decoders/pdfjs/jpg.js
/* Copyright 2014 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';
//(function (root, factory) {
// if (typeof define === 'function' && define.amd) {
// define('pdfjs/core/jpg', ['exports'], factory);
// } else if (typeof exports !== 'undefined') {
// factory(exports);
// } else {
// factory((root.pdfjsCoreJpg = {}));
// }
//}(this, function (exports) {
/*
This code was forked from https://github.com/notmasteryet/jpgjs. The original
version was created by github user notmasteryet
- The JPEG specification can be found in the ITU CCITT Recommendation T.81
(www.w3.org/Graphics/JPEG/itu-t81.pdf)
- The JFIF specification can be found in the JPEG File Interchange Format
(www.w3.org/Graphics/JPEG/jfif3.pdf)
- The Adobe Application-Specific JPEG markers in the Supporting the DCT Filters
in PostScript Level 2, Technical Note #5116
(partners.adobe.com/public/developer/en/ps/sdk/5116.DCT_Filter.pdf)
*/
var JpegImage = (function jpegImage() {
var dctZigZag = new Uint8Array([
0,
1, 8,
16, 9, 2,
3, 10, 17, 24,
32, 25, 18, 11, 4,
5, 12, 19, 26, 33, 40,
48, 41, 34, 27, 20, 13, 6,
7, 14, 21, 28, 35, 42, 49, 56,
57, 50, 43, 36, 29, 22, 15,
23, 30, 37, 44, 51, 58,
59, 52, 45, 38, 31,
39, 46, 53, 60,
61, 54, 47,
55, 62,
63
]);
var dctCos1 = 4017; // cos(pi/16)
var dctSin1 = 799; // sin(pi/16)
var dctCos3 = 3406; // cos(3*pi/16)
var dctSin3 = 2276; // sin(3*pi/16)
var dctCos6 = 1567; // cos(6*pi/16)
var dctSin6 = 3784; // sin(6*pi/16)
var dctSqrt2 = 5793; // sqrt(2)
var dctSqrt1d2 = 2896; // sqrt(2) / 2
var tMin = -2056;
var tMax = 2024;
var t8bitMax = 255;
function constructor() {
}
function buildHuffmanTable(codeLengths, values) {
var k = 0, code = [], i, j, length = 16;
while (length > 0 && !codeLengths[length - 1]) {
length--;
}
code.push({children: [], index: 0});
var p = code[0], q;
for (i = 0; i < length; i++) {
for (j = 0; j < codeLengths[i]; j++) {
p = code.pop();
p.children[p.index] = values[k];
while (p.index > 0) {
p = code.pop();
}
p.index++;
code.push(p);
while (code.length <= i) {
code.push(q = {children: [], index: 0});
p.children[p.index] = q.children;
p = q;
}
k++;
}
if (i + 1 < length) {
// p here points to last code
code.push(q = {children: [], index: 0});
p.children[p.index] = q.children;
p = q;
}
}
return code[0].children;
}
function getBlockBufferOffset(component, row, col) {
return 64 * ((component.blocksPerLine + 1) * row + col);
}
function decodeScan(data, offset, frame, components, resetInterval,
spectralStart, spectralEnd, successivePrev, successive) {
var mcusPerLine = frame.mcusPerLine;
var progressive = frame.progressive;
var startOffset = offset, bitsData = 0, bitsCount = 0;
function readBit() {
if (bitsCount > 0) {
bitsCount--;
return (bitsData >> bitsCount) & 1;
}
bitsData = data[offset++];
if (bitsData === 0xFF) {
var nextByte = data[offset++];
if (nextByte) {
throw 'unexpected marker: ' +
((bitsData << 8) | nextByte).toString(16);
}
// unstuff 0
}
bitsCount = 7;
return bitsData >>> 7;
}
function decodeHuffman(tree) {
var node = tree;
while (true) {
node = node[readBit()];
if (typeof node === 'number') {
return node;
}
if (typeof node !== 'object') {
throw 'invalid huffman sequence';
}
}
}
function receive(length) {
var n = 0;
while (length > 0) {
n = (n << 1) | readBit();
length--;
}
return n;
}
function receiveAndExtend(length) {
if (length === 1) {
return readBit() === 1 ? 1 : -1;
}
var n = receive(length);
if (n >= 1 << (length - 1)) {
return n;
}
return n + (-1 << length) + 1;
}
function decodeBaseline(component, offset) {
var t = decodeHuffman(component.huffmanTableDC);
var diff = t === 0 ? 0 : receiveAndExtend(t);
component.blockData[offset] = (component.pred += diff);
var k = 1;
while (k < 64) {
var rs = decodeHuffman(component.huffmanTableAC);
var s = rs & 15, r = rs >> 4;
if (s === 0) {
if (r < 15) {
break;
}
k += 16;
continue;
}
k += r;
var z = dctZigZag[k];
component.blockData[offset + z] = receiveAndExtend(s);
k++;
}
}
function decodeDCFirst(component, offset) {
var t = decodeHuffman(component.huffmanTableDC);
var diff = t === 0 ? 0 : (receiveAndExtend(t) << successive);
component.blockData[offset] = (component.pred += diff);
}
function decodeDCSuccessive(component, offset) {
component.blockData[offset] |= readBit() << successive;
}
var eobrun = 0;
function decodeACFirst(component, offset) {
if (eobrun > 0) {
eobrun--;
return;
}
var k = spectralStart, e = spectralEnd;
while (k <= e) {
var rs = decodeHuffman(component.huffmanTableAC);
var s = rs & 15, r = rs >> 4;
if (s === 0) {
if (r < 15) {
eobrun = receive(r) + (1 << r) - 1;
break;
}
k += 16;
continue;
}
k += r;
var z = dctZigZag[k];
component.blockData[offset + z] =
receiveAndExtend(s) * (1 << successive);
k++;
}
}
var successiveACState = 0, successiveACNextValue;
function decodeACSuccessive(component, offset) {
var k = spectralStart;
var e = spectralEnd;
var r = 0;
var s;
var rs;
while (k <= e) {
var z = dctZigZag[k];
switch (successiveACState) {
case 0: // initial state
rs = decodeHuffman(component.huffmanTableAC);
s = rs & 15;
r = rs >> 4;
if (s === 0) {
if (r < 15) {
eobrun = receive(r) + (1 << r);
successiveACState = 4;
} else {
r = 16;
successiveACState = 1;
}
} else {
if (s !== 1) {
throw 'invalid ACn encoding';
}
successiveACNextValue = receiveAndExtend(s);
successiveACState = r ? 2 : 3;
}
continue;
case 1: // skipping r zero items
case 2:
if (component.blockData[offset + z]) {
component.blockData[offset + z] += (readBit() << successive);
} else {
r--;
if (r === 0) {
successiveACState = successiveACState === 2 ? 3 : 0;
}
}
break;
case 3: // set value for a zero item
if (component.blockData[offset + z]) {
component.blockData[offset + z] += (readBit() << successive);
} else {
component.blockData[offset + z] =
successiveACNextValue << successive;
successiveACState = 0;
}
break;
case 4: // eob
if (component.blockData[offset + z]) {
component.blockData[offset + z] += (readBit() << successive);
}
break;
}
k++;
}
if (successiveACState === 4) {
eobrun--;
if (eobrun === 0) {
successiveACState = 0;
}
}
}
function decodeMcu(component, decode, mcu, row, col) {
var mcuRow = (mcu / mcusPerLine) | 0;
var mcuCol = mcu % mcusPerLine;
var blockRow = mcuRow * component.v + row;
var blockCol = mcuCol * component.h + col;
var offset = getBlockBufferOffset(component, blockRow, blockCol);
decode(component, offset);
}
function decodeBlock(component, decode, mcu) {
var blockRow = (mcu / component.blocksPerLine) | 0;
var blockCol = mcu % component.blocksPerLine;
var offset = getBlockBufferOffset(component, blockRow, blockCol);
decode(component, offset);
}
var componentsLength = components.length;
var component, i, j, k, n;
var decodeFn;
if (progressive) {
if (spectralStart === 0) {
decodeFn = successivePrev === 0 ? decodeDCFirst : decodeDCSuccessive;
} else {
decodeFn = successivePrev === 0 ? decodeACFirst : decodeACSuccessive;
}
} else {
decodeFn = decodeBaseline;
}
var mcu = 0, marker;
var mcuExpected;
if (componentsLength === 1) {
mcuExpected = components[0].blocksPerLine * components[0].blocksPerColumn;
} else {
mcuExpected = mcusPerLine * frame.mcusPerColumn;
}
if (!resetInterval) {
resetInterval = mcuExpected;
}
var h, v;
while (mcu < mcuExpected) {
// reset interval stuff
for (i = 0; i < componentsLength; i++) {
components[i].pred = 0;
}
eobrun = 0;
if (componentsLength === 1) {
component = components[0];
for (n = 0; n < resetInterval; n++) {
decodeBlock(component, decodeFn, mcu);
mcu++;
}
} else {
for (n = 0; n < resetInterval; n++) {
for (i = 0; i < componentsLength; i++) {
component = components[i];
h = component.h;
v = component.v;
for (j = 0; j < v; j++) {
for (k = 0; k < h; k++) {
decodeMcu(component, decodeFn, mcu, j, k);
}
}
}
mcu++;
}
}
// find marker
bitsCount = 0;
marker = (data[offset] << 8) | data[offset + 1];
if (marker <= 0xFF00) {
throw 'marker was not found';
}
if (marker >= 0xFFD0 && marker <= 0xFFD7) { // RSTx
offset += 2;
} else {
break;
}
}
return offset - startOffset;
}
// A port of poppler's IDCT method which in turn is taken from:
// Christoph Loeffler, Adriaan Ligtenberg, George S. Moschytz,
// 'Practical Fast 1-D DCT Algorithms with 11 Multiplications',
// IEEE Intl. Conf. on Acoustics, Speech & Signal Processing, 1989,
// 988-991.
function quantizeAndInverse(component, blockBufferOffset, p) {
var qt = component.quantizationTable, blockData = component.blockData;
var v0, v1, v2, v3, v4, v5, v6, v7;
var p0, p1, p2, p3, p4, p5, p6, p7;
var t;
// inverse DCT on rows
for (var row = 0; row < 64; row += 8) {
// gather block data
p0 = blockData[blockBufferOffset + row];
p1 = blockData[blockBufferOffset + row + 1];
p2 = blockData[blockBufferOffset + row + 2];
p3 = blockData[blockBufferOffset + row + 3];
p4 = blockData[blockBufferOffset + row + 4];
p5 = blockData[blockBufferOffset + row + 5];
p6 = blockData[blockBufferOffset + row + 6];
p7 = blockData[blockBufferOffset + row + 7];
// dequant p0
p0 *= qt[row];
// check for all-zero AC coefficients
if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {
t = (dctSqrt2 * p0 + 512) >> 10;
p[row] = t;
p[row + 1] = t;
p[row + 2] = t;
p[row + 3] = t;
p[row + 4] = t;
p[row + 5] = t;
p[row + 6] = t;
p[row + 7] = t;
continue;
}
// dequant p1 ... p7
p1 *= qt[row + 1];
p2 *= qt[row + 2];
p3 *= qt[row + 3];
p4 *= qt[row + 4];
p5 *= qt[row + 5];
p6 *= qt[row + 6];
p7 *= qt[row + 7];
// stage 4
v0 = (dctSqrt2 * p0 + 128) >> 8;
v1 = (dctSqrt2 * p4 + 128) >> 8;
v2 = p2;
v3 = p6;
v4 = (dctSqrt1d2 * (p1 - p7) + 128) >> 8;
v7 = (dctSqrt1d2 * (p1 + p7) + 128) >> 8;
v5 = p3 << 4;
v6 = p5 << 4;
// stage 3
v0 = (v0 + v1 + 1) >> 1;
v1 = v0 - v1;
t = (v2 * dctSin6 + v3 * dctCos6 + 128) >> 8;
v2 = (v2 * dctCos6 - v3 * dctSin6 + 128) >> 8;
v3 = t;
v4 = (v4 + v6 + 1) >> 1;
v6 = v4 - v6;
v7 = (v7 + v5 + 1) >> 1;
v5 = v7 - v5;
// stage 2
v0 = (v0 + v3 + 1) >> 1;
v3 = v0 - v3;
v1 = (v1 + v2 + 1) >> 1;
v2 = v1 - v2;
t = (v4 * dctSin3 + v7 * dctCos3 + 2048) >> 12;
v4 = (v4 * dctCos3 - v7 * dctSin3 + 2048) >> 12;
v7 = t;
t = (v5 * dctSin1 + v6 * dctCos1 + 2048) >> 12;
v5 = (v5 * dctCos1 - v6 * dctSin1 + 2048) >> 12;
v6 = t;
// stage 1
p[row] = v0 + v7;
p[row + 7] = v0 - v7;
p[row + 1] = v1 + v6;
p[row + 6] = v1 - v6;
p[row + 2] = v2 + v5;
p[row + 5] = v2 - v5;
p[row + 3] = v3 + v4;
p[row + 4] = v3 - v4;
}
// inverse DCT on columns
for (var col = 0; col < 8; ++col) {
p0 = p[col];
p1 = p[col + 8];
p2 = p[col + 16];
p3 = p[col + 24];
p4 = p[col + 32];
p5 = p[col + 40];
p6 = p[col + 48];
p7 = p[col + 56];
// check for all-zero AC coefficients
if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {
t = (dctSqrt2 * p0 + 8192) >> 14;
// convert to 8 bit
//t = (t < -2040) ? 0 : (t >= 2024) ? 255 : (t + 2056) >> 4;
//t = (t <= -2056 / component.bitConversion) ? 0 : (t >= 2024 / component.bitConversion) ? 255 / component.bitConversion : (t + 2056 / component.bitConversion) >> 4;
t = (t <= tMin) ? 0 : (t >= tMax) ? t8bitMax : (t - tMin) >> 4;
blockData[blockBufferOffset + col] = t;
blockData[blockBufferOffset + col + 8] = t;
blockData[blockBufferOffset + col + 16] = t;
blockData[blockBufferOffset + col + 24] = t;
blockData[blockBufferOffset + col + 32] = t;
blockData[blockBufferOffset + col + 40] = t;
blockData[blockBufferOffset + col + 48] = t;
blockData[blockBufferOffset + col + 56] = t;
continue;
}
// stage 4
v0 = (dctSqrt2 * p0 + 2048) >> 12;
v1 = (dctSqrt2 * p4 + 2048) >> 12;
v2 = p2;
v3 = p6;
v4 = (dctSqrt1d2 * (p1 - p7) + 2048) >> 12;
v7 = (dctSqrt1d2 * (p1 + p7) + 2048) >> 12;
v5 = p3;
v6 = p5;
// stage 3
// Shift v0 by 128.5 << 5 here, so we don't need to shift p0...p7 when
// converting to UInt8 range later.
//v0 = ((v0 + v1 + 1) >> 1) + 4112;
v0 = ((v0 + v1 + 1) >> 1);
v1 = v0 - v1;
t = (v2 * dctSin6 + v3 * dctCos6 + 2048) >> 12;
v2 = (v2 * dctCos6 - v3 * dctSin6 + 2048) >> 12;
v3 = t;
v4 = (v4 + v6 + 1) >> 1;
v6 = v4 - v6;
v7 = (v7 + v5 + 1) >> 1;
v5 = v7 - v5;
// stage 2
v0 = (v0 + v3 + 1) >> 1;
v3 = v0 - v3;
v1 = (v1 + v2 + 1) >> 1;
v2 = v1 - v2;
t = (v4 * dctSin3 + v7 * dctCos3 + 2048) >> 12;
v4 = (v4 * dctCos3 - v7 * dctSin3 + 2048) >> 12;
v7 = t;
t = (v5 * dctSin1 + v6 * dctCos1 + 2048) >> 12;
v5 = (v5 * dctCos1 - v6 * dctSin1 + 2048) >> 12;
v6 = t;
// stage 1
p0 = v0 + v7;
p7 = v0 - v7;
p1 = v1 + v6;
p6 = v1 - v6;
p2 = v2 + v5;
p5 = v2 - v5;
p3 = v3 + v4;
p4 = v3 - v4;
// convert to 8-bit integers
//p0 = (p0 < 16) ? 0 : (p0 >= 4080) ? 255 : p0 >> 4;
p0 = (p0 <= tMin) ? 0 : (p0 >= tMax) ? t8bitMax : (p0 - tMin) >> 4;
p1 = (p1 <= tMin) ? 0 : (p1 >= tMax) ? t8bitMax : (p1 - tMin) >> 4;
p2 = (p2 <= tMin) ? 0 : (p2 >= tMax) ? t8bitMax : (p2 - tMin) >> 4;
p3 = (p3 <= tMin) ? 0 : (p3 >= tMax) ? t8bitMax : (p3 - tMin) >> 4;
p4 = (p4 <= tMin) ? 0 : (p4 >= tMax) ? t8bitMax : (p4 - tMin) >> 4;
p5 = (p5 <= tMin) ? 0 : (p5 >= tMax) ? t8bitMax : (p5 - tMin) >> 4;
p6 = (p6 <= tMin) ? 0 : (p6 >= tMax) ? t8bitMax : (p6 - tMin) >> 4;
p7 = (p7 <= tMin) ? 0 : (p7 >= tMax) ? t8bitMax : (p7 - tMin) >> 4;
// store block data
blockData[blockBufferOffset + col] = p0;
blockData[blockBufferOffset + col + 8] = p1;
blockData[blockBufferOffset + col + 16] = p2;
blockData[blockBufferOffset + col + 24] = p3;
blockData[blockBufferOffset + col + 32] = p4;
blockData[blockBufferOffset + col + 40] = p5;
blockData[blockBufferOffset + col + 48] = p6;
blockData[blockBufferOffset + col + 56] = p7;
}
}
function buildComponentData(frame, component) {
var blocksPerLine = component.blocksPerLine;
var blocksPerColumn = component.blocksPerColumn;
//var computationBuffer = new Int16Array(64);
var computationBuffer = new Int32Array(64);
for (var blockRow = 0; blockRow < blocksPerColumn; blockRow++) {
for (var blockCol = 0; blockCol < blocksPerLine; blockCol++) {
var offset = getBlockBufferOffset(component, blockRow, blockCol);
quantizeAndInverse(component, offset, computationBuffer);
}
}
return component.blockData;
}
function clamp0to255(a) {
return a <= 0 ? 0 : a >= 255 ? 255 : a;
}
constructor.prototype = {
parse: function parse(data) {
function readUint16() {
var value = (data[offset] << 8) | data[offset + 1];
offset += 2;
return value;
}
function readDataBlock() {
var length = readUint16();
var array = data.subarray(offset, offset + length - 2);
offset += array.length;
return array;
}
function prepareComponents(frame) {
var mcusPerLine = Math.ceil(frame.samplesPerLine / 8 / frame.maxH);
var mcusPerColumn = Math.ceil(frame.scanLines / 8 / frame.maxV);
for (var i = 0; i < frame.components.length; i++) {
component = frame.components[i];
var blocksPerLine = Math.ceil(Math.ceil(frame.samplesPerLine / 8) *
component.h / frame.maxH);
var blocksPerColumn = Math.ceil(Math.ceil(frame.scanLines / 8) *
component.v / frame.maxV);
var blocksPerLineForMcu = mcusPerLine * component.h;
var blocksPerColumnForMcu = mcusPerColumn * component.v;
var blocksBufferSize = 64 * blocksPerColumnForMcu *
(blocksPerLineForMcu + 1);
component.blockData = new Int16Array(blocksBufferSize);
component.blocksPerLine = blocksPerLine;
component.blocksPerColumn = blocksPerColumn;
}
frame.mcusPerLine = mcusPerLine;
frame.mcusPerColumn = mcusPerColumn;
}
var offset = 0;
var jfif = null;
var adobe = null;
var frame, resetInterval;
var quantizationTables = [];
var huffmanTablesAC = [], huffmanTablesDC = [];
var fileMarker = readUint16();
if (fileMarker !== 0xFFD8) { // SOI (Start of Image)
throw 'SOI not found';
}
fileMarker = readUint16();
while (fileMarker !== 0xFFD9) { // EOI (End of image)
var i, j, l;
switch(fileMarker) {
case 0xFFE0: // APP0 (Application Specific)
case 0xFFE1: // APP1
case 0xFFE2: // APP2
case 0xFFE3: // APP3
case 0xFFE4: // APP4
case 0xFFE5: // APP5
case 0xFFE6: // APP6
case 0xFFE7: // APP7
case 0xFFE8: // APP8
case 0xFFE9: // APP9
case 0xFFEA: // APP10
case 0xFFEB: // APP11
case 0xFFEC: // APP12
case 0xFFED: // APP13
case 0xFFEE: // APP14
case 0xFFEF: // APP15
case 0xFFFE: // COM (Comment)
var appData = readDataBlock();
if (fileMarker === 0xFFE0) {
if (appData[0] === 0x4A && appData[1] === 0x46 &&
appData[2] === 0x49 && appData[3] === 0x46 &&
appData[4] === 0) { // 'JFIF\x00'
jfif = {
version: { major: appData[5], minor: appData[6] },
densityUnits: appData[7],
xDensity: (appData[8] << 8) | appData[9],
yDensity: (appData[10] << 8) | appData[11],
thumbWidth: appData[12],
thumbHeight: appData[13],
thumbData: appData.subarray(14, 14 +
3 * appData[12] * appData[13])
};
}
}
// TODO APP1 - Exif
if (fileMarker === 0xFFEE) {
if (appData[0] === 0x41 && appData[1] === 0x64 &&
appData[2] === 0x6F && appData[3] === 0x62 &&
appData[4] === 0x65) { // 'Adobe'
adobe = {
version: (appData[5] << 8) | appData[6],
flags0: (appData[7] << 8) | appData[8],
flags1: (appData[9] << 8) | appData[10],
transformCode: appData[11]
};
}
}
break;
case 0xFFDB: // DQT (Define Quantization Tables)
var quantizationTablesLength = readUint16();
var quantizationTablesEnd = quantizationTablesLength + offset - 2;
var z;
while (offset < quantizationTablesEnd) {
var quantizationTableSpec = data[offset++];
var tableData = new Uint16Array(64);
if ((quantizationTableSpec >> 4) === 0) { // 8 bit values
for (j = 0; j < 64; j++) {
z = dctZigZag[j];
tableData[z] = data[offset++];
}
} else if ((quantizationTableSpec >> 4) === 1) { //16 bit
for (j = 0; j < 64; j++) {
z = dctZigZag[j];
tableData[z] = readUint16();
}
} else {
throw 'DQT: invalid table spec';
}
quantizationTables[quantizationTableSpec & 15] = tableData;
}
break;
case 0xFFC0: // SOF0 (Start of Frame, Baseline DCT)
case 0xFFC1: // SOF1 (Start of Frame, Extended DCT)
case 0xFFC2: // SOF2 (Start of Frame, Progressive DCT)
if (frame) {
throw 'Only single frame JPEGs supported';
}
readUint16(); // skip data length
frame = {};
frame.extended = (fileMarker === 0xFFC1);
frame.progressive = (fileMarker === 0xFFC2);
frame.precision = data[offset++];
var frameBitConversion = 255 / ( (1<<frame.precision) - 1 );
tMin /= frameBitConversion;
tMax /= frameBitConversion;
t8bitMax /= frameBitConversion;
frame.scanLines = readUint16();
frame.samplesPerLine = readUint16();
frame.components = [];
frame.componentIds = {};
var componentsCount = data[offset++], componentId;
var maxH = 0, maxV = 0;
for (i = 0; i < componentsCount; i++) {
componentId = data[offset];
var h = data[offset + 1] >> 4;
var v = data[offset + 1] & 15;
if (maxH < h) {
maxH = h;
}
if (maxV < v) {
maxV = v;
}
var qId = data[offset + 2];
l = frame.components.push({
h: h,
v: v,
quantizationTable: quantizationTables[qId],
quantizationTableId: qId
});
frame.componentIds[componentId] = l - 1;
offset += 3;
}
frame.maxH = maxH;
frame.maxV = maxV;
prepareComponents(frame);
break;
case 0xFFC4: // DHT (Define Huffman Tables)
var huffmanLength = readUint16();
for (i = 2; i < huffmanLength;) {
var huffmanTableSpec = data[offset++];
var codeLengths = new Uint8Array(16);
var codeLengthSum = 0;
for (j = 0; j < 16; j++, offset++) {
codeLengthSum += (codeLengths[j] = data[offset]);
}
var huffmanValues = new Uint8Array(codeLengthSum);
for (j = 0; j < codeLengthSum; j++, offset++) {
huffmanValues[j] = data[offset];
}
i += 17 + codeLengthSum;
((huffmanTableSpec >> 4) === 0 ?
huffmanTablesDC : huffmanTablesAC)[huffmanTableSpec & 15] =
buildHuffmanTable(codeLengths, huffmanValues);
}
break;
case 0xFFDD: // DRI (Define Restart Interval)
readUint16(); // skip data length
resetInterval = readUint16();
break;
case 0xFFDA: // SOS (Start of Scan)
var scanLength = readUint16();
var selectorsCount = data[offset++];
var components = [], component;
for (i = 0; i < selectorsCount; i++) {
var componentIndex = frame.componentIds[data[offset++]];
component = frame.components[componentIndex];
var tableSpec = data[offset++];
component.huffmanTableDC = huffmanTablesDC[tableSpec >> 4];
component.huffmanTableAC = huffmanTablesAC[tableSpec & 15];
components.push(component);
}
var spectralStart = data[offset++];
var spectralEnd = data[offset++];
var successiveApproximation = data[offset++];
var processed = decodeScan(data, offset,
frame, components, resetInterval,
spectralStart, spectralEnd,
successiveApproximation >> 4, successiveApproximation & 15);
offset += processed;
break;
case 0xFFFF: // Fill bytes
if (data[offset] !== 0xFF) { // Avoid skipping a valid marker.
offset--;
}
break;
default:
if (data[offset - 3] === 0xFF &&
data[offset - 2] >= 0xC0 && data[offset - 2] <= 0xFE) {
// could be incorrect encoding -- last 0xFF byte of the previous
// block was eaten by the encoder
offset -= 3;
break;
}
throw 'unknown JPEG marker ' + fileMarker.toString(16);
}
fileMarker = readUint16();
}
this.width = frame.samplesPerLine;
this.height = frame.scanLines;
this.jfif = jfif;
this.adobe = adobe;
this.components = [];
for (i = 0; i < frame.components.length; i++) {
component = frame.components[i];
if ( ! component.quantizationTable && component.quantizationTableId != null )
component.quantizationTable = quantizationTables[component.quantizationTableId];
this.components.push({
output: buildComponentData(frame, component),
scaleX: component.h / frame.maxH,
scaleY: component.v / frame.maxV,
blocksPerLine: component.blocksPerLine,
blocksPerColumn: component.blocksPerColumn
});
}
this.numComponents = this.components.length;
},
_getLinearizedBlockData: function getLinearizedBlockData(width, height) {
var scaleX = this.width / width, scaleY = this.height / height;
var component, componentScaleX, componentScaleY, blocksPerScanline;
var x, y, i, j, k;
var index;
var offset = 0;
var output;
var numComponents = this.components.length;
var dataLength = width * height * numComponents;
//var data = new Uint8Array(dataLength);
var data = new Uint16Array(dataLength);
var xScaleBlockOffset = new Uint32Array(width);
var mask3LSB = 0xfffffff8; // used to clear the 3 LSBs
for (i = 0; i < numComponents; i++) {
component = this.components[i];
componentScaleX = component.scaleX * scaleX;
componentScaleY = component.scaleY * scaleY;
offset = i;
output = component.output;
blocksPerScanline = (component.blocksPerLine + 1) << 3;
// precalculate the xScaleBlockOffset
for (x = 0; x < width; x++) {
j = 0 | (x * componentScaleX);
xScaleBlockOffset[x] = ((j & mask3LSB) << 3) | (j & 7);
}
// linearize the blocks of the component
for (y = 0; y < height; y++) {
j = 0 | (y * componentScaleY);
index = blocksPerScanline * (j & mask3LSB) | ((j & 7) << 3);
for (x = 0; x < width; x++) {
data[offset] = output[index + xScaleBlockOffset[x]];
offset += numComponents;
}
}
}
// decodeTransform contains pairs of multiplier (-256..256) and additive
var transform = this.decodeTransform;
if (transform) {
for (i = 0; i < dataLength;) {
for (j = 0, k = 0; j < numComponents; j++, i++, k += 2) {
data[i] = ((data[i] * transform[k]) >> 8) + transform[k + 1];
}
}
}
return data;
},
_isColorConversionNeeded: function isColorConversionNeeded() {
if (this.adobe && this.adobe.transformCode) {
// The adobe transform marker overrides any previous setting
return true;
} else if (this.numComponents === 3) {
return true;
} else {
return false;
}
},
_convertYccToRgb: function convertYccToRgb(data) {
var Y, Cb, Cr;
for (var i = 0, length = data.length; i < length; i += 3) {
Y = data[i ];
Cb = data[i + 1];
Cr = data[i + 2];
data[i ] = clamp0to255(Y - 179.456 + 1.402 * Cr);
data[i + 1] = clamp0to255(Y + 135.459 - 0.344 * Cb - 0.714 * Cr);
data[i + 2] = clamp0to255(Y - 226.816 + 1.772 * Cb);
}
return data;
},
_convertYcckToRgb: function convertYcckToRgb(data) {
var Y, Cb, Cr, k;
var offset = 0;
for (var i = 0, length = data.length; i < length; i += 4) {
Y = data[i];
Cb = data[i + 1];
Cr = data[i + 2];
k = data[i + 3];
var r = -122.67195406894 +
Cb * (-6.60635669420364e-5 * Cb + 0.000437130475926232 * Cr -
5.4080610064599e-5 * Y + 0.00048449797120281 * k -
0.154362151871126) +
Cr * (-0.000957964378445773 * Cr + 0.000817076911346625 * Y -
0.00477271405408747 * k + 1.53380253221734) +
Y * (0.000961250184130688 * Y - 0.00266257332283933 * k +
0.48357088451265) +
k * (-0.000336197177618394 * k + 0.484791561490776);
var g = 107.268039397724 +
Cb * (2.19927104525741e-5 * Cb - 0.000640992018297945 * Cr +
0.000659397001245577 * Y + 0.000426105652938837 * k -
0.176491792462875) +
Cr * (-0.000778269941513683 * Cr + 0.00130872261408275 * Y +
0.000770482631801132 * k - 0.151051492775562) +
Y * (0.00126935368114843 * Y - 0.00265090189010898 * k +
0.25802910206845) +
k * (-0.000318913117588328 * k - 0.213742400323665);
var b = -20.810012546947 +
Cb * (-0.000570115196973677 * Cb - 2.63409051004589e-5 * Cr +
0.0020741088115012 * Y - 0.00288260236853442 * k +
0.814272968359295) +
Cr * (-1.53496057440975e-5 * Cr - 0.000132689043961446 * Y +
0.000560833691242812 * k - 0.195152027534049) +
Y * (0.00174418132927582 * Y - 0.00255243321439347 * k +
0.116935020465145) +
k * (-0.000343531996510555 * k + 0.24165260232407);
data[offset++] = clamp0to255(r);
data[offset++] = clamp0to255(g);
data[offset++] = clamp0to255(b);
}
return data;
},
_convertYcckToCmyk: function convertYcckToCmyk(data) {
var Y, Cb, Cr;
for (var i = 0, length = data.length; i < length; i += 4) {
Y = data[i];
Cb = data[i + 1];
Cr = data[i + 2];
data[i ] = clamp0to255(434.456 - Y - 1.402 * Cr);
data[i + 1] = clamp0to255(119.541 - Y + 0.344 * Cb + 0.714 * Cr);
data[i + 2] = clamp0to255(481.816 - Y - 1.772 * Cb);
// K in data[i + 3] is unchanged
}
return data;
},
_convertCmykToRgb: function convertCmykToRgb(data) {
var c, m, y, k;
var offset = 0;
var min = -255 * 255 * 255;
var scale = 1 / 255 / 255;
for (var i = 0, length = data.length; i < length; i += 4) {
c = data[i];
m = data[i + 1];
y = data[i + 2];
k = data[i + 3];
var r =
c * (-4.387332384609988 * c + 54.48615194189176 * m +
18.82290502165302 * y + 212.25662451639585 * k -
72734.4411664936) +
m * (1.7149763477362134 * m - 5.6096736904047315 * y -
17.873870861415444 * k - 1401.7366389350734) +
y * (-2.5217340131683033 * y - 21.248923337353073 * k +
4465.541406466231) -
k * (21.86122147463605 * k + 48317.86113160301);
var g =
c * (8.841041422036149 * c + 60.118027045597366 * m +
6.871425592049007 * y + 31.159100130055922 * k -
20220.756542821975) +
m * (-15.310361306967817 * m + 17.575251261109482 * y +
131.35250912493976 * k - 48691.05921601825) +
y * (4.444339102852739 * y + 9.8632861493405 * k -
6341.191035517494) -
k * (20.737325471181034 * k + 47890.15695978492);
var b =
c * (0.8842522430003296 * c + 8.078677503112928 * m +
30.89978309703729 * y - 0.23883238689178934 * k -
3616.812083916688) +
m * (10.49593273432072 * m + 63.02378494754052 * y +
50.606957656360734 * k - 28620.90484698408) +
y * (0.03296041114873217 * y + 115.60384449646641 * k -
49363.43385999684) -
k * (22.33816807309886 * k + 45932.16563550634);
data[offset++] = r >= 0 ? 255 : r <= min ? 0 : 255 + r * scale | 0;
data[offset++] = g >= 0 ? 255 : g <= min ? 0 : 255 + g * scale | 0;
data[offset++] = b >= 0 ? 255 : b <= min ? 0 : 255 + b * scale | 0;
}
return data;
},
getData: function getData(width, height, forceRGBoutput) {
if (this.numComponents > 4) {
throw 'Unsupported color mode';
}
// type of data: Uint8Array(width * height * numComponents)
var data = this._getLinearizedBlockData(width, height);
if (this.numComponents === 1 && forceRGBoutput) {
var dataLength = data.length;
//var rgbData = new Uint8Array(dataLength * 3);
var rgbData = new Uint16Array(dataLength * 3);
var offset = 0;
for (var i = 0; i < dataLength; i++) {
var grayColor = data[i];
rgbData[offset++] = grayColor;
rgbData[offset++] = grayColor;
rgbData[offset++] = grayColor;
}
return rgbData;
} else if (this.numComponents === 3) {
return this._convertYccToRgb(data);
} else if (this.numComponents === 4) {
if (this._isColorConversionNeeded()) {
if (forceRGBoutput) {
return this._convertYcckToRgb(data);
} else {
return this._convertYcckToCmyk(data);
}
} else if (forceRGBoutput) {
return this._convertCmykToRgb(data);
}
}
return data;
}
};
return constructor;
})();
//exports.JpegImage = JpegImage;
//}));