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Merge pull request #9192 from Snuffleupagus/issue-8229

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Build a fallback `ToUnicode` map for simple fonts (issue 8229)
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Jonas Jenwald 2017-11-30 10:27:32 +01:00 committed by GitHub
commit f3c50fe2f9
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5 changed files with 112 additions and 84 deletions
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180
src/core/evaluator.js
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@ -1932,98 +1932,116 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
});
},
/**
* @returns {ToUnicodeMap}
* @private
*/
_buildSimpleFontToUnicode(properties) {
assert(!properties.composite, 'Must be a simple font.');
let toUnicode = [], charcode, glyphName;
let encoding = properties.defaultEncoding.slice();
let baseEncodingName = properties.baseEncodingName;
// Merge in the differences array.
let differences = properties.differences;
for (charcode in differences) {
glyphName = differences[charcode];
if (glyphName === '.notdef') {
// Skip .notdef to prevent rendering errors, e.g. boxes appearing
// where there should be spaces (fixes issue5256.pdf).
continue;
}
encoding[charcode] = glyphName;
}
let glyphsUnicodeMap = getGlyphsUnicode();
for (charcode in encoding) {
// a) Map the character code to a character name.
glyphName = encoding[charcode];
// b) Look up the character name in the Adobe Glyph List (see the
// Bibliography) to obtain the corresponding Unicode value.
if (glyphName === '') {
continue;
} else if (glyphsUnicodeMap[glyphName] === undefined) {
// (undocumented) c) Few heuristics to recognize unknown glyphs
// NOTE: Adobe Reader does not do this step, but OSX Preview does
let code = 0;
switch (glyphName[0]) {
case 'G': // Gxx glyph
if (glyphName.length === 3) {
code = parseInt(glyphName.substr(1), 16);
}
break;
case 'g': // g00xx glyph
if (glyphName.length === 5) {
code = parseInt(glyphName.substr(1), 16);
}
break;
case 'C': // Cddd glyph
case 'c': // cddd glyph
if (glyphName.length >= 3) {
code = +glyphName.substr(1);
}
break;
default:
// 'uniXXXX'/'uXXXX{XX}' glyphs
let unicode = getUnicodeForGlyph(glyphName, glyphsUnicodeMap);
if (unicode !== -1) {
code = unicode;
}
}
if (code) {
// If `baseEncodingName` is one the predefined encodings, and `code`
// equals `charcode`, using the glyph defined in the baseEncoding
// seems to yield a better `toUnicode` mapping (fixes issue 5070).
if (baseEncodingName && code === +charcode) {
let baseEncoding = getEncoding(baseEncodingName);
if (baseEncoding && (glyphName = baseEncoding[charcode])) {
toUnicode[charcode] =
String.fromCharCode(glyphsUnicodeMap[glyphName]);
continue;
}
}
toUnicode[charcode] = String.fromCharCode(code);
}
continue;
}
toUnicode[charcode] = String.fromCharCode(glyphsUnicodeMap[glyphName]);
}
return new ToUnicodeMap(toUnicode);
},
/**
* Builds a char code to unicode map based on section 9.10 of the spec.
* @param {Object} properties Font properties object.
* @return {Promise} A Promise that is resolved with a
* {ToUnicodeMap|IdentityToUnicodeMap} object.
*/
buildToUnicode: function PartialEvaluator_buildToUnicode(properties) {
buildToUnicode(properties) {
properties.hasIncludedToUnicodeMap =
!!properties.toUnicode && properties.toUnicode.length > 0;
// Section 9.10.2 Mapping Character Codes to Unicode Values
if (properties.hasIncludedToUnicodeMap) {
// Some fonts contain incomplete ToUnicode data, causing issues with
// text-extraction. For simple fonts, containing encoding information,
// use a fallback ToUnicode map to improve this (fixes issue8229.pdf).
if (!properties.composite && properties.hasEncoding) {
properties.fallbackToUnicode =
this._buildSimpleFontToUnicode(properties);
}
return Promise.resolve(properties.toUnicode);
}
// According to the spec if the font is a simple font we should only map
// to unicode if the base encoding is MacRoman, MacExpert, or WinAnsi or
// the differences array only contains adobe standard or symbol set names,
// in pratice it seems better to always try to create a toUnicode
// map based of the default encoding.
var toUnicode, charcode, glyphName;
// in pratice it seems better to always try to create a toUnicode map
// based of the default encoding.
if (!properties.composite /* is simple font */) {
toUnicode = [];
var encoding = properties.defaultEncoding.slice();
var baseEncodingName = properties.baseEncodingName;
// Merge in the differences array.
var differences = properties.differences;
for (charcode in differences) {
glyphName = differences[charcode];
if (glyphName === '.notdef') {
// Skip .notdef to prevent rendering errors, e.g. boxes appearing
// where there should be spaces (fixes issue5256.pdf).
continue;
}
encoding[charcode] = glyphName;
}
var glyphsUnicodeMap = getGlyphsUnicode();
for (charcode in encoding) {
// a) Map the character code to a character name.
glyphName = encoding[charcode];
// b) Look up the character name in the Adobe Glyph List (see the
// Bibliography) to obtain the corresponding Unicode value.
if (glyphName === '') {
continue;
} else if (glyphsUnicodeMap[glyphName] === undefined) {
// (undocumented) c) Few heuristics to recognize unknown glyphs
// NOTE: Adobe Reader does not do this step, but OSX Preview does
var code = 0;
switch (glyphName[0]) {
case 'G': // Gxx glyph
if (glyphName.length === 3) {
code = parseInt(glyphName.substr(1), 16);
}
break;
case 'g': // g00xx glyph
if (glyphName.length === 5) {
code = parseInt(glyphName.substr(1), 16);
}
break;
case 'C': // Cddd glyph
case 'c': // cddd glyph
if (glyphName.length >= 3) {
code = +glyphName.substr(1);
}
break;
default:
// 'uniXXXX'/'uXXXX{XX}' glyphs
var unicode = getUnicodeForGlyph(glyphName, glyphsUnicodeMap);
if (unicode !== -1) {
code = unicode;
}
}
if (code) {
// If |baseEncodingName| is one the predefined encodings,
// and |code| equals |charcode|, using the glyph defined in the
// baseEncoding seems to yield a better |toUnicode| mapping
// (fixes issue 5070).
if (baseEncodingName && code === +charcode) {
var baseEncoding = getEncoding(baseEncodingName);
if (baseEncoding && (glyphName = baseEncoding[charcode])) {
toUnicode[charcode] =
String.fromCharCode(glyphsUnicodeMap[glyphName]);
continue;
}
}
toUnicode[charcode] = String.fromCharCode(code);
}
continue;
}
toUnicode[charcode] =
String.fromCharCode(glyphsUnicodeMap[glyphName]);
}
return Promise.resolve(new ToUnicodeMap(toUnicode));
return Promise.resolve(this._buildSimpleFontToUnicode(properties));
}
// If the font is a composite font that uses one of the predefined CMaps
// listed in Table 118 (except Identity–H and Identity–V) or whose
// descendant CIDFont uses the Adobe-GB1, Adobe-CNS1, Adobe-Japan1, or
@ -2042,12 +2060,12 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
// b) Obtain the registry and ordering of the character collection used
// by the font’s CMap (for example, Adobe and Japan1) from its
// CIDSystemInfo dictionary.
var registry = properties.cidSystemInfo.registry;
var ordering = properties.cidSystemInfo.ordering;
let registry = properties.cidSystemInfo.registry;
let ordering = properties.cidSystemInfo.ordering;
// c) Construct a second CMap name by concatenating the registry and
// ordering obtained in step (b) in the format registry–ordering–UCS2
// (for example, Adobe–Japan1–UCS2).
var ucs2CMapName = Name.get(registry + '-' + ordering + '-UCS2');
let ucs2CMapName = Name.get(registry + '-' + ordering + '-UCS2');
// d) Obtain the CMap with the name constructed in step (c) (available
// from the ASN Web site; see the Bibliography).
return CMapFactory.create({
@ -2055,15 +2073,15 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
fetchBuiltInCMap: this.fetchBuiltInCMap,
useCMap: null,
}).then(function (ucs2CMap) {
var cMap = properties.cMap;
toUnicode = [];
let cMap = properties.cMap;
let toUnicode = [];
cMap.forEach(function(charcode, cid) {
if (cid > 0xffff) {
throw new FormatError('Max size of CID is 65,535');
}
// e) Map the CID obtained in step (a) according to the CMap
// obtained in step (d), producing a Unicode value.
var ucs2 = ucs2CMap.lookup(cid);
let ucs2 = ucs2CMap.lookup(cid);
if (ucs2) {
toUnicode[charcode] =
String.fromCharCode((ucs2.charCodeAt(0) << 8) +

8
src/core/fonts.js
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@ -211,9 +211,9 @@ var Glyph = (function GlyphClosure() {
})();
var ToUnicodeMap = (function ToUnicodeMapClosure() {
function ToUnicodeMap(cmap) {
function ToUnicodeMap(cmap = []) {
// The elements of this._map can be integers or strings, depending on how
// |cmap| was created.
// `cmap` was created.
this._map = cmap;
}
@ -516,6 +516,7 @@ var Font = (function FontClosure() {
this.defaultEncoding = properties.defaultEncoding;
this.toUnicode = properties.toUnicode;
this.fallbackToUnicode = properties.fallbackToUnicode || new ToUnicodeMap();
this.toFontChar = [];
@ -2766,7 +2767,8 @@ var Font = (function FontClosure() {
width = isNum(width) ? width : this.defaultWidth;
var vmetric = this.vmetrics && this.vmetrics[widthCode];
var unicode = this.toUnicode.get(charcode) || charcode;
let unicode = this.toUnicode.get(charcode) ||
this.fallbackToUnicode.get(charcode) || charcode;
if (typeof unicode === 'number') {
unicode = String.fromCharCode(unicode);
}

1
test/pdfs/.gitignore vendored
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@ -53,6 +53,7 @@
!issue8061.pdf
!issue8088.pdf
!issue8125.pdf
!issue8229.pdf
!issue8372.pdf
!issue8424.pdf
!issue8480.pdf

BIN
test/pdfs/issue8229.pdf Normal file
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Binary file not shown.

7
test/test_manifest.json
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@ -1438,6 +1438,13 @@
"link": false,
"type": "text"
},
{ "id": "issue8229",
"file": "pdfs/issue8229.pdf",
"md5": "a729f663782e87ebc1efad0755ebf6a5",
"rounds": 1,
"link": false,
"type": "text"
},
{ "id": "ShowText-ShadingPattern",
"file": "pdfs/ShowText-ShadingPattern.pdf",
"md5": "fe683725db037ffe19d390969610a652",