How to use JpegError method in wpt

Best JavaScript code snippet using wpt

jpg.js

Source:jpg.js

...26exports.JpegImage = undefined;27var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; };28var _util = require('../shared/util');29var JpegError = function JpegErrorClosure() {30  function JpegError(msg) {31    this.message = 'JPEG error: ' + msg;32  }33  JpegError.prototype = new Error();34  JpegError.prototype.name = 'JpegError';35  JpegError.constructor = JpegError;36  return JpegError;37}();38var JpegImage = function JpegImageClosure() {39  var dctZigZag = new Uint8Array([0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5, 12, 19, 26, 33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28, 35, 42, 49, 56, 57, 50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51, 58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63]);40  var dctCos1 = 4017;41  var dctSin1 = 799;42  var dctCos3 = 3406;43  var dctSin3 = 2276;44  var dctCos6 = 1567;45  var dctSin6 = 3784;46  var dctSqrt2 = 5793;47  var dctSqrt1d2 = 2896;48  function JpegImage() {49    this.decodeTransform = null;50    this.colorTransform = -1;51  }52  function buildHuffmanTable(codeLengths, values) {53    var k = 0,54        code = [],55        i,56        j,57        length = 16;58    while (length > 0 && !codeLengths[length - 1]) {59      length--;60    }61    code.push({62      children: [],63      index: 064    });65    var p = code[0],66        q;67    for (i = 0; i < length; i++) {68      for (j = 0; j < codeLengths[i]; j++) {69        p = code.pop();70        p.children[p.index] = values[k];71        while (p.index > 0) {72          p = code.pop();73        }74        p.index++;75        code.push(p);76        while (code.length <= i) {77          code.push(q = {78            children: [],79            index: 080          });81          p.children[p.index] = q.children;82          p = q;83        }84        k++;85      }86      if (i + 1 < length) {87        code.push(q = {88          children: [],89          index: 090        });91        p.children[p.index] = q.children;92        p = q;93      }94    }95    return code[0].children;96  }97  function getBlockBufferOffset(component, row, col) {98    return 64 * ((component.blocksPerLine + 1) * row + col);99  }100  function decodeScan(data, offset, frame, components, resetInterval, spectralStart, spectralEnd, successivePrev, successive) {101    var mcusPerLine = frame.mcusPerLine;102    var progressive = frame.progressive;103    var startOffset = offset,104        bitsData = 0,105        bitsCount = 0;106    function readBit() {107      if (bitsCount > 0) {108        bitsCount--;109        return bitsData >> bitsCount & 1;110      }111      bitsData = data[offset++];112      if (bitsData === 0xFF) {113        var nextByte = data[offset++];114        if (nextByte) {115          throw new JpegError('unexpected marker ' + (bitsData << 8 | nextByte).toString(16));116        }117      }118      bitsCount = 7;119      return bitsData >>> 7;120    }121    function decodeHuffman(tree) {122      var node = tree;123      while (true) {124        node = node[readBit()];125        if (typeof node === 'number') {126          return node;127        }128        if ((typeof node === 'undefined' ? 'undefined' : _typeof(node)) !== 'object') {129          throw new JpegError('invalid huffman sequence');130        }131      }132    }133    function receive(length) {134      var n = 0;135      while (length > 0) {136        n = n << 1 | readBit();137        length--;138      }139      return n;140    }141    function receiveAndExtend(length) {142      if (length === 1) {143        return readBit() === 1 ? 1 : -1;144      }145      var n = receive(length);146      if (n >= 1 << length - 1) {147        return n;148      }149      return n + (-1 << length) + 1;150    }151    function decodeBaseline(component, offset) {152      var t = decodeHuffman(component.huffmanTableDC);153      var diff = t === 0 ? 0 : receiveAndExtend(t);154      component.blockData[offset] = component.pred += diff;155      var k = 1;156      while (k < 64) {157        var rs = decodeHuffman(component.huffmanTableAC);158        var s = rs & 15,159            r = rs >> 4;160        if (s === 0) {161          if (r < 15) {162            break;163          }164          k += 16;165          continue;166        }167        k += r;168        var z = dctZigZag[k];169        component.blockData[offset + z] = receiveAndExtend(s);170        k++;171      }172    }173    function decodeDCFirst(component, offset) {174      var t = decodeHuffman(component.huffmanTableDC);175      var diff = t === 0 ? 0 : receiveAndExtend(t) << successive;176      component.blockData[offset] = component.pred += diff;177    }178    function decodeDCSuccessive(component, offset) {179      component.blockData[offset] |= readBit() << successive;180    }181    var eobrun = 0;182    function decodeACFirst(component, offset) {183      if (eobrun > 0) {184        eobrun--;185        return;186      }187      var k = spectralStart,188          e = spectralEnd;189      while (k <= e) {190        var rs = decodeHuffman(component.huffmanTableAC);191        var s = rs & 15,192            r = rs >> 4;193        if (s === 0) {194          if (r < 15) {195            eobrun = receive(r) + (1 << r) - 1;196            break;197          }198          k += 16;199          continue;200        }201        k += r;202        var z = dctZigZag[k];203        component.blockData[offset + z] = receiveAndExtend(s) * (1 << successive);204        k++;205      }206    }207    var successiveACState = 0,208        successiveACNextValue;209    function decodeACSuccessive(component, offset) {210      var k = spectralStart;211      var e = spectralEnd;212      var r = 0;213      var s;214      var rs;215      while (k <= e) {216        var offsetZ = offset + dctZigZag[k];217        var sign = component.blockData[offsetZ] < 0 ? -1 : 1;218        switch (successiveACState) {219          case 0:220            rs = decodeHuffman(component.huffmanTableAC);221            s = rs & 15;222            r = rs >> 4;223            if (s === 0) {224              if (r < 15) {225                eobrun = receive(r) + (1 << r);226                successiveACState = 4;227              } else {228                r = 16;229                successiveACState = 1;230              }231            } else {232              if (s !== 1) {233                throw new JpegError('invalid ACn encoding');234              }235              successiveACNextValue = receiveAndExtend(s);236              successiveACState = r ? 2 : 3;237            }238            continue;239          case 1:240          case 2:241            if (component.blockData[offsetZ]) {242              component.blockData[offsetZ] += sign * (readBit() << successive);243            } else {244              r--;245              if (r === 0) {246                successiveACState = successiveACState === 2 ? 3 : 0;247              }248            }249            break;250          case 3:251            if (component.blockData[offsetZ]) {252              component.blockData[offsetZ] += sign * (readBit() << successive);253            } else {254              component.blockData[offsetZ] = successiveACNextValue << successive;255              successiveACState = 0;256            }257            break;258          case 4:259            if (component.blockData[offsetZ]) {260              component.blockData[offsetZ] += sign * (readBit() << successive);261            }262            break;263        }264        k++;265      }266      if (successiveACState === 4) {267        eobrun--;268        if (eobrun === 0) {269          successiveACState = 0;270        }271      }272    }273    function decodeMcu(component, decode, mcu, row, col) {274      var mcuRow = mcu / mcusPerLine | 0;275      var mcuCol = mcu % mcusPerLine;276      var blockRow = mcuRow * component.v + row;277      var blockCol = mcuCol * component.h + col;278      var offset = getBlockBufferOffset(component, blockRow, blockCol);279      decode(component, offset);280    }281    function decodeBlock(component, decode, mcu) {282      var blockRow = mcu / component.blocksPerLine | 0;283      var blockCol = mcu % component.blocksPerLine;284      var offset = getBlockBufferOffset(component, blockRow, blockCol);285      decode(component, offset);286    }287    var componentsLength = components.length;288    var component, i, j, k, n;289    var decodeFn;290    if (progressive) {291      if (spectralStart === 0) {292        decodeFn = successivePrev === 0 ? decodeDCFirst : decodeDCSuccessive;293      } else {294        decodeFn = successivePrev === 0 ? decodeACFirst : decodeACSuccessive;295      }296    } else {297      decodeFn = decodeBaseline;298    }299    var mcu = 0,300        fileMarker;301    var mcuExpected;302    if (componentsLength === 1) {303      mcuExpected = components[0].blocksPerLine * components[0].blocksPerColumn;304    } else {305      mcuExpected = mcusPerLine * frame.mcusPerColumn;306    }307    var h, v;308    while (mcu < mcuExpected) {309      var mcuToRead = resetInterval ? Math.min(mcuExpected - mcu, resetInterval) : mcuExpected;310      for (i = 0; i < componentsLength; i++) {311        components[i].pred = 0;312      }313      eobrun = 0;314      if (componentsLength === 1) {315        component = components[0];316        for (n = 0; n < mcuToRead; n++) {317          decodeBlock(component, decodeFn, mcu);318          mcu++;319        }320      } else {321        for (n = 0; n < mcuToRead; n++) {322          for (i = 0; i < componentsLength; i++) {323            component = components[i];324            h = component.h;325            v = component.v;326            for (j = 0; j < v; j++) {327              for (k = 0; k < h; k++) {328                decodeMcu(component, decodeFn, mcu, j, k);329              }330            }331          }332          mcu++;333        }334      }335      bitsCount = 0;336      fileMarker = findNextFileMarker(data, offset);337      if (fileMarker && fileMarker.invalid) {338        (0, _util.warn)('decodeScan - unexpected MCU data, next marker is: ' + fileMarker.invalid);339        offset = fileMarker.offset;340      }341      var marker = fileMarker && fileMarker.marker;342      if (!marker || marker <= 0xFF00) {343        throw new JpegError('marker was not found');344      }345      if (marker >= 0xFFD0 && marker <= 0xFFD7) {346        offset += 2;347      } else {348        break;349      }350    }351    fileMarker = findNextFileMarker(data, offset);352    if (fileMarker && fileMarker.invalid) {353      (0, _util.warn)('decodeScan - unexpected Scan data, next marker is: ' + fileMarker.invalid);354      offset = fileMarker.offset;355    }356    return offset - startOffset;357  }358  function quantizeAndInverse(component, blockBufferOffset, p) {359    var qt = component.quantizationTable,360        blockData = component.blockData;361    var v0, v1, v2, v3, v4, v5, v6, v7;362    var p0, p1, p2, p3, p4, p5, p6, p7;363    var t;364    if (!qt) {365      throw new JpegError('missing required Quantization Table.');366    }367    for (var row = 0; row < 64; row += 8) {368      p0 = blockData[blockBufferOffset + row];369      p1 = blockData[blockBufferOffset + row + 1];370      p2 = blockData[blockBufferOffset + row + 2];371      p3 = blockData[blockBufferOffset + row + 3];372      p4 = blockData[blockBufferOffset + row + 4];373      p5 = blockData[blockBufferOffset + row + 5];374      p6 = blockData[blockBufferOffset + row + 6];375      p7 = blockData[blockBufferOffset + row + 7];376      p0 *= qt[row];377      if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {378        t = dctSqrt2 * p0 + 512 >> 10;379        p[row] = t;380        p[row + 1] = t;381        p[row + 2] = t;382        p[row + 3] = t;383        p[row + 4] = t;384        p[row + 5] = t;385        p[row + 6] = t;386        p[row + 7] = t;387        continue;388      }389      p1 *= qt[row + 1];390      p2 *= qt[row + 2];391      p3 *= qt[row + 3];392      p4 *= qt[row + 4];393      p5 *= qt[row + 5];394      p6 *= qt[row + 6];395      p7 *= qt[row + 7];396      v0 = dctSqrt2 * p0 + 128 >> 8;397      v1 = dctSqrt2 * p4 + 128 >> 8;398      v2 = p2;399      v3 = p6;400      v4 = dctSqrt1d2 * (p1 - p7) + 128 >> 8;401      v7 = dctSqrt1d2 * (p1 + p7) + 128 >> 8;402      v5 = p3 << 4;403      v6 = p5 << 4;404      v0 = v0 + v1 + 1 >> 1;405      v1 = v0 - v1;406      t = v2 * dctSin6 + v3 * dctCos6 + 128 >> 8;407      v2 = v2 * dctCos6 - v3 * dctSin6 + 128 >> 8;408      v3 = t;409      v4 = v4 + v6 + 1 >> 1;410      v6 = v4 - v6;411      v7 = v7 + v5 + 1 >> 1;412      v5 = v7 - v5;413      v0 = v0 + v3 + 1 >> 1;414      v3 = v0 - v3;415      v1 = v1 + v2 + 1 >> 1;416      v2 = v1 - v2;417      t = v4 * dctSin3 + v7 * dctCos3 + 2048 >> 12;418      v4 = v4 * dctCos3 - v7 * dctSin3 + 2048 >> 12;419      v7 = t;420      t = v5 * dctSin1 + v6 * dctCos1 + 2048 >> 12;421      v5 = v5 * dctCos1 - v6 * dctSin1 + 2048 >> 12;422      v6 = t;423      p[row] = v0 + v7;424      p[row + 7] = v0 - v7;425      p[row + 1] = v1 + v6;426      p[row + 6] = v1 - v6;427      p[row + 2] = v2 + v5;428      p[row + 5] = v2 - v5;429      p[row + 3] = v3 + v4;430      p[row + 4] = v3 - v4;431    }432    for (var col = 0; col < 8; ++col) {433      p0 = p[col];434      p1 = p[col + 8];435      p2 = p[col + 16];436      p3 = p[col + 24];437      p4 = p[col + 32];438      p5 = p[col + 40];439      p6 = p[col + 48];440      p7 = p[col + 56];441      if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {442        t = dctSqrt2 * p0 + 8192 >> 14;443        t = t < -2040 ? 0 : t >= 2024 ? 255 : t + 2056 >> 4;444        blockData[blockBufferOffset + col] = t;445        blockData[blockBufferOffset + col + 8] = t;446        blockData[blockBufferOffset + col + 16] = t;447        blockData[blockBufferOffset + col + 24] = t;448        blockData[blockBufferOffset + col + 32] = t;449        blockData[blockBufferOffset + col + 40] = t;450        blockData[blockBufferOffset + col + 48] = t;451        blockData[blockBufferOffset + col + 56] = t;452        continue;453      }454      v0 = dctSqrt2 * p0 + 2048 >> 12;455      v1 = dctSqrt2 * p4 + 2048 >> 12;456      v2 = p2;457      v3 = p6;458      v4 = dctSqrt1d2 * (p1 - p7) + 2048 >> 12;459      v7 = dctSqrt1d2 * (p1 + p7) + 2048 >> 12;460      v5 = p3;461      v6 = p5;462      v0 = (v0 + v1 + 1 >> 1) + 4112;463      v1 = v0 - v1;464      t = v2 * dctSin6 + v3 * dctCos6 + 2048 >> 12;465      v2 = v2 * dctCos6 - v3 * dctSin6 + 2048 >> 12;466      v3 = t;467      v4 = v4 + v6 + 1 >> 1;468      v6 = v4 - v6;469      v7 = v7 + v5 + 1 >> 1;470      v5 = v7 - v5;471      v0 = v0 + v3 + 1 >> 1;472      v3 = v0 - v3;473      v1 = v1 + v2 + 1 >> 1;474      v2 = v1 - v2;475      t = v4 * dctSin3 + v7 * dctCos3 + 2048 >> 12;476      v4 = v4 * dctCos3 - v7 * dctSin3 + 2048 >> 12;477      v7 = t;478      t = v5 * dctSin1 + v6 * dctCos1 + 2048 >> 12;479      v5 = v5 * dctCos1 - v6 * dctSin1 + 2048 >> 12;480      v6 = t;481      p0 = v0 + v7;482      p7 = v0 - v7;483      p1 = v1 + v6;484      p6 = v1 - v6;485      p2 = v2 + v5;486      p5 = v2 - v5;487      p3 = v3 + v4;488      p4 = v3 - v4;489      p0 = p0 < 16 ? 0 : p0 >= 4080 ? 255 : p0 >> 4;490      p1 = p1 < 16 ? 0 : p1 >= 4080 ? 255 : p1 >> 4;491      p2 = p2 < 16 ? 0 : p2 >= 4080 ? 255 : p2 >> 4;492      p3 = p3 < 16 ? 0 : p3 >= 4080 ? 255 : p3 >> 4;493      p4 = p4 < 16 ? 0 : p4 >= 4080 ? 255 : p4 >> 4;494      p5 = p5 < 16 ? 0 : p5 >= 4080 ? 255 : p5 >> 4;495      p6 = p6 < 16 ? 0 : p6 >= 4080 ? 255 : p6 >> 4;496      p7 = p7 < 16 ? 0 : p7 >= 4080 ? 255 : p7 >> 4;497      blockData[blockBufferOffset + col] = p0;498      blockData[blockBufferOffset + col + 8] = p1;499      blockData[blockBufferOffset + col + 16] = p2;500      blockData[blockBufferOffset + col + 24] = p3;501      blockData[blockBufferOffset + col + 32] = p4;502      blockData[blockBufferOffset + col + 40] = p5;503      blockData[blockBufferOffset + col + 48] = p6;504      blockData[blockBufferOffset + col + 56] = p7;505    }506  }507  function buildComponentData(frame, component) {508    var blocksPerLine = component.blocksPerLine;509    var blocksPerColumn = component.blocksPerColumn;510    var computationBuffer = new Int16Array(64);511    for (var blockRow = 0; blockRow < blocksPerColumn; blockRow++) {512      for (var blockCol = 0; blockCol < blocksPerLine; blockCol++) {513        var offset = getBlockBufferOffset(component, blockRow, blockCol);514        quantizeAndInverse(component, offset, computationBuffer);515      }516    }517    return component.blockData;518  }519  function findNextFileMarker(data, currentPos, startPos) {520    function peekUint16(pos) {521      return data[pos] << 8 | data[pos + 1];522    }523    var maxPos = data.length - 1;524    var newPos = startPos < currentPos ? startPos : currentPos;525    if (currentPos >= maxPos) {526      return null;527    }528    var currentMarker = peekUint16(currentPos);529    if (currentMarker >= 0xFFC0 && currentMarker <= 0xFFFE) {530      return {531        invalid: null,532        marker: currentMarker,533        offset: currentPos534      };535    }536    var newMarker = peekUint16(newPos);537    while (!(newMarker >= 0xFFC0 && newMarker <= 0xFFFE)) {538      if (++newPos >= maxPos) {539        return null;540      }541      newMarker = peekUint16(newPos);542    }543    return {544      invalid: currentMarker.toString(16),545      marker: newMarker,546      offset: newPos547    };548  }549  JpegImage.prototype = {550    parse: function parse(data) {551      function readUint16() {552        var value = data[offset] << 8 | data[offset + 1];553        offset += 2;554        return value;555      }556      function readDataBlock() {557        var length = readUint16();558        var endOffset = offset + length - 2;559        var fileMarker = findNextFileMarker(data, endOffset, offset);560        if (fileMarker && fileMarker.invalid) {561          (0, _util.warn)('readDataBlock - incorrect length, next marker is: ' + fileMarker.invalid);562          endOffset = fileMarker.offset;563        }564        var array = data.subarray(offset, endOffset);565        offset += array.length;566        return array;567      }568      function prepareComponents(frame) {569        var mcusPerLine = Math.ceil(frame.samplesPerLine / 8 / frame.maxH);570        var mcusPerColumn = Math.ceil(frame.scanLines / 8 / frame.maxV);571        for (var i = 0; i < frame.components.length; i++) {572          component = frame.components[i];573          var blocksPerLine = Math.ceil(Math.ceil(frame.samplesPerLine / 8) * component.h / frame.maxH);574          var blocksPerColumn = Math.ceil(Math.ceil(frame.scanLines / 8) * component.v / frame.maxV);575          var blocksPerLineForMcu = mcusPerLine * component.h;576          var blocksPerColumnForMcu = mcusPerColumn * component.v;577          var blocksBufferSize = 64 * blocksPerColumnForMcu * (blocksPerLineForMcu + 1);578          component.blockData = new Int16Array(blocksBufferSize);579          component.blocksPerLine = blocksPerLine;580          component.blocksPerColumn = blocksPerColumn;581        }582        frame.mcusPerLine = mcusPerLine;583        frame.mcusPerColumn = mcusPerColumn;584      }585      var offset = 0;586      var jfif = null;587      var adobe = null;588      var frame, resetInterval;589      var quantizationTables = [];590      var huffmanTablesAC = [],591          huffmanTablesDC = [];592      var fileMarker = readUint16();593      if (fileMarker !== 0xFFD8) {594        throw new JpegError('SOI not found');595      }596      fileMarker = readUint16();597      while (fileMarker !== 0xFFD9) {598        var i, j, l;599        switch (fileMarker) {600          case 0xFFE0:601          case 0xFFE1:602          case 0xFFE2:603          case 0xFFE3:604          case 0xFFE4:605          case 0xFFE5:606          case 0xFFE6:607          case 0xFFE7:608          case 0xFFE8:609          case 0xFFE9:610          case 0xFFEA:611          case 0xFFEB:612          case 0xFFEC:613          case 0xFFED:614          case 0xFFEE:615          case 0xFFEF:616          case 0xFFFE:617            var appData = readDataBlock();618            if (fileMarker === 0xFFE0) {619              if (appData[0] === 0x4A && appData[1] === 0x46 && appData[2] === 0x49 && appData[3] === 0x46 && appData[4] === 0) {620                jfif = {621                  version: {622                    major: appData[5],623                    minor: appData[6]624                  },625                  densityUnits: appData[7],626                  xDensity: appData[8] << 8 | appData[9],627                  yDensity: appData[10] << 8 | appData[11],628                  thumbWidth: appData[12],629                  thumbHeight: appData[13],630                  thumbData: appData.subarray(14, 14 + 3 * appData[12] * appData[13])631                };632              }633            }634            if (fileMarker === 0xFFEE) {635              if (appData[0] === 0x41 && appData[1] === 0x64 && appData[2] === 0x6F && appData[3] === 0x62 && appData[4] === 0x65) {636                adobe = {637                  version: appData[5] << 8 | appData[6],638                  flags0: appData[7] << 8 | appData[8],639                  flags1: appData[9] << 8 | appData[10],640                  transformCode: appData[11]641                };642              }643            }644            break;645          case 0xFFDB:646            var quantizationTablesLength = readUint16();647            var quantizationTablesEnd = quantizationTablesLength + offset - 2;648            var z;649            while (offset < quantizationTablesEnd) {650              var quantizationTableSpec = data[offset++];651              var tableData = new Uint16Array(64);652              if (quantizationTableSpec >> 4 === 0) {653                for (j = 0; j < 64; j++) {654                  z = dctZigZag[j];655                  tableData[z] = data[offset++];656                }657              } else if (quantizationTableSpec >> 4 === 1) {658                for (j = 0; j < 64; j++) {659                  z = dctZigZag[j];660                  tableData[z] = readUint16();661                }662              } else {663                throw new JpegError('DQT - invalid table spec');664              }665              quantizationTables[quantizationTableSpec & 15] = tableData;666            }667            break;668          case 0xFFC0:669          case 0xFFC1:670          case 0xFFC2:671            if (frame) {672              throw new JpegError('Only single frame JPEGs supported');673            }674            readUint16();675            frame = {};676            frame.extended = fileMarker === 0xFFC1;677            frame.progressive = fileMarker === 0xFFC2;678            frame.precision = data[offset++];679            frame.scanLines = readUint16();680            frame.samplesPerLine = readUint16();681            frame.components = [];682            frame.componentIds = {};683            var componentsCount = data[offset++],684                componentId;685            var maxH = 0,686                maxV = 0;687            for (i = 0; i < componentsCount; i++) {688              componentId = data[offset];689              var h = data[offset + 1] >> 4;690              var v = data[offset + 1] & 15;691              if (maxH < h) {692                maxH = h;693              }694              if (maxV < v) {695                maxV = v;696              }697              var qId = data[offset + 2];698              l = frame.components.push({699                h: h,700                v: v,701                quantizationId: qId,702                quantizationTable: null703              });704              frame.componentIds[componentId] = l - 1;705              offset += 3;706            }707            frame.maxH = maxH;708            frame.maxV = maxV;709            prepareComponents(frame);710            break;711          case 0xFFC4:712            var huffmanLength = readUint16();713            for (i = 2; i < huffmanLength;) {714              var huffmanTableSpec = data[offset++];715              var codeLengths = new Uint8Array(16);716              var codeLengthSum = 0;717              for (j = 0; j < 16; j++, offset++) {718                codeLengthSum += codeLengths[j] = data[offset];719              }720              var huffmanValues = new Uint8Array(codeLengthSum);721              for (j = 0; j < codeLengthSum; j++, offset++) {722                huffmanValues[j] = data[offset];723              }724              i += 17 + codeLengthSum;725              (huffmanTableSpec >> 4 === 0 ? huffmanTablesDC : huffmanTablesAC)[huffmanTableSpec & 15] = buildHuffmanTable(codeLengths, huffmanValues);726            }727            break;728          case 0xFFDD:729            readUint16();730            resetInterval = readUint16();731            break;732          case 0xFFDA:733            readUint16();734            var selectorsCount = data[offset++];735            var components = [],736                component;737            for (i = 0; i < selectorsCount; i++) {738              var componentIndex = frame.componentIds[data[offset++]];739              component = frame.components[componentIndex];740              var tableSpec = data[offset++];741              component.huffmanTableDC = huffmanTablesDC[tableSpec >> 4];742              component.huffmanTableAC = huffmanTablesAC[tableSpec & 15];743              components.push(component);744            }745            var spectralStart = data[offset++];746            var spectralEnd = data[offset++];747            var successiveApproximation = data[offset++];748            var processed = decodeScan(data, offset, frame, components, resetInterval, spectralStart, spectralEnd, successiveApproximation >> 4, successiveApproximation & 15);749            offset += processed;750            break;751          case 0xFFFF:752            if (data[offset] !== 0xFF) {753              offset--;754            }755            break;756          default:757            if (data[offset - 3] === 0xFF && data[offset - 2] >= 0xC0 && data[offset - 2] <= 0xFE) {758              offset -= 3;759              break;760            }761            throw new JpegError('unknown marker ' + fileMarker.toString(16));762        }763        fileMarker = readUint16();764      }765      this.width = frame.samplesPerLine;766      this.height = frame.scanLines;767      this.jfif = jfif;768      this.adobe = adobe;769      this.components = [];770      for (i = 0; i < frame.components.length; i++) {771        component = frame.components[i];772        var quantizationTable = quantizationTables[component.quantizationId];773        if (quantizationTable) {774          component.quantizationTable = quantizationTable;775        }776        this.components.push({777          output: buildComponentData(frame, component),778          scaleX: component.h / frame.maxH,779          scaleY: component.v / frame.maxV,780          blocksPerLine: component.blocksPerLine,781          blocksPerColumn: component.blocksPerColumn782        });783      }784      this.numComponents = this.components.length;785    },786    _getLinearizedBlockData: function getLinearizedBlockData(width, height) {787      var scaleX = this.width / width,788          scaleY = this.height / height;789      var component, componentScaleX, componentScaleY, blocksPerScanline;790      var x, y, i, j, k;791      var index;792      var offset = 0;793      var output;794      var numComponents = this.components.length;795      var dataLength = width * height * numComponents;796      var data = new Uint8ClampedArray(dataLength);797      var xScaleBlockOffset = new Uint32Array(width);798      var mask3LSB = 0xfffffff8;799      for (i = 0; i < numComponents; i++) {800        component = this.components[i];801        componentScaleX = component.scaleX * scaleX;802        componentScaleY = component.scaleY * scaleY;803        offset = i;804        output = component.output;805        blocksPerScanline = component.blocksPerLine + 1 << 3;806        for (x = 0; x < width; x++) {807          j = 0 | x * componentScaleX;808          xScaleBlockOffset[x] = (j & mask3LSB) << 3 | j & 7;809        }810        for (y = 0; y < height; y++) {811          j = 0 | y * componentScaleY;812          index = blocksPerScanline * (j & mask3LSB) | (j & 7) << 3;813          for (x = 0; x < width; x++) {814            data[offset] = output[index + xScaleBlockOffset[x]];815            offset += numComponents;816          }817        }818      }819      var transform = this.decodeTransform;820      if (transform) {821        for (i = 0; i < dataLength;) {822          for (j = 0, k = 0; j < numComponents; j++, i++, k += 2) {823            data[i] = (data[i] * transform[k] >> 8) + transform[k + 1];824          }825        }826      }827      return data;828    },829    _isColorConversionNeeded: function _isColorConversionNeeded() {830      if (this.adobe) {831        return !!this.adobe.transformCode;832      }833      if (this.numComponents === 3) {834        if (this.colorTransform === 0) {835          return false;836        }837        return true;838      }839      if (this.colorTransform === 1) {840        return true;841      }842      return false;843    },844    _convertYccToRgb: function convertYccToRgb(data) {845      var Y, Cb, Cr;846      for (var i = 0, length = data.length; i < length; i += 3) {847        Y = data[i];848        Cb = data[i + 1];849        Cr = data[i + 2];850        data[i] = Y - 179.456 + 1.402 * Cr;851        data[i + 1] = Y + 135.459 - 0.344 * Cb - 0.714 * Cr;852        data[i + 2] = Y - 226.816 + 1.772 * Cb;853      }854      return data;855    },856    _convertYcckToRgb: function convertYcckToRgb(data) {857      var Y, Cb, Cr, k;858      var offset = 0;859      for (var i = 0, length = data.length; i < length; i += 4) {860        Y = data[i];861        Cb = data[i + 1];862        Cr = data[i + 2];863        k = data[i + 3];864        data[offset++] = -122.67195406894 + Cb * (-6.60635669420364e-5 * Cb + 0.000437130475926232 * Cr - 5.4080610064599e-5 * Y + 0.00048449797120281 * k - 0.154362151871126) + Cr * (-0.000957964378445773 * Cr + 0.000817076911346625 * Y - 0.00477271405408747 * k + 1.53380253221734) + Y * (0.000961250184130688 * Y - 0.00266257332283933 * k + 0.48357088451265) + k * (-0.000336197177618394 * k + 0.484791561490776);865        data[offset++] = 107.268039397724 + Cb * (2.19927104525741e-5 * Cb - 0.000640992018297945 * Cr + 0.000659397001245577 * Y + 0.000426105652938837 * k - 0.176491792462875) + Cr * (-0.000778269941513683 * Cr + 0.00130872261408275 * Y + 0.000770482631801132 * k - 0.151051492775562) + Y * (0.00126935368114843 * Y - 0.00265090189010898 * k + 0.25802910206845) + k * (-0.000318913117588328 * k - 0.213742400323665);866        data[offset++] = -20.810012546947 + Cb * (-0.000570115196973677 * Cb - 2.63409051004589e-5 * Cr + 0.0020741088115012 * Y - 0.00288260236853442 * k + 0.814272968359295) + Cr * (-1.53496057440975e-5 * Cr - 0.000132689043961446 * Y + 0.000560833691242812 * k - 0.195152027534049) + Y * (0.00174418132927582 * Y - 0.00255243321439347 * k + 0.116935020465145) + k * (-0.000343531996510555 * k + 0.24165260232407);867      }868      return data;869    },870    _convertYcckToCmyk: function convertYcckToCmyk(data) {871      var Y, Cb, Cr;872      for (var i = 0, length = data.length; i < length; i += 4) {873        Y = data[i];874        Cb = data[i + 1];875        Cr = data[i + 2];876        data[i] = 434.456 - Y - 1.402 * Cr;877        data[i + 1] = 119.541 - Y + 0.344 * Cb + 0.714 * Cr;878        data[i + 2] = 481.816 - Y - 1.772 * Cb;879      }880      return data;881    },882    _convertCmykToRgb: function convertCmykToRgb(data) {883      var c, m, y, k;884      var offset = 0;885      var scale = 1 / 255;886      for (var i = 0, length = data.length; i < length; i += 4) {887        c = data[i] * scale;888        m = data[i + 1] * scale;889        y = data[i + 2] * scale;890        k = data[i + 3] * scale;891        data[offset++] = 255 + c * (-4.387332384609988 * c + 54.48615194189176 * m + 18.82290502165302 * y + 212.25662451639585 * k - 285.2331026137004) + m * (1.7149763477362134 * m - 5.6096736904047315 * y - 17.873870861415444 * k - 5.497006427196366) + y * (-2.5217340131683033 * y - 21.248923337353073 * k + 17.5119270841813) - k * (21.86122147463605 * k + 189.48180835922747);892        data[offset++] = 255 + c * (8.841041422036149 * c + 60.118027045597366 * m + 6.871425592049007 * y + 31.159100130055922 * k - 79.2970844816548) + m * (-15.310361306967817 * m + 17.575251261109482 * y + 131.35250912493976 * k - 190.9453302588951) + y * (4.444339102852739 * y + 9.8632861493405 * k - 24.86741582555878) - k * (20.737325471181034 * k + 187.80453709719578);893        data[offset++] = 255 + c * (0.8842522430003296 * c + 8.078677503112928 * m + 30.89978309703729 * y - 0.23883238689178934 * k - 14.183576799673286) + m * (10.49593273432072 * m + 63.02378494754052 * y + 50.606957656360734 * k - 112.23884253719248) + y * (0.03296041114873217 * y + 115.60384449646641 * k - 193.58209356861505) - k * (22.33816807309886 * k + 180.12613974708367);894      }895      return data;896    },897    getData: function getData(width, height, forceRGBoutput) {898      if (this.numComponents > 4) {899        throw new JpegError('Unsupported color mode');900      }901      var data = this._getLinearizedBlockData(width, height);902      if (this.numComponents === 1 && forceRGBoutput) {903        var dataLength = data.length;904        var rgbData = new Uint8ClampedArray(dataLength * 3);905        var offset = 0;906        for (var i = 0; i < dataLength; i++) {907          var grayColor = data[i];908          rgbData[offset++] = grayColor;909          rgbData[offset++] = grayColor;910          rgbData[offset++] = grayColor;911        }912        return rgbData;913      } else if (this.numComponents === 3 && this._isColorConversionNeeded()) {...

jpg.ts

Source:jpg.ts

...19} : function(obj) {20  return obj && typeof Symbol === 'function' && obj.constructor === Symbol && obj !== Symbol.prototype ? 'symbol' : typeof obj;21};22let JpegError = function JpegErrorClosure() {23  function JpegError(msg) {24    this.message = 'JPEG error: ' + msg;25  }26  JpegError.prototype = new Error();27  JpegError.prototype.name = 'JpegError';28  JpegError.constructor = JpegError;29  return JpegError;30}();31let JpegImage = function JpegImageClosure() {32  let dctZigZag = new Uint8Array([0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5, 12, 19, 26, 33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28, 35, 42, 49, 56, 57, 50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51, 58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63]);33  let dctCos1 = 4017;34  let dctSin1 = 799;35  let dctCos3 = 3406;36  let dctSin3 = 2276;37  let dctCos6 = 1567;38  let dctSin6 = 3784;39  let dctSqrt2 = 5793;40  let dctSqrt1d2 = 2896;41  function JpegImage() {42    this.decodeTransform = null;43    this.colorTransform = -1;44  }45  function buildHuffmanTable(codeLengths, values) {46    let k = 0,47      code = [],48      i,49      j,50      length = 16;51    while (length > 0 && !codeLengths[length - 1]) {52      length--;53    }54    code.push({55      children: [],56      index: 0,57    });58    let p = code[0],59      q;60    for (i = 0; i < length; i++) {61      for (j = 0; j < codeLengths[i]; j++) {62        p = code.pop();63        p.children[p.index] = values[k];64        while (p.index > 0) {65          p = code.pop();66        }67        p.index++;68        code.push(p);69        while (code.length <= i) {70          code.push(q = {71            children: [],72            index: 0,73          });74          p.children[p.index] = q.children;75          p = q;76        }77        k++;78      }79      if (i + 1 < length) {80        code.push(q = {81          children: [],82          index: 0,83        });84        p.children[p.index] = q.children;85        p = q;86      }87    }88    return code[0].children;89  }90  function getBlockBufferOffset(component, row, col) {91    return 64 * ((component.blocksPerLine + 1) * row + col);92  }93  function decodeScan(data, offset, frame, components, resetInterval, spectralStart, spectralEnd, successivePrev, successive) {94    let mcusPerLine = frame.mcusPerLine;95    let progressive = frame.progressive;96    let startOffset = offset,97      bitsData = 0,98      bitsCount = 0;99    function readBit() {100      if (bitsCount > 0) {101        bitsCount--;102        return bitsData >> bitsCount & 1;103      }104      bitsData = data[offset++];105      if (bitsData === 0xFF) {106        let nextByte = data[offset++];107        if (nextByte) {108          throw new JpegError('unexpected marker ' + (bitsData << 8 | nextByte).toString(16));109        }110      }111      bitsCount = 7;112      return bitsData >>> 7;113    }114    function decodeHuffman(tree) {115      let node = tree;116      while (true) {117        node = node[readBit()];118        if (typeof node === 'number') {119          return node;120        }121        if ((typeof node === 'undefined' ? 'undefined' : _typeof(node)) !== 'object') {122          throw new JpegError('invalid huffman sequence');123        }124      }125    }126    function receive(length) {127      let n = 0;128      while (length > 0) {129        n = n << 1 | readBit();130        length--;131      }132      return n;133    }134    function receiveAndExtend(length) {135      if (length === 1) {136        return readBit() === 1 ? 1 : -1;137      }138      let n = receive(length);139      if (n >= 1 << length - 1) {140        return n;141      }142      return n + (-1 << length) + 1;143    }144    function decodeBaseline(component, offset) {145      let t = decodeHuffman(component.huffmanTableDC);146      let diff = t === 0 ? 0 : receiveAndExtend(t);147      component.blockData[offset] = component.pred += diff;148      let k = 1;149      while (k < 64) {150        let rs = decodeHuffman(component.huffmanTableAC);151        let s = rs & 15,152          r = rs >> 4;153        if (s === 0) {154          if (r < 15) {155            break;156          }157          k += 16;158          continue;159        }160        k += r;161        let z = dctZigZag[k];162        component.blockData[offset + z] = receiveAndExtend(s);163        k++;164      }165    }166    function decodeDCFirst(component, offset) {167      let t = decodeHuffman(component.huffmanTableDC);168      let diff = t === 0 ? 0 : receiveAndExtend(t) << successive;169      component.blockData[offset] = component.pred += diff;170    }171    function decodeDCSuccessive(component, offset) {172      component.blockData[offset] |= readBit() << successive;173    }174    let eobrun = 0;175    function decodeACFirst(component, offset) {176      if (eobrun > 0) {177        eobrun--;178        return;179      }180      let k = spectralStart,181        e = spectralEnd;182      while (k <= e) {183        let rs = decodeHuffman(component.huffmanTableAC);184        let s = rs & 15,185          r = rs >> 4;186        if (s === 0) {187          if (r < 15) {188            eobrun = receive(r) + (1 << r) - 1;189            break;190          }191          k += 16;192          continue;193        }194        k += r;195        let z = dctZigZag[k];196        component.blockData[offset + z] = receiveAndExtend(s) * (1 << successive);197        k++;198      }199    }200    let successiveACState = 0,201      successiveACNextValue;202    function decodeACSuccessive(component, offset) {203      let k = spectralStart;204      let e = spectralEnd;205      let r = 0;206      let s;207      let rs;208      while (k <= e) {209        let z = dctZigZag[k];210        switch (successiveACState) {211          case 0:212            rs = decodeHuffman(component.huffmanTableAC);213            s = rs & 15;214            r = rs >> 4;215            if (s === 0) {216              if (r < 15) {217                eobrun = receive(r) + (1 << r);218                successiveACState = 4;219              } else {220                r = 16;221                successiveACState = 1;222              }223            } else {224              if (s !== 1) {225                throw new JpegError('invalid ACn encoding');226              }227              successiveACNextValue = receiveAndExtend(s);228              successiveACState = r ? 2 : 3;229            }230            continue;231          case 1:232          case 2:233            if (component.blockData[offset + z]) {234              component.blockData[offset + z] += readBit() << successive;235            } else {236              r--;237              if (r === 0) {238                successiveACState = successiveACState === 2 ? 3 : 0;239              }240            }241            break;242          case 3:243            if (component.blockData[offset + z]) {244              component.blockData[offset + z] += readBit() << successive;245            } else {246              component.blockData[offset + z] = successiveACNextValue << successive;247              successiveACState = 0;248            }249            break;250          case 4:251            if (component.blockData[offset + z]) {252              component.blockData[offset + z] += readBit() << successive;253            }254            break;255        }256        k++;257      }258      if (successiveACState === 4) {259        eobrun--;260        if (eobrun === 0) {261          successiveACState = 0;262        }263      }264    }265    function decodeMcu(component, decode, mcu, row, col) {266      let mcuRow = mcu / mcusPerLine | 0;267      let mcuCol = mcu % mcusPerLine;268      let blockRow = mcuRow * component.v + row;269      let blockCol = mcuCol * component.h + col;270      let offset = getBlockBufferOffset(component, blockRow, blockCol);271      decode(component, offset);272    }273    function decodeBlock(component, decode, mcu) {274      let blockRow = mcu / component.blocksPerLine | 0;275      let blockCol = mcu % component.blocksPerLine;276      let offset = getBlockBufferOffset(component, blockRow, blockCol);277      decode(component, offset);278    }279    let componentsLength = components.length;280    let component, i, j, k, n;281    let decodeFn;282    if (progressive) {283      if (spectralStart === 0) {284        decodeFn = successivePrev === 0 ? decodeDCFirst : decodeDCSuccessive;285      } else {286        decodeFn = successivePrev === 0 ? decodeACFirst : decodeACSuccessive;287      }288    } else {289      decodeFn = decodeBaseline;290    }291    let mcu = 0,292      fileMarker;293    let mcuExpected;294    if (componentsLength === 1) {295      mcuExpected = components[0].blocksPerLine * components[0].blocksPerColumn;296    } else {297      mcuExpected = mcusPerLine * frame.mcusPerColumn;298    }299    let h, v;300    while (mcu < mcuExpected) {301      let mcuToRead = resetInterval ? Math.min(mcuExpected - mcu, resetInterval) : mcuExpected;302      for (i = 0; i < componentsLength; i++) {303        components[i].pred = 0;304      }305      eobrun = 0;306      if (componentsLength === 1) {307        component = components[0];308        for (n = 0; n < mcuToRead; n++) {309          decodeBlock(component, decodeFn, mcu);310          mcu++;311        }312      } else {313        for (n = 0; n < mcuToRead; n++) {314          for (i = 0; i < componentsLength; i++) {315            component = components[i];316            h = component.h;317            v = component.v;318            for (j = 0; j < v; j++) {319              for (k = 0; k < h; k++) {320                decodeMcu(component, decodeFn, mcu, j, k);321              }322            }323          }324          mcu++;325        }326      }327      bitsCount = 0;328      fileMarker = findNextFileMarker(data, offset, undefined);329      if (fileMarker && fileMarker.invalid) {330        // (0, _util.warn)('decodeScan - unexpected MCU data, next marker is: ' + fileMarker.invalid);331        offset = fileMarker.offset;332      }333      let marker = fileMarker && fileMarker.marker;334      if (!marker || marker <= 0xFF00) {335        throw new JpegError('marker was not found');336      }337      if (marker >= 0xFFD0 && marker <= 0xFFD7) {338        offset += 2;339      } else {340        break;341      }342    }343    fileMarker = findNextFileMarker(data, offset, undefined);344    if (fileMarker && fileMarker.invalid) {345      // (0, _util.warn)('decodeScan - unexpected Scan data, next marker is: ' + fileMarker.invalid);346      offset = fileMarker.offset;347    }348    return offset - startOffset;349  }350  function quantizeAndInverse(component, blockBufferOffset, p) {351    let qt = component.quantizationTable,352      blockData = component.blockData;353    let v0, v1, v2, v3, v4, v5, v6, v7;354    let p0, p1, p2, p3, p4, p5, p6, p7;355    let t;356    if (!qt) {357      throw new JpegError('missing required Quantization Table.');358    }359    for (let row = 0; row < 64; row += 8) {360      p0 = blockData[blockBufferOffset + row];361      p1 = blockData[blockBufferOffset + row + 1];362      p2 = blockData[blockBufferOffset + row + 2];363      p3 = blockData[blockBufferOffset + row + 3];364      p4 = blockData[blockBufferOffset + row + 4];365      p5 = blockData[blockBufferOffset + row + 5];366      p6 = blockData[blockBufferOffset + row + 6];367      p7 = blockData[blockBufferOffset + row + 7];368      p0 *= qt[row];369      if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {370        t = dctSqrt2 * p0 + 512 >> 10;371        p[row] = t;372        p[row + 1] = t;373        p[row + 2] = t;374        p[row + 3] = t;375        p[row + 4] = t;376        p[row + 5] = t;377        p[row + 6] = t;378        p[row + 7] = t;379        continue;380      }381      p1 *= qt[row + 1];382      p2 *= qt[row + 2];383      p3 *= qt[row + 3];384      p4 *= qt[row + 4];385      p5 *= qt[row + 5];386      p6 *= qt[row + 6];387      p7 *= qt[row + 7];388      v0 = dctSqrt2 * p0 + 128 >> 8;389      v1 = dctSqrt2 * p4 + 128 >> 8;390      v2 = p2;391      v3 = p6;392      v4 = dctSqrt1d2 * (p1 - p7) + 128 >> 8;393      v7 = dctSqrt1d2 * (p1 + p7) + 128 >> 8;394      v5 = p3 << 4;395      v6 = p5 << 4;396      v0 = v0 + v1 + 1 >> 1;397      v1 = v0 - v1;398      t = v2 * dctSin6 + v3 * dctCos6 + 128 >> 8;399      v2 = v2 * dctCos6 - v3 * dctSin6 + 128 >> 8;400      v3 = t;401      v4 = v4 + v6 + 1 >> 1;402      v6 = v4 - v6;403      v7 = v7 + v5 + 1 >> 1;404      v5 = v7 - v5;405      v0 = v0 + v3 + 1 >> 1;406      v3 = v0 - v3;407      v1 = v1 + v2 + 1 >> 1;408      v2 = v1 - v2;409      t = v4 * dctSin3 + v7 * dctCos3 + 2048 >> 12;410      v4 = v4 * dctCos3 - v7 * dctSin3 + 2048 >> 12;411      v7 = t;412      t = v5 * dctSin1 + v6 * dctCos1 + 2048 >> 12;413      v5 = v5 * dctCos1 - v6 * dctSin1 + 2048 >> 12;414      v6 = t;415      p[row] = v0 + v7;416      p[row + 7] = v0 - v7;417      p[row + 1] = v1 + v6;418      p[row + 6] = v1 - v6;419      p[row + 2] = v2 + v5;420      p[row + 5] = v2 - v5;421      p[row + 3] = v3 + v4;422      p[row + 4] = v3 - v4;423    }424    for (let col = 0; col < 8; ++col) {425      p0 = p[col];426      p1 = p[col + 8];427      p2 = p[col + 16];428      p3 = p[col + 24];429      p4 = p[col + 32];430      p5 = p[col + 40];431      p6 = p[col + 48];432      p7 = p[col + 56];433      if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) === 0) {434        t = dctSqrt2 * p0 + 8192 >> 14;435        t = t < -2040 ? 0 : t >= 2024 ? 255 : t + 2056 >> 4;436        blockData[blockBufferOffset + col] = t;437        blockData[blockBufferOffset + col + 8] = t;438        blockData[blockBufferOffset + col + 16] = t;439        blockData[blockBufferOffset + col + 24] = t;440        blockData[blockBufferOffset + col + 32] = t;441        blockData[blockBufferOffset + col + 40] = t;442        blockData[blockBufferOffset + col + 48] = t;443        blockData[blockBufferOffset + col + 56] = t;444        continue;445      }446      v0 = dctSqrt2 * p0 + 2048 >> 12;447      v1 = dctSqrt2 * p4 + 2048 >> 12;448      v2 = p2;449      v3 = p6;450      v4 = dctSqrt1d2 * (p1 - p7) + 2048 >> 12;451      v7 = dctSqrt1d2 * (p1 + p7) + 2048 >> 12;452      v5 = p3;453      v6 = p5;454      v0 = (v0 + v1 + 1 >> 1) + 4112;455      v1 = v0 - v1;456      t = v2 * dctSin6 + v3 * dctCos6 + 2048 >> 12;457      v2 = v2 * dctCos6 - v3 * dctSin6 + 2048 >> 12;458      v3 = t;459      v4 = v4 + v6 + 1 >> 1;460      v6 = v4 - v6;461      v7 = v7 + v5 + 1 >> 1;462      v5 = v7 - v5;463      v0 = v0 + v3 + 1 >> 1;464      v3 = v0 - v3;465      v1 = v1 + v2 + 1 >> 1;466      v2 = v1 - v2;467      t = v4 * dctSin3 + v7 * dctCos3 + 2048 >> 12;468      v4 = v4 * dctCos3 - v7 * dctSin3 + 2048 >> 12;469      v7 = t;470      t = v5 * dctSin1 + v6 * dctCos1 + 2048 >> 12;471      v5 = v5 * dctCos1 - v6 * dctSin1 + 2048 >> 12;472      v6 = t;473      p0 = v0 + v7;474      p7 = v0 - v7;475      p1 = v1 + v6;476      p6 = v1 - v6;477      p2 = v2 + v5;478      p5 = v2 - v5;479      p3 = v3 + v4;480      p4 = v3 - v4;481      p0 = p0 < 16 ? 0 : p0 >= 4080 ? 255 : p0 >> 4;482      p1 = p1 < 16 ? 0 : p1 >= 4080 ? 255 : p1 >> 4;483      p2 = p2 < 16 ? 0 : p2 >= 4080 ? 255 : p2 >> 4;484      p3 = p3 < 16 ? 0 : p3 >= 4080 ? 255 : p3 >> 4;485      p4 = p4 < 16 ? 0 : p4 >= 4080 ? 255 : p4 >> 4;486      p5 = p5 < 16 ? 0 : p5 >= 4080 ? 255 : p5 >> 4;487      p6 = p6 < 16 ? 0 : p6 >= 4080 ? 255 : p6 >> 4;488      p7 = p7 < 16 ? 0 : p7 >= 4080 ? 255 : p7 >> 4;489      blockData[blockBufferOffset + col] = p0;490      blockData[blockBufferOffset + col + 8] = p1;491      blockData[blockBufferOffset + col + 16] = p2;492      blockData[blockBufferOffset + col + 24] = p3;493      blockData[blockBufferOffset + col + 32] = p4;494      blockData[blockBufferOffset + col + 40] = p5;495      blockData[blockBufferOffset + col + 48] = p6;496      blockData[blockBufferOffset + col + 56] = p7;497    }498  }499  function buildComponentData(frame, component) {500    let blocksPerLine = component.blocksPerLine;501    let blocksPerColumn = component.blocksPerColumn;502    let computationBuffer = new Int16Array(64);503    for (let blockRow = 0; blockRow < blocksPerColumn; blockRow++) {504      for (let blockCol = 0; blockCol < blocksPerLine; blockCol++) {505        let offset = getBlockBufferOffset(component, blockRow, blockCol);506        quantizeAndInverse(component, offset, computationBuffer);507      }508    }509    return component.blockData;510  }511  function clamp0to255(a) {512    return a <= 0 ? 0 : a >= 255 ? 255 : a;513  }514  function findNextFileMarker(data, currentPos, startPos) {515    function peekUint16(pos) {516      return data[pos] << 8 | data[pos + 1];517    }518    let maxPos = data.length - 1;519    let newPos = startPos < currentPos ? startPos : currentPos;520    if (currentPos >= maxPos) {521      return null;522    }523    let currentMarker = peekUint16(currentPos);524    if (currentMarker >= 0xFFC0 && currentMarker <= 0xFFFE) {525      return {526        invalid: null,527        marker: currentMarker,528        offset: currentPos,529      };530    }531    let newMarker = peekUint16(newPos);532    while (!(newMarker >= 0xFFC0 && newMarker <= 0xFFFE)) {533      if (++newPos >= maxPos) {534        return null;535      }536      newMarker = peekUint16(newPos);537    }538    return {539      invalid: currentMarker.toString(16),540      marker: newMarker,541      offset: newPos,542    };543  }544  JpegImage.prototype = {545    parse: function parse(data) {546      function readUint16() {547        let value = data[offset] << 8 | data[offset + 1];548        offset += 2;549        return value;550      }551      function readDataBlock() {552        let length = readUint16();553        let endOffset = offset + length - 2;554        let fileMarker = findNextFileMarker(data, endOffset, offset);555        if (fileMarker && fileMarker.invalid) {556          // (0, _util.warn)('readDataBlock - incorrect length, next marker is: ' + fileMarker.invalid);557          endOffset = fileMarker.offset;558        }559        let array = data.subarray(offset, endOffset);560        offset += array.length;561        return array;562      }563      function prepareComponents(frame) {564        let mcusPerLine = Math.ceil(frame.samplesPerLine / 8 / frame.maxH);565        let mcusPerColumn = Math.ceil(frame.scanLines / 8 / frame.maxV);566        for (let i = 0; i < frame.components.length; i++) {567          component = frame.components[i];568          let blocksPerLine = Math.ceil(Math.ceil(frame.samplesPerLine / 8) * component.h / frame.maxH);569          let blocksPerColumn = Math.ceil(Math.ceil(frame.scanLines / 8) * component.v / frame.maxV);570          let blocksPerLineForMcu = mcusPerLine * component.h;571          let blocksPerColumnForMcu = mcusPerColumn * component.v;572          let blocksBufferSize = 64 * blocksPerColumnForMcu * (blocksPerLineForMcu + 1);573          component.blockData = new Int16Array(blocksBufferSize);574          component.blocksPerLine = blocksPerLine;575          component.blocksPerColumn = blocksPerColumn;576        }577        frame.mcusPerLine = mcusPerLine;578        frame.mcusPerColumn = mcusPerColumn;579      }580      var offset = 0;581      let jfif = null;582      let adobe = null;583      let frame, resetInterval;584      let quantizationTables = [];585      let huffmanTablesAC = [],586        huffmanTablesDC = [];587      let fileMarker = readUint16();588      if (fileMarker !== 0xFFD8) {589        throw new JpegError('SOI not found');590      }591      fileMarker = readUint16();592      while (fileMarker !== 0xFFD9) {593        var i, j, l;594        switch (fileMarker) {595          case 0xFFE0:596          case 0xFFE1:597          case 0xFFE2:598          case 0xFFE3:599          case 0xFFE4:600          case 0xFFE5:601          case 0xFFE6:602          case 0xFFE7:603          case 0xFFE8:604          case 0xFFE9:605          case 0xFFEA:606          case 0xFFEB:607          case 0xFFEC:608          case 0xFFED:609          case 0xFFEE:610          case 0xFFEF:611          case 0xFFFE:612            var appData = readDataBlock();613            if (fileMarker === 0xFFE0) {614              if (appData[0] === 0x4A && appData[1] === 0x46 && appData[2] === 0x49 && appData[3] === 0x46 && appData[4] === 0) {615                jfif = {616                  version: {617                    major: appData[5],618                    minor: appData[6],619                  },620                  densityUnits: appData[7],621                  xDensity: appData[8] << 8 | appData[9],622                  yDensity: appData[10] << 8 | appData[11],623                  thumbWidth: appData[12],624                  thumbHeight: appData[13],625                  thumbData: appData.subarray(14, 14 + 3 * appData[12] * appData[13]),626                };627              }628            }629            if (fileMarker === 0xFFEE) {630              if (appData[0] === 0x41 && appData[1] === 0x64 && appData[2] === 0x6F && appData[3] === 0x62 && appData[4] === 0x65) {631                adobe = {632                  version: appData[5] << 8 | appData[6],633                  flags0: appData[7] << 8 | appData[8],634                  flags1: appData[9] << 8 | appData[10],635                  transformCode: appData[11],636                };637              }638            }639            break;640          case 0xFFDB:641            var quantizationTablesLength = readUint16();642            var quantizationTablesEnd = quantizationTablesLength + offset - 2;643            var z;644            while (offset < quantizationTablesEnd) {645              let quantizationTableSpec = data[offset++];646              let tableData = new Uint16Array(64);647              if (quantizationTableSpec >> 4 === 0) {648                for (j = 0; j < 64; j++) {649                  z = dctZigZag[j];650                  tableData[z] = data[offset++];651                }652              } else if (quantizationTableSpec >> 4 === 1) {653                for (j = 0; j < 64; j++) {654                  z = dctZigZag[j];655                  tableData[z] = readUint16();656                }657              } else {658                throw new JpegError('DQT - invalid table spec');659              }660              quantizationTables[quantizationTableSpec & 15] = tableData;661            }662            break;663          case 0xFFC0:664          case 0xFFC1:665          case 0xFFC2:666            if (frame) {667              throw new JpegError('Only single frame JPEGs supported');668            }669            readUint16();670            frame = {};671            frame.extended = fileMarker === 0xFFC1;672            frame.progressive = fileMarker === 0xFFC2;673            frame.precision = data[offset++];674            frame.scanLines = readUint16();675            frame.samplesPerLine = readUint16();676            frame.components = [];677            frame.componentIds = {};678            var componentsCount = data[offset++],679              componentId;680            var maxH = 0,681              maxV = 0;682            for (i = 0; i < componentsCount; i++) {683              componentId = data[offset];684              let h = data[offset + 1] >> 4;685              let v = data[offset + 1] & 15;686              if (maxH < h) {687                maxH = h;688              }689              if (maxV < v) {690                maxV = v;691              }692              let qId = data[offset + 2];693              l = frame.components.push({694                h: h,695                v: v,696                quantizationId: qId,697                quantizationTable: null,698              });699              frame.componentIds[componentId] = l - 1;700              offset += 3;701            }702            frame.maxH = maxH;703            frame.maxV = maxV;704            prepareComponents(frame);705            break;706          case 0xFFC4:707            var huffmanLength = readUint16();708            for (i = 2; i < huffmanLength;) {709              let huffmanTableSpec = data[offset++];710              let codeLengths = new Uint8Array(16);711              let codeLengthSum = 0;712              for (j = 0; j < 16; j++ , offset++) {713                codeLengthSum += codeLengths[j] = data[offset];714              }715              let huffmanValues = new Uint8Array(codeLengthSum);716              for (j = 0; j < codeLengthSum; j++ , offset++) {717                huffmanValues[j] = data[offset];718              }719              i += 17 + codeLengthSum;720              (huffmanTableSpec >> 4 === 0 ? huffmanTablesDC : huffmanTablesAC)[huffmanTableSpec & 15] = buildHuffmanTable(codeLengths, huffmanValues);721            }722            break;723          case 0xFFDD:724            readUint16();725            resetInterval = readUint16();726            break;727          case 0xFFDA:728            readUint16();729            var selectorsCount = data[offset++];730            var components = [],731              component;732            for (i = 0; i < selectorsCount; i++) {733              let componentIndex = frame.componentIds[data[offset++]];734              component = frame.components[componentIndex];735              let tableSpec = data[offset++];736              component.huffmanTableDC = huffmanTablesDC[tableSpec >> 4];737              component.huffmanTableAC = huffmanTablesAC[tableSpec & 15];738              components.push(component);739            }740            var spectralStart = data[offset++];741            var spectralEnd = data[offset++];742            var successiveApproximation = data[offset++];743            var processed = decodeScan(data, offset, frame, components, resetInterval, spectralStart, spectralEnd, successiveApproximation >> 4, successiveApproximation & 15);744            offset += processed;745            break;746          case 0xFFFF:747            if (data[offset] !== 0xFF) {748              offset--;749            }750            break;751          default:752            if (data[offset - 3] === 0xFF && data[offset - 2] >= 0xC0 && data[offset - 2] <= 0xFE) {753              offset -= 3;754              break;755            }756            throw new JpegError('unknown marker ' + fileMarker.toString(16));757        }758        fileMarker = readUint16();759      }760      this.width = frame.samplesPerLine;761      this.height = frame.scanLines;762      this.jfif = jfif;763      this.adobe = adobe;764      this.components = [];765      for (i = 0; i < frame.components.length; i++) {766        component = frame.components[i];767        let quantizationTable = quantizationTables[component.quantizationId];768        if (quantizationTable) {769          component.quantizationTable = quantizationTable;770        }...

Using AI Code Generation

1var wpt = require('wpt');2wpt.JpegError('test.jpg', function (err, data) {3    if (err) {4        console.log(err);5    }6    else {7        console.log(data);8    }9});10{ "Error": "Unsupported format or corrupted file" }11{ "Error": "File not found" }12function(err, data) {13    if (err) {14        console.log(err);15    }16    else {17        console.log(data);18    }19}20JpegInfo(image, callback)21var wpt = require('wpt');22wpt.JpegInfo('test.jpg', function (err, data) {23    if (err) {24        console.log(err);25    }26    else {27        console.log(data);28    }29});30{31}32{ "Error": "File not found" }33function(err, data) {34    if (err) {35        console.log(err);36    }37    else {38        console.log(data);39    }40}41JpegThumbnail(image, width, height, callback)

Using AI Code Generation

1var wpt = require('wpt');2wpt.on('error', function(err) {3  console.log('Error: ' + err);4});5wpt.on('result', function(result) {6  console.log('Result: ' + result);7});8  if (err) {9    console.log('Error: ' + err);10  } else {11    console.log('Data: ' + data);12  }13});

Automation Testing Tutorials

Learn to execute automation testing from scratch with LambdaTest Learning Hub. Right from setting up the prerequisites to run your first automation test, to following best practices and diving deeper into advanced test scenarios. LambdaTest Learning Hubs compile a list of step-by-step guides to help you be proficient with different test automation frameworks i.e. Selenium, Cypress, TestNG etc.