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Adds basic symbol dictionary and text region.

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This commit is contained in:
Yury Delendik 2012-06-18 15:03:20 -05:00
parent 95bc99f698
commit e09eb529d9
3 changed files with 450 additions and 21 deletions
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457
src/jbig2.js
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@ -5,6 +5,7 @@
var Jbig2Image = (function Jbig2ImageClosure() {
// Annex E. Arithmetic Coding
var ArithmeticDecoder = (function ArithmeticDecoderClosure() {
var QeTable = [
{qe: 0x5601, nmps: 1, nlps: 1, switchFlag: 1},
@ -167,6 +168,128 @@ var Jbig2Image = (function Jbig2ImageClosure() {
return ArithmeticDecoder;
})();
// Annex A. Arithmetic Integer Decoding Procedure
// A.2 Procedure for decoding values
function decodeInteger(contextCache, procedure, decoder) {
var contexts;
if (procedure in contextCache)
contexts = contextCache[procedure];
else
contextCache[procedure] = contexts = [];
var prev = 1;
var state = 1, v = 0, s;
var toRead = 32, offset = 4436; // defaults for state 7
while (state) {
var cx = contexts[prev];
if (!cx)
contexts[prev] = cx = {index: 0, mps: 0};
var bit = decoder.readBit(cx);
prev = prev < 256 ? (prev << 1) | bit :
(((prev << 1) | bit) & 511) | 256;
switch (state) {
case 1:
s = !!bit;
break;
case 2:
if (bit) break;
state = 7;
toRead = 2;
offset = 0;
break;
case 3:
if (bit) break;
state = 7;
toRead = 4;
offset = 4;
break;
case 4:
if (bit) break;
state = 7;
toRead = 6;
offset = 20;
break;
case 5:
if (bit) break;
state = 7;
toRead = 8;
offset = 84;
break;
case 6:
if (bit) break;
state = 7;
toRead = 12;
offset = 340;
break;
default:
v = v * 2 + bit;
if (--toRead == 0)
state = 0;
continue;
}
state++;
}
v += offset;
return !s ? v : v > 0 ? -v : null;
}
// A.3 The IAID decoding procedure
function decodeIAID(contextCache, decoder, codeLength) {
var contexts;
if ('IAID' in contextCache)
contexts = contextCache['IAID'];
else
contextCache['IAID'] = contexts = [];
var prev = 1;
for (var i = 0; i < codeLength; i++) {
var cx = contexts[prev];
if (!cx)
contexts[prev] = cx = {index: 0, mps: 0};
var bit = decoder.readBit(cx);
prev = (prev * 2) + bit;
}
if (codeLength < 31)
return prev & ((1 << codeLength) - 1);
else
return prev - Math.pow(2, codeLength);
}
// Annex B. Huffman Table Decoding Procedure
// B.5 Standard Huffman tables
function TableB1(reader) {
if (!reader.readBit())
return reader.readBits(4); // 0 + VAL
if (!reader.readBit())
return reader.readBits(8) + 16; // 10 + (VAL - 16)
if (!reader.readBit())
return reader.readBits(16) + 272; // 110 + (VAL - 272)
if (!reader.readBit())
return reader.readBits(32) + 65808; // 1110 + (VAL - 65808)
}
function TableB2(reader) {
if (!reader.readBit())
return 0; // 0
if (!reader.readBit())
return 1; // 10
if (!reader.readBit())
return 2; // 110
if (!reader.readBit())
return reader.readBits(3) + 3; // 1110 + (VAL - 3)
if (!reader.readBit())
return reader.readBits(6) + 11; // 11110 + (VAL - 11)
if (!reader.readBit())
return reader.readBits(32) + 75; // 111110 + (VAL - 75)
return null; // OOB
}
function TableB3(reader) {}
function TableB4(reader) {}
function TableB5(reader) {}
// 7.3 Segment types
var SegmentTypes = [
'SymbolDictionary', null, null, null, 'IntermediateTextRegion', null,
'ImmediateTextRegion', 'ImmediateLosslessTextRegion', null, null, null,
@ -203,6 +326,15 @@ var Jbig2Image = (function Jbig2ImageClosure() {
0x018B // '011000101' + '1'
];
function log2(x) {
var n = 1, i = 0;
while (x > n) {
n <<= 1;
i++;
}
return i;
}
function readInt32(data, start) {
return (data[start] << 24) | (data[start + 1] << 16) |
(data[start + 2] << 8) | data[start + 3];
@ -221,6 +353,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
return (data[start] << 24) >> 24;
}
// 6.2
function decodeBitmap(mmr, width, height, templateIndex, prediction, skip, at,
data, start, end) {
if (mmr)
@ -237,8 +370,18 @@ var Jbig2Image = (function Jbig2ImageClosure() {
}
var pseudoPixelContext = ReusedContexts[template];
var bitmap = [];
var decoder = new ArithmeticDecoder(data, start, end);
var contexts = [], cx;
var decoder, contexts, cx;
if (data instanceof ArithmeticDecoder) {
decoder = data;
var contextCache = start;
if ('GB' in contextCache)
contexts = contextCache['GB'];
else
contextCache['GB'] = contexts = [];
} else {
decoder = new ArithmeticDecoder(data, start, end);
contexts = [];
}
var ltp = 0;
for (var i = 0; i < height; i++) {
if (prediction) {
@ -277,6 +420,126 @@ var Jbig2Image = (function Jbig2ImageClosure() {
return bitmap;
}
// 6.5.5 Decoding the symbol dictionary
function decodeSymbolDictionary(huffman, refinement, symbols,
numberOfNewSymbols, numberOfExportedSymbols,
huffmanTables, templateIndex, at,
refinementTemplateIndex, refinementAt,
data, start, end) {
if (huffman)
throw 'huffman is not supported';
if (refinement)
throw 'refinement is not supported';
var newSymbols = [];
var currentHeight = 0;
var contextCache = {};
var decoder = new ArithmeticDecoder(data, start, end);
while (newSymbols.length < numberOfNewSymbols) {
var deltaHeight = decodeInteger(contextCache, 'IADH', decoder); // 6.5.6
currentHeight += deltaHeight;
var currentWidth = 0;
var totalWidth = 0;
while (true) {
var deltaWidth = decodeInteger(contextCache, 'IADW', decoder); // 6.5.7
if (deltaWidth == null)
break; // OOB
currentWidth += deltaWidth;
totalWidth += currentWidth;
// 6.5.8.1 Direct-coded symbol bitmap
var bitmap = decodeBitmap(false, currentWidth, currentHeight,
templateIndex, false, null, at, decoder, contextCache);
newSymbols.push(bitmap);
}
}
// 6.5.10 Exported symbols
var exportedSymbols = [];
var flags = [], currentFlag = false;
while (flags.length < symbols.length + numberOfNewSymbols) {
var runLength = decodeInteger(contextCache, 'IAEX', decoder);
while (runLength--)
flags.push(currentFlag);
currentFlag = !currentFlag;
}
for (var i = 0; i < symbols.length; i++)
if (flags[i]) exportedSymbols.push(symbols[i]);
for (var j = 0; j < numberOfNewSymbols; i++, j++)
if (flags[i]) exportedSymbols.push(newSymbols[j]);
return exportedSymbols;
}
function decodeTextRegion(huffman, refinement, width, height,
defaultPixelValue, numberOfSymbolInstances,
stripSize, inputSymbols, symbolCodeLength,
transposed, dsOffset, referenceCorner,
combinationOperator, huffmanTables,
refinementTemplate, refinementAt,
data, start, end) {
if (huffman)
throw 'huffman is not supported';
if (refinement)
throw 'refinement is not supported';
// Prepare bitmap
var bitmap = [];
for (var i = 0; i < height; i++) {
var row = new Uint8Array(width);
if (defaultPixelValue) {
for (var j = 0; j < width; j++)
row[j] = defaultPixelValue;
}
bitmap.push(row);
}
var contextCache = {};
var decoder = new ArithmeticDecoder(data, start, end);
if (transposed)
throw 'transposed!=0 is not supported';
if (combinationOperator != 0)
throw 'combinationOperator==' + combinationOperator + ' is not supported';
var stripT = -decodeInteger(contextCache, 'IADT', decoder); // 6.4.6
var firstS = 0;
var i = 0;
while (i < numberOfSymbolInstances) {
var deltaT = decodeInteger(contextCache, 'IADT', decoder); // 6.4.6
stripT += deltaT;
var deltaFirstS = decodeInteger(contextCache, 'IAFS', decoder); // 6.4.7
firstS += deltaFirstS;
var currentS = firstS;
do {
var currentT = stripSize == 1 ? 0 :
decodeInteger(contextCache, 'IAIT', decoder); // 6.4.9
var t = stripT + currentT;
var symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);
var symbolBitmap = inputSymbols[symbolId];
var symbolWidth = symbolBitmap[0].length;
var symbolHeight = symbolBitmap.length;
var offsetT = t - ((referenceCorner & 1) ? 0 : symbolHeight);
var offsetS = currentS - ((referenceCorner & 2) ? symbolWidth : 0);
for (var t2 = 0; t2 < symbolHeight; t2++) {
var row = bitmap[offsetT + t2];
if (!row) continue;
var symbolRow = symbolBitmap[t2];
for (var s2 = 0; s2 < symbolWidth; s2++)
row[offsetS + s2] |= symbolRow[s2];
}
currentS += symbolWidth - 1;
i++;
var deltaS = decodeInteger(contextCache, 'IADS', decoder); // 6.4.8
if (deltaS == null)
break; // OOB
currentS += deltaS + dsOffset;
} while (true);
}
return bitmap;
}
function readSegmentHeader(data, start) {
var segmentHeader = {};
segmentHeader.number = readUint32(data, start);
@ -302,7 +565,6 @@ var Jbig2Image = (function Jbig2ImageClosure() {
}
} else if (referredFlags == 5 || referredFlags == 6)
throw 'Invalid referred-to flags';
segmentHeader.referredToCount = referredToCount;
segmentHeader.retainBits = retainBits;
var referredToSegmentNumberSize = segmentHeader.number <= 256 ? 1 :
segmentHeader.number <= 65536 ? 2 : 4;
@ -358,6 +620,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
return segments;
}
// 7.4.1 Region segment information field
function readRegionSegmentInformation(data, start) {
return {
width: readUint32(data, start),
@ -374,8 +637,100 @@ var Jbig2Image = (function Jbig2ImageClosure() {
if (!(header.typeName in visitor))
return;
var data = segment.data, position = segment.start, args;
var data = segment.data, position = segment.start, end = segment.end;
var args;
switch (header.type) {
case 0: // SymbolDictionary
// 7.4.2 Symbol dictionary segment syntax
var dictionary = {};
var dictionaryFlags = readUint16(data, position); // 7.4.2.1.1
dictionary.huffman = !!(dictionaryFlags & 1);
dictionary.refinement = !!(dictionaryFlags & 2);
dictionary.huffmanDHSelector = (dictionaryFlags >> 2) & 3;
dictionary.huffmanDWSelector = (dictionaryFlags >> 4) & 3;
dictionary.bitmapSizeSelector = (dictionaryFlags >> 6) & 1;
dictionary.aggregationInstancesSelector = (dictionaryFlags >> 7) & 1;
dictionary.bitmapCodingContextUsed = !!(dictionaryFlags & 256);
dictionary.bitmapCodingContextRetained = !!(dictionaryFlags & 512);
dictionary.template = (dictionaryFlags >> 10) & 3;
dictionary.refinementTemplate = (dictionaryFlags >> 12) & 1;
position += 2;
if (!dictionary.huffman) {
var atLength = dictionary.template == 0 ? 4 : 1;
var at = [];
for (var i = 0; i < atLength; i++) {
at.push({
x: readInt8(data, position),
y: readInt8(data, position + 1)
});
position += 2;
}
dictionary.at = at;
}
if (dictionary.refinement && !dictionary.refinementTemplate) {
var at = [];
for (var i = 0; i < 2; i++) {
at.push({
x: readInt8(data, position),
y: readInt8(data, position + 1)
});
position += 2;
}
dictionary.refinementAt = at;
}
dictionary.numberOfExportedSymbols = readUint32(data, position);
position += 4;
dictionary.numberOfNewSymbols = readUint32(data, position);
position += 4;
args = [dictionary, header.number, header.referredTo,
data, position, end];
break;
case 6: // ImmediateTextRegion
var textRegion = {};
textRegion.info = readRegionSegmentInformation(data, position);
position += RegionSegmentInformationFieldLength;
var textRegionSegmentFlags = readUint16(data, position);
position += 2;
textRegion.huffman = !!(textRegionSegmentFlags & 1);
textRegion.refinement = !!(textRegionSegmentFlags & 2);
textRegion.stripSize = 1 << ((textRegionSegmentFlags >> 2) & 3);
textRegion.referenceCorner = (textRegionSegmentFlags >> 4) & 3;
textRegion.transposed = !!(textRegionSegmentFlags & 64);
textRegion.combinationOperator = (textRegionSegmentFlags >> 7) & 3;
textRegion.defaultPixelValue = (textRegionSegmentFlags >> 9) & 1;
textRegion.dsOffset = (textRegionSegmentFlags >> 10) & 31;
textRegion.refinementTemplate = (textRegionSegmentFlags >> 15) & 1;
if (textRegion.huffman) {
var textRegionHuffmanFlags = readUint16(data, position);
position += 2;
textRegion.huffmanFS = (textRegionHuffmanFlags) & 3;
textRegion.huffmanDS = (textRegionHuffmanFlags >> 2) & 3;
textRegion.huffmanDT = (textRegionHuffmanFlags >> 4) & 3;
textRegion.huffmanRefinementDW = (textRegionHuffmanFlags >> 6) & 3;
textRegion.huffmanRefinementDH = (textRegionHuffmanFlags >> 8) & 3;
textRegion.huffmanRefinementDX = (textRegionHuffmanFlags >> 10) & 3;
textRegion.huffmanRefinementDY = (textRegionHuffmanFlags >> 12) & 3;
textRegion.huffmanRefinementSizeSelector =
!!(textRegionHuffmanFlags & 14);
}
if (textRegion.refinement && !textRegion.refinementTemplate) {
var at = [];
for (var i = 0; i < 2; i++) {
at.push({
x: readInt8(data, position),
y: readInt8(data, position + 1)
});
position += 2;
}
dictionary.refinementAt = at;
}
textRegion.numberOfSymbolInstances = readUint32(data, position);
position += 4;
// TODO 7.4.3.1.7 Symbol ID Huffman table decoding
if (textRegion.huffman)
throw 'huffman is not supported';
args = [textRegion, header.referredTo, data, position, end];
break;
case 38: // ImmediateGenericRegion
var genericRegion = {};
genericRegion.info = readRegionSegmentInformation(data, position);
@ -396,7 +751,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
}
genericRegion.at = at;
}
args = [genericRegion, data, position, segment.end];
args = [genericRegion, data, position, end];
break;
case 48: // PageInformation
var pageInfo = {
@ -450,15 +805,20 @@ var Jbig2Image = (function Jbig2ImageClosure() {
// processSegments(segments, new SimpleSegmentVisitor());
}
function parseJbig2Chunk(data, start, end) {
var segments = readSegments({}, data, start, end);
function parseJbig2Chunks(chunks) {
var visitor = new SimpleSegmentVisitor();
for (var i = 0; i < chunks.length; i++) {
var chunk = chunks[i];
var segments = readSegments({}, chunk.data, chunk.start, chunk.end);
processSegments(segments, visitor);
}
return visitor.buffer;
}
function SimpleSegmentVisitor() {
this.PageInformation = function(info) {
function SimpleSegmentVisitor() {}
SimpleSegmentVisitor.prototype = {
PageInformation: function SimpleSegmentVisitor_PageInformation(info) {
this.currentPageInfo = info;
var rowSize = (info.width + 7) >> 3;
var buffer = new Uint8Array(rowSize * info.height);
@ -466,12 +826,9 @@ var Jbig2Image = (function Jbig2ImageClosure() {
for (var i = 0; i < buffer.length; i++)
buffer[i] = fill;
this.buffer = buffer;
};
this.ImmediateGenericRegion = function(region, data, start, end) {
var regionInfo = region.info, pageInfo = this.currentPageInfo;
var bitmap = decodeBitmap(region.mmr, regionInfo.width, regionInfo.height,
region.template, region.prediction, null,
region.at, data, start, end);
},
drawBitmap: function SimpleSegmentVisitor_drawBitmap(regionInfo, bitmap) {
var pageInfo = this.currentPageInfo;
var width = regionInfo.width, height = regionInfo.height;
var rowSize = (pageInfo.width + 7) >> 3;
var operator = pageInfo.combinationOperatorOverride ?
@ -505,14 +862,78 @@ var Jbig2Image = (function Jbig2ImageClosure() {
throw 'Unimplemented operator: ' + operator;
}
}
};
},
ImmediateGenericRegion:
function SimpleSegmentVisitor_ImmediateGenericRegion(region, data,
start, end) {
var regionInfo = region.info;
var bitmap = decodeBitmap(region.mmr, regionInfo.width, regionInfo.height,
region.template, region.prediction, null,
region.at, data, start, end);
this.drawBitmap(regionInfo, bitmap);
},
SymbolDictionary:
function SimpleSegmentVisitor_SymbolDictionary(dictionary, currentSegment,
referredSegments,
data, start, end) {
var symbols = this.symbols;
var huffmanTables;
if (dictionary.huffman) {
huffmanTables = {};
huffmanTables.DeltaHeights = dictionary.huffmanDHSelector == 0 ?
TableB4 : dictionary.huffmanDHSelector == 1 ? TableB5 :
this.userTable;
huffmanTables.DeltaWidths = dictionary.huffmanDHSelector == 0 ?
TableB2 : dictionary.huffmanDHSelector == 2 ? TableB3 :
this.userTable;
huffmanTables.BitmapSize = dictionary.huffmanBitmapSizeSelector == 0 ?
TableB1 : this.userTable;
huffmanTables.AggregationInstances =
dictionary.aggregationInstancesSelector == 0 ? TableB1 :
this.userTable;
}
// Combines exported symbols from all referred segments
var inputSymbols = [];
for (var i = 0; i < referredSegments.length; i++)
inputSymbols = inputSymbols.concat(symbols[referredSegments[i]]);
if (!symbols)
this.symbols = symbols = {};
symbols[currentSegment] = decodeSymbolDictionary(dictionary.huffman,
dictionary.refinement, inputSymbols, dictionary.numberOfNewSymbols,
dictionary.numberOfExportedSymbols, huffmanTables,
dictionary.template, dictionary.at,
dictionary.refinementTemplate, dictionary.refinementAt,
data, start, end);
},
ImmediateTextRegion:
function SimpleSegmentVisitor_ImmediateTextRegion(region,
referredSegments,
data, start, end) {
var regionInfo = region.info;
var symbols = this.symbols;
var huffmanTables;
// Combines exported symbols from all referred segments
var inputSymbols = [];
for (var i = 0; i < referredSegments.length; i++)
inputSymbols = inputSymbols.concat(symbols[referredSegments[i]]);
var symbolCodeLength = log2(inputSymbols.length);
var bitmap = decodeTextRegion(region.huffman, region.refinement,
regionInfo.width, regionInfo.height, region.defaultPixelValue,
region.numberOfSymbolInstances, region.stripSize, inputSymbols,
symbolCodeLength, region.transposed, region.dsOffset,
region.referenceCorner, region.combinationOperator, huffmanTables,
region.refinementTemplate, region.refinementAt, data, start, end);
this.drawBitmap(regionInfo, bitmap);
}
};
function Jbig2Image() {}
Jbig2Image.prototype = {
parseChunk: function Jbig2Image_parseChunk(data, start, end) {
return parseJbig2Chunk(data, start, end);
parseChunks: function Jbig2Image_parseChunks(chunks) {
return parseJbig2Chunks(chunks);
}
};

9
src/stream.js
View File

@ -999,7 +999,14 @@ var Jbig2Stream = (function Jbig2StreamClosure() {
var jbig2Image = new Jbig2Image();
var data = jbig2Image.parseChunk(this.bytes, 0, this.bytes.length);
var chunks = [], decodeParams = this.dict.get('DecodeParms');
if (decodeParams && decodeParams.has('JBIG2Globals')) {
var globalsStream = decodeParams.get('JBIG2Globals');
var globals = globalsStream.getBytes();
chunks.push({data: globals, start: 0, end: globals.length});
}
chunks.push({data: this.bytes, start: 0, end: this.bytes.length});
var data = jbig2Image.parseChunks(chunks);
var dataLength = data.length;
// JBIG2 had black as 1 and white as 0, inverting the colors

1
web/viewer.html
View File

@ -35,6 +35,7 @@
<script type="text/javascript" src="../src/worker.js"></script> <!-- PDFJSSCRIPT_REMOVE_CORE -->
<script type="text/javascript" src="../external/jpgjs/jpg.js"></script> <!-- PDFJSSCRIPT_REMOVE_CORE -->
<script type="text/javascript" src="../src/jpx.js"></script> <!-- PDFJSSCRIPT_REMOVE_CORE -->
<script type="text/javascript" src="../src/jbig2.js"></script> <!-- PDFJSSCRIPT_REMOVE_CORE -->
<script type="text/javascript" src="../src/bidi.js"></script> <!-- PDFJSSCRIPT_REMOVE_CORE -->
<script type="text/javascript">PDFJS.workerSrc = '../src/worker_loader.js';</script> <!-- PDFJSSCRIPT_REMOVE_CORE -->
<script type="text/javascript" src="debugger.js"></script>