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s.golasch
2023-08-01 13:49:46 +02:00
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/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- /
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
/*
Copyright 2011 notmasteryet
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.
*/
// - 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() {
"use strict";
var dctZigZag = new Int32Array([
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
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 decodeScan(data, offset,
frame, components, resetInterval,
spectralStart, spectralEnd,
successivePrev, successive) {
var precision = frame.precision;
var samplesPerLine = frame.samplesPerLine;
var scanLines = frame.scanLines;
var mcusPerLine = frame.mcusPerLine;
var progressive = frame.progressive;
var maxH = frame.maxH, maxV = frame.maxV;
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, bit;
while ((bit = readBit()) !== null) {
node = node[bit];
if (typeof node === 'number')
return node;
if (typeof node !== 'object')
throw "invalid huffman sequence";
}
return null;
}
function receive(length) {
var n = 0;
while (length > 0) {
var bit = readBit();
if (bit === null) return;
n = (n << 1) | bit;
length--;
}
return n;
}
function receiveAndExtend(length) {
var n = receive(length);
if (n >= 1 << (length - 1))
return n;
return n + (-1 << length) + 1;
}
function decodeBaseline(component, zz) {
var t = decodeHuffman(component.huffmanTableDC);
var diff = t === 0 ? 0 : receiveAndExtend(t);
zz[0]= (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];
zz[z] = receiveAndExtend(s);
k++;
}
}
function decodeDCFirst(component, zz) {
var t = decodeHuffman(component.huffmanTableDC);
var diff = t === 0 ? 0 : (receiveAndExtend(t) << successive);
zz[0] = (component.pred += diff);
}
function decodeDCSuccessive(component, zz) {
zz[0] |= readBit() << successive;
}
var eobrun = 0;
function decodeACFirst(component, zz) {
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];
zz[z] = receiveAndExtend(s) * (1 << successive);
k++;
}
}
var successiveACState = 0, successiveACNextValue;
function decodeACSuccessive(component, zz) {
var k = spectralStart, e = spectralEnd, r = 0;
while (k <= e) {
var z = dctZigZag[k];
switch (successiveACState) {
case 0: // initial state
var rs = decodeHuffman(component.huffmanTableAC);
var 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 (zz[z])
zz[z] += (readBit() << successive);
else {
r--;
if (r === 0)
successiveACState = successiveACState == 2 ? 3 : 0;
}
break;
case 3: // set value for a zero item
if (zz[z])
zz[z] += (readBit() << successive);
else {
zz[z] = successiveACNextValue << successive;
successiveACState = 0;
}
break;
case 4: // eob
if (zz[z])
zz[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;
decode(component, component.blocks[blockRow][blockCol]);
}
function decodeBlock(component, decode, mcu) {
var blockRow = (mcu / component.blocksPerLine) | 0;
var blockCol = mcu % component.blocksPerLine;
decode(component, component.blocks[blockRow][blockCol]);
}
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++;
// If we've reached our expected MCU's, stop decoding
if (mcu === mcuExpected) break;
}
}
// 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;
}
function buildComponentData(frame, component) {
var lines = [];
var blocksPerLine = component.blocksPerLine;
var blocksPerColumn = component.blocksPerColumn;
var samplesPerLine = blocksPerLine << 3;
var R = new Int32Array(64), r = new Uint8Array(64);
// 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(zz, dataOut, dataIn) {
var qt = component.quantizationTable;
var v0, v1, v2, v3, v4, v5, v6, v7, t;
var p = dataIn;
var i;
// dequant
for (i = 0; i < 64; i++)
p[i] = zz[i] * qt[i];
// inverse DCT on rows
for (i = 0; i < 8; ++i) {
var row = 8 * i;
// check for all-zero AC coefficients
if (p[1 + row] == 0 && p[2 + row] == 0 && p[3 + row] == 0 &&
p[4 + row] == 0 && p[5 + row] == 0 && p[6 + row] == 0 &&
p[7 + row] == 0) {
t = (dctSqrt2 * p[0 + row] + 512) >> 10;
p[0 + row] = t;
p[1 + row] = t;
p[2 + row] = t;
p[3 + row] = t;
p[4 + row] = t;
p[5 + row] = t;
p[6 + row] = t;
p[7 + row] = t;
continue;
}
// stage 4
v0 = (dctSqrt2 * p[0 + row] + 128) >> 8;
v1 = (dctSqrt2 * p[4 + row] + 128) >> 8;
v2 = p[2 + row];
v3 = p[6 + row];
v4 = (dctSqrt1d2 * (p[1 + row] - p[7 + row]) + 128) >> 8;
v7 = (dctSqrt1d2 * (p[1 + row] + p[7 + row]) + 128) >> 8;
v5 = p[3 + row] << 4;
v6 = p[5 + row] << 4;
// stage 3
t = (v0 - v1+ 1) >> 1;
v0 = (v0 + v1 + 1) >> 1;
v1 = t;
t = (v2 * dctSin6 + v3 * dctCos6 + 128) >> 8;
v2 = (v2 * dctCos6 - v3 * dctSin6 + 128) >> 8;
v3 = t;
t = (v4 - v6 + 1) >> 1;
v4 = (v4 + v6 + 1) >> 1;
v6 = t;
t = (v7 + v5 + 1) >> 1;
v5 = (v7 - v5 + 1) >> 1;
v7 = t;
// stage 2
t = (v0 - v3 + 1) >> 1;
v0 = (v0 + v3 + 1) >> 1;
v3 = t;
t = (v1 - v2 + 1) >> 1;
v1 = (v1 + v2 + 1) >> 1;
v2 = t;
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[0 + row] = v0 + v7;
p[7 + row] = v0 - v7;
p[1 + row] = v1 + v6;
p[6 + row] = v1 - v6;
p[2 + row] = v2 + v5;
p[5 + row] = v2 - v5;
p[3 + row] = v3 + v4;
p[4 + row] = v3 - v4;
}
// inverse DCT on columns
for (i = 0; i < 8; ++i) {
var col = i;
// check for all-zero AC coefficients
if (p[1*8 + col] == 0 && p[2*8 + col] == 0 && p[3*8 + col] == 0 &&
p[4*8 + col] == 0 && p[5*8 + col] == 0 && p[6*8 + col] == 0 &&
p[7*8 + col] == 0) {
t = (dctSqrt2 * dataIn[i+0] + 8192) >> 14;
p[0*8 + col] = t;
p[1*8 + col] = t;
p[2*8 + col] = t;
p[3*8 + col] = t;
p[4*8 + col] = t;
p[5*8 + col] = t;
p[6*8 + col] = t;
p[7*8 + col] = t;
continue;
}
// stage 4
v0 = (dctSqrt2 * p[0*8 + col] + 2048) >> 12;
v1 = (dctSqrt2 * p[4*8 + col] + 2048) >> 12;
v2 = p[2*8 + col];
v3 = p[6*8 + col];
v4 = (dctSqrt1d2 * (p[1*8 + col] - p[7*8 + col]) + 2048) >> 12;
v7 = (dctSqrt1d2 * (p[1*8 + col] + p[7*8 + col]) + 2048) >> 12;
v5 = p[3*8 + col];
v6 = p[5*8 + col];
// stage 3
t = (v0 - v1 + 1) >> 1;
v0 = (v0 + v1 + 1) >> 1;
v1 = t;
t = (v2 * dctSin6 + v3 * dctCos6 + 2048) >> 12;
v2 = (v2 * dctCos6 - v3 * dctSin6 + 2048) >> 12;
v3 = t;
t = (v4 - v6 + 1) >> 1;
v4 = (v4 + v6 + 1) >> 1;
v6 = t;
t = (v7 + v5 + 1) >> 1;
v5 = (v7 - v5 + 1) >> 1;
v7 = t;
// stage 2
t = (v0 - v3 + 1) >> 1;
v0 = (v0 + v3 + 1) >> 1;
v3 = t;
t = (v1 - v2 + 1) >> 1;
v1 = (v1 + v2 + 1) >> 1;
v2 = t;
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[0*8 + col] = v0 + v7;
p[7*8 + col] = v0 - v7;
p[1*8 + col] = v1 + v6;
p[6*8 + col] = v1 - v6;
p[2*8 + col] = v2 + v5;
p[5*8 + col] = v2 - v5;
p[3*8 + col] = v3 + v4;
p[4*8 + col] = v3 - v4;
}
// convert to 8-bit integers
for (i = 0; i < 64; ++i) {
var sample = 128 + ((p[i] + 8) >> 4);
dataOut[i] = sample < 0 ? 0 : sample > 0xFF ? 0xFF : sample;
}
}
var i, j;
for (var blockRow = 0; blockRow < blocksPerColumn; blockRow++) {
var scanLine = blockRow << 3;
for (i = 0; i < 8; i++)
lines.push(new Uint8Array(samplesPerLine));
for (var blockCol = 0; blockCol < blocksPerLine; blockCol++) {
quantizeAndInverse(component.blocks[blockRow][blockCol], r, R);
var offset = 0, sample = blockCol << 3;
for (j = 0; j < 8; j++) {
var line = lines[scanLine + j];
for (i = 0; i < 8; i++)
line[sample + i] = r[offset++];
}
}
}
return lines;
}
function clampTo8bit(a) {
return a < 0 ? 0 : a > 255 ? 255 : a;
}
constructor.prototype = {
load: function load(path) {
var xhr = new XMLHttpRequest();
xhr.open("GET", path, true);
xhr.responseType = "arraybuffer";
xhr.onload = (function() {
// TODO catch parse error
var data = new Uint8Array(xhr.response || xhr.mozResponseArrayBuffer);
this.parse(data);
if (this.onload)
this.onload();
}).bind(this);
xhr.send(null);
},
parse: function parse(data) {
var offset = 0, length = data.length;
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 maxH = 0, maxV = 0;
var component, componentId;
for (componentId in frame.components) {
if (frame.components.hasOwnProperty(componentId)) {
component = frame.components[componentId];
if (maxH < component.h) maxH = component.h;
if (maxV < component.v) maxV = component.v;
}
}
var mcusPerLine = Math.ceil(frame.samplesPerLine / 8 / maxH);
var mcusPerColumn = Math.ceil(frame.scanLines / 8 / maxV);
for (componentId in frame.components) {
if (frame.components.hasOwnProperty(componentId)) {
component = frame.components[componentId];
var blocksPerLine = Math.ceil(Math.ceil(frame.samplesPerLine / 8) * component.h / maxH);
var blocksPerColumn = Math.ceil(Math.ceil(frame.scanLines / 8) * component.v / maxV);
var blocksPerLineForMcu = mcusPerLine * component.h;
var blocksPerColumnForMcu = mcusPerColumn * component.v;
var blocks = [];
for (var i = 0; i < blocksPerColumnForMcu; i++) {
var row = [];
for (var j = 0; j < blocksPerLineForMcu; j++)
row.push(new Int32Array(64));
blocks.push(row);
}
component.blocksPerLine = blocksPerLine;
component.blocksPerColumn = blocksPerColumn;
component.blocks = blocks;
}
}
frame.maxH = maxH;
frame.maxV = maxV;
frame.mcusPerLine = mcusPerLine;
frame.mcusPerColumn = mcusPerColumn;
}
var jfif = null;
var adobe = null;
var pixels = null;
var frame, resetInterval;
var quantizationTables = [], frames = [];
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 0xFF00: break;
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 && appData[5] === 0) { // 'Adobe\x00'
adobe = {
version: 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;
while (offset < quantizationTablesEnd) {
var quantizationTableSpec = data[offset++];
var tableData = new Int32Array(64);
if ((quantizationTableSpec >> 4) === 0) { // 8 bit values
for (j = 0; j < 64; j++) {
var z = dctZigZag[j];
tableData[z] = data[offset++];
}
} else if ((quantizationTableSpec >> 4) === 1) { //16 bit
for (j = 0; j < 64; j++) {
var 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)
readUint16(); // skip data length
frame = {};
frame.extended = (fileMarker === 0xFFC1);
frame.progressive = (fileMarker === 0xFFC2);
frame.precision = data[offset++];
frame.scanLines = readUint16();
frame.samplesPerLine = readUint16();
frame.components = {};
frame.componentsOrder = [];
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;
var qId = data[offset + 2];
frame.componentsOrder.push(componentId);
frame.components[componentId] = {
h: h,
v: v,
quantizationIdx: qId
};
offset += 3;
}
prepareComponents(frame);
frames.push(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++) {
component = frame.components[data[offset++]];
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;
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();
}
if (frames.length != 1)
throw "only single frame JPEGs supported";
// set each frame's components quantization table
for (var i = 0; i < frames.length; i++) {
var cp = frames[i].components;
for (var j in cp) {
cp[j].quantizationTable = quantizationTables[cp[j].quantizationIdx];
delete cp[j].quantizationIdx;
}
}
this.width = frame.samplesPerLine;
this.height = frame.scanLines;
this.jfif = jfif;
this.adobe = adobe;
this.components = [];
for (var i = 0; i < frame.componentsOrder.length; i++) {
var component = frame.components[frame.componentsOrder[i]];
this.components.push({
lines: buildComponentData(frame, component),
scaleX: component.h / frame.maxH,
scaleY: component.v / frame.maxV
});
}
},
getData: function getData(width, height) {
var scaleX = this.width / width, scaleY = this.height / height;
var component1, component2, component3, component4;
var component1Line, component2Line, component3Line, component4Line;
var x, y;
var offset = 0;
var Y, Cb, Cr, K, C, M, Ye, R, G, B;
var colorTransform;
var dataLength = width * height * this.components.length;
var data = new Uint8Array(dataLength);
switch (this.components.length) {
case 1:
component1 = this.components[0];
for (y = 0; y < height; y++) {
component1Line = component1.lines[0 | (y * component1.scaleY * scaleY)];
for (x = 0; x < width; x++) {
Y = component1Line[0 | (x * component1.scaleX * scaleX)];
data[offset++] = Y;
}
}
break;
case 2:
// PDF might compress two component data in custom colorspace
component1 = this.components[0];
component2 = this.components[1];
for (y = 0; y < height; y++) {
component1Line = component1.lines[0 | (y * component1.scaleY * scaleY)];
component2Line = component2.lines[0 | (y * component2.scaleY * scaleY)];
for (x = 0; x < width; x++) {
Y = component1Line[0 | (x * component1.scaleX * scaleX)];
data[offset++] = Y;
Y = component2Line[0 | (x * component2.scaleX * scaleX)];
data[offset++] = Y;
}
}
break;
case 3:
// The default transform for three components is true
colorTransform = true;
// The adobe transform marker overrides any previous setting
if (this.adobe && this.adobe.transformCode)
colorTransform = true;
else if (typeof this.colorTransform !== 'undefined')
colorTransform = !!this.colorTransform;
component1 = this.components[0];
component2 = this.components[1];
component3 = this.components[2];
for (y = 0; y < height; y++) {
component1Line = component1.lines[0 | (y * component1.scaleY * scaleY)];
component2Line = component2.lines[0 | (y * component2.scaleY * scaleY)];
component3Line = component3.lines[0 | (y * component3.scaleY * scaleY)];
for (x = 0; x < width; x++) {
if (!colorTransform) {
R = component1Line[0 | (x * component1.scaleX * scaleX)];
G = component2Line[0 | (x * component2.scaleX * scaleX)];
B = component3Line[0 | (x * component3.scaleX * scaleX)];
} else {
Y = component1Line[0 | (x * component1.scaleX * scaleX)];
Cb = component2Line[0 | (x * component2.scaleX * scaleX)];
Cr = component3Line[0 | (x * component3.scaleX * scaleX)];
R = clampTo8bit(Y + 1.402 * (Cr - 128));
G = clampTo8bit(Y - 0.3441363 * (Cb - 128) - 0.71413636 * (Cr - 128));
B = clampTo8bit(Y + 1.772 * (Cb - 128));
}
data[offset++] = R;
data[offset++] = G;
data[offset++] = B;
}
}
break;
case 4:
if (!this.adobe)
throw 'Unsupported color mode (4 components)';
// The default transform for four components is false
colorTransform = false;
// The adobe transform marker overrides any previous setting
if (this.adobe && this.adobe.transformCode)
colorTransform = true;
else if (typeof this.colorTransform !== 'undefined')
colorTransform = !!this.colorTransform;
component1 = this.components[0];
component2 = this.components[1];
component3 = this.components[2];
component4 = this.components[3];
for (y = 0; y < height; y++) {
component1Line = component1.lines[0 | (y * component1.scaleY * scaleY)];
component2Line = component2.lines[0 | (y * component2.scaleY * scaleY)];
component3Line = component3.lines[0 | (y * component3.scaleY * scaleY)];
component4Line = component4.lines[0 | (y * component4.scaleY * scaleY)];
for (x = 0; x < width; x++) {
if (!colorTransform) {
C = component1Line[0 | (x * component1.scaleX * scaleX)];
M = component2Line[0 | (x * component2.scaleX * scaleX)];
Ye = component3Line[0 | (x * component3.scaleX * scaleX)];
K = component4Line[0 | (x * component4.scaleX * scaleX)];
} else {
Y = component1Line[0 | (x * component1.scaleX * scaleX)];
Cb = component2Line[0 | (x * component2.scaleX * scaleX)];
Cr = component3Line[0 | (x * component3.scaleX * scaleX)];
K = component4Line[0 | (x * component4.scaleX * scaleX)];
C = 255 - clampTo8bit(Y + 1.402 * (Cr - 128));
M = 255 - clampTo8bit(Y - 0.3441363 * (Cb - 128) - 0.71413636 * (Cr - 128));
Ye = 255 - clampTo8bit(Y + 1.772 * (Cb - 128));
}
data[offset++] = 255-C;
data[offset++] = 255-M;
data[offset++] = 255-Ye;
data[offset++] = 255-K;
}
}
break;
default:
throw 'Unsupported color mode';
}
return data;
},
copyToImageData: function copyToImageData(imageData) {
var width = imageData.width, height = imageData.height;
var imageDataArray = imageData.data;
var data = this.getData(width, height);
var i = 0, j = 0, x, y;
var Y, K, C, M, R, G, B;
switch (this.components.length) {
case 1:
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
Y = data[i++];
imageDataArray[j++] = Y;
imageDataArray[j++] = Y;
imageDataArray[j++] = Y;
imageDataArray[j++] = 255;
}
}
break;
case 3:
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
R = data[i++];
G = data[i++];
B = data[i++];
imageDataArray[j++] = R;
imageDataArray[j++] = G;
imageDataArray[j++] = B;
imageDataArray[j++] = 255;
}
}
break;
case 4:
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
C = data[i++];
M = data[i++];
Y = data[i++];
K = data[i++];
R = 255 - clampTo8bit(C * (1 - K / 255) + K);
G = 255 - clampTo8bit(M * (1 - K / 255) + K);
B = 255 - clampTo8bit(Y * (1 - K / 255) + K);
imageDataArray[j++] = R;
imageDataArray[j++] = G;
imageDataArray[j++] = B;
imageDataArray[j++] = 255;
}
}
break;
default:
throw 'Unsupported color mode';
}
}
};
return constructor;
})();
module.exports = decode;
function decode(jpegData, useTArray) {
var arr = new Uint8Array(jpegData);
var decoder = new JpegImage();
decoder.parse(arr);
var image = {
width: decoder.width,
height: decoder.height,
data: useTArray ?
new Uint8Array(decoder.width * decoder.height * 4) :
new Buffer(decoder.width * decoder.height * 4)
};
decoder.copyToImageData(image);
return image;
}

766
build/node_modules/jpeg-js/lib/encoder.js generated vendored Normal file
View File

@@ -0,0 +1,766 @@
/*
Copyright (c) 2008, Adobe Systems Incorporated
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Adobe Systems Incorporated nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
JPEG encoder ported to JavaScript and optimized by Andreas Ritter, www.bytestrom.eu, 11/2009
Basic GUI blocking jpeg encoder
*/
var btoa = btoa || function(buf) {
return new Buffer(buf).toString('base64');
};
function JPEGEncoder(quality) {
var self = this;
var fround = Math.round;
var ffloor = Math.floor;
var YTable = new Array(64);
var UVTable = new Array(64);
var fdtbl_Y = new Array(64);
var fdtbl_UV = new Array(64);
var YDC_HT;
var UVDC_HT;
var YAC_HT;
var UVAC_HT;
var bitcode = new Array(65535);
var category = new Array(65535);
var outputfDCTQuant = new Array(64);
var DU = new Array(64);
var byteout = [];
var bytenew = 0;
var bytepos = 7;
var YDU = new Array(64);
var UDU = new Array(64);
var VDU = new Array(64);
var clt = new Array(256);
var RGB_YUV_TABLE = new Array(2048);
var currentQuality;
var ZigZag = [
0, 1, 5, 6,14,15,27,28,
2, 4, 7,13,16,26,29,42,
3, 8,12,17,25,30,41,43,
9,11,18,24,31,40,44,53,
10,19,23,32,39,45,52,54,
20,22,33,38,46,51,55,60,
21,34,37,47,50,56,59,61,
35,36,48,49,57,58,62,63
];
var std_dc_luminance_nrcodes = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0];
var std_dc_luminance_values = [0,1,2,3,4,5,6,7,8,9,10,11];
var std_ac_luminance_nrcodes = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d];
var std_ac_luminance_values = [
0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,
0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,
0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08,
0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0,
0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16,
0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28,
0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39,
0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,
0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59,
0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,
0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,
0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,
0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,
0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6,
0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,
0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,
0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2,
0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,
0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
0xf9,0xfa
];
var std_dc_chrominance_nrcodes = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0];
var std_dc_chrominance_values = [0,1,2,3,4,5,6,7,8,9,10,11];
var std_ac_chrominance_nrcodes = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77];
var std_ac_chrominance_values = [
0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,
0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,
0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,
0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0,
0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34,
0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26,
0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38,
0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,
0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,
0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68,
0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,
0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87,
0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96,
0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,
0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,
0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3,
0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,
0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,
0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,
0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
0xf9,0xfa
];
function initQuantTables(sf){
var YQT = [
16, 11, 10, 16, 24, 40, 51, 61,
12, 12, 14, 19, 26, 58, 60, 55,
14, 13, 16, 24, 40, 57, 69, 56,
14, 17, 22, 29, 51, 87, 80, 62,
18, 22, 37, 56, 68,109,103, 77,
24, 35, 55, 64, 81,104,113, 92,
49, 64, 78, 87,103,121,120,101,
72, 92, 95, 98,112,100,103, 99
];
for (var i = 0; i < 64; i++) {
var t = ffloor((YQT[i]*sf+50)/100);
if (t < 1) {
t = 1;
} else if (t > 255) {
t = 255;
}
YTable[ZigZag[i]] = t;
}
var UVQT = [
17, 18, 24, 47, 99, 99, 99, 99,
18, 21, 26, 66, 99, 99, 99, 99,
24, 26, 56, 99, 99, 99, 99, 99,
47, 66, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99
];
for (var j = 0; j < 64; j++) {
var u = ffloor((UVQT[j]*sf+50)/100);
if (u < 1) {
u = 1;
} else if (u > 255) {
u = 255;
}
UVTable[ZigZag[j]] = u;
}
var aasf = [
1.0, 1.387039845, 1.306562965, 1.175875602,
1.0, 0.785694958, 0.541196100, 0.275899379
];
var k = 0;
for (var row = 0; row < 8; row++)
{
for (var col = 0; col < 8; col++)
{
fdtbl_Y[k] = (1.0 / (YTable [ZigZag[k]] * aasf[row] * aasf[col] * 8.0));
fdtbl_UV[k] = (1.0 / (UVTable[ZigZag[k]] * aasf[row] * aasf[col] * 8.0));
k++;
}
}
}
function computeHuffmanTbl(nrcodes, std_table){
var codevalue = 0;
var pos_in_table = 0;
var HT = new Array();
for (var k = 1; k <= 16; k++) {
for (var j = 1; j <= nrcodes[k]; j++) {
HT[std_table[pos_in_table]] = [];
HT[std_table[pos_in_table]][0] = codevalue;
HT[std_table[pos_in_table]][1] = k;
pos_in_table++;
codevalue++;
}
codevalue*=2;
}
return HT;
}
function initHuffmanTbl()
{
YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes,std_dc_luminance_values);
UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes,std_dc_chrominance_values);
YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes,std_ac_luminance_values);
UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes,std_ac_chrominance_values);
}
function initCategoryNumber()
{
var nrlower = 1;
var nrupper = 2;
for (var cat = 1; cat <= 15; cat++) {
//Positive numbers
for (var nr = nrlower; nr<nrupper; nr++) {
category[32767+nr] = cat;
bitcode[32767+nr] = [];
bitcode[32767+nr][1] = cat;
bitcode[32767+nr][0] = nr;
}
//Negative numbers
for (var nrneg =-(nrupper-1); nrneg<=-nrlower; nrneg++) {
category[32767+nrneg] = cat;
bitcode[32767+nrneg] = [];
bitcode[32767+nrneg][1] = cat;
bitcode[32767+nrneg][0] = nrupper-1+nrneg;
}
nrlower <<= 1;
nrupper <<= 1;
}
}
function initRGBYUVTable() {
for(var i = 0; i < 256;i++) {
RGB_YUV_TABLE[i] = 19595 * i;
RGB_YUV_TABLE[(i+ 256)>>0] = 38470 * i;
RGB_YUV_TABLE[(i+ 512)>>0] = 7471 * i + 0x8000;
RGB_YUV_TABLE[(i+ 768)>>0] = -11059 * i;
RGB_YUV_TABLE[(i+1024)>>0] = -21709 * i;
RGB_YUV_TABLE[(i+1280)>>0] = 32768 * i + 0x807FFF;
RGB_YUV_TABLE[(i+1536)>>0] = -27439 * i;
RGB_YUV_TABLE[(i+1792)>>0] = - 5329 * i;
}
}
// IO functions
function writeBits(bs)
{
var value = bs[0];
var posval = bs[1]-1;
while ( posval >= 0 ) {
if (value & (1 << posval) ) {
bytenew |= (1 << bytepos);
}
posval--;
bytepos--;
if (bytepos < 0) {
if (bytenew == 0xFF) {
writeByte(0xFF);
writeByte(0);
}
else {
writeByte(bytenew);
}
bytepos=7;
bytenew=0;
}
}
}
function writeByte(value)
{
//byteout.push(clt[value]); // write char directly instead of converting later
byteout.push(value);
}
function writeWord(value)
{
writeByte((value>>8)&0xFF);
writeByte((value )&0xFF);
}
// DCT & quantization core
function fDCTQuant(data, fdtbl)
{
var d0, d1, d2, d3, d4, d5, d6, d7;
/* Pass 1: process rows. */
var dataOff=0;
var i;
const I8 = 8;
const I64 = 64;
for (i=0; i<I8; ++i)
{
d0 = data[dataOff];
d1 = data[dataOff+1];
d2 = data[dataOff+2];
d3 = data[dataOff+3];
d4 = data[dataOff+4];
d5 = data[dataOff+5];
d6 = data[dataOff+6];
d7 = data[dataOff+7];
var tmp0 = d0 + d7;
var tmp7 = d0 - d7;
var tmp1 = d1 + d6;
var tmp6 = d1 - d6;
var tmp2 = d2 + d5;
var tmp5 = d2 - d5;
var tmp3 = d3 + d4;
var tmp4 = d3 - d4;
/* Even part */
var tmp10 = tmp0 + tmp3; /* phase 2 */
var tmp13 = tmp0 - tmp3;
var tmp11 = tmp1 + tmp2;
var tmp12 = tmp1 - tmp2;
data[dataOff] = tmp10 + tmp11; /* phase 3 */
data[dataOff+4] = tmp10 - tmp11;
var z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */
data[dataOff+2] = tmp13 + z1; /* phase 5 */
data[dataOff+6] = tmp13 - z1;
/* Odd part */
tmp10 = tmp4 + tmp5; /* phase 2 */
tmp11 = tmp5 + tmp6;
tmp12 = tmp6 + tmp7;
/* The rotator is modified from fig 4-8 to avoid extra negations. */
var z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */
var z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */
var z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */
var z3 = tmp11 * 0.707106781; /* c4 */
var z11 = tmp7 + z3; /* phase 5 */
var z13 = tmp7 - z3;
data[dataOff+5] = z13 + z2; /* phase 6 */
data[dataOff+3] = z13 - z2;
data[dataOff+1] = z11 + z4;
data[dataOff+7] = z11 - z4;
dataOff += 8; /* advance pointer to next row */
}
/* Pass 2: process columns. */
dataOff = 0;
for (i=0; i<I8; ++i)
{
d0 = data[dataOff];
d1 = data[dataOff + 8];
d2 = data[dataOff + 16];
d3 = data[dataOff + 24];
d4 = data[dataOff + 32];
d5 = data[dataOff + 40];
d6 = data[dataOff + 48];
d7 = data[dataOff + 56];
var tmp0p2 = d0 + d7;
var tmp7p2 = d0 - d7;
var tmp1p2 = d1 + d6;
var tmp6p2 = d1 - d6;
var tmp2p2 = d2 + d5;
var tmp5p2 = d2 - d5;
var tmp3p2 = d3 + d4;
var tmp4p2 = d3 - d4;
/* Even part */
var tmp10p2 = tmp0p2 + tmp3p2; /* phase 2 */
var tmp13p2 = tmp0p2 - tmp3p2;
var tmp11p2 = tmp1p2 + tmp2p2;
var tmp12p2 = tmp1p2 - tmp2p2;
data[dataOff] = tmp10p2 + tmp11p2; /* phase 3 */
data[dataOff+32] = tmp10p2 - tmp11p2;
var z1p2 = (tmp12p2 + tmp13p2) * 0.707106781; /* c4 */
data[dataOff+16] = tmp13p2 + z1p2; /* phase 5 */
data[dataOff+48] = tmp13p2 - z1p2;
/* Odd part */
tmp10p2 = tmp4p2 + tmp5p2; /* phase 2 */
tmp11p2 = tmp5p2 + tmp6p2;
tmp12p2 = tmp6p2 + tmp7p2;
/* The rotator is modified from fig 4-8 to avoid extra negations. */
var z5p2 = (tmp10p2 - tmp12p2) * 0.382683433; /* c6 */
var z2p2 = 0.541196100 * tmp10p2 + z5p2; /* c2-c6 */
var z4p2 = 1.306562965 * tmp12p2 + z5p2; /* c2+c6 */
var z3p2 = tmp11p2 * 0.707106781; /* c4 */
var z11p2 = tmp7p2 + z3p2; /* phase 5 */
var z13p2 = tmp7p2 - z3p2;
data[dataOff+40] = z13p2 + z2p2; /* phase 6 */
data[dataOff+24] = z13p2 - z2p2;
data[dataOff+ 8] = z11p2 + z4p2;
data[dataOff+56] = z11p2 - z4p2;
dataOff++; /* advance pointer to next column */
}
// Quantize/descale the coefficients
var fDCTQuant;
for (i=0; i<I64; ++i)
{
// Apply the quantization and scaling factor & Round to nearest integer
fDCTQuant = data[i]*fdtbl[i];
outputfDCTQuant[i] = (fDCTQuant > 0.0) ? ((fDCTQuant + 0.5)|0) : ((fDCTQuant - 0.5)|0);
//outputfDCTQuant[i] = fround(fDCTQuant);
}
return outputfDCTQuant;
}
function writeAPP0()
{
writeWord(0xFFE0); // marker
writeWord(16); // length
writeByte(0x4A); // J
writeByte(0x46); // F
writeByte(0x49); // I
writeByte(0x46); // F
writeByte(0); // = "JFIF",'\0'
writeByte(1); // versionhi
writeByte(1); // versionlo
writeByte(0); // xyunits
writeWord(1); // xdensity
writeWord(1); // ydensity
writeByte(0); // thumbnwidth
writeByte(0); // thumbnheight
}
function writeSOF0(width, height)
{
writeWord(0xFFC0); // marker
writeWord(17); // length, truecolor YUV JPG
writeByte(8); // precision
writeWord(height);
writeWord(width);
writeByte(3); // nrofcomponents
writeByte(1); // IdY
writeByte(0x11); // HVY
writeByte(0); // QTY
writeByte(2); // IdU
writeByte(0x11); // HVU
writeByte(1); // QTU
writeByte(3); // IdV
writeByte(0x11); // HVV
writeByte(1); // QTV
}
function writeDQT()
{
writeWord(0xFFDB); // marker
writeWord(132); // length
writeByte(0);
for (var i=0; i<64; i++) {
writeByte(YTable[i]);
}
writeByte(1);
for (var j=0; j<64; j++) {
writeByte(UVTable[j]);
}
}
function writeDHT()
{
writeWord(0xFFC4); // marker
writeWord(0x01A2); // length
writeByte(0); // HTYDCinfo
for (var i=0; i<16; i++) {
writeByte(std_dc_luminance_nrcodes[i+1]);
}
for (var j=0; j<=11; j++) {
writeByte(std_dc_luminance_values[j]);
}
writeByte(0x10); // HTYACinfo
for (var k=0; k<16; k++) {
writeByte(std_ac_luminance_nrcodes[k+1]);
}
for (var l=0; l<=161; l++) {
writeByte(std_ac_luminance_values[l]);
}
writeByte(1); // HTUDCinfo
for (var m=0; m<16; m++) {
writeByte(std_dc_chrominance_nrcodes[m+1]);
}
for (var n=0; n<=11; n++) {
writeByte(std_dc_chrominance_values[n]);
}
writeByte(0x11); // HTUACinfo
for (var o=0; o<16; o++) {
writeByte(std_ac_chrominance_nrcodes[o+1]);
}
for (var p=0; p<=161; p++) {
writeByte(std_ac_chrominance_values[p]);
}
}
function writeSOS()
{
writeWord(0xFFDA); // marker
writeWord(12); // length
writeByte(3); // nrofcomponents
writeByte(1); // IdY
writeByte(0); // HTY
writeByte(2); // IdU
writeByte(0x11); // HTU
writeByte(3); // IdV
writeByte(0x11); // HTV
writeByte(0); // Ss
writeByte(0x3f); // Se
writeByte(0); // Bf
}
function processDU(CDU, fdtbl, DC, HTDC, HTAC){
var EOB = HTAC[0x00];
var M16zeroes = HTAC[0xF0];
var pos;
const I16 = 16;
const I63 = 63;
const I64 = 64;
var DU_DCT = fDCTQuant(CDU, fdtbl);
//ZigZag reorder
for (var j=0;j<I64;++j) {
DU[ZigZag[j]]=DU_DCT[j];
}
var Diff = DU[0] - DC; DC = DU[0];
//Encode DC
if (Diff==0) {
writeBits(HTDC[0]); // Diff might be 0
} else {
pos = 32767+Diff;
writeBits(HTDC[category[pos]]);
writeBits(bitcode[pos]);
}
//Encode ACs
var end0pos = 63; // was const... which is crazy
for (; (end0pos>0)&&(DU[end0pos]==0); end0pos--) {};
//end0pos = first element in reverse order !=0
if ( end0pos == 0) {
writeBits(EOB);
return DC;
}
var i = 1;
var lng;
while ( i <= end0pos ) {
var startpos = i;
for (; (DU[i]==0) && (i<=end0pos); ++i) {}
var nrzeroes = i-startpos;
if ( nrzeroes >= I16 ) {
lng = nrzeroes>>4;
for (var nrmarker=1; nrmarker <= lng; ++nrmarker)
writeBits(M16zeroes);
nrzeroes = nrzeroes&0xF;
}
pos = 32767+DU[i];
writeBits(HTAC[(nrzeroes<<4)+category[pos]]);
writeBits(bitcode[pos]);
i++;
}
if ( end0pos != I63 ) {
writeBits(EOB);
}
return DC;
}
function initCharLookupTable(){
var sfcc = String.fromCharCode;
for(var i=0; i < 256; i++){ ///// ACHTUNG // 255
clt[i] = sfcc(i);
}
}
this.encode = function(image,quality) // image data object
{
var time_start = new Date().getTime();
if(quality) setQuality(quality);
// Initialize bit writer
byteout = new Array();
bytenew=0;
bytepos=7;
// Add JPEG headers
writeWord(0xFFD8); // SOI
writeAPP0();
writeDQT();
writeSOF0(image.width,image.height);
writeDHT();
writeSOS();
// Encode 8x8 macroblocks
var DCY=0;
var DCU=0;
var DCV=0;
bytenew=0;
bytepos=7;
this.encode.displayName = "_encode_";
var imageData = image.data;
var width = image.width;
var height = image.height;
var quadWidth = width*4;
var tripleWidth = width*3;
var x, y = 0;
var r, g, b;
var start,p, col,row,pos;
while(y < height){
x = 0;
while(x < quadWidth){
start = quadWidth * y + x;
p = start;
col = -1;
row = 0;
for(pos=0; pos < 64; pos++){
row = pos >> 3;// /8
col = ( pos & 7 ) * 4; // %8
p = start + ( row * quadWidth ) + col;
if(y+row >= height){ // padding bottom
p-= (quadWidth*(y+1+row-height));
}
if(x+col >= quadWidth){ // padding right
p-= ((x+col) - quadWidth +4)
}
r = imageData[ p++ ];
g = imageData[ p++ ];
b = imageData[ p++ ];
/* // calculate YUV values dynamically
YDU[pos]=((( 0.29900)*r+( 0.58700)*g+( 0.11400)*b))-128; //-0x80
UDU[pos]=(((-0.16874)*r+(-0.33126)*g+( 0.50000)*b));
VDU[pos]=((( 0.50000)*r+(-0.41869)*g+(-0.08131)*b));
*/
// use lookup table (slightly faster)
YDU[pos] = ((RGB_YUV_TABLE[r] + RGB_YUV_TABLE[(g + 256)>>0] + RGB_YUV_TABLE[(b + 512)>>0]) >> 16)-128;
UDU[pos] = ((RGB_YUV_TABLE[(r + 768)>>0] + RGB_YUV_TABLE[(g + 1024)>>0] + RGB_YUV_TABLE[(b + 1280)>>0]) >> 16)-128;
VDU[pos] = ((RGB_YUV_TABLE[(r + 1280)>>0] + RGB_YUV_TABLE[(g + 1536)>>0] + RGB_YUV_TABLE[(b + 1792)>>0]) >> 16)-128;
}
DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
x+=32;
}
y+=8;
}
////////////////////////////////////////////////////////////////
// Do the bit alignment of the EOI marker
if ( bytepos >= 0 ) {
var fillbits = [];
fillbits[1] = bytepos+1;
fillbits[0] = (1<<(bytepos+1))-1;
writeBits(fillbits);
}
writeWord(0xFFD9); //EOI
//return new Uint8Array(byteout);
return new Buffer(byteout);
var jpegDataUri = 'data:image/jpeg;base64,' + btoa(byteout.join(''));
byteout = [];
// benchmarking
var duration = new Date().getTime() - time_start;
//console.log('Encoding time: '+ duration + 'ms');
//
return jpegDataUri
}
function setQuality(quality){
if (quality <= 0) {
quality = 1;
}
if (quality > 100) {
quality = 100;
}
if(currentQuality == quality) return // don't recalc if unchanged
var sf = 0;
if (quality < 50) {
sf = Math.floor(5000 / quality);
} else {
sf = Math.floor(200 - quality*2);
}
initQuantTables(sf);
currentQuality = quality;
//console.log('Quality set to: '+quality +'%');
}
function init(){
var time_start = new Date().getTime();
if(!quality) quality = 50;
// Create tables
initCharLookupTable()
initHuffmanTbl();
initCategoryNumber();
initRGBYUVTable();
setQuality(quality);
var duration = new Date().getTime() - time_start;
//console.log('Initialization '+ duration + 'ms');
}
init();
};
module.exports = encode;
function encode(imgData, qu) {
if (typeof qu === 'undefined') qu = 50;
var encoder = new JPEGEncoder(qu);
var data = encoder.encode(imgData, qu);
return {
data: data,
width: imgData.width,
height: imgData.height
};
}
// helper function to get the imageData of an existing image on the current page.
function getImageDataFromImage(idOrElement){
var theImg = (typeof(idOrElement)=='string')? document.getElementById(idOrElement):idOrElement;
var cvs = document.createElement('canvas');
cvs.width = theImg.width;
cvs.height = theImg.height;
var ctx = cvs.getContext("2d");
ctx.drawImage(theImg,0,0);
return (ctx.getImageData(0, 0, cvs.width, cvs.height));
}