feat(security,ui): self-host React deps, Tailwind, fonts; strict CSP; local QR; better selection state

Replace CDN React/ReactDOM/Babel with local libs; remove Babel and inline scripts
Build Tailwind locally, add safelist; switch to assets/tailwind.css
Self-host Font Awesome and Inter (CSS + woff2); remove external font CDNs
Implement strict CSP (no unsafe-inline/eval; scripts/styles/fonts from self)
Extract inline handlers; move PWA scripts to external files
Add local QR code generation (qrcode lib) and remove api.qrserver.com
Improve SessionTypeSelector visual selection (highlighted background and ring)
Keep PWA working with service worker and offline assets
Refs: CSP hardening, offline-first, no external dependencies

node_modules/pngjs/lib/bitmapper.js

@@ -0,0 +1,267 @@
+"use strict";
+
+let interlaceUtils = require("./interlace");
+
+let pixelBppMapper = [
+  // 0 - dummy entry
+  function () {},
+
+  // 1 - L
+  // 0: 0, 1: 0, 2: 0, 3: 0xff
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos === data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    let pixel = data[rawPos];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = 0xff;
+  },
+
+  // 2 - LA
+  // 0: 0, 1: 0, 2: 0, 3: 1
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos + 1 >= data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    let pixel = data[rawPos];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = data[rawPos + 1];
+  },
+
+  // 3 - RGB
+  // 0: 0, 1: 1, 2: 2, 3: 0xff
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos + 2 >= data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    pxData[pxPos] = data[rawPos];
+    pxData[pxPos + 1] = data[rawPos + 1];
+    pxData[pxPos + 2] = data[rawPos + 2];
+    pxData[pxPos + 3] = 0xff;
+  },
+
+  // 4 - RGBA
+  // 0: 0, 1: 1, 2: 2, 3: 3
+  function (pxData, data, pxPos, rawPos) {
+    if (rawPos + 3 >= data.length) {
+      throw new Error("Ran out of data");
+    }
+
+    pxData[pxPos] = data[rawPos];
+    pxData[pxPos + 1] = data[rawPos + 1];
+    pxData[pxPos + 2] = data[rawPos + 2];
+    pxData[pxPos + 3] = data[rawPos + 3];
+  },
+];
+
+let pixelBppCustomMapper = [
+  // 0 - dummy entry
+  function () {},
+
+  // 1 - L
+  // 0: 0, 1: 0, 2: 0, 3: 0xff
+  function (pxData, pixelData, pxPos, maxBit) {
+    let pixel = pixelData[0];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = maxBit;
+  },
+
+  // 2 - LA
+  // 0: 0, 1: 0, 2: 0, 3: 1
+  function (pxData, pixelData, pxPos) {
+    let pixel = pixelData[0];
+    pxData[pxPos] = pixel;
+    pxData[pxPos + 1] = pixel;
+    pxData[pxPos + 2] = pixel;
+    pxData[pxPos + 3] = pixelData[1];
+  },
+
+  // 3 - RGB
+  // 0: 0, 1: 1, 2: 2, 3: 0xff
+  function (pxData, pixelData, pxPos, maxBit) {
+    pxData[pxPos] = pixelData[0];
+    pxData[pxPos + 1] = pixelData[1];
+    pxData[pxPos + 2] = pixelData[2];
+    pxData[pxPos + 3] = maxBit;
+  },
+
+  // 4 - RGBA
+  // 0: 0, 1: 1, 2: 2, 3: 3
+  function (pxData, pixelData, pxPos) {
+    pxData[pxPos] = pixelData[0];
+    pxData[pxPos + 1] = pixelData[1];
+    pxData[pxPos + 2] = pixelData[2];
+    pxData[pxPos + 3] = pixelData[3];
+  },
+];
+
+function bitRetriever(data, depth) {
+  let leftOver = [];
+  let i = 0;
+
+  function split() {
+    if (i === data.length) {
+      throw new Error("Ran out of data");
+    }
+    let byte = data[i];
+    i++;
+    let byte8, byte7, byte6, byte5, byte4, byte3, byte2, byte1;
+    switch (depth) {
+      default:
+        throw new Error("unrecognised depth");
+      case 16:
+        byte2 = data[i];
+        i++;
+        leftOver.push((byte << 8) + byte2);
+        break;
+      case 4:
+        byte2 = byte & 0x0f;
+        byte1 = byte >> 4;
+        leftOver.push(byte1, byte2);
+        break;
+      case 2:
+        byte4 = byte & 3;
+        byte3 = (byte >> 2) & 3;
+        byte2 = (byte >> 4) & 3;
+        byte1 = (byte >> 6) & 3;
+        leftOver.push(byte1, byte2, byte3, byte4);
+        break;
+      case 1:
+        byte8 = byte & 1;
+        byte7 = (byte >> 1) & 1;
+        byte6 = (byte >> 2) & 1;
+        byte5 = (byte >> 3) & 1;
+        byte4 = (byte >> 4) & 1;
+        byte3 = (byte >> 5) & 1;
+        byte2 = (byte >> 6) & 1;
+        byte1 = (byte >> 7) & 1;
+        leftOver.push(byte1, byte2, byte3, byte4, byte5, byte6, byte7, byte8);
+        break;
+    }
+  }
+
+  return {
+    get: function (count) {
+      while (leftOver.length < count) {
+        split();
+      }
+      let returner = leftOver.slice(0, count);
+      leftOver = leftOver.slice(count);
+      return returner;
+    },
+    resetAfterLine: function () {
+      leftOver.length = 0;
+    },
+    end: function () {
+      if (i !== data.length) {
+        throw new Error("extra data found");
+      }
+    },
+  };
+}
+
+function mapImage8Bit(image, pxData, getPxPos, bpp, data, rawPos) {
+  // eslint-disable-line max-params
+  let imageWidth = image.width;
+  let imageHeight = image.height;
+  let imagePass = image.index;
+  for (let y = 0; y < imageHeight; y++) {
+    for (let x = 0; x < imageWidth; x++) {
+      let pxPos = getPxPos(x, y, imagePass);
+      pixelBppMapper[bpp](pxData, data, pxPos, rawPos);
+      rawPos += bpp; //eslint-disable-line no-param-reassign
+    }
+  }
+  return rawPos;
+}
+
+function mapImageCustomBit(image, pxData, getPxPos, bpp, bits, maxBit) {
+  // eslint-disable-line max-params
+  let imageWidth = image.width;
+  let imageHeight = image.height;
+  let imagePass = image.index;
+  for (let y = 0; y < imageHeight; y++) {
+    for (let x = 0; x < imageWidth; x++) {
+      let pixelData = bits.get(bpp);
+      let pxPos = getPxPos(x, y, imagePass);
+      pixelBppCustomMapper[bpp](pxData, pixelData, pxPos, maxBit);
+    }
+    bits.resetAfterLine();
+  }
+}
+
+exports.dataToBitMap = function (data, bitmapInfo) {
+  let width = bitmapInfo.width;
+  let height = bitmapInfo.height;
+  let depth = bitmapInfo.depth;
+  let bpp = bitmapInfo.bpp;
+  let interlace = bitmapInfo.interlace;
+  let bits;
+
+  if (depth !== 8) {
+    bits = bitRetriever(data, depth);
+  }
+  let pxData;
+  if (depth <= 8) {
+    pxData = Buffer.alloc(width * height * 4);
+  } else {
+    pxData = new Uint16Array(width * height * 4);
+  }
+  let maxBit = Math.pow(2, depth) - 1;
+  let rawPos = 0;
+  let images;
+  let getPxPos;
+
+  if (interlace) {
+    images = interlaceUtils.getImagePasses(width, height);
+    getPxPos = interlaceUtils.getInterlaceIterator(width, height);
+  } else {
+    let nonInterlacedPxPos = 0;
+    getPxPos = function () {
+      let returner = nonInterlacedPxPos;
+      nonInterlacedPxPos += 4;
+      return returner;
+    };
+    images = [{ width: width, height: height }];
+  }
+
+  for (let imageIndex = 0; imageIndex < images.length; imageIndex++) {
+    if (depth === 8) {
+      rawPos = mapImage8Bit(
+        images[imageIndex],
+        pxData,
+        getPxPos,
+        bpp,
+        data,
+        rawPos
+      );
+    } else {
+      mapImageCustomBit(
+        images[imageIndex],
+        pxData,
+        getPxPos,
+        bpp,
+        bits,
+        maxBit
+      );
+    }
+  }
+  if (depth === 8) {
+    if (rawPos !== data.length) {
+      throw new Error("extra data found");
+    }
+  } else {
+    bits.end();
+  }
+
+  return pxData;
+};

node_modules/pngjs/lib/bitpacker.js

@@ -0,0 +1,158 @@
+"use strict";
+
+let constants = require("./constants");
+
+module.exports = function (dataIn, width, height, options) {
+  let outHasAlpha =
+    [constants.COLORTYPE_COLOR_ALPHA, constants.COLORTYPE_ALPHA].indexOf(
+      options.colorType
+    ) !== -1;
+  if (options.colorType === options.inputColorType) {
+    let bigEndian = (function () {
+      let buffer = new ArrayBuffer(2);
+      new DataView(buffer).setInt16(0, 256, true /* littleEndian */);
+      // Int16Array uses the platform's endianness.
+      return new Int16Array(buffer)[0] !== 256;
+    })();
+    // If no need to convert to grayscale and alpha is present/absent in both, take a fast route
+    if (options.bitDepth === 8 || (options.bitDepth === 16 && bigEndian)) {
+      return dataIn;
+    }
+  }
+
+  // map to a UInt16 array if data is 16bit, fix endianness below
+  let data = options.bitDepth !== 16 ? dataIn : new Uint16Array(dataIn.buffer);
+
+  let maxValue = 255;
+  let inBpp = constants.COLORTYPE_TO_BPP_MAP[options.inputColorType];
+  if (inBpp === 4 && !options.inputHasAlpha) {
+    inBpp = 3;
+  }
+  let outBpp = constants.COLORTYPE_TO_BPP_MAP[options.colorType];
+  if (options.bitDepth === 16) {
+    maxValue = 65535;
+    outBpp *= 2;
+  }
+  let outData = Buffer.alloc(width * height * outBpp);
+
+  let inIndex = 0;
+  let outIndex = 0;
+
+  let bgColor = options.bgColor || {};
+  if (bgColor.red === undefined) {
+    bgColor.red = maxValue;
+  }
+  if (bgColor.green === undefined) {
+    bgColor.green = maxValue;
+  }
+  if (bgColor.blue === undefined) {
+    bgColor.blue = maxValue;
+  }
+
+  function getRGBA() {
+    let red;
+    let green;
+    let blue;
+    let alpha = maxValue;
+    switch (options.inputColorType) {
+      case constants.COLORTYPE_COLOR_ALPHA:
+        alpha = data[inIndex + 3];
+        red = data[inIndex];
+        green = data[inIndex + 1];
+        blue = data[inIndex + 2];
+        break;
+      case constants.COLORTYPE_COLOR:
+        red = data[inIndex];
+        green = data[inIndex + 1];
+        blue = data[inIndex + 2];
+        break;
+      case constants.COLORTYPE_ALPHA:
+        alpha = data[inIndex + 1];
+        red = data[inIndex];
+        green = red;
+        blue = red;
+        break;
+      case constants.COLORTYPE_GRAYSCALE:
+        red = data[inIndex];
+        green = red;
+        blue = red;
+        break;
+      default:
+        throw new Error(
+          "input color type:" +
+            options.inputColorType +
+            " is not supported at present"
+        );
+    }
+
+    if (options.inputHasAlpha) {
+      if (!outHasAlpha) {
+        alpha /= maxValue;
+        red = Math.min(
+          Math.max(Math.round((1 - alpha) * bgColor.red + alpha * red), 0),
+          maxValue
+        );
+        green = Math.min(
+          Math.max(Math.round((1 - alpha) * bgColor.green + alpha * green), 0),
+          maxValue
+        );
+        blue = Math.min(
+          Math.max(Math.round((1 - alpha) * bgColor.blue + alpha * blue), 0),
+          maxValue
+        );
+      }
+    }
+    return { red: red, green: green, blue: blue, alpha: alpha };
+  }
+
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      let rgba = getRGBA(data, inIndex);
+
+      switch (options.colorType) {
+        case constants.COLORTYPE_COLOR_ALPHA:
+        case constants.COLORTYPE_COLOR:
+          if (options.bitDepth === 8) {
+            outData[outIndex] = rgba.red;
+            outData[outIndex + 1] = rgba.green;
+            outData[outIndex + 2] = rgba.blue;
+            if (outHasAlpha) {
+              outData[outIndex + 3] = rgba.alpha;
+            }
+          } else {
+            outData.writeUInt16BE(rgba.red, outIndex);
+            outData.writeUInt16BE(rgba.green, outIndex + 2);
+            outData.writeUInt16BE(rgba.blue, outIndex + 4);
+            if (outHasAlpha) {
+              outData.writeUInt16BE(rgba.alpha, outIndex + 6);
+            }
+          }
+          break;
+        case constants.COLORTYPE_ALPHA:
+        case constants.COLORTYPE_GRAYSCALE: {
+          // Convert to grayscale and alpha
+          let grayscale = (rgba.red + rgba.green + rgba.blue) / 3;
+          if (options.bitDepth === 8) {
+            outData[outIndex] = grayscale;
+            if (outHasAlpha) {
+              outData[outIndex + 1] = rgba.alpha;
+            }
+          } else {
+            outData.writeUInt16BE(grayscale, outIndex);
+            if (outHasAlpha) {
+              outData.writeUInt16BE(rgba.alpha, outIndex + 2);
+            }
+          }
+          break;
+        }
+        default:
+          throw new Error("unrecognised color Type " + options.colorType);
+      }
+
+      inIndex += inBpp;
+      outIndex += outBpp;
+    }
+  }
+
+  return outData;
+};

node_modules/pngjs/lib/chunkstream.js

@@ -0,0 +1,189 @@
+"use strict";
+
+let util = require("util");
+let Stream = require("stream");
+
+let ChunkStream = (module.exports = function () {
+  Stream.call(this);
+
+  this._buffers = [];
+  this._buffered = 0;
+
+  this._reads = [];
+  this._paused = false;
+
+  this._encoding = "utf8";
+  this.writable = true;
+});
+util.inherits(ChunkStream, Stream);
+
+ChunkStream.prototype.read = function (length, callback) {
+  this._reads.push({
+    length: Math.abs(length), // if length < 0 then at most this length
+    allowLess: length < 0,
+    func: callback,
+  });
+
+  process.nextTick(
+    function () {
+      this._process();
+
+      // its paused and there is not enought data then ask for more
+      if (this._paused && this._reads && this._reads.length > 0) {
+        this._paused = false;
+
+        this.emit("drain");
+      }
+    }.bind(this)
+  );
+};
+
+ChunkStream.prototype.write = function (data, encoding) {
+  if (!this.writable) {
+    this.emit("error", new Error("Stream not writable"));
+    return false;
+  }
+
+  let dataBuffer;
+  if (Buffer.isBuffer(data)) {
+    dataBuffer = data;
+  } else {
+    dataBuffer = Buffer.from(data, encoding || this._encoding);
+  }
+
+  this._buffers.push(dataBuffer);
+  this._buffered += dataBuffer.length;
+
+  this._process();
+
+  // ok if there are no more read requests
+  if (this._reads && this._reads.length === 0) {
+    this._paused = true;
+  }
+
+  return this.writable && !this._paused;
+};
+
+ChunkStream.prototype.end = function (data, encoding) {
+  if (data) {
+    this.write(data, encoding);
+  }
+
+  this.writable = false;
+
+  // already destroyed
+  if (!this._buffers) {
+    return;
+  }
+
+  // enqueue or handle end
+  if (this._buffers.length === 0) {
+    this._end();
+  } else {
+    this._buffers.push(null);
+    this._process();
+  }
+};
+
+ChunkStream.prototype.destroySoon = ChunkStream.prototype.end;
+
+ChunkStream.prototype._end = function () {
+  if (this._reads.length > 0) {
+    this.emit("error", new Error("Unexpected end of input"));
+  }
+
+  this.destroy();
+};
+
+ChunkStream.prototype.destroy = function () {
+  if (!this._buffers) {
+    return;
+  }
+
+  this.writable = false;
+  this._reads = null;
+  this._buffers = null;
+
+  this.emit("close");
+};
+
+ChunkStream.prototype._processReadAllowingLess = function (read) {
+  // ok there is any data so that we can satisfy this request
+  this._reads.shift(); // == read
+
+  // first we need to peek into first buffer
+  let smallerBuf = this._buffers[0];
+
+  // ok there is more data than we need
+  if (smallerBuf.length > read.length) {
+    this._buffered -= read.length;
+    this._buffers[0] = smallerBuf.slice(read.length);
+
+    read.func.call(this, smallerBuf.slice(0, read.length));
+  } else {
+    // ok this is less than maximum length so use it all
+    this._buffered -= smallerBuf.length;
+    this._buffers.shift(); // == smallerBuf
+
+    read.func.call(this, smallerBuf);
+  }
+};
+
+ChunkStream.prototype._processRead = function (read) {
+  this._reads.shift(); // == read
+
+  let pos = 0;
+  let count = 0;
+  let data = Buffer.alloc(read.length);
+
+  // create buffer for all data
+  while (pos < read.length) {
+    let buf = this._buffers[count++];
+    let len = Math.min(buf.length, read.length - pos);
+
+    buf.copy(data, pos, 0, len);
+    pos += len;
+
+    // last buffer wasn't used all so just slice it and leave
+    if (len !== buf.length) {
+      this._buffers[--count] = buf.slice(len);
+    }
+  }
+
+  // remove all used buffers
+  if (count > 0) {
+    this._buffers.splice(0, count);
+  }
+
+  this._buffered -= read.length;
+
+  read.func.call(this, data);
+};
+
+ChunkStream.prototype._process = function () {
+  try {
+    // as long as there is any data and read requests
+    while (this._buffered > 0 && this._reads && this._reads.length > 0) {
+      let read = this._reads[0];
+
+      // read any data (but no more than length)
+      if (read.allowLess) {
+        this._processReadAllowingLess(read);
+      } else if (this._buffered >= read.length) {
+        // ok we can meet some expectations
+
+        this._processRead(read);
+      } else {
+        // not enought data to satisfy first request in queue
+        // so we need to wait for more
+        break;
+      }
+    }
+
+    if (this._buffers && !this.writable) {
+      this._end();
+    }
+  } catch (ex) {
+    this.emit("error", ex);
+  }
+};

node_modules/pngjs/lib/constants.js

@@ -0,0 +1,32 @@
+"use strict";
+
+module.exports = {
+  PNG_SIGNATURE: [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a],
+
+  TYPE_IHDR: 0x49484452,
+  TYPE_IEND: 0x49454e44,
+  TYPE_IDAT: 0x49444154,
+  TYPE_PLTE: 0x504c5445,
+  TYPE_tRNS: 0x74524e53, // eslint-disable-line camelcase
+  TYPE_gAMA: 0x67414d41, // eslint-disable-line camelcase
+
+  // color-type bits
+  COLORTYPE_GRAYSCALE: 0,
+  COLORTYPE_PALETTE: 1,
+  COLORTYPE_COLOR: 2,
+  COLORTYPE_ALPHA: 4, // e.g. grayscale and alpha
+
+  // color-type combinations
+  COLORTYPE_PALETTE_COLOR: 3,
+  COLORTYPE_COLOR_ALPHA: 6,
+
+  COLORTYPE_TO_BPP_MAP: {
+    0: 1,
+    2: 3,
+    3: 1,
+    4: 2,
+    6: 4,
+  },
+
+  GAMMA_DIVISION: 100000,
+};

node_modules/pngjs/lib/crc.js

@@ -0,0 +1,40 @@
+"use strict";
+
+let crcTable = [];
+
+(function () {
+  for (let i = 0; i < 256; i++) {
+    let currentCrc = i;
+    for (let j = 0; j < 8; j++) {
+      if (currentCrc & 1) {
+        currentCrc = 0xedb88320 ^ (currentCrc >>> 1);
+      } else {
+        currentCrc = currentCrc >>> 1;
+      }
+    }
+    crcTable[i] = currentCrc;
+  }
+})();
+
+let CrcCalculator = (module.exports = function () {
+  this._crc = -1;
+});
+
+CrcCalculator.prototype.write = function (data) {
+  for (let i = 0; i < data.length; i++) {
+    this._crc = crcTable[(this._crc ^ data[i]) & 0xff] ^ (this._crc >>> 8);
+  }
+  return true;
+};
+
+CrcCalculator.prototype.crc32 = function () {
+  return this._crc ^ -1;
+};
+
+CrcCalculator.crc32 = function (buf) {
+  let crc = -1;
+  for (let i = 0; i < buf.length; i++) {
+    crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
+  }
+  return crc ^ -1;
+};

node_modules/pngjs/lib/filter-pack.js

@@ -0,0 +1,171 @@
+"use strict";
+
+let paethPredictor = require("./paeth-predictor");
+
+function filterNone(pxData, pxPos, byteWidth, rawData, rawPos) {
+  for (let x = 0; x < byteWidth; x++) {
+    rawData[rawPos + x] = pxData[pxPos + x];
+  }
+}
+
+function filterSumNone(pxData, pxPos, byteWidth) {
+  let sum = 0;
+  let length = pxPos + byteWidth;
+
+  for (let i = pxPos; i < length; i++) {
+    sum += Math.abs(pxData[i]);
+  }
+  return sum;
+}
+
+function filterSub(pxData, pxPos, byteWidth, rawData, rawPos, bpp) {
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let val = pxData[pxPos + x] - left;
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumSub(pxData, pxPos, byteWidth, bpp) {
+  let sum = 0;
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let val = pxData[pxPos + x] - left;
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+function filterUp(pxData, pxPos, byteWidth, rawData, rawPos) {
+  for (let x = 0; x < byteWidth; x++) {
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let val = pxData[pxPos + x] - up;
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumUp(pxData, pxPos, byteWidth) {
+  let sum = 0;
+  let length = pxPos + byteWidth;
+  for (let x = pxPos; x < length; x++) {
+    let up = pxPos > 0 ? pxData[x - byteWidth] : 0;
+    let val = pxData[x] - up;
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+function filterAvg(pxData, pxPos, byteWidth, rawData, rawPos, bpp) {
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let val = pxData[pxPos + x] - ((left + up) >> 1);
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumAvg(pxData, pxPos, byteWidth, bpp) {
+  let sum = 0;
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let val = pxData[pxPos + x] - ((left + up) >> 1);
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+function filterPaeth(pxData, pxPos, byteWidth, rawData, rawPos, bpp) {
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let upleft =
+      pxPos > 0 && x >= bpp ? pxData[pxPos + x - (byteWidth + bpp)] : 0;
+    let val = pxData[pxPos + x] - paethPredictor(left, up, upleft);
+
+    rawData[rawPos + x] = val;
+  }
+}
+
+function filterSumPaeth(pxData, pxPos, byteWidth, bpp) {
+  let sum = 0;
+  for (let x = 0; x < byteWidth; x++) {
+    let left = x >= bpp ? pxData[pxPos + x - bpp] : 0;
+    let up = pxPos > 0 ? pxData[pxPos + x - byteWidth] : 0;
+    let upleft =
+      pxPos > 0 && x >= bpp ? pxData[pxPos + x - (byteWidth + bpp)] : 0;
+    let val = pxData[pxPos + x] - paethPredictor(left, up, upleft);
+
+    sum += Math.abs(val);
+  }
+
+  return sum;
+}
+
+let filters = {
+  0: filterNone,
+  1: filterSub,
+  2: filterUp,
+  3: filterAvg,
+  4: filterPaeth,
+};
+
+let filterSums = {
+  0: filterSumNone,
+  1: filterSumSub,
+  2: filterSumUp,
+  3: filterSumAvg,
+  4: filterSumPaeth,
+};
+
+module.exports = function (pxData, width, height, options, bpp) {
+  let filterTypes;
+  if (!("filterType" in options) || options.filterType === -1) {
+    filterTypes = [0, 1, 2, 3, 4];
+  } else if (typeof options.filterType === "number") {
+    filterTypes = [options.filterType];
+  } else {
+    throw new Error("unrecognised filter types");
+  }
+
+  if (options.bitDepth === 16) {
+    bpp *= 2;
+  }
+  let byteWidth = width * bpp;
+  let rawPos = 0;
+  let pxPos = 0;
+  let rawData = Buffer.alloc((byteWidth + 1) * height);
+
+  let sel = filterTypes[0];
+
+  for (let y = 0; y < height; y++) {
+    if (filterTypes.length > 1) {
+      // find best filter for this line (with lowest sum of values)
+      let min = Infinity;
+
+      for (let i = 0; i < filterTypes.length; i++) {
+        let sum = filterSums[filterTypes[i]](pxData, pxPos, byteWidth, bpp);
+        if (sum < min) {
+          sel = filterTypes[i];
+          min = sum;
+        }
+      }
+    }
+
+    rawData[rawPos] = sel;
+    rawPos++;
+    filters[sel](pxData, pxPos, byteWidth, rawData, rawPos, bpp);
+    rawPos += byteWidth;
+    pxPos += byteWidth;
+  }
+  return rawData;
+};

node_modules/pngjs/lib/filter-parse-async.js

@@ -0,0 +1,24 @@
+"use strict";
+
+let util = require("util");
+let ChunkStream = require("./chunkstream");
+let Filter = require("./filter-parse");
+
+let FilterAsync = (module.exports = function (bitmapInfo) {
+  ChunkStream.call(this);
+
+  let buffers = [];
+  let that = this;
+  this._filter = new Filter(bitmapInfo, {
+    read: this.read.bind(this),
+    write: function (buffer) {
+      buffers.push(buffer);
+    },
+    complete: function () {
+      that.emit("complete", Buffer.concat(buffers));
+    },
+  });
+
+  this._filter.start();
+});
+util.inherits(FilterAsync, ChunkStream);

node_modules/pngjs/lib/filter-parse-sync.js

@@ -0,0 +1,21 @@
+"use strict";
+
+let SyncReader = require("./sync-reader");
+let Filter = require("./filter-parse");
+
+exports.process = function (inBuffer, bitmapInfo) {
+  let outBuffers = [];
+  let reader = new SyncReader(inBuffer);
+  let filter = new Filter(bitmapInfo, {
+    read: reader.read.bind(reader),
+    write: function (bufferPart) {
+      outBuffers.push(bufferPart);
+    },
+    complete: function () {},
+  });
+
+  filter.start();
+  reader.process();
+
+  return Buffer.concat(outBuffers);
+};

node_modules/pngjs/lib/filter-parse.js

@@ -0,0 +1,177 @@
+"use strict";
+
+let interlaceUtils = require("./interlace");
+let paethPredictor = require("./paeth-predictor");
+
+function getByteWidth(width, bpp, depth) {
+  let byteWidth = width * bpp;
+  if (depth !== 8) {
+    byteWidth = Math.ceil(byteWidth / (8 / depth));
+  }
+  return byteWidth;
+}
+
+let Filter = (module.exports = function (bitmapInfo, dependencies) {
+  let width = bitmapInfo.width;
+  let height = bitmapInfo.height;
+  let interlace = bitmapInfo.interlace;
+  let bpp = bitmapInfo.bpp;
+  let depth = bitmapInfo.depth;
+
+  this.read = dependencies.read;
+  this.write = dependencies.write;
+  this.complete = dependencies.complete;
+
+  this._imageIndex = 0;
+  this._images = [];
+  if (interlace) {
+    let passes = interlaceUtils.getImagePasses(width, height);
+    for (let i = 0; i < passes.length; i++) {
+      this._images.push({
+        byteWidth: getByteWidth(passes[i].width, bpp, depth),
+        height: passes[i].height,
+        lineIndex: 0,
+      });
+    }
+  } else {
+    this._images.push({
+      byteWidth: getByteWidth(width, bpp, depth),
+      height: height,
+      lineIndex: 0,
+    });
+  }
+
+  // when filtering the line we look at the pixel to the left
+  // the spec also says it is done on a byte level regardless of the number of pixels
+  // so if the depth is byte compatible (8 or 16) we subtract the bpp in order to compare back
+  // a pixel rather than just a different byte part. However if we are sub byte, we ignore.
+  if (depth === 8) {
+    this._xComparison = bpp;
+  } else if (depth === 16) {
+    this._xComparison = bpp * 2;
+  } else {
+    this._xComparison = 1;
+  }
+});
+
+Filter.prototype.start = function () {
+  this.read(
+    this._images[this._imageIndex].byteWidth + 1,
+    this._reverseFilterLine.bind(this)
+  );
+};
+
+Filter.prototype._unFilterType1 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let xComparison = this._xComparison;
+  let xBiggerThan = xComparison - 1;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f1Left = x > xBiggerThan ? unfilteredLine[x - xComparison] : 0;
+    unfilteredLine[x] = rawByte + f1Left;
+  }
+};
+
+Filter.prototype._unFilterType2 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let lastLine = this._lastLine;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f2Up = lastLine ? lastLine[x] : 0;
+    unfilteredLine[x] = rawByte + f2Up;
+  }
+};
+
+Filter.prototype._unFilterType3 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let xComparison = this._xComparison;
+  let xBiggerThan = xComparison - 1;
+  let lastLine = this._lastLine;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f3Up = lastLine ? lastLine[x] : 0;
+    let f3Left = x > xBiggerThan ? unfilteredLine[x - xComparison] : 0;
+    let f3Add = Math.floor((f3Left + f3Up) / 2);
+    unfilteredLine[x] = rawByte + f3Add;
+  }
+};
+
+Filter.prototype._unFilterType4 = function (
+  rawData,
+  unfilteredLine,
+  byteWidth
+) {
+  let xComparison = this._xComparison;
+  let xBiggerThan = xComparison - 1;
+  let lastLine = this._lastLine;
+
+  for (let x = 0; x < byteWidth; x++) {
+    let rawByte = rawData[1 + x];
+    let f4Up = lastLine ? lastLine[x] : 0;
+    let f4Left = x > xBiggerThan ? unfilteredLine[x - xComparison] : 0;
+    let f4UpLeft = x > xBiggerThan && lastLine ? lastLine[x - xComparison] : 0;
+    let f4Add = paethPredictor(f4Left, f4Up, f4UpLeft);
+    unfilteredLine[x] = rawByte + f4Add;
+  }
+};
+
+Filter.prototype._reverseFilterLine = function (rawData) {
+  let filter = rawData[0];
+  let unfilteredLine;
+  let currentImage = this._images[this._imageIndex];
+  let byteWidth = currentImage.byteWidth;
+
+  if (filter === 0) {
+    unfilteredLine = rawData.slice(1, byteWidth + 1);
+  } else {
+    unfilteredLine = Buffer.alloc(byteWidth);
+
+    switch (filter) {
+      case 1:
+        this._unFilterType1(rawData, unfilteredLine, byteWidth);
+        break;
+      case 2:
+        this._unFilterType2(rawData, unfilteredLine, byteWidth);
+        break;
+      case 3:
+        this._unFilterType3(rawData, unfilteredLine, byteWidth);
+        break;
+      case 4:
+        this._unFilterType4(rawData, unfilteredLine, byteWidth);
+        break;
+      default:
+        throw new Error("Unrecognised filter type - " + filter);
+    }
+  }
+
+  this.write(unfilteredLine);
+
+  currentImage.lineIndex++;
+  if (currentImage.lineIndex >= currentImage.height) {
+    this._lastLine = null;
+    this._imageIndex++;
+    currentImage = this._images[this._imageIndex];
+  } else {
+    this._lastLine = unfilteredLine;
+  }
+
+  if (currentImage) {
+    // read, using the byte width that may be from the new current image
+    this.read(currentImage.byteWidth + 1, this._reverseFilterLine.bind(this));
+  } else {
+    this._lastLine = null;
+    this.complete();
+  }
+};

node_modules/pngjs/lib/format-normaliser.js

@@ -0,0 +1,93 @@
+"use strict";
+
+function dePalette(indata, outdata, width, height, palette) {
+  let pxPos = 0;
+  // use values from palette
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      let color = palette[indata[pxPos]];
+
+      if (!color) {
+        throw new Error("index " + indata[pxPos] + " not in palette");
+      }
+
+      for (let i = 0; i < 4; i++) {
+        outdata[pxPos + i] = color[i];
+      }
+      pxPos += 4;
+    }
+  }
+}
+
+function replaceTransparentColor(indata, outdata, width, height, transColor) {
+  let pxPos = 0;
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      let makeTrans = false;
+
+      if (transColor.length === 1) {
+        if (transColor[0] === indata[pxPos]) {
+          makeTrans = true;
+        }
+      } else if (
+        transColor[0] === indata[pxPos] &&
+        transColor[1] === indata[pxPos + 1] &&
+        transColor[2] === indata[pxPos + 2]
+      ) {
+        makeTrans = true;
+      }
+      if (makeTrans) {
+        for (let i = 0; i < 4; i++) {
+          outdata[pxPos + i] = 0;
+        }
+      }
+      pxPos += 4;
+    }
+  }
+}
+
+function scaleDepth(indata, outdata, width, height, depth) {
+  let maxOutSample = 255;
+  let maxInSample = Math.pow(2, depth) - 1;
+  let pxPos = 0;
+
+  for (let y = 0; y < height; y++) {
+    for (let x = 0; x < width; x++) {
+      for (let i = 0; i < 4; i++) {
+        outdata[pxPos + i] = Math.floor(
+          (indata[pxPos + i] * maxOutSample) / maxInSample + 0.5
+        );
+      }
+      pxPos += 4;
+    }
+  }
+}
+
+module.exports = function (indata, imageData) {
+  let depth = imageData.depth;
+  let width = imageData.width;
+  let height = imageData.height;
+  let colorType = imageData.colorType;
+  let transColor = imageData.transColor;
+  let palette = imageData.palette;
+
+  let outdata = indata; // only different for 16 bits
+
+  if (colorType === 3) {
+    // paletted
+    dePalette(indata, outdata, width, height, palette);
+  } else {
+    if (transColor) {
+      replaceTransparentColor(indata, outdata, width, height, transColor);
+    }
+    // if it needs scaling
+    if (depth !== 8) {
+      // if we need to change the buffer size
+      if (depth === 16) {
+        outdata = Buffer.alloc(width * height * 4);
+      }
+      scaleDepth(indata, outdata, width, height, depth);
+    }
+  }
+  return outdata;
+};

node_modules/pngjs/lib/interlace.js

@@ -0,0 +1,95 @@
+"use strict";
+
+// Adam 7
+//   0 1 2 3 4 5 6 7
+// 0 x 6 4 6 x 6 4 6
+// 1 7 7 7 7 7 7 7 7
+// 2 5 6 5 6 5 6 5 6
+// 3 7 7 7 7 7 7 7 7
+// 4 3 6 4 6 3 6 4 6
+// 5 7 7 7 7 7 7 7 7
+// 6 5 6 5 6 5 6 5 6
+// 7 7 7 7 7 7 7 7 7
+
+let imagePasses = [
+  {
+    // pass 1 - 1px
+    x: [0],
+    y: [0],
+  },
+  {
+    // pass 2 - 1px
+    x: [4],
+    y: [0],
+  },
+  {
+    // pass 3 - 2px
+    x: [0, 4],
+    y: [4],
+  },
+  {
+    // pass 4 - 4px
+    x: [2, 6],
+    y: [0, 4],
+  },
+  {
+    // pass 5 - 8px
+    x: [0, 2, 4, 6],
+    y: [2, 6],
+  },
+  {
+    // pass 6 - 16px
+    x: [1, 3, 5, 7],
+    y: [0, 2, 4, 6],
+  },
+  {
+    // pass 7 - 32px
+    x: [0, 1, 2, 3, 4, 5, 6, 7],
+    y: [1, 3, 5, 7],
+  },
+];
+
+exports.getImagePasses = function (width, height) {
+  let images = [];
+  let xLeftOver = width % 8;
+  let yLeftOver = height % 8;
+  let xRepeats = (width - xLeftOver) / 8;
+  let yRepeats = (height - yLeftOver) / 8;
+  for (let i = 0; i < imagePasses.length; i++) {
+    let pass = imagePasses[i];
+    let passWidth = xRepeats * pass.x.length;
+    let passHeight = yRepeats * pass.y.length;
+    for (let j = 0; j < pass.x.length; j++) {
+      if (pass.x[j] < xLeftOver) {
+        passWidth++;
+      } else {
+        break;
+      }
+    }
+    for (let j = 0; j < pass.y.length; j++) {
+      if (pass.y[j] < yLeftOver) {
+        passHeight++;
+      } else {
+        break;
+      }
+    }
+    if (passWidth > 0 && passHeight > 0) {
+      images.push({ width: passWidth, height: passHeight, index: i });
+    }
+  }
+  return images;
+};
+
+exports.getInterlaceIterator = function (width) {
+  return function (x, y, pass) {
+    let outerXLeftOver = x % imagePasses[pass].x.length;
+    let outerX =
+      ((x - outerXLeftOver) / imagePasses[pass].x.length) * 8 +
+      imagePasses[pass].x[outerXLeftOver];
+    let outerYLeftOver = y % imagePasses[pass].y.length;
+    let outerY =
+      ((y - outerYLeftOver) / imagePasses[pass].y.length) * 8 +
+      imagePasses[pass].y[outerYLeftOver];
+    return outerX * 4 + outerY * width * 4;
+  };
+};

node_modules/pngjs/lib/packer-async.js

@@ -0,0 +1,50 @@
+"use strict";
+
+let util = require("util");
+let Stream = require("stream");
+let constants = require("./constants");
+let Packer = require("./packer");
+
+let PackerAsync = (module.exports = function (opt) {
+  Stream.call(this);
+
+  let options = opt || {};
+
+  this._packer = new Packer(options);
+  this._deflate = this._packer.createDeflate();
+
+  this.readable = true;
+});
+util.inherits(PackerAsync, Stream);
+
+PackerAsync.prototype.pack = function (data, width, height, gamma) {
+  // Signature
+  this.emit("data", Buffer.from(constants.PNG_SIGNATURE));
+  this.emit("data", this._packer.packIHDR(width, height));
+
+  if (gamma) {
+    this.emit("data", this._packer.packGAMA(gamma));
+  }
+
+  let filteredData = this._packer.filterData(data, width, height);
+
+  // compress it
+  this._deflate.on("error", this.emit.bind(this, "error"));
+
+  this._deflate.on(
+    "data",
+    function (compressedData) {
+      this.emit("data", this._packer.packIDAT(compressedData));
+    }.bind(this)
+  );
+
+  this._deflate.on(
+    "end",
+    function () {
+      this.emit("data", this._packer.packIEND());
+      this.emit("end");
+    }.bind(this)
+  );
+
+  this._deflate.end(filteredData);
+};

node_modules/pngjs/lib/packer-sync.js

@@ -0,0 +1,56 @@
+"use strict";
+
+let hasSyncZlib = true;
+let zlib = require("zlib");
+if (!zlib.deflateSync) {
+  hasSyncZlib = false;
+}
+let constants = require("./constants");
+let Packer = require("./packer");
+
+module.exports = function (metaData, opt) {
+  if (!hasSyncZlib) {
+    throw new Error(
+      "To use the sync capability of this library in old node versions, please pin pngjs to v2.3.0"
+    );
+  }
+
+  let options = opt || {};
+
+  let packer = new Packer(options);
+
+  let chunks = [];
+
+  // Signature
+  chunks.push(Buffer.from(constants.PNG_SIGNATURE));
+
+  // Header
+  chunks.push(packer.packIHDR(metaData.width, metaData.height));
+
+  if (metaData.gamma) {
+    chunks.push(packer.packGAMA(metaData.gamma));
+  }
+
+  let filteredData = packer.filterData(
+    metaData.data,
+    metaData.width,
+    metaData.height
+  );
+
+  // compress it
+  let compressedData = zlib.deflateSync(
+    filteredData,
+    packer.getDeflateOptions()
+  );
+  filteredData = null;
+
+  if (!compressedData || !compressedData.length) {
+    throw new Error("bad png - invalid compressed data response");
+  }
+  chunks.push(packer.packIDAT(compressedData));
+
+  // End
+  chunks.push(packer.packIEND());
+
+  return Buffer.concat(chunks);
+};

node_modules/pngjs/lib/packer.js

@@ -0,0 +1,129 @@
+"use strict";
+
+let constants = require("./constants");
+let CrcStream = require("./crc");
+let bitPacker = require("./bitpacker");
+let filter = require("./filter-pack");
+let zlib = require("zlib");
+
+let Packer = (module.exports = function (options) {
+  this._options = options;
+
+  options.deflateChunkSize = options.deflateChunkSize || 32 * 1024;
+  options.deflateLevel =
+    options.deflateLevel != null ? options.deflateLevel : 9;
+  options.deflateStrategy =
+    options.deflateStrategy != null ? options.deflateStrategy : 3;
+  options.inputHasAlpha =
+    options.inputHasAlpha != null ? options.inputHasAlpha : true;
+  options.deflateFactory = options.deflateFactory || zlib.createDeflate;
+  options.bitDepth = options.bitDepth || 8;
+  // This is outputColorType
+  options.colorType =
+    typeof options.colorType === "number"
+      ? options.colorType
+      : constants.COLORTYPE_COLOR_ALPHA;
+  options.inputColorType =
+    typeof options.inputColorType === "number"
+      ? options.inputColorType
+      : constants.COLORTYPE_COLOR_ALPHA;
+
+  if (
+    [
+      constants.COLORTYPE_GRAYSCALE,
+      constants.COLORTYPE_COLOR,
+      constants.COLORTYPE_COLOR_ALPHA,
+      constants.COLORTYPE_ALPHA,
+    ].indexOf(options.colorType) === -1
+  ) {
+    throw new Error(
+      "option color type:" + options.colorType + " is not supported at present"
+    );
+  }
+  if (
+    [
+      constants.COLORTYPE_GRAYSCALE,
+      constants.COLORTYPE_COLOR,
+      constants.COLORTYPE_COLOR_ALPHA,
+      constants.COLORTYPE_ALPHA,
+    ].indexOf(options.inputColorType) === -1
+  ) {
+    throw new Error(
+      "option input color type:" +
+        options.inputColorType +
+        " is not supported at present"
+    );
+  }
+  if (options.bitDepth !== 8 && options.bitDepth !== 16) {
+    throw new Error(
+      "option bit depth:" + options.bitDepth + " is not supported at present"
+    );
+  }
+});
+
+Packer.prototype.getDeflateOptions = function () {
+  return {
+    chunkSize: this._options.deflateChunkSize,
+    level: this._options.deflateLevel,
+    strategy: this._options.deflateStrategy,
+  };
+};
+
+Packer.prototype.createDeflate = function () {
+  return this._options.deflateFactory(this.getDeflateOptions());
+};
+
+Packer.prototype.filterData = function (data, width, height) {
+  // convert to correct format for filtering (e.g. right bpp and bit depth)
+  let packedData = bitPacker(data, width, height, this._options);
+
+  // filter pixel data
+  let bpp = constants.COLORTYPE_TO_BPP_MAP[this._options.colorType];
+  let filteredData = filter(packedData, width, height, this._options, bpp);
+  return filteredData;
+};
+
+Packer.prototype._packChunk = function (type, data) {
+  let len = data ? data.length : 0;
+  let buf = Buffer.alloc(len + 12);
+
+  buf.writeUInt32BE(len, 0);
+  buf.writeUInt32BE(type, 4);
+
+  if (data) {
+    data.copy(buf, 8);
+  }
+
+  buf.writeInt32BE(
+    CrcStream.crc32(buf.slice(4, buf.length - 4)),
+    buf.length - 4
+  );
+  return buf;
+};
+
+Packer.prototype.packGAMA = function (gamma) {
+  let buf = Buffer.alloc(4);
+  buf.writeUInt32BE(Math.floor(gamma * constants.GAMMA_DIVISION), 0);
+  return this._packChunk(constants.TYPE_gAMA, buf);
+};
+
+Packer.prototype.packIHDR = function (width, height) {
+  let buf = Buffer.alloc(13);
+  buf.writeUInt32BE(width, 0);
+  buf.writeUInt32BE(height, 4);
+  buf[8] = this._options.bitDepth; // Bit depth
+  buf[9] = this._options.colorType; // colorType
+  buf[10] = 0; // compression
+  buf[11] = 0; // filter
+  buf[12] = 0; // interlace
+
+  return this._packChunk(constants.TYPE_IHDR, buf);
+};
+
+Packer.prototype.packIDAT = function (data) {
+  return this._packChunk(constants.TYPE_IDAT, data);
+};
+
+Packer.prototype.packIEND = function () {
+  return this._packChunk(constants.TYPE_IEND, null);
+};

node_modules/pngjs/lib/paeth-predictor.js

@@ -0,0 +1,16 @@
+"use strict";
+
+module.exports = function paethPredictor(left, above, upLeft) {
+  let paeth = left + above - upLeft;
+  let pLeft = Math.abs(paeth - left);
+  let pAbove = Math.abs(paeth - above);
+  let pUpLeft = Math.abs(paeth - upLeft);
+
+  if (pLeft <= pAbove && pLeft <= pUpLeft) {
+    return left;
+  }
+  if (pAbove <= pUpLeft) {
+    return above;
+  }
+  return upLeft;
+};

node_modules/pngjs/lib/parser-async.js

@@ -0,0 +1,165 @@
+"use strict";
+
+let util = require("util");
+let zlib = require("zlib");
+let ChunkStream = require("./chunkstream");
+let FilterAsync = require("./filter-parse-async");
+let Parser = require("./parser");
+let bitmapper = require("./bitmapper");
+let formatNormaliser = require("./format-normaliser");
+
+let ParserAsync = (module.exports = function (options) {
+  ChunkStream.call(this);
+
+  this._parser = new Parser(options, {
+    read: this.read.bind(this),
+    error: this._handleError.bind(this),
+    metadata: this._handleMetaData.bind(this),
+    gamma: this.emit.bind(this, "gamma"),
+    palette: this._handlePalette.bind(this),
+    transColor: this._handleTransColor.bind(this),
+    finished: this._finished.bind(this),
+    inflateData: this._inflateData.bind(this),
+    simpleTransparency: this._simpleTransparency.bind(this),
+    headersFinished: this._headersFinished.bind(this),
+  });
+  this._options = options;
+  this.writable = true;
+
+  this._parser.start();
+});
+util.inherits(ParserAsync, ChunkStream);
+
+ParserAsync.prototype._handleError = function (err) {
+  this.emit("error", err);
+
+  this.writable = false;
+
+  this.destroy();
+
+  if (this._inflate && this._inflate.destroy) {
+    this._inflate.destroy();
+  }
+
+  if (this._filter) {
+    this._filter.destroy();
+    // For backward compatibility with Node 7 and below.
+    // Suppress errors due to _inflate calling write() even after
+    // it's destroy()'ed.
+    this._filter.on("error", function () {});
+  }
+
+  this.errord = true;
+};
+
+ParserAsync.prototype._inflateData = function (data) {
+  if (!this._inflate) {
+    if (this._bitmapInfo.interlace) {
+      this._inflate = zlib.createInflate();
+
+      this._inflate.on("error", this.emit.bind(this, "error"));
+      this._filter.on("complete", this._complete.bind(this));
+
+      this._inflate.pipe(this._filter);
+    } else {
+      let rowSize =
+        ((this._bitmapInfo.width *
+          this._bitmapInfo.bpp *
+          this._bitmapInfo.depth +
+          7) >>
+          3) +
+        1;
+      let imageSize = rowSize * this._bitmapInfo.height;
+      let chunkSize = Math.max(imageSize, zlib.Z_MIN_CHUNK);
+
+      this._inflate = zlib.createInflate({ chunkSize: chunkSize });
+      let leftToInflate = imageSize;
+
+      let emitError = this.emit.bind(this, "error");
+      this._inflate.on("error", function (err) {
+        if (!leftToInflate) {
+          return;
+        }
+
+        emitError(err);
+      });
+      this._filter.on("complete", this._complete.bind(this));
+
+      let filterWrite = this._filter.write.bind(this._filter);
+      this._inflate.on("data", function (chunk) {
+        if (!leftToInflate) {
+          return;
+        }
+
+        if (chunk.length > leftToInflate) {
+          chunk = chunk.slice(0, leftToInflate);
+        }
+
+        leftToInflate -= chunk.length;
+
+        filterWrite(chunk);
+      });
+
+      this._inflate.on("end", this._filter.end.bind(this._filter));
+    }
+  }
+  this._inflate.write(data);
+};
+
+ParserAsync.prototype._handleMetaData = function (metaData) {
+  this._metaData = metaData;
+  this._bitmapInfo = Object.create(metaData);
+
+  this._filter = new FilterAsync(this._bitmapInfo);
+};
+
+ParserAsync.prototype._handleTransColor = function (transColor) {
+  this._bitmapInfo.transColor = transColor;
+};
+
+ParserAsync.prototype._handlePalette = function (palette) {
+  this._bitmapInfo.palette = palette;
+};
+
+ParserAsync.prototype._simpleTransparency = function () {
+  this._metaData.alpha = true;
+};
+
+ParserAsync.prototype._headersFinished = function () {
+  // Up until this point, we don't know if we have a tRNS chunk (alpha)
+  // so we can't emit metadata any earlier
+  this.emit("metadata", this._metaData);
+};
+
+ParserAsync.prototype._finished = function () {
+  if (this.errord) {
+    return;
+  }
+
+  if (!this._inflate) {
+    this.emit("error", "No Inflate block");
+  } else {
+    // no more data to inflate
+    this._inflate.end();
+  }
+};
+
+ParserAsync.prototype._complete = function (filteredData) {
+  if (this.errord) {
+    return;
+  }
+
+  let normalisedBitmapData;
+
+  try {
+    let bitmapData = bitmapper.dataToBitMap(filteredData, this._bitmapInfo);
+
+    normalisedBitmapData = formatNormaliser(bitmapData, this._bitmapInfo);
+    bitmapData = null;
+  } catch (ex) {
+    this._handleError(ex);
+    return;
+  }
+
+  this.emit("parsed", normalisedBitmapData);
+};

node_modules/pngjs/lib/parser-sync.js

@@ -0,0 +1,108 @@
+"use strict";
+
+let hasSyncZlib = true;
+let zlib = require("zlib");
+let inflateSync = require("./sync-inflate");
+if (!zlib.deflateSync) {
+  hasSyncZlib = false;
+}
+let SyncReader = require("./sync-reader");
+let FilterSync = require("./filter-parse-sync");
+let Parser = require("./parser");
+let bitmapper = require("./bitmapper");
+let formatNormaliser = require("./format-normaliser");
+
+module.exports = function (buffer, options) {
+  if (!hasSyncZlib) {
+    throw new Error(
+      "To use the sync capability of this library in old node versions, please pin pngjs to v2.3.0"
+    );
+  }
+
+  let err;
+  function handleError(_err_) {
+    err = _err_;
+  }
+
+  let metaData;
+  function handleMetaData(_metaData_) {
+    metaData = _metaData_;
+  }
+
+  function handleTransColor(transColor) {
+    metaData.transColor = transColor;
+  }
+
+  function handlePalette(palette) {
+    metaData.palette = palette;
+  }
+
+  function handleSimpleTransparency() {
+    metaData.alpha = true;
+  }
+
+  let gamma;
+  function handleGamma(_gamma_) {
+    gamma = _gamma_;
+  }
+
+  let inflateDataList = [];
+  function handleInflateData(inflatedData) {
+    inflateDataList.push(inflatedData);
+  }
+
+  let reader = new SyncReader(buffer);
+
+  let parser = new Parser(options, {
+    read: reader.read.bind(reader),
+    error: handleError,
+    metadata: handleMetaData,
+    gamma: handleGamma,
+    palette: handlePalette,
+    transColor: handleTransColor,
+    inflateData: handleInflateData,
+    simpleTransparency: handleSimpleTransparency,
+  });
+
+  parser.start();
+  reader.process();
+
+  if (err) {
+    throw err;
+  }
+
+  //join together the inflate datas
+  let inflateData = Buffer.concat(inflateDataList);
+  inflateDataList.length = 0;
+
+  let inflatedData;
+  if (metaData.interlace) {
+    inflatedData = zlib.inflateSync(inflateData);
+  } else {
+    let rowSize =
+      ((metaData.width * metaData.bpp * metaData.depth + 7) >> 3) + 1;
+    let imageSize = rowSize * metaData.height;
+    inflatedData = inflateSync(inflateData, {
+      chunkSize: imageSize,
+      maxLength: imageSize,
+    });
+  }
+  inflateData = null;
+
+  if (!inflatedData || !inflatedData.length) {
+    throw new Error("bad png - invalid inflate data response");
+  }
+
+  let unfilteredData = FilterSync.process(inflatedData, metaData);
+  inflateData = null;
+
+  let bitmapData = bitmapper.dataToBitMap(unfilteredData, metaData);
+  unfilteredData = null;
+
+  let normalisedBitmapData = formatNormaliser(bitmapData, metaData);
+
+  metaData.data = normalisedBitmapData;
+  metaData.gamma = gamma || 0;
+
+  return metaData;
+};

node_modules/pngjs/lib/parser.js

@@ -0,0 +1,290 @@
+"use strict";
+
+let constants = require("./constants");
+let CrcCalculator = require("./crc");
+
+let Parser = (module.exports = function (options, dependencies) {
+  this._options = options;
+  options.checkCRC = options.checkCRC !== false;
+
+  this._hasIHDR = false;
+  this._hasIEND = false;
+  this._emittedHeadersFinished = false;
+
+  // input flags/metadata
+  this._palette = [];
+  this._colorType = 0;
+
+  this._chunks = {};
+  this._chunks[constants.TYPE_IHDR] = this._handleIHDR.bind(this);
+  this._chunks[constants.TYPE_IEND] = this._handleIEND.bind(this);
+  this._chunks[constants.TYPE_IDAT] = this._handleIDAT.bind(this);
+  this._chunks[constants.TYPE_PLTE] = this._handlePLTE.bind(this);
+  this._chunks[constants.TYPE_tRNS] = this._handleTRNS.bind(this);
+  this._chunks[constants.TYPE_gAMA] = this._handleGAMA.bind(this);
+
+  this.read = dependencies.read;
+  this.error = dependencies.error;
+  this.metadata = dependencies.metadata;
+  this.gamma = dependencies.gamma;
+  this.transColor = dependencies.transColor;
+  this.palette = dependencies.palette;
+  this.parsed = dependencies.parsed;
+  this.inflateData = dependencies.inflateData;
+  this.finished = dependencies.finished;
+  this.simpleTransparency = dependencies.simpleTransparency;
+  this.headersFinished = dependencies.headersFinished || function () {};
+});
+
+Parser.prototype.start = function () {
+  this.read(constants.PNG_SIGNATURE.length, this._parseSignature.bind(this));
+};
+
+Parser.prototype._parseSignature = function (data) {
+  let signature = constants.PNG_SIGNATURE;
+
+  for (let i = 0; i < signature.length; i++) {
+    if (data[i] !== signature[i]) {
+      this.error(new Error("Invalid file signature"));
+      return;
+    }
+  }
+  this.read(8, this._parseChunkBegin.bind(this));
+};
+
+Parser.prototype._parseChunkBegin = function (data) {
+  // chunk content length
+  let length = data.readUInt32BE(0);
+
+  // chunk type
+  let type = data.readUInt32BE(4);
+  let name = "";
+  for (let i = 4; i < 8; i++) {
+    name += String.fromCharCode(data[i]);
+  }
+
+  //console.log('chunk ', name, length);
+
+  // chunk flags
+  let ancillary = Boolean(data[4] & 0x20); // or critical
+  //    priv = Boolean(data[5] & 0x20), // or public
+  //    safeToCopy = Boolean(data[7] & 0x20); // or unsafe
+
+  if (!this._hasIHDR && type !== constants.TYPE_IHDR) {
+    this.error(new Error("Expected IHDR on beggining"));
+    return;
+  }
+
+  this._crc = new CrcCalculator();
+  this._crc.write(Buffer.from(name));
+
+  if (this._chunks[type]) {
+    return this._chunks[type](length);
+  }
+
+  if (!ancillary) {
+    this.error(new Error("Unsupported critical chunk type " + name));
+    return;
+  }
+
+  this.read(length + 4, this._skipChunk.bind(this));
+};
+
+Parser.prototype._skipChunk = function (/*data*/) {
+  this.read(8, this._parseChunkBegin.bind(this));
+};
+
+Parser.prototype._handleChunkEnd = function () {
+  this.read(4, this._parseChunkEnd.bind(this));
+};
+
+Parser.prototype._parseChunkEnd = function (data) {
+  let fileCrc = data.readInt32BE(0);
+  let calcCrc = this._crc.crc32();
+
+  // check CRC
+  if (this._options.checkCRC && calcCrc !== fileCrc) {
+    this.error(new Error("Crc error - " + fileCrc + " - " + calcCrc));
+    return;
+  }
+
+  if (!this._hasIEND) {
+    this.read(8, this._parseChunkBegin.bind(this));
+  }
+};
+
+Parser.prototype._handleIHDR = function (length) {
+  this.read(length, this._parseIHDR.bind(this));
+};
+Parser.prototype._parseIHDR = function (data) {
+  this._crc.write(data);
+
+  let width = data.readUInt32BE(0);
+  let height = data.readUInt32BE(4);
+  let depth = data[8];
+  let colorType = data[9]; // bits: 1 palette, 2 color, 4 alpha
+  let compr = data[10];
+  let filter = data[11];
+  let interlace = data[12];
+
+  // console.log('    width', width, 'height', height,
+  //     'depth', depth, 'colorType', colorType,
+  //     'compr', compr, 'filter', filter, 'interlace', interlace
+  // );
+
+  if (
+    depth !== 8 &&
+    depth !== 4 &&
+    depth !== 2 &&
+    depth !== 1 &&
+    depth !== 16
+  ) {
+    this.error(new Error("Unsupported bit depth " + depth));
+    return;
+  }
+  if (!(colorType in constants.COLORTYPE_TO_BPP_MAP)) {
+    this.error(new Error("Unsupported color type"));
+    return;
+  }
+  if (compr !== 0) {
+    this.error(new Error("Unsupported compression method"));
+    return;
+  }
+  if (filter !== 0) {
+    this.error(new Error("Unsupported filter method"));
+    return;
+  }
+  if (interlace !== 0 && interlace !== 1) {
+    this.error(new Error("Unsupported interlace method"));
+    return;
+  }
+
+  this._colorType = colorType;
+
+  let bpp = constants.COLORTYPE_TO_BPP_MAP[this._colorType];
+
+  this._hasIHDR = true;
+
+  this.metadata({
+    width: width,
+    height: height,
+    depth: depth,
+    interlace: Boolean(interlace),
+    palette: Boolean(colorType & constants.COLORTYPE_PALETTE),
+    color: Boolean(colorType & constants.COLORTYPE_COLOR),
+    alpha: Boolean(colorType & constants.COLORTYPE_ALPHA),
+    bpp: bpp,
+    colorType: colorType,
+  });
+
+  this._handleChunkEnd();
+};
+
+Parser.prototype._handlePLTE = function (length) {
+  this.read(length, this._parsePLTE.bind(this));
+};
+Parser.prototype._parsePLTE = function (data) {
+  this._crc.write(data);
+
+  let entries = Math.floor(data.length / 3);
+  // console.log('Palette:', entries);
+
+  for (let i = 0; i < entries; i++) {
+    this._palette.push([data[i * 3], data[i * 3 + 1], data[i * 3 + 2], 0xff]);
+  }
+
+  this.palette(this._palette);
+
+  this._handleChunkEnd();
+};
+
+Parser.prototype._handleTRNS = function (length) {
+  this.simpleTransparency();
+  this.read(length, this._parseTRNS.bind(this));
+};
+Parser.prototype._parseTRNS = function (data) {
+  this._crc.write(data);
+
+  // palette
+  if (this._colorType === constants.COLORTYPE_PALETTE_COLOR) {
+    if (this._palette.length === 0) {
+      this.error(new Error("Transparency chunk must be after palette"));
+      return;
+    }
+    if (data.length > this._palette.length) {
+      this.error(new Error("More transparent colors than palette size"));
+      return;
+    }
+    for (let i = 0; i < data.length; i++) {
+      this._palette[i][3] = data[i];
+    }
+    this.palette(this._palette);
+  }
+
+  // for colorType 0 (grayscale) and 2 (rgb)
+  // there might be one gray/color defined as transparent
+  if (this._colorType === constants.COLORTYPE_GRAYSCALE) {
+    // grey, 2 bytes
+    this.transColor([data.readUInt16BE(0)]);
+  }
+  if (this._colorType === constants.COLORTYPE_COLOR) {
+    this.transColor([
+      data.readUInt16BE(0),
+      data.readUInt16BE(2),
+      data.readUInt16BE(4),
+    ]);
+  }
+
+  this._handleChunkEnd();
+};
+
+Parser.prototype._handleGAMA = function (length) {
+  this.read(length, this._parseGAMA.bind(this));
+};
+Parser.prototype._parseGAMA = function (data) {
+  this._crc.write(data);
+  this.gamma(data.readUInt32BE(0) / constants.GAMMA_DIVISION);
+
+  this._handleChunkEnd();
+};
+
+Parser.prototype._handleIDAT = function (length) {
+  if (!this._emittedHeadersFinished) {
+    this._emittedHeadersFinished = true;
+    this.headersFinished();
+  }
+  this.read(-length, this._parseIDAT.bind(this, length));
+};
+Parser.prototype._parseIDAT = function (length, data) {
+  this._crc.write(data);
+
+  if (
+    this._colorType === constants.COLORTYPE_PALETTE_COLOR &&
+    this._palette.length === 0
+  ) {
+    throw new Error("Expected palette not found");
+  }
+
+  this.inflateData(data);
+  let leftOverLength = length - data.length;
+
+  if (leftOverLength > 0) {
+    this._handleIDAT(leftOverLength);
+  } else {
+    this._handleChunkEnd();
+  }
+};
+
+Parser.prototype._handleIEND = function (length) {
+  this.read(length, this._parseIEND.bind(this));
+};
+Parser.prototype._parseIEND = function (data) {
+  this._crc.write(data);
+
+  this._hasIEND = true;
+  this._handleChunkEnd();
+
+  if (this.finished) {
+    this.finished();
+  }
+};

node_modules/pngjs/lib/png-sync.js

@@ -0,0 +1,12 @@
+"use strict";
+
+let parse = require("./parser-sync");
+let pack = require("./packer-sync");
+
+exports.read = function (buffer, options) {
+  return parse(buffer, options || {});
+};
+
+exports.write = function (png, options) {
+  return pack(png, options);
+};

node_modules/pngjs/lib/png.js

@@ -0,0 +1,194 @@
+"use strict";
+
+let util = require("util");
+let Stream = require("stream");
+let Parser = require("./parser-async");
+let Packer = require("./packer-async");
+let PNGSync = require("./png-sync");
+
+let PNG = (exports.PNG = function (options) {
+  Stream.call(this);
+
+  options = options || {}; // eslint-disable-line no-param-reassign
+
+  // coerce pixel dimensions to integers (also coerces undefined -> 0):
+  this.width = options.width | 0;
+  this.height = options.height | 0;
+
+  this.data =
+    this.width > 0 && this.height > 0
+      ? Buffer.alloc(4 * this.width * this.height)
+      : null;
+
+  if (options.fill && this.data) {
+    this.data.fill(0);
+  }
+
+  this.gamma = 0;
+  this.readable = this.writable = true;
+
+  this._parser = new Parser(options);
+
+  this._parser.on("error", this.emit.bind(this, "error"));
+  this._parser.on("close", this._handleClose.bind(this));
+  this._parser.on("metadata", this._metadata.bind(this));
+  this._parser.on("gamma", this._gamma.bind(this));
+  this._parser.on(
+    "parsed",
+    function (data) {
+      this.data = data;
+      this.emit("parsed", data);
+    }.bind(this)
+  );
+
+  this._packer = new Packer(options);
+  this._packer.on("data", this.emit.bind(this, "data"));
+  this._packer.on("end", this.emit.bind(this, "end"));
+  this._parser.on("close", this._handleClose.bind(this));
+  this._packer.on("error", this.emit.bind(this, "error"));
+});
+util.inherits(PNG, Stream);
+
+PNG.sync = PNGSync;
+
+PNG.prototype.pack = function () {
+  if (!this.data || !this.data.length) {
+    this.emit("error", "No data provided");
+    return this;
+  }
+
+  process.nextTick(
+    function () {
+      this._packer.pack(this.data, this.width, this.height, this.gamma);
+    }.bind(this)
+  );
+
+  return this;
+};
+
+PNG.prototype.parse = function (data, callback) {
+  if (callback) {
+    let onParsed, onError;
+
+    onParsed = function (parsedData) {
+      this.removeListener("error", onError);
+
+      this.data = parsedData;
+      callback(null, this);
+    }.bind(this);
+
+    onError = function (err) {
+      this.removeListener("parsed", onParsed);
+
+      callback(err, null);
+    }.bind(this);
+
+    this.once("parsed", onParsed);
+    this.once("error", onError);
+  }
+
+  this.end(data);
+  return this;
+};
+
+PNG.prototype.write = function (data) {
+  this._parser.write(data);
+  return true;
+};
+
+PNG.prototype.end = function (data) {
+  this._parser.end(data);
+};
+
+PNG.prototype._metadata = function (metadata) {
+  this.width = metadata.width;
+  this.height = metadata.height;
+
+  this.emit("metadata", metadata);
+};
+
+PNG.prototype._gamma = function (gamma) {
+  this.gamma = gamma;
+};
+
+PNG.prototype._handleClose = function () {
+  if (!this._parser.writable && !this._packer.readable) {
+    this.emit("close");
+  }
+};
+
+PNG.bitblt = function (src, dst, srcX, srcY, width, height, deltaX, deltaY) {
+  // eslint-disable-line max-params
+  // coerce pixel dimensions to integers (also coerces undefined -> 0):
+  /* eslint-disable no-param-reassign */
+  srcX |= 0;
+  srcY |= 0;
+  width |= 0;
+  height |= 0;
+  deltaX |= 0;
+  deltaY |= 0;
+  /* eslint-enable no-param-reassign */
+
+  if (
+    srcX > src.width ||
+    srcY > src.height ||
+    srcX + width > src.width ||
+    srcY + height > src.height
+  ) {
+    throw new Error("bitblt reading outside image");
+  }
+
+  if (
+    deltaX > dst.width ||
+    deltaY > dst.height ||
+    deltaX + width > dst.width ||
+    deltaY + height > dst.height
+  ) {
+    throw new Error("bitblt writing outside image");
+  }
+
+  for (let y = 0; y < height; y++) {
+    src.data.copy(
+      dst.data,
+      ((deltaY + y) * dst.width + deltaX) << 2,
+      ((srcY + y) * src.width + srcX) << 2,
+      ((srcY + y) * src.width + srcX + width) << 2
+    );
+  }
+};
+
+PNG.prototype.bitblt = function (
+  dst,
+  srcX,
+  srcY,
+  width,
+  height,
+  deltaX,
+  deltaY
+) {
+  // eslint-disable-line max-params
+
+  PNG.bitblt(this, dst, srcX, srcY, width, height, deltaX, deltaY);
+  return this;
+};
+
+PNG.adjustGamma = function (src) {
+  if (src.gamma) {
+    for (let y = 0; y < src.height; y++) {
+      for (let x = 0; x < src.width; x++) {
+        let idx = (src.width * y + x) << 2;
+
+        for (let i = 0; i < 3; i++) {
+          let sample = src.data[idx + i] / 255;
+          sample = Math.pow(sample, 1 / 2.2 / src.gamma);
+          src.data[idx + i] = Math.round(sample * 255);
+        }
+      }
+    }
+    src.gamma = 0;
+  }
+};
+
+PNG.prototype.adjustGamma = function () {
+  PNG.adjustGamma(this);
+};

node_modules/pngjs/lib/sync-inflate.js

@@ -0,0 +1,168 @@
+"use strict";
+
+let assert = require("assert").ok;
+let zlib = require("zlib");
+let util = require("util");
+
+let kMaxLength = require("buffer").kMaxLength;
+
+function Inflate(opts) {
+  if (!(this instanceof Inflate)) {
+    return new Inflate(opts);
+  }
+
+  if (opts && opts.chunkSize < zlib.Z_MIN_CHUNK) {
+    opts.chunkSize = zlib.Z_MIN_CHUNK;
+  }
+
+  zlib.Inflate.call(this, opts);
+
+  // Node 8 --> 9 compatibility check
+  this._offset = this._offset === undefined ? this._outOffset : this._offset;
+  this._buffer = this._buffer || this._outBuffer;
+
+  if (opts && opts.maxLength != null) {
+    this._maxLength = opts.maxLength;
+  }
+}
+
+function createInflate(opts) {
+  return new Inflate(opts);
+}
+
+function _close(engine, callback) {
+  if (callback) {
+    process.nextTick(callback);
+  }
+
+  // Caller may invoke .close after a zlib error (which will null _handle).
+  if (!engine._handle) {
+    return;
+  }
+
+  engine._handle.close();
+  engine._handle = null;
+}
+
+Inflate.prototype._processChunk = function (chunk, flushFlag, asyncCb) {
+  if (typeof asyncCb === "function") {
+    return zlib.Inflate._processChunk.call(this, chunk, flushFlag, asyncCb);
+  }
+
+  let self = this;
+
+  let availInBefore = chunk && chunk.length;
+  let availOutBefore = this._chunkSize - this._offset;
+  let leftToInflate = this._maxLength;
+  let inOff = 0;
+
+  let buffers = [];
+  let nread = 0;
+
+  let error;
+  this.on("error", function (err) {
+    error = err;
+  });
+
+  function handleChunk(availInAfter, availOutAfter) {
+    if (self._hadError) {
+      return;
+    }
+
+    let have = availOutBefore - availOutAfter;
+    assert(have >= 0, "have should not go down");
+
+    if (have > 0) {
+      let out = self._buffer.slice(self._offset, self._offset + have);
+      self._offset += have;
+
+      if (out.length > leftToInflate) {
+        out = out.slice(0, leftToInflate);
+      }
+
+      buffers.push(out);
+      nread += out.length;
+      leftToInflate -= out.length;
+
+      if (leftToInflate === 0) {
+        return false;
+      }
+    }
+
+    if (availOutAfter === 0 || self._offset >= self._chunkSize) {
+      availOutBefore = self._chunkSize;
+      self._offset = 0;
+      self._buffer = Buffer.allocUnsafe(self._chunkSize);
+    }
+
+    if (availOutAfter === 0) {
+      inOff += availInBefore - availInAfter;
+      availInBefore = availInAfter;
+
+      return true;
+    }
+
+    return false;
+  }
+
+  assert(this._handle, "zlib binding closed");
+  let res;
+  do {
+    res = this._handle.writeSync(
+      flushFlag,
+      chunk, // in
+      inOff, // in_off
+      availInBefore, // in_len
+      this._buffer, // out
+      this._offset, //out_off
+      availOutBefore
+    ); // out_len
+    // Node 8 --> 9 compatibility check
+    res = res || this._writeState;
+  } while (!this._hadError && handleChunk(res[0], res[1]));
+
+  if (this._hadError) {
+    throw error;
+  }
+
+  if (nread >= kMaxLength) {
+    _close(this);
+    throw new RangeError(
+      "Cannot create final Buffer. It would be larger than 0x" +
+        kMaxLength.toString(16) +
+        " bytes"
+    );
+  }
+
+  let buf = Buffer.concat(buffers, nread);
+  _close(this);
+
+  return buf;
+};
+
+util.inherits(Inflate, zlib.Inflate);
+
+function zlibBufferSync(engine, buffer) {
+  if (typeof buffer === "string") {
+    buffer = Buffer.from(buffer);
+  }
+  if (!(buffer instanceof Buffer)) {
+    throw new TypeError("Not a string or buffer");
+  }
+
+  let flushFlag = engine._finishFlushFlag;
+  if (flushFlag == null) {
+    flushFlag = zlib.Z_FINISH;
+  }
+
+  return engine._processChunk(buffer, flushFlag);
+}
+
+function inflateSync(buffer, opts) {
+  return zlibBufferSync(new Inflate(opts), buffer);
+}
+
+module.exports = exports = inflateSync;
+exports.Inflate = Inflate;
+exports.createInflate = createInflate;
+exports.inflateSync = inflateSync;

node_modules/pngjs/lib/sync-reader.js

@@ -0,0 +1,45 @@
+"use strict";
+
+let SyncReader = (module.exports = function (buffer) {
+  this._buffer = buffer;
+  this._reads = [];
+});
+
+SyncReader.prototype.read = function (length, callback) {
+  this._reads.push({
+    length: Math.abs(length), // if length < 0 then at most this length
+    allowLess: length < 0,
+    func: callback,
+  });
+};
+
+SyncReader.prototype.process = function () {
+  // as long as there is any data and read requests
+  while (this._reads.length > 0 && this._buffer.length) {
+    let read = this._reads[0];
+
+    if (
+      this._buffer.length &&
+      (this._buffer.length >= read.length || read.allowLess)
+    ) {
+      // ok there is any data so that we can satisfy this request
+      this._reads.shift(); // == read
+
+      let buf = this._buffer;
+
+      this._buffer = buf.slice(read.length);
+
+      read.func.call(this, buf.slice(0, read.length));
+    } else {
+      break;
+    }
+  }
+
+  if (this._reads.length > 0) {
+    return new Error("There are some read requests waitng on finished stream");
+  }
+
+  if (this._buffer.length > 0) {
+    return new Error("unrecognised content at end of stream");
+  }
+};