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Implements refinement

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This commit is contained in:
Yury Delendik 2012-06-21 17:26:24 -05:00
parent e09eb529d9
commit aa877e1d40
1 changed files with 154 additions and 16 deletions
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170
src/jbig2.js
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@ -319,6 +319,19 @@ var Jbig2Image = (function Jbig2ImageClosure() {
{x: 1, y: -1}, {x: -4, y: 0}, {x: -3, y: 0}, {x: -2, y: 0}, {x: -1, y: 0}]
];
var RefinementTemplates = [
{
coding: [{x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}],
reference: [{x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}, {x: 0, y: 0},
{x: 1, y: 0}, {x: -1, y: 1}, {x: 0, y: 1}, {x: 1, y: 1}]
},
{
coding: [{x: -1, y: -1}, {x: 0, y: -1}, {x: 1, y: -1}, {x: -1, y: 0}],
reference: [{x: 0, y: -1}, {x: -1, y: 0}, {x: 0, y: 0}, {x: 1, y: 0},
{x: 0, y: 1}, {x: 1, y: 1}]
}
];
var ReusedContexts = [
0x1CD3, // '00111001101' (template) + '0011' (at),
0x079A, // '001111001101' + '0',
@ -326,6 +339,11 @@ var Jbig2Image = (function Jbig2ImageClosure() {
0x018B // '011000101' + '1'
];
var RefinementReusedContexts = [
0x0020, // '000' + '0' (coding) + '00010000' + '0' (reference)
0x0008 // '0000' + '001000'
];
function log2(x) {
var n = 1, i = 0;
while (x > n) {
@ -353,7 +371,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
return (data[start] << 24) >> 24;
}
// 6.2
// 6.2 Generic Region Decoding Procedure
function decodeBitmap(mmr, width, height, templateIndex, prediction, skip, at,
data, start, end) {
if (mmr)
@ -368,7 +386,8 @@ var Jbig2Image = (function Jbig2ImageClosure() {
templateX[k] = template[k].x;
templateY[k] = template[k].y;
}
var pseudoPixelContext = ReusedContexts[template];
var pseudoPixelContext = ReusedContexts[templateIndex];
var bitmap = [];
var decoder, contexts, cx;
if (data instanceof ArithmeticDecoder) {
@ -382,6 +401,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
decoder = new ArithmeticDecoder(data, start, end);
contexts = [];
}
var ltp = 0;
for (var i = 0; i < height; i++) {
if (prediction) {
@ -420,6 +440,90 @@ var Jbig2Image = (function Jbig2ImageClosure() {
return bitmap;
}
// 6.3.2 Generic Refinement Region Decoding Procedure
function decodeRefinement(width, height, templateIndex, referenceBitmap,
offsetX, offsetY, prediction, at,
data, start, end) {
var codingTemplate = RefinementTemplates[templateIndex].coding;
if (templateIndex == 0)
codingTemplate = codingTemplate.concat([at[0]]);
var codingTemplateLength = codingTemplate.length;
var codingTemplateX = new Int32Array(codingTemplateLength);
var codingTemplateY = new Int32Array(codingTemplateLength);
for (var k = 0; k < codingTemplateLength; k++) {
codingTemplateX[k] = codingTemplate[k].x;
codingTemplateY[k] = codingTemplate[k].y;
}
var referenceTemplate = RefinementTemplates[templateIndex].reference;
if (templateIndex == 0)
referenceTemplate = referenceTemplate.concat([at[1]]);
var referenceTemplateLength = referenceTemplate.length;
var referenceTemplateX = new Int32Array(referenceTemplateLength);
var referenceTemplateY = new Int32Array(referenceTemplateLength);
for (var k = 0; k < referenceTemplateLength; k++) {
referenceTemplateX[k] = referenceTemplate[k].x;
referenceTemplateY[k] = referenceTemplate[k].y;
}
var referenceWidth = referenceBitmap[0].length;
var referenceHeight = referenceBitmap.length;
var pseudoPixelContext = RefinementReusedContexts[templateIndex];
var bitmap = [];
var decoder, contexts, cx;
if (data instanceof ArithmeticDecoder) {
decoder = data;
var contextCache = start;
if ('GR' in contextCache)
contexts = contextCache['GR'];
else
contextCache['GR'] = contexts = [];
} else {
decoder = new ArithmeticDecoder(data, start, end);
contexts = [];
}
var ltp = 0;
for (var i = 0; i < height; i++) {
if (prediction) {
cx = contexts[pseudoPixelContext];
if (!cx)
contexts[pseudoPixelContext] = cx = {index: 0, mps: 0};
var sltp = decoder.readBit(cx);
ltp ^= sltp;
}
var row = new Uint8Array(width);
bitmap.push(row);
for (var j = 0; j < width; j++) {
if (ltp)
throw 'prediction is not supported';
var contextLabel = 0;
for (var k = 0; k < codingTemplateLength; k++) {
var i0 = i + codingTemplateY[k], j0 = j + codingTemplateX[k];
if (i0 < 0 || j0 < 0 || j0 >= width)
contextLabel <<= 1; // out of bound pixel
else
contextLabel = (contextLabel << 1) | bitmap[i0][j0];
}
for (var k = 0; k < referenceTemplateLength; k++) {
var i0 = i + referenceTemplateY[k] + offsetY;
var j0 = j + referenceTemplateX[k] + offsetX;
if (i0 < 0 || i0 >= referenceHeight || j0 < 0 || j0 >= referenceWidth)
contextLabel <<= 1; // out of bound pixel
else
contextLabel = (contextLabel << 1) | referenceBitmap[i0][j0];
}
cx = contexts[contextLabel];
if (!cx)
contexts[contextLabel] = cx = {index: 0, mps: 0};
var pixel = decoder.readBit(cx);
row[j] = pixel;
}
}
return bitmap;
}
// 6.5.5 Decoding the symbol dictionary
function decodeSymbolDictionary(huffman, refinement, symbols,
numberOfNewSymbols, numberOfExportedSymbols,
@ -428,12 +532,11 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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 symbolCodeLength = log2(symbols.length + numberOfNewSymbols);
var decoder = new ArithmeticDecoder(data, start, end);
while (newSymbols.length < numberOfNewSymbols) {
var deltaHeight = decodeInteger(contextCache, 'IADH', decoder); // 6.5.6
@ -446,9 +549,25 @@ var Jbig2Image = (function Jbig2ImageClosure() {
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);
var bitmap;
if (refinement) {
// 6.5.8.2 Refinement/aggregate-coded symbol bitmap
var numberOfInstances = decodeInteger(contextCache, 'IAAI', decoder);
if (numberOfInstances > 1)
throw 'number of instances > 1 is not supported';
var symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);
var rdx = decodeInteger(contextCache, 'IARDX', decoder); // 6.4.11.3
var rdy = decodeInteger(contextCache, 'IARDY', decoder); // 6.4.11.4
var symbol = symbolId < symbols.length ? symbols[symbolId] :
newSymbols[symbolId - symbols.length];
bitmap = decodeRefinement(currentWidth, currentHeight,
refinementTemplateIndex, symbol, rdx, rdy, false, refinementAt,
decoder, contextCache);
} else {
// 6.5.8.1 Direct-coded symbol bitmap
bitmap = decodeBitmap(false, currentWidth, currentHeight,
templateIndex, false, null, at, decoder, contextCache);
}
newSymbols.push(bitmap);
}
}
@ -473,12 +592,10 @@ var Jbig2Image = (function Jbig2ImageClosure() {
stripSize, inputSymbols, symbolCodeLength,
transposed, dsOffset, referenceCorner,
combinationOperator, huffmanTables,
refinementTemplate, refinementAt,
refinementTemplateIndex, refinementAt,
data, start, end) {
if (huffman)
throw 'huffman is not supported';
if (refinement)
throw 'refinement is not supported';
// Prepare bitmap
var bitmap = [];
@ -496,7 +613,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
if (transposed)
throw 'transposed!=0 is not supported';
if (combinationOperator != 0)
if (combinationOperator != 0 && combinationOperator != 2)
throw 'combinationOperator==' + combinationOperator + ' is not supported';
var stripT = -decodeInteger(contextCache, 'IADT', decoder); // 6.4.6
@ -512,20 +629,41 @@ var Jbig2Image = (function Jbig2ImageClosure() {
do {
var currentT = stripSize == 1 ? 0 :
decodeInteger(contextCache, 'IAIT', decoder); // 6.4.9
var t = stripT + currentT;
var t = stripSize * stripT + currentT;
var symbolId = decodeIAID(contextCache, decoder, symbolCodeLength);
var applyRefinement = refinement &&
decodeInteger(contextCache, 'IARI', decoder);
var symbolBitmap = inputSymbols[symbolId];
var symbolWidth = symbolBitmap[0].length;
var symbolHeight = symbolBitmap.length;
if (applyRefinement) {
var rdw = decodeInteger(contextCache, 'IARDW', decoder); // 6.4.11.1
var rdh = decodeInteger(contextCache, 'IARDH', decoder); // 6.4.11.2
var rdx = decodeInteger(contextCache, 'IARDX', decoder); // 6.4.11.3
var rdy = decodeInteger(contextCache, 'IARDY', decoder); // 6.4.11.4
symbolWidth += rdw;
symbolHeight += rdh;
symbolBitmap = decodeRefinement(symbolWidth, symbolHeight,
refinementTemplateIndex, symbolBitmap, (rdw >> 1) + rdx,
(rdh >> 1) + rdy, false, refinementAt,
decoder, contextCache);
}
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];
switch (combinationOperator) {
case 0: // OR
for (var s2 = 0; s2 < symbolWidth; s2++)
row[offsetS + s2] |= symbolRow[s2];
break;
case 2: // XOR
for (var s2 = 0; s2 < symbolWidth; s2++)
row[offsetS + s2] ^= symbolRow[s2];
break;
}
}
currentS += symbolWidth - 1;
@ -722,7 +860,7 @@ var Jbig2Image = (function Jbig2ImageClosure() {
});
position += 2;
}
dictionary.refinementAt = at;
textRegion.refinementAt = at;
}
textRegion.numberOfSymbolInstances = readUint32(data, position);
position += 4;