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Transposed feature for text decoding in jbig2

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Sriram 2013-09-26 20:49:02 +02:00 • committed by Tim van der Meij
parent ea50c078b0
commit f6eee819e2
3 changed files with 62 additions and 23 deletions
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74
src/core/jbig2.js
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@ -572,10 +572,6 @@ var Jbig2Image = (function Jbig2ImageClosure() {
var decoder = decodingContext.decoder;
var contextCache = decodingContext.contextCache;
if (transposed)
error('JBIG2 error: transposed is not supported');
var stripT = -decodeInteger(contextCache, 'IADT', decoder); // 6.4.6
var firstS = 0;
var i = 0;
@ -610,28 +606,60 @@ var Jbig2Image = (function Jbig2ImageClosure() {
}
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];
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;
default:
error('JBIG2 error: operator ' + combinationOperator +
' is not supported');
if (transposed) {
// Place Symbol Bitmap from T1,S1
for (var s2 = 0; s2 < symbolHeight; s2++) {
var row = bitmap[offsetS + s2];
if (!row) {
continue;
}
var symbolRow = symbolBitmap[s2];
// To ignore Parts of Symbol bitmap which goes
// outside bitmap region
var maxWidth = Math.min(width - offsetT, symbolWidth);
switch (combinationOperator) {
case 0: // OR
for (var t2 = 0; t2 < maxWidth; t2++) {
row[offsetT + t2] |= symbolRow[t2];
}
break;
case 2: // XOR
for (var t2 = 0; t2 < maxWidth; t2++) {
row[offsetT + t2] ^= symbolRow[t2];
}
break;
default:
error('JBIG2 error: operator ' + combinationOperator +
' is not supported');
}
}
currentS += symbolHeight - 1;
} else {
for (var t2 = 0; t2 < symbolHeight; t2++) {
var row = bitmap[offsetT + t2];
if (!row) {
continue;
}
var symbolRow = symbolBitmap[t2];
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;
default:
error('JBIG2 error: operator ' + combinationOperator +
' is not supported');
}
}
currentS += symbolWidth - 1;
}
currentS += symbolWidth - 1;
i++;
var deltaS = decodeInteger(contextCache, 'IADS', decoder); // 6.4.8
if (deltaS === null)
break; // OOB