jpeg -> array
当前为
此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.cn-greasyfork.org/scripts/38665/252976/bv7_jpeg2array_b.js
// ==UserScript==
// @name bv7_jpeg2array_b
// @namespace bv7
// @version 0.3
// @description jpeg -> array
// @author bv7
// @grant GM_xmlhttpRequest
// ==/UserScript==
class BaseImage {
load(url, onload) {
GM_xmlhttpRequest({
method : 'GET',
url : this.nodesCaptchaImgs[iImg].src,
overrideMimeType: 'text/plain; charset=x-user-defined',
onload : (v) => {
this.data = v.responseText;
this.seek(0);
if (onload) onload(v);
}
});
}
seek(iData = 0) {
this.iData = iData;
}
skip(i) {
this.iData +=i;
}
getUint8() {
return this.iData < this.data.length ? this.data.charCodeAt(this.iData) && 0xff : 0;
}
readUint8() {
return this.iData < this.data.length ? this.data.charCodeAt(this.iData++) && 0xff : 0;
}
readUint16() {
return (this.readUint8() << 8) | this.readUint8();
}
}
class JpegImage extends BaseImage {
constructor() {
this.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
]);
this.dctCos1 = 4017 // cos(pi/16)
this.dctSin1 = 799 // sin(pi/16)
this.dctCos3 = 3406 // cos(3*pi/16)
this.dctSin3 = 2276 // sin(3*pi/16)
this.dctCos6 = 1567 // cos(6*pi/16)
this.dctSin6 = 3784 // sin(6*pi/16)
this.dctSqrt2 = 5793 // sqrt(2)
this.dctSqrt1d2 = 2896 // sqrt(2) / 2
}
readDataBlock() {
value = new Array(this.readUint16() - 2);
value.forEach((v, i) => value[i] = this.readUint8());
return value;
}
seekBit() {
this.bitsData = 0;
this.bitsCount = 0;
}
readBit() {
if (this.bitsCount > 0) this.bitsCount--;
else {
this.bitsData = this.readUint8();
if (this.bitsData == 0xFF) {
let nextByte = this.readUint8();
if (nextByte) {
console.log('JpegImage: Error: unexpected marker: ' + ((this.bitsData << 8) | nextByte).toString(16));
return;
}
// unstuff 0
}
this.bitsCount = 7;
}
return (this.bitsData >> this.bitsCount) & 1;
}
prepareComponents(frame) {
frame.maxH = 0;
frame.maxV = 0;
frame.componentsOrder.forEach((v) => {
let 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 / maxH);
frame.mcusPerColumn = Math.ceil(frame.scanLines / 8 / maxV);
frame.componentsOrder.forEach((v) => {
let component = frame.components[v];
component.blocksPerLine = Math.ceil(Math.ceil(frame.samplesPerLine / 8) * component.h / maxH);
component.blocksPerColumn = Math.ceil(Math.ceil(frame.scanLines / 8) * component.v / maxV);
component.blocks = [];
let blocksPerLineForMcu = mcusPerLine * component.h;
let blocksPerColumnForMcu = mcusPerColumn * component.v;
for (let i = 0; i < blocksPerColumnForMcu; i++) {
let row = [];
for (let j = 0; j < blocksPerLineForMcu; j++) row.push(new Int32Array(64));
component.blocks.push(row);
}
});
}
buildHuffmanTable(codeLengths, values) {
let length = codeLengths.length;
while (length > 0 && !codeLengths[length - 1]) length--;
let p = {children: [], index: 0};
let code = [p];
for (let i = 0, k = 0, q; i < length; i++) {
for (let j = 0; j < codeLengths[i]; 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;
}
decodeScan(data, frame, components, resetInterval, spectralStart, spectralEnd, successivePrev, successive) {
this.seekBit();
let decodeHuffman = (tree) => {
let node = tree;
let bit;
while ((bit = this.readBit()) !== null) {
node = node[bit];
if (typeof node === 'number') return node;
if (typeof node !== 'object') {
console.log('JpegImage: Error: invalid huffman sequence');
return;
}
}
return null;
};
let receive = (length) => {
let n = 0;
for (; length > 0; length--) {
let bit = this.readBit();
if (bit === null) return;
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 t = decodeHuffman(component.huffmanTableDC);
let diff = t === 0 ? 0 : receiveAndExtend(t);
zz[0] = (component.pred += diff);
let k = 1;
while (k < 64) {
let rs = decodeHuffman(component.huffmanTableAC);
let s = rs & 15;
let r = rs >> 4;
if (s === 0) {
if (r < 15) break;
else {
k += 16;
continue;
}
} else {
k += r;
zz[dctZigZag[k]] = receiveAndExtend(s);
k++;
}
}
}
let decodeDCFirst = (component, zz) => {
let t = decodeHuffman(component.huffmanTableDC);
let diff = t === 0 ? 0 : (receiveAndExtend(t) << successive);
zz[0] = (component.pred += diff);
}
let decodeDCSuccessive = (component, zz) => zz[0] |= this.readBit() << successive;
let eobrun = 0;
let decodeACFirst = (component, zz) => {
if (eobrun > 0) eobrun--;
else {
let k = spectralStart;
while (k <= spectralEnd) {
let rs = decodeHuffman(component.huffmanTableAC);
let s = rs & 15;
let r = rs >> 4;
if (s === 0) {
if (r < 15) {
eobrun = receive(r) + (1 << r) - 1;
break;
} else k += 16;
} else {
k += r;
let z = ;
zz[this.dctZigZag[k]] = receiveAndExtend(s) * (1 << successive);
k++;
}
}
}
};
let successiveACState = 0;
let successiveACNextValue = 0;
let decodeACSuccessive = (component, zz) => {
let k = spectralStart;
let r = 0;
while(k <= spectralEnd) {
let z = dctZigZag[k];
let direction = zz[z] < 0 ? -1 : 1;
switch (successiveACState) {
case 0: // initial state
let rs = decodeHuffman(component.huffmanTableAC);
let 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) {
console.log('JpegImage: Error: invalid ACn encoding');
return;
} else {
successiveACNextValue = receiveAndExtend(s);
successiveACState = r ? 2 : 3;
}
continue;
case 1: // skipping r zero items
case 2:
if (zz[z]) zz[z] += (this.readBit() << successive) * direction;
else {
r--;
if (r === 0) successiveACState = successiveACState == 2 ? 3 : 0;
}
break;
case 3: // set value for a zero item
if (zz[z]) zz[z] += (this.readBit() << successive) * direction;
else {
zz[z] = successiveACNextValue << successive;
successiveACState = 0;
}
break;
case 4: // eob
if (zz[z]) zz[z] += (this.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;
while (mcu < mcuExpected) {
// reset interval stuff
components.forEach((v) => v.pred = 0);
eobrun = 0;
if (components.length == 1) {
let component = components[0];
for (let n = 0; n < resetInterval; n++, mcu++) decodeBlock(component, decodeFn, mcu);
} else for (let n = 0; n < resetInterval; n++) {
for (let i = 0; i < components.length; i++) {
let component = components[i];
for (let j = 0; j < component.v; j++) for (let k = 0; k < component.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
this.bitsCount = 0;
let marker = this.readUint16();
if (marker < 0xFFD0 || marker > 0xFFD7) { // !RSTx
this.seek(this.iData - 2);
if (marker < 0xFF00) console.log('JpegImage: Error: marker was not found');
break;
}
}
}
parse() {
this.jfif = null;
this.adobe = null;
let frame;
let resetInterval;
let quantizationTables = [];
let frames = [];
let huffmanTablesAC = [];
let huffmanTablesDC = [];
this.seek(0);
let fileMarker = readUint16();
if (fileMarker != 0xFFD8) { // SOI (Start of Image)
console.log('JpegImage: Error: SOI not found');
return;
}
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 = this.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])
};
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)
for(let quantizationTablesLength = this.readUint16() - 2; quantizationTablesLength > 0; quantizationTablesLength--) {
let quantizationTableSpec = this.readUint8();
let tableData = new Int32Array(64);
switch(quantizationTableSpec >> 4){
case 0: // 8 bit values
tableData.forEach((v, i) => tableData[this.dctZigZag[i]] = this.readUint8());
break;
case 1: //16 bit
tableData.forEach((v, i) => tableData[this.dctZigZag[i]] = this.readUint16());
break;
default:
console.log('JpegImage: Error: DQT: invalid table spec');
return;
}
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)
this.readUint16(); // skip data length
frame = {
extended : fileMarker === 0xFFC1,
progressive : fileMarker === 0xFFC2,
precision : this.readUint8(),
scanLines : this.readUint16(),
samplesPerLine : this.readUint16(),
components : {},
componentsOrder: new Array(this.readUint8())
};
frame.componentsOrder.forEach((v, i) => {
let componentId = this.readUint8();
let b = this.readUint8();
frame.componentsOrder[i] = componentId;
frame.components[componentId] = {
h : b >> 4,
v : b & 15,
quantizationIdx: this.readUint8()
};
});
this.prepareComponents(frame);
frames.push(frame);
break;
case 0xFFC4: // DHT (Define Huffman Tables)
let huffmanLength = this.readUint16() - 2;
while (huffmanLength > 0) {
let huffmanTableSpec = this.readUint8();
let codeLengths = new Uint8Array(16);
let codeLengthSum = 0;
codeLengths.forEach((v, i) => codeLengthSum += (codeLengths[i] = this.readUint8()));
let huffmanValues = new Uint8Array(codeLengthSum);
huffmanValues.forEach((v, i) => huffmanValues[i] = this.readUint8());
huffmanLength -= 1 + codeLengths.length + huffmanValues.length;
((huffmanTableSpec >> 4) === 0 ? huffmanTablesDC : huffmanTablesAC)[huffmanTableSpec & 15] = this.buildHuffmanTable(codeLengths, huffmanValues);
}
break;
case 0xFFDD: // DRI (Define Restart Interval)
this.readUint16(); // skip data length
resetInterval = this.readUint16();
break;
case 0xFFDA: // SOS (Start of Scan)
this.readUint16(); // scanLength
let components = [];
for (let selectorsCount = this.readUint8; selectorsCount > 0; selectorsCount--) {
let component = frame.components[this.readUint8()];
let tableSpec = this.readUint8();
component.huffmanTableDC = huffmanTablesDC[tableSpec >> 4];
component.huffmanTableAC = huffmanTablesAC[tableSpec & 15];
components.push(component);
}
let spectralStart = this.readUint8();
let spectralEnd = this.readUint8();
let successiveApproximation = this.readUint8();
decodeScan(
data,
frame,
components,
resetInterval,
spectralStart,
spectralEnd,
successiveApproximation >> 4,
successiveApproximation & 15
);
break;
case 0xFFFF: // Fill bytes
if (this.getUint8() !== 0xFF) this.skip(-1); // Avoid skipping a valid marker.
break;
default:
this.skip(-2);
let d1 = this.getUint8();
this.skip(-1);
let d0 = this.getUint(8);
// could be incorrect encoding -- last 0xFF byte of the previous
// block was eaten by the encoder
if (d0 == 0xFF && d1 >= 0xC0 && d1 <= 0xFE) break;
else {
console.log('JpegImage: Error: unknown JPEG marker ' + fileMarker.toString(16));
return;
}
}
}
if (frames.length != 1)
throw new Error("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
});
}
}
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 new Error("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 new Error("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;
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 new Error("unknown JPEG marker " + fileMarker.toString(16));
}
fileMarker = readUint16();
}
if (frames.length != 1)
throw new Error("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
});
}
},
}
class Jpeg {
decode(jpegData) {
}
}
jpeg = new Jpeg();