// ==UserScript==
// @name         bv7_jpeg2array_b
// @namespace    bv7
// @version      0.7
// @description  jpeg -> array
// @author       bv7
// @include      file:///D:/projects/JSProjects/bv7bbc/bv7_bbc_dark/bv_dev_canvas*.html
// @run-at       document-idle
// @grant        GM_xmlhttpRequest
// ==/UserScript==
class BaseImage {
constructor() {
this._src   = null;
this.onload = (() => '');
}
load() {
GM_xmlhttpRequest({
method          : 'GET',
url             : this._src,
overrideMimeType: 'text/plain; charset=x-user-defined',
onload          : (v) => {
//let t = new Date();
let data = new Uint8Array(v.responseText.length);
data.forEach((val, i) => data[i] = v.responseText.charCodeAt(i));
this.parse(data);
this.onload();
//console.log('Parse image for', ((new Date()) - t), 'ms');
}
});
}
get src() {return this._src;}
set src(v) {
if (this._src !== v) {
this._src = v;
this.load();
}
}
drawCanvas(canvas, dx, dy, dWidth, dHeight, sx, sy, sWidth, sHeight) {
let context = canvas.getContext('2d');
let imageData = context.getImageData(0, 0, canvas.width, canvas.height);
this.copyToImageData(imageData);
context.putImageData(imageData, 0, 0);
}
}
class JpegImage extends BaseImage {
parse(data) {
this.jfif  = null;
this.adobe = null;
const 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
]);
const dctCos1    = 4017; // cos(  pi/16)
const dctSin1    =  799; // sin(  pi/16)
const dctCos3    = 3406; // cos(3*pi/16)
const dctSin3    = 2276; // sin(3*pi/16)
const dctCos6    = 1567; // cos(6*pi/16)
const dctSin6    = 3784; // sin(6*pi/16)
const dctSqrt2   = 5793; // sqrt(2)
const dctSqrt1d2 = 2896; // sqrt(2) / 2
let frame;
let resetInterval;
let quantizationTables = [];
let frames             = [];
let huffmanTablesAC    = [];
let huffmanTablesDC    = [];
let offset             = 0;
//let readUint8  = () => data[offset++];
let readUint16 = () => ((data[offset++] << 8) | data[offset++]);
let readDataBlock = () => {
let length = readUint16() - 2;
let value = data.slice(offset, offset + length - 2);
offset += length;
return value;
};
let buildHuffmanTable = (codeLengths, values) => {
let length = codeLengths.length;
while (length > 0 && !codeLengths[length - 1]) length--;
let p = {children: [], index: 0};
let code = [p];
let i, j, k, q, codeLength;
for (i = 0, k = 0; i < length; i++) {
codeLength = codeLengths[i];
for (j = 0; j < codeLength; j++, k++) {
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;
}
}
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;
};
let buildComponentData = (component) => {
let lines          = [];
let samplesPerLine = component.blocksPerLine << 3;
let R              = new Int32Array(64);
let 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.
let quantizeAndInverse = (zz, dataOut, dataIn) => {
let v, u, i;
let v0, v1, v2, v3, v4, v5, v6, v7;
let u0, u1, u2, u3, u4, u5, u6, u7;
// dequant
for (i = 0; i < 64; i++) dataIn[i] = zz[i] * component.quantizationTable[i];
for (i = 0; i < 64; i += 8) {
v0 = dataIn[i    ];
v1 = dataIn[i + 1];
v2 = dataIn[i + 2];
v3 = dataIn[i + 3];
v4 = dataIn[i + 4];
v5 = dataIn[i + 5];
v6 = dataIn[i + 6];
v7 = dataIn[i + 7];
// check for all-zero AC coefficients
if (
v1 == 0 &&
v2 == 0 &&
v3 == 0 &&
v4 == 0 &&
v5 == 0 &&
v6 == 0 &&
v7 == 0
) dataIn[i    ] =
dataIn[i + 1] =
dataIn[i + 2] =
dataIn[i + 3] =
dataIn[i + 4] =
dataIn[i + 5] =
dataIn[i + 6] =
dataIn[i + 7] = (dctSqrt2 * v0 + 512) >> 10;
else {
// stage 4
u0 = (dctSqrt2 * v0 + 128) >> 8;
u1 = (dctSqrt2 * v4 + 128) >> 8;
u4 = (dctSqrt1d2 * (v1 - v7) + 128) >> 8;
u5 = v3 << 4;
u6 = v5 << 4;
u7 = (dctSqrt1d2 * (v1 + v7) + 128) >> 8;
// stage 3
v0 = (u0 + u1 + 1) >> 1;
v1 = (u0 - u1 + 1) >> 1;
u2 = (v2 * dctCos6 - v6 * dctSin6 + 128) >> 8;
v3 = (v2 * dctSin6 + v6 * dctCos6 + 128) >> 8;
v4 = (u4 + u6 + 1) >> 1;
v5 = (u7 - u5 + 1) >> 1;
u3 = (u4 - u6 + 1) >> 1;
v7 = (u7 + u5 + 1) >> 1;
// stage 2
u0 = (v0 + v3 + 1) >> 1;
u1 = (v1 + u2 + 1) >> 1;
v2 = (v1 - u2 + 1) >> 1;
v6 = (v0 - v3 + 1) >> 1;
u4 = (v4 * dctCos3 - v7 * dctSin3 + 2048) >> 12;
u5 = (v5 * dctCos1 - u3 * dctSin1 + 2048) >> 12;
u6 = (v5 * dctSin1 + u3 * dctCos1 + 2048) >> 12;
u7 = (v4 * dctSin3 + v7 * dctCos3 + 2048) >> 12;
// stage 1
dataIn[i    ] = u0 + u7;
dataIn[i + 1] = u1 + u6;
dataIn[i + 2] = v2 + u5;
dataIn[i + 3] = v6 + u4;
dataIn[i + 4] = v6 - u4;
dataIn[i + 5] = v2 - u5;
dataIn[i + 6] = u1 - u6;
dataIn[i + 7] = u0 - u7;
}
}
// inverse DCT on columns
for (i = 0; i < 8; ++i) {
v0 = dataIn[i     ];
v1 = dataIn[i +  8];
v2 = dataIn[i + 16];
v3 = dataIn[i + 24];
v4 = dataIn[i + 32];
v5 = dataIn[i + 40];
v6 = dataIn[i + 48];
v7 = dataIn[i + 56];
// check for all-zero AC coefficients
if (
v1 == 0 &&
v2 == 0 &&
v3 == 0 &&
v4 == 0 &&
v5 == 0 &&
v6 == 0 &&
v7 == 0
) dataIn[i] =
dataIn[i +  8] =
dataIn[i + 16] =
dataIn[i + 24] =
dataIn[i + 32] =
dataIn[i + 40] =
dataIn[i + 48] =
dataIn[i + 56] = (dctSqrt2 * v0 + 8192) >> 14;
else {
// stage 4
u0 = (dctSqrt2 * v0 + 2048) >> 12;
u1 = (dctSqrt2 * v4 + 2048) >> 12;
u4 = (dctSqrt1d2 * (v1 - v7) + 2048) >> 12;
u7 = (dctSqrt1d2 * (v1 + v7) + 2048) >> 12;
// stage 3
v0 = (u0 + u1 + 1) >> 1;
v1 = (u0 - u1 + 1) >> 1;
u2 = (v2 * dctCos6 - v6 * dctSin6 + 2048) >> 12;
u5 = (v2 * dctSin6 + v6 * dctCos6 + 2048) >> 12;
v4 = (u4 + v5 + 1) >> 1;
u6 = (u7 - v3 + 1) >> 1;
u3 = (u4 - v5 + 1) >> 1;
v7 = (u7 + v3 + 1) >> 1;
// stage 2
u0 = (v0 + u5 + 1) >> 1;
u1 = (v1 + u2 + 1) >> 1;
v2 = (v1 - u2 + 1) >> 1;
v6 = (v0 - u5 + 1) >> 1;
u4 = (v4 * dctCos3 - v7 * dctSin3 + 2048) >> 12;
v3 = (u6 * dctCos1 - u3 * dctSin1 + 2048) >> 12;
v5 = (u6 * dctSin1 + u3 * dctCos1 + 2048) >> 12;
u7 = (v4 * dctSin3 + v7 * dctCos3 + 2048) >> 12;
// stage 1
dataIn[i     ] = u0 + u7;
dataIn[i +  8] = u1 + v5;
dataIn[i + 16] = v2 + v3;
dataIn[i + 24] = v6 + u4;
dataIn[i + 32] = v6 - u4;
dataIn[i + 40] = v2 - v3;
dataIn[i + 48] = u1 - v5;
dataIn[i + 56] = u0 - u7;
}
}
// convert to 8-bit integers
let sample;
for (i = 0; i < 64; i++) {
sample = 128 + ((dataIn[i] + 8) >> 4);
dataOut[i] = sample < 0 ? 0 : sample > 0xFF ? 0xFF : sample;
}
};
let scanLine, j, sample, line, samleI, scanLineJ;
let blockRow;
let blockCol;
for (blockRow = 0; blockRow < component.blocksPerColumn; blockRow++) {
scanLine = blockRow << 3;
lines.push(new Uint8Array(samplesPerLine));
lines.push(new Uint8Array(samplesPerLine));
lines.push(new Uint8Array(samplesPerLine));
lines.push(new Uint8Array(samplesPerLine));
lines.push(new Uint8Array(samplesPerLine));
lines.push(new Uint8Array(samplesPerLine));
lines.push(new Uint8Array(samplesPerLine));
lines.push(new Uint8Array(samplesPerLine));
for (blockCol = 0; blockCol < component.blocksPerLine; blockCol++) {
quantizeAndInverse(component.blocks[blockRow][blockCol], r, R);
sample = blockCol << 3;
for (j = 0, offset = 0, scanLineJ = scanLine; j < 8; j++) {
line = lines[scanLineJ++];
samleI = sample;
line[samleI++] = r[offset++];
line[samleI++] = r[offset++];
line[samleI++] = r[offset++];
line[samleI++] = r[offset++];
line[samleI++] = r[offset++];
line[samleI++] = r[offset++];
line[samleI++] = r[offset++];
line[samleI++] = r[offset++];
}
}
}
return lines;
}
let prepareComponents = (frame) => {
let component, i, j, row;
let blocksPerLineForMcu;
let blocksPerColumnForMcu;
frame.maxH = 0;
frame.maxV = 0;
frame.componentsOrder.forEach((v) => {
component = frame.components[v];
if (frame.maxH < component.h) frame.maxH = component.h;
if (frame.maxV < component.v) frame.maxV = component.v;
});
frame.mcusPerLine   = Math.ceil(frame.samplesPerLine / 8 / frame.maxH);
frame.mcusPerColumn = Math.ceil(frame.scanLines      / 8 / frame.maxV);
frame.componentsOrder.forEach((v) => {
component = frame.components[v];
component.blocksPerLine   = Math.ceil(Math.ceil(frame.samplesPerLine / 8) * component.h / frame.maxH);
component.blocksPerColumn = Math.ceil(Math.ceil(frame.scanLines      / 8) * component.v / frame.maxV);
component.blocks          = [];
blocksPerLineForMcu       = frame.mcusPerLine   * component.h;
blocksPerColumnForMcu     = frame.mcusPerColumn * component.v;
for (i = 0; i < blocksPerColumnForMcu; i++) {
row = [];
for (j = 0; j < blocksPerLineForMcu; j++) row.push(new Int32Array(64));
component.blocks.push(row);
}
});
};
let decodeScan = (components, resetInterval, spectralStart, spectralEnd, successivePrev, successive) => {
let bitsData  = 0;
let bitsCount = 0;
let readBit = () => {
if (bitsCount > 0) bitsCount--;
else {
bitsData = data[offset++];
if (bitsData == 0xFF) {
let nextByte = data[offset++];
if (nextByte) throw new Error('Unexpected marker: ' + ((bitsData << 8) | nextByte).toString(16));
// unstuff 0
}
bitsCount = 7;
}
return (bitsData >> bitsCount) & 1;
};
let decodeHuffman = (tree) => {
let node = tree;
let bit;
while ((bit = readBit()) !== null) if (typeof (node = node[bit]) === 'number') return node;
else if (typeof node !== 'object') throw new Error('Invalid huffman sequence');
return null;
};
let receive = (length) => {
let bit;
let n = 0;
while ((length--) > 0) if ((bit = readBit()) === null) return;
else n = (n << 1) | bit;
return n;
};
let receiveAndExtend = (length) => {
let n = receive(length);
return (n >= 1 << (length - 1)) ? n : (n + (-1 << length) + 1);
};
let decodeBaseline = (component, zz) => {
let rs, s, r;
let t = decodeHuffman(component.huffmanTableDC);
let diff = t === 0 ? 0 : receiveAndExtend(t);
zz[0] = (component.pred += diff);
let k = 1;
while (k < 64) {
r  = (rs = decodeHuffman(component.huffmanTableAC)) >> 4;
if ((s  = rs & 15) === 0) {
if (r < 15) break;
else {
k += 16;
continue;
}
} else {
zz[dctZigZag[k += r]] = receiveAndExtend(s);
k++;
}
}
}
let decodeDCFirst = (component, zz) => {
let t = decodeHuffman(component.huffmanTableDC);
zz[0] = (component.pred += t === 0 ? 0 : (receiveAndExtend(t) << successive));
}
let decodeDCSuccessive = (component, zz) => zz[0] |= readBit() << successive;
let eobrun = 0;
let decodeACFirst = (component, zz) => {
if (eobrun > 0) eobrun--;
else {
let rs, s, r;
let k = spectralStart;
while (k <= spectralEnd) {
r  = (rs = decodeHuffman(component.huffmanTableAC)) >> 4;
if ((s  = rs & 15) === 0) {
if (r < 15) {
eobrun = receive(r) + (1 << r) - 1;
break;
} else k += 16;
} else {
zz[dctZigZag[k += r]] = receiveAndExtend(s) * (1 << successive);
k++;
}
}
}
};
let successiveACState     = 0;
let successiveACNextValue = 0;
let decodeACSuccessive = (component, zz) => {
let z, direction, rs, s;
let k = spectralStart;
let r = 0;
while(k <= spectralEnd) {
direction = zz[z = dctZigZag[k]] < 0 ? -1 : 1;
switch (successiveACState) {
case 0: // initial state
r = (rs = decodeHuffman(component.huffmanTableAC)) >> 4;
if ((s  = rs & 15) === 0) {
if (r < 15) {
eobrun            = receive(r) + (1 << r);
successiveACState = 4;
} else {
r = 16;
successiveACState = 1;
}
} else if (s !== 1) throw new Error('Invalid ACn encoding');
else {
successiveACNextValue = receiveAndExtend(s);
successiveACState     = r ? 2 : 3;
}
continue;
case 1: // skipping r zero items
case 2:
if (zz[z]) zz[z] += (readBit() << successive) * direction;
else if ((--r) === 0) successiveACState = successiveACState == 2 ? 3 : 0;
break;
case 3: // set value for a zero item
if (zz[z]) zz[z] += (readBit() << successive) * direction;
else {
zz[z]             = successiveACNextValue << successive;
successiveACState = 0;
}
break;
case 4: // eob
if (zz[z]) zz[z] += (readBit() << successive) * direction;
break;
}
k++;
}
if (successiveACState === 4) {
eobrun--;
if (eobrun === 0) successiveACState = 0;
}
};
let decodeMcu = (component, decode, mcu, row, col) => decode(
component,
component.blocks[((mcu / frame.mcusPerLine) | 0) * component.v + row][(mcu % frame.mcusPerLine) * component.h + col]
);
let decodeBlock = (component, decode, mcu) => decode(
component,
component.blocks[(mcu / component.blocksPerLine) | 0][mcu % component.blocksPerLine]
);
let decodeFn = frame.progressive ? (
spectralStart === 0 ? (
successivePrev === 0 ? decodeDCFirst : decodeDCSuccessive
) : (
successivePrev === 0 ? decodeACFirst : decodeACSuccessive
)
) : decodeBaseline;
let mcu         = 0;
let mcuExpected = (components.length == 1) ? (
components[0].blocksPerLine * components[0].blocksPerColumn
) : (
frame.mcusPerLine * frame.mcusPerColumn
);
if (!resetInterval) resetInterval = mcuExpected;
let component, n, i, j, k, marker;
while (mcu < mcuExpected) {
// reset interval stuff
components.forEach((v) => v.pred = 0);
eobrun = 0;
if (components.length == 1) {
component = components[0];
for (n = 0; n < resetInterval; n++, mcu++) decodeBlock(component, decodeFn, mcu);
} else for (n = 0; n < resetInterval; n++) {
for (i = 0; i < components.length; i++) {
component = components[i];
for (j = 0; j < component.v; j++) for (k = 0; k < component.h; k++) decodeMcu(component, decodeFn, mcu, j, k);
}
if ((++mcu) === mcuExpected) break; // If we've reached our expected MCU's, stop decoding
}
// find marker
bitsCount = 0;
marker    = readUint16();
if (marker < 0xFFD0 || marker > 0xFFD7) { // !RSTx
offset -= 2;
if (marker < 0xFF00) throw new Error('Marker was not found');
break;
}
}
};
let fileMarker = readUint16();
if (fileMarker != 0xFFD8) throw new Error('SOI not found'); // SOI (Start of Image)
//let length;
while ((fileMarker = readUint16()) != 0xFFD9) { // EOI (End of image)
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)
let appData = readDataBlock();
switch(fileMarker){
case 0xFFE0:
if (
appData[0] === 0x4A &&
appData[1] === 0x46 &&
appData[2] === 0x49 &&
appData[3] === 0x46 &&
appData[4] === 0
) this.jfif = { // 'JFIF\x00'
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.slice(14, 14 + 3 * appData[12] * appData[13] + 1)
};
break;
// TODO APP1 - Exif
case 0xFFEE:
if (
appData[0] === 0x41 &&
appData[1] === 0x64 &&
appData[2] === 0x6F &&
appData[3] === 0x62 &&
appData[4] === 0x65 &&
appData[5] === 0
) this.adobe = { // 'Adobe\x00'
version      : appData[6],
flags0       : (appData[7] << 8) | appData[8],
flags1       : (appData[9] << 8) | appData[10],
transformCode: appData[11]
};
break;
}
break;
case 0xFFDB: // DQT (Define Quantization Tables)
let quantizationTableSpec, tableData;
let quantizationTablesLength = readUint16();
let quantizationTablesEnd = quantizationTablesLength + offset - 2;
while (offset < quantizationTablesEnd) {
quantizationTableSpec = data[offset++];
tableData = new Int32Array(64);
switch(quantizationTableSpec >> 4){
case 0: // 8 bit values
tableData.forEach((v, i) => tableData[dctZigZag[i]] = data[offset++]);
break;
case 1: //16 bit
tableData.forEach((v, i) => tableData[dctZigZag[i]] = readUint16());
break;
default:
throw new Error('DQT: invalid table spec: ' + (quantizationTableSpec >> 4));
}
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)
let b;
readUint16(); // skip data length
frame = {
extended       : fileMarker === 0xFFC1,
progressive    : fileMarker === 0xFFC2,
precision      : data[offset++],
scanLines      : readUint16(),
samplesPerLine : readUint16(),
components     : {},
componentsOrder: new Uint8Array(data[offset++])
};
frame.componentsOrder.forEach((v, i) => {
frame.components[frame.componentsOrder[i] = data[offset++]] = {
h              : (b = data[offset++]) >> 4,
v              : b & 15,
quantizationIdx: data[offset++]
};
});
prepareComponents(frame);
frames.push(frame);
break;
case 0xFFC4: // DHT (Define Huffman Tables)
let huffmanLength = readUint16() - 2;
while (huffmanLength > 0) {
let huffmanTableSpec = data[offset++];
let codeLengths      = new Uint8Array(16);
let codeLengthSum    = 0;
codeLengths.forEach((v, i) => codeLengthSum += (codeLengths[i] = data[offset++]));
let huffmanValues = new Uint8Array(codeLengthSum);
huffmanValues.forEach((v, i) => huffmanValues[i] = data[offset++]);
huffmanLength -= 1 + codeLengths.length + huffmanValues.length;
((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)
readUint16(); // scanLength
let components = [];
for (let selectorsCount = data[offset++]; selectorsCount > 0; selectorsCount--) {
let component = frame.components[data[offset++]];
let tableSpec = data[offset++];
component.huffmanTableDC = huffmanTablesDC[tableSpec >> 4];
component.huffmanTableAC = huffmanTablesAC[tableSpec & 15];
components.push(component);
}
let spectralStart = data[offset++];
let spectralEnd   = data[offset++];
let successiveApproximation = data[offset++];
decodeScan(
components,
resetInterval,
spectralStart,
spectralEnd,
successiveApproximation >> 4,
successiveApproximation & 15
);
break;
case 0xFFFF: // Fill bytes
if (data[offset] !== 0xFF) offset--; // Avoid skipping a valid marker.
break;
default:
// could be incorrect encoding -- last 0xFF byte of the previous
// block was eaten by the encoder
if (data[offset - 3] == data[offset - 2] && data[offset - 2] >= 0xC0 && d1 <= 0xFE) {
offset -= 3;
break;
}
else throw new Error('Unknown JPEG marker ' + fileMarker.toString(16));
}
}
if (frames.length != 1) throw new Error("Only single frame JPEGs supported");
// set each frame's components quantization table
let j;
frames.forEach((v) => {
for (j in v.components) {
v.components[j].quantizationTable = quantizationTables[v.components[j].quantizationIdx];
delete v.components[j].quantizationIdx;
}
});
this.width      = frame.samplesPerLine;
this.height     = frame.scanLines;
this.components = [];
frame.componentsOrder.forEach((v) => {
let component = frame.components[v];
this.components.push({
lines : buildComponentData(component),
scaleX: component.h / frame.maxH,
scaleY: component.v / frame.maxV
});
});
}
clampTo8bit(a) {
return a < 0 ? 0 : a > 255 ? 255 : a;
}
getData(width, height) {
let scaleX = this.width  / width ;
let scaleY = this.height / height;
let data   = new Uint8Array(width * height * this.components.length);
let offset = 0;
// The default transform for three components is true
// The adobe transform marker overrides any previous setting
let colorTransform = (this.adobe && this.adobe.transformCode) ||
(typeof this.colorTransform === 'undefined') ||
!!this.colorTransform;
let y, x;
let component0Line, component1Line, component2Line, component3Line;
let component0    , component1    , component2    , component3    ;
let c0            , c1            , c2            , c3            ;
switch (this.components.length) {
case 1:
component0 = this.components[0];
for (y = 0; y < height; y++) {
component0Line = component0.lines[0 | (y * component0.scaleY * scaleY)];
for (x = 0; x < width; x++) data[offset++] = component0Line[0 | (x * component0.scaleX * scaleX)]; // Y
}
break;
case 2:
component0 = this.components[0];
component1 = this.components[1];
for (y = 0; y < height; y++) {
component0Line = component0.lines[0 | (y * component0.scaleY * scaleY)];
component1Line = component1.lines[0 | (y * component1.scaleY * scaleY)];
for (x = 0; x < width; x++) {
data[offset++] = component0Line[0 | (x * component0.scaleX * scaleX)]; // Y
data[offset++] = component1Line[0 | (x * component1.scaleX * scaleX)]; // Y
}
}
break;
case 3:
component0 = this.components[0];
component1 = this.components[1];
component2 = this.components[2];
for (y = 0; y < height; y++) {
component0Line = component0.lines[0 | (y * component0.scaleY * scaleY)];
component1Line = component1.lines[0 | (y * component1.scaleY * scaleY)];
component2Line = component2.lines[0 | (y * component2.scaleY * scaleY)];
for (x = 0; x < width; x++) {
c0 = component0Line[0 | (x * component0.scaleX * scaleX)]; // R / Y
c1 = component1Line[0 | (x * component1.scaleX * scaleX)]; // G / Cb
c2 = component2Line[0 | (x * component2.scaleX * scaleX)]; // B / Cr
if (colorTransform) {
data[offset++] = this.clampTo8bit(c0 + 1.402 * (c2 - 128));                               // R
data[offset++] = this.clampTo8bit(c0 - 0.3441363 * (c1 - 128) - 0.71413636 * (c2 - 128)); // G
data[offset++] = this.clampTo8bit(c0 + 1.772 * (c1 - 128));                               // B
} else {
data[offset++] = c0; // R
data[offset++] = c1; // G
data[offset++] = c2; // B
}
}
}
break;
case 4:
if (this.adobe) { // PDF might compress two component data in custom colorspace
component0 = this.components[0];
component1 = this.components[1];
component2 = this.components[2];
component3 = this.components[3];
for (y = 0; y < height; y++) {
component0Line = component0.lines[0 | (y * component0.scaleY * scaleY)];
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++) {
c0 = component0Line[0 | (x * component0.scaleX * scaleX)]; // C  / Y
c1 = component1Line[0 | (x * component1.scaleX * scaleX)]; // M  / Cb
c2 = component2Line[0 | (x * component2.scaleX * scaleX)]; // Ye / Cr
c3 = component3Line[0 | (x * component3.scaleX * scaleX)]; // K  / K
if (colorTransform) {
data[offset++] = this.clampTo8bit(c0 + 1.402 * (c2 - 128));                               // C
data[offset++] = this.clampTo8bit(c0 - 0.3441363 * (c1 - 128) - 0.71413636 * (c2 - 128)); // M
data[offset++] = this.clampTo8bit(c0 + 1.772 * (c1 - 128));                               // Ye
} else {
data[offset++] = 255 - c0; // C
data[offset++] = 255 - c1; // M
data[offset++] = 255 - c2; // Ye
}
data[offset++] = 255 - c3;     // K
}
}
}
else throw new Error('Unsupported color mode (4 components)');
break;
default:
throw new Error('Unsupported color mode');
}
return data;
}
copyToImageData(imageData) {
let scaleX = this.width  / imageData.width ;
let scaleY = this.height / imageData.height;
let offset = 0;
let j      = 0;
// The default transform for three components is true
// The adobe transform marker overrides any previous setting
let colorTransform = (this.adobe && this.adobe.transformCode) ||
(typeof this.colorTransform === 'undefined') ||
!!this.colorTransform;
let y, x;
let component0Line, component1Line, component2Line, component3Line;
let component0    , component1    , component2    , component3    ;
let c0            , c1            , c2            , c3            ;
switch (this.components.length) {
case 1:
component0 = this.components[0];
for (y = 0; y < imageData.height; y++) {
component0Line = component0.lines[0 | (y * component0.scaleY * scaleY)];
for (x = 0; x < imageData.width; x++) {
imageData.data[j++] =
imageData.data[j++] =
imageData.data[j++] = component0Line[0 | (x * component0.scaleX * scaleX)]; // Y
imageData.data[j++] = 255;
}
}
break;
case 3:
component0 = this.components[0];
component1 = this.components[1];
component2 = this.components[2];
for (y = 0; y < imageData.height; y++) {
component0Line = component0.lines[0 | (y * component0.scaleY * scaleY)];
component1Line = component1.lines[0 | (y * component1.scaleY * scaleY)];
component2Line = component2.lines[0 | (y * component2.scaleY * scaleY)];
for (x = 0; x < imageData.width; x++) {
c0 = component0Line[0 | (x * component0.scaleX * scaleX)]; // R / Y
c1 = component1Line[0 | (x * component1.scaleX * scaleX)]; // G / Cb
c2 = component2Line[0 | (x * component2.scaleX * scaleX)]; // B / Cr
if (colorTransform) {
imageData.data[j++] = this.clampTo8bit(c0 + 1.402 * (c2 - 128));                               // R
imageData.data[j++] = this.clampTo8bit(c0 - 0.3441363 * (c1 - 128) - 0.71413636 * (c2 - 128)); // G
imageData.data[j++] = this.clampTo8bit(c0 + 1.772 * (c1 - 128));                               // B
} else {
imageData.data[j++] = c0; // R
imageData.data[j++] = c1; // G
imageData.data[j++] = c2; // B
}
imageData.data[j++] = 255;
}
}
break;
case 4:
if (this.adobe) { // PDF might compress two component data in custom colorspace
component0 = this.components[0];
component1 = this.components[1];
component2 = this.components[2];
component3 = this.components[3];
for (y = 0; y < imageData.height; y++) {
component0Line = component0.lines[0 | (y * component0.scaleY * scaleY)];
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 < imageData.width; x++) {
c0 = component0Line[0 | (x * component0.scaleX * scaleX)]; // C  / Y
c1 = component1Line[0 | (x * component1.scaleX * scaleX)]; // M  / Cb
c2 = component2Line[0 | (x * component2.scaleX * scaleX)]; // Ye / Cr
c3 = component3Line[0 | (x * component3.scaleX * scaleX)]; // K  / K
if (colorTransform) {
imageData.data[j++] = 0 | ((255 - this.clampTo8bit(c0 + 1.402     * (c2 - 128)                          )) * c3 / 255); // R
imageData.data[j++] = 0 | ((255 - this.clampTo8bit(c0 - 0.3441363 * (c1 - 128) - 0.71413636 * (c2 - 128))) * c3 / 255); // G
imageData.data[j++] = 0 | ((255 - this.clampTo8bit(c0 + 1.772     * (c1 - 128)                          )) * c3 / 255); // B
} else {
imageData.data[j++] = 0 | (c0 * c3 / 255); // R
imageData.data[j++] = 0 | (c1 * c3 / 255); // G
imageData.data[j++] = 0 | (c2 * c3 / 255); // B
}
imageData.data[j++] = 255;
}
}
} else throw new Error('Unsupported color mode (4 components)');
break;
default:
throw new Error('Unsupported color mode');
}
return imageData;
}
}
/*
let jpeg = new JpegImage();
jpeg.onload = function() {
this.drawCanvas(document.getElementById('canvas'), 10, 10, 400, 500, 50, 50);
console.log('jpeg =', this);
};
jpeg.src = document.getElementById('img1').src;
*/