font.gsubrsBias;
     subrCode = font.gsubrs[n];
     if (subrCode) {
      parse(subrCode);
     }
     break;
    case 30:
     while (stack.length > 0) {
      xa = x;
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb + (stack.length === 1 ? stack.shift() : 0);
      bezierCurveTo(xa, ya, xb, yb, x, y);
      if (stack.length === 0) {
       break;
      }
      xa = x + stack.shift();
      ya = y;
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      y = yb + stack.shift();
      x = xb + (stack.length === 1 ? stack.shift() : 0);
      bezierCurveTo(xa, ya, xb, yb, x, y);
     }
     break;
    case 31:
     while (stack.length > 0) {
      xa = x + stack.shift();
      ya = y;
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      y = yb + stack.shift();
      x = xb + (stack.length === 1 ? stack.shift() : 0);
      bezierCurveTo(xa, ya, xb, yb, x, y);
      if (stack.length === 0) {
       break;
      }
      xa = x;
      ya = y + stack.shift();
      xb = xa + stack.shift();
      yb = ya + stack.shift();
      x = xb + stack.shift();
      y = yb + (stack.length === 1 ? stack.shift() : 0);
      bezierCurveTo(xa, ya, xb, yb, x, y);
     }
     break;
    default:
     if (v < 32) {
      error('unknown operator: ' + v);
     }
     if (v < 247) {
      stack.push(v - 139);
     } else if (v < 251) {
      stack.push((v - 247) * 256 + code[i++] + 108);
     } else if (v < 255) {
      stack.push(-(v - 251) * 256 - code[i++] - 108);
     } else {
      stack.push((code[i] << 24 | code[i + 1] << 16 | code[i + 2] << 8 | code[i + 3]) / 65536);
      i += 4;
     }
     break;
    }
    if (stackClean) {
     stack.length = 0;
    }
   }
  }
  parse(code);
 }
 var noop = '';
 function CompiledFont(fontMatrix) {
  this.compiledGlyphs = Object.create(null);
  this.compiledCharCodeToGlyphId = Object.create(null);
  this.fontMatrix = fontMatrix;
 }
 CompiledFont.prototype = {
  getPathJs: function (unicode) {
   var cmap = lookupCmap(this.cmap, unicode);
   var fn = this.compiledGlyphs[cmap.glyphId];
   if (!fn) {
    fn = this.compileGlyph(this.glyphs[cmap.glyphId]);
    this.compiledGlyphs[cmap.glyphId] = fn;
   }
   if (this.compiledCharCodeToGlyphId[cmap.charCode] === undefined) {
    this.compiledCharCodeToGlyphId[cmap.charCode] = cmap.glyphId;
   }
   return fn;
  },
  compileGlyph: function (code) {
   if (!code || code.length === 0 || code[0] === 14) {
    return noop;
   }
   var cmds = [];
   cmds.push({ cmd: 'save' });
   cmds.push({
    cmd: 'transform',
    args: this.fontMatrix.slice()
   });
   cmds.push({
    cmd: 'scale',
    args: [
     'size',
     '-size'
    ]
   });
   this.compileGlyphImpl(code, cmds);
   cmds.push({ cmd: 'restore' });
   return cmds;
  },
  compileGlyphImpl: function () {
   error('Children classes should implement this.');
  },
  hasBuiltPath: function (unicode) {
   var cmap = lookupCmap(this.cmap, unicode);
   return this.compiledGlyphs[cmap.glyphId] !== undefined && this.compiledCharCodeToGlyphId[cmap.charCode] !== undefined;
  }
 };
 function TrueTypeCompiled(glyphs, cmap, fontMatrix) {
  fontMatrix = fontMatrix || [
   0.000488,
   0,
   0,
   0.000488,
   0,
   0
  ];
  CompiledFont.call(this, fontMatrix);
  this.glyphs = glyphs;
  this.cmap = cmap;
 }
 Util.inherit(TrueTypeCompiled, CompiledFont, {
  compileGlyphImpl: function (code, cmds) {
   compileGlyf(code, cmds, this);
  }
 });
 function Type2Compiled(cffInfo, cmap, fontMatrix, glyphNameMap) {
  fontMatrix = fontMatrix || [
   0.001,
   0,
   0,
   0.001,
   0,
   0
  ];
  CompiledFont.call(this, fontMatrix);
  this.glyphs = cffInfo.glyphs;
  this.gsubrs = cffInfo.gsubrs || [];
  this.subrs = cffInfo.subrs || [];
  this.cmap = cmap;
  this.glyphNameMap = glyphNameMap || getGlyphsUnicode();
  this.gsubrsBias = this.gsubrs.length < 1240 ? 107 : this.gsubrs.length < 33900 ? 1131 : 32768;
  this.subrsBias = this.subrs.length < 1240 ? 107 : this.subrs.length < 33900 ? 1131 : 32768;
 }
 Util.inherit(Type2Compiled, CompiledFont, {
  compileGlyphImpl: function (code, cmds) {
   compileCharString(code, cmds, this);
  }
 });
 return {
  create: function FontRendererFactory_create(font, seacAnalysisEnabled) {
   var data = new Uint8Array(font.data);
   var cmap, glyf, loca, cff, indexToLocFormat, unitsPerEm;
   var numTables = getUshort(data, 4);
   for (var i = 0, p = 12; i < numTables; i++, p += 16) {
    var tag = bytesToString(data.subarray(p, p + 4));
    var offset = getLong(data, p + 8);
    var length = getLong(data, p + 12);
    switch (tag) {
    case 'cmap':
     cmap = parseCmap(data, offset, offset + length);
     break;
    case 'glyf':
     glyf = data.subarray(offset, offset + length);
     break;
    case 'loca':
     loca = data.subarray(offset, offset + length);
     break;
    case 'head':
     unitsPerEm = getUshort(data, offset + 18);
     indexToLocFormat = getUshort(data, offset + 50);
     break;
    case 'CFF ':
     cff = parseCff(data, offset, offset + length, seacAnalysisEnabled);
     break;
    }
   }
   if (glyf) {
    var fontMatrix = !unitsPerEm ? font.fontMatrix : [
     1 / unitsPerEm,
     0,
     0,
     1 / unitsPerEm,
     0,
     0
    ];
    return new TrueTypeCompiled(parseGlyfTable(glyf, loca, indexToLocFormat), cmap, fontMatrix);
   }
   return new Type2Compiled(cff, cmap, font.fontMatrix, font.glyphNameMap);
  }
 };
}();
exports.FontRendererFactory = FontRendererFactory;