add image decode

package.json

@@ -23,5 +23,10 @@
   "homepage": "https://github.com/cnwhy/QRCode-decode#readme",
   "devDependencies": {
     "parcel": "^1.9.7"
+  },
+  "dependencies": {
+    "bmp-js": "^0.1.0",
+    "image-type": "^3.0.0",
+    "pako": "^1.0.6"
   }
 }

server.js

@@ -0,0 +1,85 @@
+var fs = require('fs')
+var imgDecode = require('./src/imageDecode')
+var imgType = require('image-type')
+var qrDecode = require('./')
+// var jpg = require('./src/imageDecode/jpg');
+
+
+function decode(buffer) {
+	var type;
+	return new Promise(function (res, rej) {
+		type = (imgType(buffer) || {}).ext;
+		switch (type) {
+			case 'bmp':
+				res(imgDecode.bmp(buffer));
+				break;
+			case 'jpg':
+				res(imgDecode.jpg(buffer));
+				break;
+			case 'png':
+				res(imgDecode.png(buffer));
+				break;
+			case 'gif':
+				// var t1 = Date.now();
+				res(imgDecode.gif1(buffer));
+				// console.log('gif: ',Date.now() - t1);
+				break;
+			default:
+				if (type) {
+					throw 'Support for this type! type as ' + type
+				}
+				throw 'not image!'
+		}
+	}).then(function (imageData) {
+		if (type == 'gif') {
+			return new Promise(function (res, rej) {
+				var errList = [];
+				var images = imageData;
+				var onerr = function (e) {
+					errList.push(e);
+					if (errList.length < images.length) return;
+					rej('解码失败!')
+				}
+				// console.log('length',imageData.length)
+				if (imageData.length <= 0) {
+					rej('解码失败!')
+				} else if (imageData.length > 3) {
+					images = [];
+					var l = 1;
+					var i = 0;
+					while ( Math.pow(2,++l) < imageData.length){
+					}
+					// console.log('l:',l)
+					var sp = (imageData.length-1)/l;
+					// console.log('sp:',sp)
+					do{
+						// console.log(Math.floor(i*sp));
+						images.push(imageData[Math.floor(i*sp)])
+					}while(i++<l)
+				}
+				// console.log(images.length)
+				images.forEach(function (v) {
+					setTimeout(function () {
+						try {
+							res(qrDecode(v));
+						} catch (e) {
+							console.log(e);
+							onerr(e)
+						}
+					}, 0)
+				})
+			})
+		}
+		return qrDecode(imageData);
+	})
+}
+exports.decodeQRFile = function (path) {
+	return new Promise(function (res, rej) {
+		fs.readFile(path, function (err, buffer) {
+			if (err) { return rej(err) }
+			res(decode(buffer));
+		})
+	})
+}
+
+exports.decode = decode;

src/QRCodeDecode.js

@@ -116,7 +116,7 @@ function decode(imageDate,debugfn){
 }
 
 var process = function (data,base) {
-    var start = new Date().getTime();
+    // var start = new Date().getTime();
     // var image = grayScaleToBitmap(grayscale(),base);
     // var image = binarize(128);
 	var image = binarize(data,base,153); //转为位图;
@@ -146,10 +146,9 @@ var process = function (data,base) {
             str += String.fromCharCode(data[i][j]);
     }
 
-    var end = new Date().getTime();
+    // var end = new Date().getTime();
-    var time = end - start;
+    // var time = end - start;
-
+    // console.log("Time:" + time + " Code: "+str);
-    console.log("Time:" + time + " Code: "+str);
     return str;
 }
 

src/imageDecode/bmp.js

@@ -0,0 +1,17 @@
+var BmpDecode = require('bmp-js/lib/decoder');
+
+module.exports = function(buff){
+	var bmp = BmpDecode(buff);
+	var abgr = bmp.data;
+	var data = [];
+	var max = abgr.length/4;
+	for(var i = 0; i<max; i++){
+		var s = i*4;
+		data.push(abgr[s+3],abgr[s+2],abgr[s+1],255)
+	}
+	return {
+		width: bmp.width,
+		height: bmp.height,
+		data : data
+	}
+}

src/imageDecode/gif.1.js

@@ -0,0 +1,525 @@
+//https://github.com/shachaf/jsgif
+
+// Generic functions
+var bitsToNum = function (ba) {
+	return ba.reduce(function (s, n) { return s * 2 + n; }, 0);
+};
+
+var byteToBitArr = function (bite) {
+	var a = [];
+	for (var i = 7; i >= 0; i--) {
+		a.push(!!(bite & (1 << i)));
+	}
+	return a;
+};
+
+// Stream
+/**
+ * @constructor
+ */ // Make compiler happy.
+var Stream = function (data) {
+	
+	this.data = data;
+	var len = this.data.length;
+	var pos = 0;
+
+	this.readByte = function () {
+		if (pos >= len) {
+			throw new Error('Attempted to read past end of stream.');
+		}
+		// return data.charCodeAt(pos++) & 0xFF;
+		// var bit = data[pos++];
+		// return String.fromCharCode(bit).charCodeAt(0) & 0xff;
+		return data[pos++];
+	};
+
+	this.readBytes = function (n) {
+		var bytes = [];
+		for (var i = 0; i < n; i++) {
+			bytes.push(this.readByte());
+		}
+		return bytes;
+		// var start = pos
+		// pos += n;
+		// if(start>= len || pos > len){
+		// 	throw new Error('Attempted to read past end of stream.');
+		// }
+		// return [].slice.call(data,start,pos)
+	};
+
+	this.read = function (n) {
+		var s = '';
+		for (var i = 0; i < n; i++) {
+			s += String.fromCharCode(this.readByte());
+		}
+		return s;
+	};
+
+	this.readUnsigned = function () { // Little-endian.
+		var a = this.readBytes(2);
+		return (a[1] << 8) + a[0];
+	};
+};
+
+var lzwDecode = function (minCodeSize, data, gct,GCE) {
+	// TODO: Now that the GIF parser is a bit different, maybe this should get an array of bytes instead of a String?
+	var pos = 0; // Maybe this streaming thing should be merged with the Stream?
+
+	var readCode = function (size) {
+		var code = 0;
+		for (var i = 0; i < size; i++) {
+			if (data[pos >> 3] & (1 << (pos & 7))) {
+				code |= 1 << i;
+			}
+			pos++;
+		}
+		return code;
+	};
+
+	var output = [];
+	var imageData = [];
+
+	var clearCode = 1 << minCodeSize;
+	var eoiCode = clearCode + 1;
+
+	var codeSize = minCodeSize + 1;
+
+	var dict = [];
+
+	var clear = function () {
+		dict = [];
+		codeSize = minCodeSize + 1;
+		for (var i = 0; i < clearCode; i++) {
+			dict[i] = [i];
+		}
+		dict[clearCode] = [];
+		dict[eoiCode] = null;
+
+	};
+
+	var code;
+	var last;
+
+	while (true) {
+		last = code;
+		code = readCode(codeSize);
+
+		if (code === clearCode) {
+			clear();
+			continue;
+		}
+		if (code === eoiCode) break;
+
+		if (code < dict.length) {
+			if (last !== clearCode) {
+				dict.push(dict[last].concat(dict[code][0]));
+			}
+		} else {
+			if (code !== dict.length) throw new Error('Invalid LZW code.');
+			// try{
+				dict.push(dict[last].concat(dict[last][0]));
+
+			// }catch(e){
+			// 	console.log(minCodeSize,data);
+			// 	console.log(dict,last);
+			// 	throw e
+			// }
+		}
+		var inItem = dict[code];
+		// output.push.apply(output, inItem);
+
+		inItem.forEach(function(v){
+			// output.push(v);
+			var rgb = gct[v]
+			imageData.push(rgb[0],rgb[1],rgb[2],GCE.transparencyIndex == v ? 0 : 255)
+		})
+
+		// imageData.push.apply(imageData, inItem.map(function(v){
+		// 	var c = gct[v];
+		// 	var rgba = [c[0],c[1],c[2],GCE.transparencyIndex == v ? 0 : 255]
+		// 	//rgba.push(GCE.transparencyIndex == v ? 0 : 255)
+		// 	// return color;
+		// 	return rgba;
+		// 	// return color.slice(0).push(GCE.transparencyIndex == v ? 0 : 255)
+		// }))
+
+		if (dict.length === (1 << codeSize) && codeSize < 12) {
+			// If we're at the last code and codeSize is 12, the next code will be a clearCode, and it'll be 12 bits long.
+			codeSize++;
+		}
+	}
+
+	// I don't know if this is technically an error, but some GIFs do it.
+	//if (Math.ceil(pos / 8) !== data.length) throw new Error('Extraneous LZW bytes.');
+	return [output,imageData];	
+};
+
+// The actual parsing; returns an object with properties.
+var parseGIF = function (st, handler) {
+	handler || (handler = {});
+	var GCE,gct;
+	// LZW (GIF-specific)
+	var parseCT = function (entries) { // Each entry is 3 bytes, for RGB.
+		var ct = [];
+		for (var i = 0; i < entries; i++) {
+			ct.push(st.readBytes(3));
+		}
+		return ct;
+	};
+
+	var readSubBlocks = function () {
+		var size, data;
+		data = '';
+		do {
+			size = st.readByte();
+			data += st.read(size);
+		} while (size !== 0);
+		return data;
+	};
+
+	var readByteBlocks = function(){
+		var size, data;
+		data = [];
+		do {
+			size = st.readByte();
+			data.push.apply(data,st.readBytes(size))
+			// data = data.concat(st.readBytes(size));
+		} while (size !== 0);
+		return data;
+	}
+
+	var parseHeader = function () {
+		var hdr = {};
+		hdr.sig = st.read(3);
+		hdr.ver = st.read(3);
+		if (hdr.sig !== 'GIF') throw new Error('Not a GIF file.'); // XXX: This should probably be handled more nicely.
+
+		hdr.width = st.readUnsigned();
+		hdr.height = st.readUnsigned();
+
+		var bits = byteToBitArr(st.readByte());
+		hdr.gctFlag = bits.shift();
+		hdr.colorRes = bitsToNum(bits.splice(0, 3));
+		hdr.sorted = bits.shift();
+		hdr.gctSize = bitsToNum(bits.splice(0, 3));
+
+		hdr.bgColor = st.readByte();
+		hdr.pixelAspectRatio = st.readByte(); // if not 0, aspectRatio = (pixelAspectRatio + 15) / 64
+
+		if (hdr.gctFlag) {
+			gct = hdr.gct = parseCT(1 << (hdr.gctSize + 1));
+		}
+		handler.hdr && handler.hdr(hdr);
+	};
+
+	var parseExt = function (block) {
+		var parseGCExt = function (block) {
+			var blockSize = st.readByte(); // Always 4
+
+			var bits = byteToBitArr(st.readByte());
+			block.reserved = bits.splice(0, 3); // Reserved; should be 000.
+			block.disposalMethod = bitsToNum(bits.splice(0, 3));
+			block.userInput = bits.shift();
+			block.transparencyGiven = bits.shift();
+
+			block.delayTime = st.readUnsigned();
+
+			block.transparencyIndex = st.readByte();
+
+			block.terminator = st.readByte();
+			GCE = block;
+			handler.gce && handler.gce(block);
+		};
+
+		var parseComExt = function (block) {
+			block.comment = readSubBlocks();
+			handler.com && handler.com(block);
+		};
+
+		var parsePTExt = function (block) {
+			// No one *ever* uses this. If you use it, deal with parsing it yourself.
+			var blockSize = st.readByte(); // Always 12
+			block.ptHeader = st.readBytes(12);
+			block.ptData = readSubBlocks();
+			handler.pte && handler.pte(block);
+		};
+
+		var parseAppExt = function (block) {
+			var parseNetscapeExt = function (block) {
+				var blockSize = st.readByte(); // Always 3
+				block.unknown = st.readByte(); // ??? Always 1? What is this?
+				block.iterations = st.readUnsigned();
+				block.terminator = st.readByte();
+				handler.app && handler.app.NETSCAPE && handler.app.NETSCAPE(block);
+			};
+
+			var parseUnknownAppExt = function (block) {
+				block.appData = readSubBlocks();
+				// FIXME: This won't work if a handler wants to match on any identifier.
+				handler.app && handler.app[block.identifier] && handler.app[block.identifier](block);
+			};
+
+			var blockSize = st.readByte(); // Always 11
+			block.identifier = st.read(8);
+			block.authCode = st.read(3);
+			switch (block.identifier) {
+				case 'NETSCAPE':
+					parseNetscapeExt(block);
+					break;
+				default:
+					parseUnknownAppExt(block);
+					break;
+			}
+		};
+
+		var parseUnknownExt = function (block) {
+			block.data = readSubBlocks();
+			handler.unknown && handler.unknown(block);
+		};
+
+		block.label = st.readByte();
+		switch (block.label) {
+			case 0xF9:
+				block.extType = 'gce';
+				parseGCExt(block);
+				break;
+			case 0xFE:
+				block.extType = 'com';
+				parseComExt(block);
+				break;
+			case 0x01:
+				block.extType = 'pte';
+				parsePTExt(block);
+				break;
+			case 0xFF:
+				block.extType = 'app';
+				parseAppExt(block);
+				break;
+			default:
+				block.extType = 'unknown';
+				parseUnknownExt(block);
+				break;
+		}
+	};
+
+	var parseImg = function (img) {
+		var deinterlace = function (pixels, width) {
+			// Of course this defeats the purpose of interlacing. And it's *probably*
+			// the least efficient way it's ever been implemented. But nevertheless...
+
+			var newPixels = new Array(pixels.length);
+			var rows = pixels.length / width;
+			var cpRow = function (toRow, fromRow) {
+				var fromPixels = pixels.slice(fromRow * width, (fromRow + 1) * width);
+				newPixels.splice.apply(newPixels, [toRow * width, width].concat(fromPixels));
+			};
+
+			// See appendix E.
+			var offsets = [0, 4, 2, 1];
+			var steps = [8, 8, 4, 2];
+
+			var fromRow = 0;
+			for (var pass = 0; pass < 4; pass++) {
+				for (var toRow = offsets[pass]; toRow < rows; toRow += steps[pass]) {
+					cpRow(toRow, fromRow)
+					fromRow++;
+				}
+			}
+
+			return newPixels;
+		};
+
+		img.leftPos = st.readUnsigned();
+		img.topPos = st.readUnsigned();
+		img.width = st.readUnsigned();
+		img.height = st.readUnsigned();
+
+		var bits = byteToBitArr(st.readByte());
+		img.lctFlag = bits.shift();
+		img.interlaced = bits.shift();
+		img.sorted = bits.shift();
+		img.reserved = bits.splice(0, 2);
+		img.lctSize = bitsToNum(bits.splice(0, 3));
+
+		if (img.lctFlag) {
+			img.lct = parseCT(1 << (img.lctSize + 1));
+		}
+
+		img.lzwMinCodeSize = st.readByte();
+
+		// var lzwData = readSubBlocks();
+		var lzwData = readByteBlocks();
+		var lzwd = lzwDecode(img.lzwMinCodeSize, lzwData, gct,GCE);
+		img.pixels = lzwd[0];
+		img.data = lzwd[1];
+		// console.log(img.imageData)
+		if (img.interlaced) { // Move
+			console.log(img.pixels)
+			img.pixels = deinterlace(img.pixels, img.width);
+			console.log(img.pixels)
+
+		}
+
+		handler.img && handler.img(img);
+	};
+
+	var parseBlock = function () {
+		var block = {};
+		block.sentinel = st.readByte();
+
+		switch (String.fromCharCode(block.sentinel)) { // For ease of matching
+			case '!':
+				block.type = 'ext';
+				parseExt(block);
+				break;
+			case ',':
+				block.type = 'img';
+				parseImg(block);
+				break;
+			case ';':
+				block.type = 'eof';
+				handler.eof && handler.eof(block);
+				break;
+			default:
+				throw new Error('Unknown block: 0x' + block.sentinel.toString(16)); // TODO: Pad this with a 0.
+		}
+
+		// if (block.type !== 'eof') setTimeout(parseBlock,0);
+		if (block.type !== 'eof') parseBlock();
+	};
+
+	var parse = function () {
+		parseHeader();
+		parseBlock();
+		// setTimeout(parseBlock, 0);
+	};
+
+	parse();
+};
+
+// BEGIN_NON_BOOKMARKLET_CODE
+exports.Stream = Stream;
+exports.parseGIF = parseGIF;
+exports.decode = function (buffer) {
+	var gifData = { images: [] };
+	var gct;
+	var GCE;
+	var log = console.log;
+
+	// var showBool = function (b) {
+	// 	return b ? 'yes' : 'no';
+	// };
+
+	// var showColor = function (rgb) {
+	// 	// FIXME When I have an Internet connection.
+	// 	var showHex = function (n) { // Two-digit code.
+	// 		var hexChars = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'];
+	// 		return hexChars[(n >>> 4) & 0xF] + hexChars[n & 0xF];
+	// 	};
+	// 	return '#' + showHex(rgb[0]) + showHex(rgb[1]) + showHex(rgb[2]);
+	// };
+
+	// var showDisposalMethod = function (dm) {
+	// 	var map = {
+	// 		0: 'None',
+	// 		1: 'Do not dispose',
+	// 		2: 'Restore to background',
+	// 		3: 'Restore to previous'
+	// 	};
+	// 	return map[dm] || 'Unknown';
+	// }
+
+	//尺寸 背景色 调色板 等
+	var doHdr = function (hdr) {
+		// log('Header:');
+		// log('  Version: %s', hdr.ver);
+		// log('  Size: %dx%d', hdr.width, hdr.height);
+		// log('  GCT? %s%s', showBool(hdr.gctFlag), hdr.gctFlag ? ' (' + hdr.gct.length + ' entries)' : '');
+		// log('  Color resolution: %d', hdr.colorRes);
+		// log('  Sorted? %s', showBool(hdr.sorted));
+		// log('  Background color: %s (%d)', hdr.gctFlag ? showColor(hdr.bgColor) : 'no GCT', hdr.bgColor);
+		// log('  Pixel aspect ratio: %d FIXME', hdr.pixelAspectRatio);
+		gct = hdr.gct;
+		gifData.width = hdr.width;
+		gifData.height = hdr.height;
+	};
+	//当前帧的非颜色信息 (透明色,延时 等))
+	var doGCE = function (gce) {
+		// log('GCE:');
+		// log('  Disposal method: %d (%s)', gce.disposalMethod, showDisposalMethod(gce.disposalMethod));
+		// log('  User input expected? %s', showBool(gce.userInput));
+		// log('  Transparency given? %s%s', showBool(gce.transparencyGiven),
+		// 	gce.transparencyGiven ? ' (index: ' + gce.transparencyIndex + ')' : '');
+		// log('  Delay time: %d', gce.delayTime);
+		GCE = gce;
+	};
+	//当前帧的图片图像信息
+	// var doimgTime = 0;
+	var doImg = function (img) {
+		// log('Image descriptor:');
+		// log(Object.assign({},img,{'pixels':Math.max.apply(Math,img.pixels)}));
+		// log('  Geometry: %dx%d+%d+%d', img.width, img.height, img.leftPos, img.topPos);
+		// log('  LCT? %s%s', showBool(img.lctFlag), img.lctFlag ? ' (' + img.lct.length + ' entries)' : '');
+		// log('  Interlaced? %s', showBool(img.interlaced));
+		// log('  %d pixels', img.pixels.length);
+		// var t1 = Date.now();
+		// var data = [];
+		// console.log(data.length , img.width * img.height)
+		var imageData = {
+			left: img.leftPos,
+			top: img.topPos,
+			width: img.width,
+			height: img.height,
+			// data: data,
+			data: img.data,
+		}
+		// img.pixels.forEach(function (v) {
+		// 	var color = gct[v];
+		// 	data.push.apply(data, color.concat(GCE.transparencyIndex == v ? 0 : 255));
+		// })
+		// console.log(data.length)
+		// console.log(img.imageData.length)
+		gifData.images.push(imageData);
+		// doimgTime += Date.now() - t1;
+	};
+
+	var doNetscape = function (block) {
+		// log('Netscape application extension:');
+		// log('  Iterations: %d%s', block.iterations, block.iterations === 0 ? ' (infinite)' : '');
+	};
+
+	var doCom = function (com) {
+		// log('Comment extension:');
+		// log('  Comment: %s', com.comment);
+	};
+
+	var doEOF = function (eof) {
+		// log('EOF:');
+		// log(eof);
+	};
+
+	var doUnknownApp = function (block) {
+		// log(block)
+	};
+
+	var doUnknownExt = function (block) {
+		// log(block)
+	}
+
+	var handler = {
+		hdr: doHdr,
+		img: doImg,
+		gce: doGCE,
+		com: doCom,
+		app: {
+			NETSCAPE: doNetscape,
+			unknown: doUnknownApp
+		},
+		eof: doEOF
+	};
+
+	var st = new Stream(buffer);
+	parseGIF(st, handler);
+	// console.log('doimgTime:',doimgTime)
+	return gifData;
+}

src/imageDecode/gif.js

@@ -0,0 +1,467 @@
+//https://github.com/shachaf/jsgif
+
+// Generic functions
+var bitsToNum = function (ba) {
+	return ba.reduce(function (s, n) { return s * 2 + n; }, 0);
+};
+
+var byteToBitArr = function (bite) {
+	var a = [];
+	for (var i = 7; i >= 0; i--) {
+		a.push(!!(bite & (1 << i)));
+	}
+	return a;
+};
+
+// Stream
+/**
+ * @constructor
+ */ // Make compiler happy.
+var Stream = function (data) {
+	this.data = data;
+	this.len = this.data.length;
+	this.pos = 0;
+
+	this.readByte = function () {
+		if (this.pos >= this.data.length) {
+			throw new Error('Attempted to read past end of stream.');
+		}
+		return data.charCodeAt(this.pos++) & 0xFF;
+	};
+
+	this.readBytes = function (n) {
+		var bytes = [];
+		for (var i = 0; i < n; i++) {
+			bytes.push(this.readByte());
+		}
+		return bytes;
+	};
+
+	this.read = function (n) {
+		var s = '';
+		for (var i = 0; i < n; i++) {
+			s += String.fromCharCode(this.readByte());
+		}
+		return s;
+	};
+
+	this.readUnsigned = function () { // Little-endian.
+		var a = this.readBytes(2);
+		return (a[1] << 8) + a[0];
+	};
+};
+
+var lzwDecode = function (minCodeSize, data) {
+	// TODO: Now that the GIF parser is a bit different, maybe this should get an array of bytes instead of a String?
+	var pos = 0; // Maybe this streaming thing should be merged with the Stream?
+
+	var readCode = function (size) {
+		var code = 0;
+		for (var i = 0; i < size; i++) {
+			if (data.charCodeAt(pos >> 3) & (1 << (pos & 7))) {
+				code |= 1 << i;
+			}
+			pos++;
+		}
+		return code;
+	};
+
+	var output = [];
+
+	var clearCode = 1 << minCodeSize;
+	var eoiCode = clearCode + 1;
+
+	var codeSize = minCodeSize + 1;
+
+	var dict = [];
+
+	var clear = function () {
+		dict = [];
+		codeSize = minCodeSize + 1;
+		for (var i = 0; i < clearCode; i++) {
+			dict[i] = [i];
+		}
+		dict[clearCode] = [];
+		dict[eoiCode] = null;
+
+	};
+
+	var code;
+	var last;
+
+	while (true) {
+		last = code;
+		code = readCode(codeSize);
+
+		if (code === clearCode) {
+			clear();
+			continue;
+		}
+		if (code === eoiCode) break;
+
+		if (code < dict.length) {
+			if (last !== clearCode) {
+				dict.push(dict[last].concat(dict[code][0]));
+			}
+		} else {
+			if (code !== dict.length) throw new Error('Invalid LZW code.');
+			dict.push(dict[last].concat(dict[last][0]));
+		}
+		output.push.apply(output, dict[code]);
+
+		if (dict.length === (1 << codeSize) && codeSize < 12) {
+			// If we're at the last code and codeSize is 12, the next code will be a clearCode, and it'll be 12 bits long.
+			codeSize++;
+		}
+	}
+
+	// I don't know if this is technically an error, but some GIFs do it.
+	//if (Math.ceil(pos / 8) !== data.length) throw new Error('Extraneous LZW bytes.');
+	return output;
+};
+
+// The actual parsing; returns an object with properties.
+var parseGIF = function (st, handler) {
+	handler || (handler = {});
+
+	// LZW (GIF-specific)
+	var parseCT = function (entries) { // Each entry is 3 bytes, for RGB.
+		var ct = [];
+		for (var i = 0; i < entries; i++) {
+			ct.push(st.readBytes(3));
+		}
+		return ct;
+	};
+
+	var readSubBlocks = function () {
+		var size, data;
+		data = '';
+		do {
+			size = st.readByte();
+			data += st.read(size);
+		} while (size !== 0);
+		return data;
+	};
+
+	var parseHeader = function () {
+		var hdr = {};
+		hdr.sig = st.read(3);
+		hdr.ver = st.read(3);
+		if (hdr.sig !== 'GIF') throw new Error('Not a GIF file.'); // XXX: This should probably be handled more nicely.
+
+		hdr.width = st.readUnsigned();
+		hdr.height = st.readUnsigned();
+
+		var bits = byteToBitArr(st.readByte());
+		hdr.gctFlag = bits.shift();
+		hdr.colorRes = bitsToNum(bits.splice(0, 3));
+		hdr.sorted = bits.shift();
+		hdr.gctSize = bitsToNum(bits.splice(0, 3));
+
+		hdr.bgColor = st.readByte();
+		hdr.pixelAspectRatio = st.readByte(); // if not 0, aspectRatio = (pixelAspectRatio + 15) / 64
+
+		if (hdr.gctFlag) {
+			hdr.gct = parseCT(1 << (hdr.gctSize + 1));
+		}
+		handler.hdr && handler.hdr(hdr);
+	};
+
+	var parseExt = function (block) {
+		var parseGCExt = function (block) {
+			var blockSize = st.readByte(); // Always 4
+
+			var bits = byteToBitArr(st.readByte());
+			block.reserved = bits.splice(0, 3); // Reserved; should be 000.
+			block.disposalMethod = bitsToNum(bits.splice(0, 3));
+			block.userInput = bits.shift();
+			block.transparencyGiven = bits.shift();
+
+			block.delayTime = st.readUnsigned();
+
+			block.transparencyIndex = st.readByte();
+
+			block.terminator = st.readByte();
+
+			handler.gce && handler.gce(block);
+		};
+
+		var parseComExt = function (block) {
+			block.comment = readSubBlocks();
+			handler.com && handler.com(block);
+		};
+
+		var parsePTExt = function (block) {
+			// No one *ever* uses this. If you use it, deal with parsing it yourself.
+			var blockSize = st.readByte(); // Always 12
+			block.ptHeader = st.readBytes(12);
+			block.ptData = readSubBlocks();
+			handler.pte && handler.pte(block);
+		};
+
+		var parseAppExt = function (block) {
+			var parseNetscapeExt = function (block) {
+				var blockSize = st.readByte(); // Always 3
+				block.unknown = st.readByte(); // ??? Always 1? What is this?
+				block.iterations = st.readUnsigned();
+				block.terminator = st.readByte();
+				handler.app && handler.app.NETSCAPE && handler.app.NETSCAPE(block);
+			};
+
+			var parseUnknownAppExt = function (block) {
+				block.appData = readSubBlocks();
+				// FIXME: This won't work if a handler wants to match on any identifier.
+				handler.app && handler.app[block.identifier] && handler.app[block.identifier](block);
+			};
+
+			var blockSize = st.readByte(); // Always 11
+			block.identifier = st.read(8);
+			block.authCode = st.read(3);
+			switch (block.identifier) {
+				case 'NETSCAPE':
+					parseNetscapeExt(block);
+					break;
+				default:
+					parseUnknownAppExt(block);
+					break;
+			}
+		};
+
+		var parseUnknownExt = function (block) {
+			block.data = readSubBlocks();
+			handler.unknown && handler.unknown(block);
+		};
+
+		block.label = st.readByte();
+		switch (block.label) {
+			case 0xF9:
+				block.extType = 'gce';
+				parseGCExt(block);
+				break;
+			case 0xFE:
+				block.extType = 'com';
+				parseComExt(block);
+				break;
+			case 0x01:
+				block.extType = 'pte';
+				parsePTExt(block);
+				break;
+			case 0xFF:
+				block.extType = 'app';
+				parseAppExt(block);
+				break;
+			default:
+				block.extType = 'unknown';
+				parseUnknownExt(block);
+				break;
+		}
+	};
+
+	var parseImg = function (img) {
+		var deinterlace = function (pixels, width) {
+			// Of course this defeats the purpose of interlacing. And it's *probably*
+			// the least efficient way it's ever been implemented. But nevertheless...
+
+			var newPixels = new Array(pixels.length);
+			var rows = pixels.length / width;
+			var cpRow = function (toRow, fromRow) {
+				var fromPixels = pixels.slice(fromRow * width, (fromRow + 1) * width);
+				newPixels.splice.apply(newPixels, [toRow * width, width].concat(fromPixels));
+			};
+
+			// See appendix E.
+			var offsets = [0, 4, 2, 1];
+			var steps = [8, 8, 4, 2];
+
+			var fromRow = 0;
+			for (var pass = 0; pass < 4; pass++) {
+				for (var toRow = offsets[pass]; toRow < rows; toRow += steps[pass]) {
+					cpRow(toRow, fromRow)
+					fromRow++;
+				}
+			}
+
+			return newPixels;
+		};
+
+		img.leftPos = st.readUnsigned();
+		img.topPos = st.readUnsigned();
+		img.width = st.readUnsigned();
+		img.height = st.readUnsigned();
+
+		var bits = byteToBitArr(st.readByte());
+		img.lctFlag = bits.shift();
+		img.interlaced = bits.shift();
+		img.sorted = bits.shift();
+		img.reserved = bits.splice(0, 2);
+		img.lctSize = bitsToNum(bits.splice(0, 3));
+
+		if (img.lctFlag) {
+			img.lct = parseCT(1 << (img.lctSize + 1));
+		}
+
+		img.lzwMinCodeSize = st.readByte();
+
+		var lzwData = readSubBlocks();
+
+		img.pixels = lzwDecode(img.lzwMinCodeSize, lzwData);
+
+		if (img.interlaced) { // Move
+			img.pixels = deinterlace(img.pixels, img.width);
+		}
+
+		handler.img && handler.img(img);
+	};
+
+	var parseBlock = function () {
+		var block = {};
+		block.sentinel = st.readByte();
+
+		switch (String.fromCharCode(block.sentinel)) { // For ease of matching
+			case '!':
+				block.type = 'ext';
+				parseExt(block);
+				break;
+			case ',':
+				block.type = 'img';
+				parseImg(block);
+				break;
+			case ';':
+				block.type = 'eof';
+				handler.eof && handler.eof(block);
+				break;
+			default:
+				throw new Error('Unknown block: 0x' + block.sentinel.toString(16)); // TODO: Pad this with a 0.
+		}
+
+		// if (block.type !== 'eof') setTimeout(parseBlock,0);
+		if (block.type !== 'eof') parseBlock();
+	};
+
+	var parse = function () {
+		parseHeader();
+		parseBlock();
+		// setTimeout(parseBlock, 0);
+	};
+
+	parse();
+};
+
+// BEGIN_NON_BOOKMARKLET_CODE
+exports.Stream = Stream;
+exports.parseGIF = parseGIF;
+exports.decode = function (buffer) {
+	var gifData = { images: [] };
+	var gct;
+	var GCE;
+	var log = console.log;
+
+	// var showBool = function (b) {
+	// 	return b ? 'yes' : 'no';
+	// };
+
+	// var showColor = function (rgb) {
+	// 	// FIXME When I have an Internet connection.
+	// 	var showHex = function (n) { // Two-digit code.
+	// 		var hexChars = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'];
+	// 		return hexChars[(n >>> 4) & 0xF] + hexChars[n & 0xF];
+	// 	};
+	// 	return '#' + showHex(rgb[0]) + showHex(rgb[1]) + showHex(rgb[2]);
+	// };
+
+	// var showDisposalMethod = function (dm) {
+	// 	var map = {
+	// 		0: 'None',
+	// 		1: 'Do not dispose',
+	// 		2: 'Restore to background',
+	// 		3: 'Restore to previous'
+	// 	};
+	// 	return map[dm] || 'Unknown';
+	// }
+
+	//尺寸 背景色 调色板 等
+	var doHdr = function (hdr) {
+		// log('Header:');
+		// log('  Version: %s', hdr.ver);
+		// log('  Size: %dx%d', hdr.width, hdr.height);
+		// log('  GCT? %s%s', showBool(hdr.gctFlag), hdr.gctFlag ? ' (' + hdr.gct.length + ' entries)' : '');
+		// log('  Color resolution: %d', hdr.colorRes);
+		// log('  Sorted? %s', showBool(hdr.sorted));
+		// log('  Background color: %s (%d)', hdr.gctFlag ? showColor(hdr.bgColor) : 'no GCT', hdr.bgColor);
+		// log('  Pixel aspect ratio: %d FIXME', hdr.pixelAspectRatio);
+		gct = hdr.gct;
+		gifData.width = hdr.width;
+		gifData.height = hdr.height;
+	};
+	//当前帧的非颜色信息 (透明色,延时 等))
+	var doGCE = function (gce) {
+		// log('GCE:');
+		// log('  Disposal method: %d (%s)', gce.disposalMethod, showDisposalMethod(gce.disposalMethod));
+		// log('  User input expected? %s', showBool(gce.userInput));
+		// log('  Transparency given? %s%s', showBool(gce.transparencyGiven),
+		// 	gce.transparencyGiven ? ' (index: ' + gce.transparencyIndex + ')' : '');
+		// log('  Delay time: %d', gce.delayTime);
+		GCE = gce;
+	};
+	//当前帧的图片图像信息
+	var doImg = function (img) {
+		// log('Image descriptor:');
+		// log(Object.assign({},img,{'pixels':Math.max.apply(Math,img.pixels)}));
+		// log('  Geometry: %dx%d+%d+%d', img.width, img.height, img.leftPos, img.topPos);
+		// log('  LCT? %s%s', showBool(img.lctFlag), img.lctFlag ? ' (' + img.lct.length + ' entries)' : '');
+		// log('  Interlaced? %s', showBool(img.interlaced));
+		// log('  %d pixels', img.pixels.length);
+		var data = [];
+		var imageData = {
+			left: img.leftPos,
+			top: img.topPos,
+			width: img.width,
+			height: img.height,
+			data: data
+		}
+		img.pixels.forEach(function (v) {
+			var color = gct[v];
+			data.push.apply(data, color.concat(GCE.transparencyIndex == v ? 0 : 255));
+		})
+		gifData.images.push(imageData);
+	};
+
+	var doNetscape = function (block) {
+		// log('Netscape application extension:');
+		// log('  Iterations: %d%s', block.iterations, block.iterations === 0 ? ' (infinite)' : '');
+	};
+
+	var doCom = function (com) {
+		// log('Comment extension:');
+		// log('  Comment: %s', com.comment);
+	};
+
+	var doEOF = function (eof) {
+		// log('EOF:');
+		// log(eof);
+	};
+
+	var doUnknownApp = function (block) {
+		// log(block)
+	};
+
+	var doUnknownExt = function (block) {
+		// log(block)
+	}
+
+	var handler = {
+		hdr: doHdr,
+		img: doImg,
+		gce: doGCE,
+		com: doCom,
+		app: {
+			NETSCAPE: doNetscape,
+			unknown: doUnknownApp
+		},
+		eof: doEOF
+	};
+
+	var st = new Stream(buffer.toString('binary'));
+	parseGIF(st, handler);
+	return gifData;
+}

src/imageDecode/index.js

@@ -0,0 +1,59 @@
+var jpg = require('./jpg');
+var jpgDecode = new jpg.JpegDecoder();
+var pngDecode = require('./png').decode;
+var bmpDecode = require('./bmp');
+var gifDecode = require('./gif').decode;
+var gif1Decode = require('./gif.1').decode;
+
+exports.bmp = function (buffer) {
+	// return new Promise(function (res, rej) {
+	// 	res(bmpDecode(buffer));
+	// })
+	return bmpDecode(buffer);
+};
+
+exports.jpg = function (buffer) {
+	// return new Promise(function (res, rej) {
+	// 	jpgDecode.parse(buffer);
+	// 	res(jpgDecode.getImageData());
+	// })
+	jpgDecode.parse(buffer);
+	return jpgDecode.getImageData();
+}
+
+exports.png = function (buffer) {
+	// return new Promise(function (res, rej) {
+	// 	var png = pngDecode(buffer);
+	// 	res({
+	// 		data: png.data,
+	// 		width: png.width,
+	// 		height: png.height
+	// 	});
+	// })
+	var png = pngDecode(buffer);
+	return {
+		data: png.data,
+		width: png.width,
+		height: png.height
+	};
+}
+
+exports.gif = function (data) {
+	// return new Promise(function (res, rej) {
+	// 	var gif = gifDecode(data);
+	// 	res(gif.images);
+	// })
+	var gif = gifDecode(data);
+	return gif.images;
+
+}
+
+exports.gif1 = function (data) {
+	// return new Promise(function (res, rej) {
+	// 	var gif = gifDecode(data);
+	// 	res(gif.images);
+	// })
+	var gif = gif1Decode(data);
+	return gif.images;
+
+}

src/imageDecode/png.js

@@ -0,0 +1,875 @@
+// https://github.com/arian/pngjs
+
+var UPNG = {};
+
+// Make available for import by `require()`
+var pako = require("pako");
+function log() { if (typeof process == "undefined" || process.env.NODE_ENV == "development") console.log.apply(console, arguments); }
+UPNG.toRGBA8 = function (out) {
+	var w = out.width, h = out.height;
+	if (out.tabs.acTL == null) return [UPNG.toRGBA8.decodeImage(out.data, w, h, out).buffer];
+
+	var frms = [];
+	if (out.frames[0].data == null) out.frames[0].data = out.data;
+
+	var img, empty = new Uint8Array(w * h * 4);
+	for (var i = 0; i < out.frames.length; i++) {
+		var frm = out.frames[i];
+		var fx = frm.rect.x, fy = frm.rect.y, fw = frm.rect.width, fh = frm.rect.height;
+		var fdata = UPNG.toRGBA8.decodeImage(frm.data, fw, fh, out);
+
+		if (i == 0) img = fdata;
+		else if (frm.blend == 0) UPNG._copyTile(fdata, fw, fh, img, w, h, fx, fy, 0);
+		else if (frm.blend == 1) UPNG._copyTile(fdata, fw, fh, img, w, h, fx, fy, 1);
+
+		frms.push(img.buffer); img = img.slice(0);
+
+		if (frm.dispose == 0) { }
+		else if (frm.dispose == 1) UPNG._copyTile(empty, fw, fh, img, w, h, fx, fy, 0);
+		else if (frm.dispose == 2) {
+			var pi = i - 1;
+			while (out.frames[pi].dispose == 2) pi--;
+			img = new Uint8Array(frms[pi]).slice(0);
+		}
+	}
+	return frms;
+}
+
+UPNG.toRGBA8.decodeImage = function (data, w, h, out) {
+	var area = w * h, bpp = UPNG.decode._getBPP(out);
+	var bpl = Math.ceil(w * bpp / 8);	// bytes per line
+
+	var bf = new Uint8Array(area * 4), bf32 = new Uint32Array(bf.buffer);
+	var ctype = out.ctype, depth = out.depth;
+	var rs = UPNG._bin.readUshort;
+
+	//console.log(ctype, depth);
+
+	if (ctype == 6) { // RGB + alpha
+		var qarea = area << 2;
+		if (depth == 8) for (var i = 0; i < qarea; i++) { bf[i] = data[i];  /*if((i&3)==3 && data[i]!=0) bf[i]=255;*/ }
+		if (depth == 16) for (var i = 0; i < qarea; i++) { bf[i] = data[i << 1]; }
+	}
+	else if (ctype == 2) {	// RGB
+		var ts = out.tabs["tRNS"], tr = -1, tg = -1, tb = -1;
+		if (ts) { tr = ts[0]; tg = ts[1]; tb = ts[2]; }
+		if (depth == 8) for (var i = 0; i < area; i++) {
+			var qi = i << 2, ti = i * 3; bf[qi] = data[ti]; bf[qi + 1] = data[ti + 1]; bf[qi + 2] = data[ti + 2]; bf[qi + 3] = 255;
+			if (tr != -1 && data[ti] == tr && data[ti + 1] == tg && data[ti + 2] == tb) bf[qi + 3] = 0;
+		}
+		if (depth == 16) for (var i = 0; i < area; i++) {
+			var qi = i << 2, ti = i * 6; bf[qi] = data[ti]; bf[qi + 1] = data[ti + 2]; bf[qi + 2] = data[ti + 4]; bf[qi + 3] = 255;
+			if (tr != -1 && rs(data, ti) == tr && rs(data, ti + 2) == tg && rs(data, ti + 4) == tb) bf[qi + 3] = 0;
+		}
+	}
+	else if (ctype == 3) {	// palette
+		var p = out.tabs["PLTE"], ap = out.tabs["tRNS"], tl = ap ? ap.length : 0;
+		//console.log(p, ap);
+		if (depth == 1) for (var y = 0; y < h; y++) {
+			var s0 = y * bpl, t0 = y * w;
+			for (var i = 0; i < w; i++) { var qi = (t0 + i) << 2, j = ((data[s0 + (i >> 3)] >> (7 - ((i & 7) << 0))) & 1), cj = 3 * j; bf[qi] = p[cj]; bf[qi + 1] = p[cj + 1]; bf[qi + 2] = p[cj + 2]; bf[qi + 3] = (j < tl) ? ap[j] : 255; }
+		}
+		if (depth == 2) for (var y = 0; y < h; y++) {
+			var s0 = y * bpl, t0 = y * w;
+			for (var i = 0; i < w; i++) { var qi = (t0 + i) << 2, j = ((data[s0 + (i >> 2)] >> (6 - ((i & 3) << 1))) & 3), cj = 3 * j; bf[qi] = p[cj]; bf[qi + 1] = p[cj + 1]; bf[qi + 2] = p[cj + 2]; bf[qi + 3] = (j < tl) ? ap[j] : 255; }
+		}
+		if (depth == 4) for (var y = 0; y < h; y++) {
+			var s0 = y * bpl, t0 = y * w;
+			for (var i = 0; i < w; i++) { var qi = (t0 + i) << 2, j = ((data[s0 + (i >> 1)] >> (4 - ((i & 1) << 2))) & 15), cj = 3 * j; bf[qi] = p[cj]; bf[qi + 1] = p[cj + 1]; bf[qi + 2] = p[cj + 2]; bf[qi + 3] = (j < tl) ? ap[j] : 255; }
+		}
+		if (depth == 8) for (var i = 0; i < area; i++) { var qi = i << 2, j = data[i], cj = 3 * j; bf[qi] = p[cj]; bf[qi + 1] = p[cj + 1]; bf[qi + 2] = p[cj + 2]; bf[qi + 3] = (j < tl) ? ap[j] : 255; }
+	}
+	else if (ctype == 4) {	// gray + alpha
+		if (depth == 8) for (var i = 0; i < area; i++) { var qi = i << 2, di = i << 1, gr = data[di]; bf[qi] = gr; bf[qi + 1] = gr; bf[qi + 2] = gr; bf[qi + 3] = data[di + 1]; }
+		if (depth == 16) for (var i = 0; i < area; i++) { var qi = i << 2, di = i << 2, gr = data[di]; bf[qi] = gr; bf[qi + 1] = gr; bf[qi + 2] = gr; bf[qi + 3] = data[di + 2]; }
+	}
+	else if (ctype == 0) {	// gray
+		var tr = out.tabs["tRNS"] ? out.tabs["tRNS"] : -1;
+		if (depth == 1) for (var i = 0; i < area; i++) { var gr = 255 * ((data[i >> 3] >> (7 - ((i & 7)))) & 1), al = (gr == tr * 255) ? 0 : 255; bf32[i] = (al << 24) | (gr << 16) | (gr << 8) | gr; }
+		if (depth == 2) for (var i = 0; i < area; i++) { var gr = 85 * ((data[i >> 2] >> (6 - ((i & 3) << 1))) & 3), al = (gr == tr * 85) ? 0 : 255; bf32[i] = (al << 24) | (gr << 16) | (gr << 8) | gr; }
+		if (depth == 4) for (var i = 0; i < area; i++) { var gr = 17 * ((data[i >> 1] >> (4 - ((i & 1) << 2))) & 15), al = (gr == tr * 17) ? 0 : 255; bf32[i] = (al << 24) | (gr << 16) | (gr << 8) | gr; }
+		if (depth == 8) for (var i = 0; i < area; i++) { var gr = data[i], al = (gr == tr) ? 0 : 255; bf32[i] = (al << 24) | (gr << 16) | (gr << 8) | gr; }
+		if (depth == 16) for (var i = 0; i < area; i++) { var gr = data[i << 1], al = (rs(data, i << 1) == tr) ? 0 : 255; bf32[i] = (al << 24) | (gr << 16) | (gr << 8) | gr; }
+	}
+	return bf;
+}
+
+UPNG.decode = function (buff) {
+	var data = new Uint8Array(buff), offset = 8, bin = UPNG._bin, rUs = bin.readUshort, rUi = bin.readUint;
+	var out = { tabs: {}, frames: [] };
+	var dd = new Uint8Array(data.length), doff = 0;	 // put all IDAT data into it
+	var fd, foff = 0;	// frames
+
+	var mgck = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
+	for (var i = 0; i < 8; i++) if (data[i] != mgck[i]) throw "The input is not a PNG file!";
+
+	while (offset < data.length) {
+		var len = bin.readUint(data, offset); offset += 4;
+		var type = bin.readASCII(data, offset, 4); offset += 4;
+		//console.log(type,len);
+
+		if (type == "IHDR") { UPNG.decode._IHDR(data, offset, out); }
+		else if (type == "IDAT") {
+			for (var i = 0; i < len; i++) dd[doff + i] = data[offset + i];
+			doff += len;
+		}
+		else if (type == "acTL") {
+			out.tabs[type] = { num_frames: rUi(data, offset), num_plays: rUi(data, offset + 4) };
+			fd = new Uint8Array(data.length);
+		}
+		else if (type == "fcTL") {
+			if (foff != 0) {
+				var fr = out.frames[out.frames.length - 1];
+				fr.data = UPNG.decode._decompress(out, fd.slice(0, foff), fr.rect.width, fr.rect.height); foff = 0;
+			}
+			var rct = { x: rUi(data, offset + 12), y: rUi(data, offset + 16), width: rUi(data, offset + 4), height: rUi(data, offset + 8) };
+			var del = rUs(data, offset + 22); del = rUs(data, offset + 20) / (del == 0 ? 100 : del);
+			var frm = { rect: rct, delay: Math.round(del * 1000), dispose: data[offset + 24], blend: data[offset + 25] };
+			//console.log(frm);
+			out.frames.push(frm);
+		}
+		else if (type == "fdAT") {
+			for (var i = 0; i < len - 4; i++) fd[foff + i] = data[offset + i + 4];
+			foff += len - 4;
+		}
+		else if (type == "pHYs") {
+			out.tabs[type] = [bin.readUint(data, offset), bin.readUint(data, offset + 4), data[offset + 8]];
+		}
+		else if (type == "cHRM") {
+			out.tabs[type] = [];
+			for (var i = 0; i < 8; i++) out.tabs[type].push(bin.readUint(data, offset + i * 4));
+		}
+		else if (type == "tEXt") {
+			if (out.tabs[type] == null) out.tabs[type] = {};
+			var nz = bin.nextZero(data, offset);
+			var keyw = bin.readASCII(data, offset, nz - offset);
+			var text = bin.readASCII(data, nz + 1, offset + len - nz - 1);
+			out.tabs[type][keyw] = text;
+		}
+		else if (type == "iTXt") {
+			if (out.tabs[type] == null) out.tabs[type] = {};
+			var nz = 0, off = offset;
+			nz = bin.nextZero(data, off);
+			var keyw = bin.readASCII(data, off, nz - off); off = nz + 1;
+			var cflag = data[off], cmeth = data[off + 1]; off += 2;
+			nz = bin.nextZero(data, off);
+			var ltag = bin.readASCII(data, off, nz - off); off = nz + 1;
+			nz = bin.nextZero(data, off);
+			var tkeyw = bin.readUTF8(data, off, nz - off); off = nz + 1;
+			var text = bin.readUTF8(data, off, len - (off - offset));
+			out.tabs[type][keyw] = text;
+		}
+		else if (type == "PLTE") {
+			out.tabs[type] = bin.readBytes(data, offset, len);
+		}
+		else if (type == "hIST") {
+			var pl = out.tabs["PLTE"].length / 3;
+			out.tabs[type] = []; for (var i = 0; i < pl; i++) out.tabs[type].push(rUs(data, offset + i * 2));
+		}
+		else if (type == "tRNS") {
+			if (out.ctype == 3) out.tabs[type] = bin.readBytes(data, offset, len);
+			else if (out.ctype == 0) out.tabs[type] = rUs(data, offset);
+			else if (out.ctype == 2) out.tabs[type] = [rUs(data, offset), rUs(data, offset + 2), rUs(data, offset + 4)];
+			//else console.log("tRNS for unsupported color type",out.ctype, len);
+		}
+		else if (type == "gAMA") out.tabs[type] = bin.readUint(data, offset) / 100000;
+		else if (type == "sRGB") out.tabs[type] = data[offset];
+		else if (type == "bKGD") {
+			if (out.ctype == 0 || out.ctype == 4) out.tabs[type] = [rUs(data, offset)];
+			else if (out.ctype == 2 || out.ctype == 6) out.tabs[type] = [rUs(data, offset), rUs(data, offset + 2), rUs(data, offset + 4)];
+			else if (out.ctype == 3) out.tabs[type] = data[offset];
+		}
+		else if (type == "IEND") {
+			break;
+		}
+		//else {  log("unknown chunk type", type, len);  }
+		offset += len;
+		var crc = bin.readUint(data, offset); offset += 4;
+	}
+	if (foff != 0) {
+		var fr = out.frames[out.frames.length - 1];
+		fr.data = UPNG.decode._decompress(out, fd.slice(0, foff), fr.rect.width, fr.rect.height); foff = 0;
+	}
+	out.data = UPNG.decode._decompress(out, dd, out.width, out.height);
+
+	delete out.compress; delete out.interlace; delete out.filter;
+	return out;
+}
+
+UPNG.decode._decompress = function (out, dd, w, h) {
+	if (out.compress == 0) dd = UPNG.decode._inflate(dd);
+
+	if (out.interlace == 0) dd = UPNG.decode._filterZero(dd, out, 0, w, h);
+	else if (out.interlace == 1) dd = UPNG.decode._readInterlace(dd, out);
+	return dd;
+}
+
+UPNG.decode._inflate = function (data) { return pako["inflate"](data); }
+
+UPNG.decode._readInterlace = function (data, out) {
+	var w = out.width, h = out.height;
+	var bpp = UPNG.decode._getBPP(out), cbpp = bpp >> 3, bpl = Math.ceil(w * bpp / 8);
+	var img = new Uint8Array(h * bpl);
+	var di = 0;
+
+	var starting_row = [0, 0, 4, 0, 2, 0, 1];
+	var starting_col = [0, 4, 0, 2, 0, 1, 0];
+	var row_increment = [8, 8, 8, 4, 4, 2, 2];
+	var col_increment = [8, 8, 4, 4, 2, 2, 1];
+
+	var pass = 0;
+	while (pass < 7) {
+		var ri = row_increment[pass], ci = col_increment[pass];
+		var sw = 0, sh = 0;
+		var cr = starting_row[pass]; while (cr < h) { cr += ri; sh++; }
+		var cc = starting_col[pass]; while (cc < w) { cc += ci; sw++; }
+		var bpll = Math.ceil(sw * bpp / 8);
+		UPNG.decode._filterZero(data, out, di, sw, sh);
+
+		var y = 0, row = starting_row[pass];
+		while (row < h) {
+			var col = starting_col[pass];
+			var cdi = (di + y * bpll) << 3;
+
+			while (col < w) {
+				if (bpp == 1) {
+					var val = data[cdi >> 3]; val = (val >> (7 - (cdi & 7))) & 1;
+					img[row * bpl + (col >> 3)] |= (val << (7 - ((col & 3) << 0)));
+				}
+				if (bpp == 2) {
+					var val = data[cdi >> 3]; val = (val >> (6 - (cdi & 7))) & 3;
+					img[row * bpl + (col >> 2)] |= (val << (6 - ((col & 3) << 1)));
+				}
+				if (bpp == 4) {
+					var val = data[cdi >> 3]; val = (val >> (4 - (cdi & 7))) & 15;
+					img[row * bpl + (col >> 1)] |= (val << (4 - ((col & 1) << 2)));
+				}
+				if (bpp >= 8) {
+					var ii = row * bpl + col * cbpp;
+					for (var j = 0; j < cbpp; j++) img[ii + j] = data[(cdi >> 3) + j];
+				}
+				cdi += bpp; col += ci;
+			}
+			y++; row += ri;
+		}
+		if (sw * sh != 0) di += sh * (1 + bpll);
+		pass = pass + 1;
+	}
+	return img;
+}
+
+UPNG.decode._getBPP = function (out) {
+	var noc = [1, null, 3, 1, 2, null, 4][out.ctype];
+	return noc * out.depth;
+}
+
+UPNG.decode._filterZero = function (data, out, off, w, h) {
+	var bpp = UPNG.decode._getBPP(out), bpl = Math.ceil(w * bpp / 8), paeth = UPNG.decode._paeth;
+	bpp = Math.ceil(bpp / 8);
+
+	for (var y = 0; y < h; y++) {
+		var i = off + y * bpl, di = i + y + 1;
+		var type = data[di - 1];
+
+		if (type == 0) for (var x = 0; x < bpl; x++) data[i + x] = data[di + x];
+		else if (type == 1) {
+			for (var x = 0; x < bpp; x++) data[i + x] = data[di + x];
+			for (var x = bpp; x < bpl; x++) data[i + x] = (data[di + x] + data[i + x - bpp]) & 255;
+		}
+		else if (y == 0) {
+			for (var x = 0; x < bpp; x++) data[i + x] = data[di + x];
+			if (type == 2) for (var x = bpp; x < bpl; x++) data[i + x] = (data[di + x]) & 255;
+			if (type == 3) for (var x = bpp; x < bpl; x++) data[i + x] = (data[di + x] + (data[i + x - bpp] >> 1)) & 255;
+			if (type == 4) for (var x = bpp; x < bpl; x++) data[i + x] = (data[di + x] + paeth(data[i + x - bpp], 0, 0)) & 255;
+		}
+		else {
+			if (type == 2) { for (var x = 0; x < bpl; x++) data[i + x] = (data[di + x] + data[i + x - bpl]) & 255; }
+
+			if (type == 3) {
+				for (var x = 0; x < bpp; x++) data[i + x] = (data[di + x] + (data[i + x - bpl] >> 1)) & 255;
+				for (var x = bpp; x < bpl; x++) data[i + x] = (data[di + x] + ((data[i + x - bpl] + data[i + x - bpp]) >> 1)) & 255;
+			}
+
+			if (type == 4) {
+				for (var x = 0; x < bpp; x++) data[i + x] = (data[di + x] + paeth(0, data[i + x - bpl], 0)) & 255;
+				for (var x = bpp; x < bpl; x++) data[i + x] = (data[di + x] + paeth(data[i + x - bpp], data[i + x - bpl], data[i + x - bpp - bpl])) & 255;
+			}
+		}
+	}
+	return data;
+}
+
+UPNG.decode._paeth = function (a, b, c) {
+	var p = a + b - c, pa = Math.abs(p - a), pb = Math.abs(p - b), pc = Math.abs(p - c);
+	if (pa <= pb && pa <= pc) return a;
+	else if (pb <= pc) return b;
+	return c;
+}
+
+UPNG.decode._IHDR = function (data, offset, out) {
+	var bin = UPNG._bin;
+	out.width = bin.readUint(data, offset); offset += 4;
+	out.height = bin.readUint(data, offset); offset += 4;
+	out.depth = data[offset]; offset++;
+	out.ctype = data[offset]; offset++;
+	out.compress = data[offset]; offset++;
+	out.filter = data[offset]; offset++;
+	out.interlace = data[offset]; offset++;
+}
+
+UPNG._bin = {
+	nextZero: function (data, p) { while (data[p] != 0) p++; return p; },
+	readUshort: function (buff, p) { return (buff[p] << 8) | buff[p + 1]; },
+	writeUshort: function (buff, p, n) { buff[p] = (n >> 8) & 255; buff[p + 1] = n & 255; },
+	readUint: function (buff, p) { return (buff[p] * (256 * 256 * 256)) + ((buff[p + 1] << 16) | (buff[p + 2] << 8) | buff[p + 3]); },
+	writeUint: function (buff, p, n) { buff[p] = (n >> 24) & 255; buff[p + 1] = (n >> 16) & 255; buff[p + 2] = (n >> 8) & 255; buff[p + 3] = n & 255; },
+	readASCII: function (buff, p, l) { var s = ""; for (var i = 0; i < l; i++) s += String.fromCharCode(buff[p + i]); return s; },
+	writeASCII: function (data, p, s) { for (var i = 0; i < s.length; i++) data[p + i] = s.charCodeAt(i); },
+	readBytes: function (buff, p, l) { var arr = []; for (var i = 0; i < l; i++) arr.push(buff[p + i]); return arr; },
+	pad: function (n) { return n.length < 2 ? "0" + n : n; },
+	readUTF8: function (buff, p, l) {
+		var s = "", ns;
+		for (var i = 0; i < l; i++) s += "%" + UPNG._bin.pad(buff[p + i].toString(16));
+		try { ns = decodeURIComponent(s); }
+		catch (e) { return UPNG._bin.readASCII(buff, p, l); }
+		return ns;
+	}
+}
+UPNG._copyTile = function (sb, sw, sh, tb, tw, th, xoff, yoff, mode) {
+	var w = Math.min(sw, tw), h = Math.min(sh, th);
+	var si = 0, ti = 0;
+	for (var y = 0; y < h; y++)
+		for (var x = 0; x < w; x++) {
+			if (xoff >= 0 && yoff >= 0) { si = (y * sw + x) << 2; ti = ((yoff + y) * tw + xoff + x) << 2; }
+			else { si = ((-yoff + y) * sw - xoff + x) << 2; ti = (y * tw + x) << 2; }
+
+			if (mode == 0) { tb[ti] = sb[si]; tb[ti + 1] = sb[si + 1]; tb[ti + 2] = sb[si + 2]; tb[ti + 3] = sb[si + 3]; }
+			else if (mode == 1) {
+				var fa = sb[si + 3] * (1 / 255), fr = sb[si] * fa, fg = sb[si + 1] * fa, fb = sb[si + 2] * fa;
+				var ba = tb[ti + 3] * (1 / 255), br = tb[ti] * ba, bg = tb[ti + 1] * ba, bb = tb[ti + 2] * ba;
+
+				var ifa = 1 - fa, oa = fa + ba * ifa, ioa = (oa == 0 ? 0 : 1 / oa);
+				tb[ti + 3] = 255 * oa;
+				tb[ti + 0] = (fr + br * ifa) * ioa;
+				tb[ti + 1] = (fg + bg * ifa) * ioa;
+				tb[ti + 2] = (fb + bb * ifa) * ioa;
+			}
+			else if (mode == 2) {	// copy only differences, otherwise zero
+				var fa = sb[si + 3], fr = sb[si], fg = sb[si + 1], fb = sb[si + 2];
+				var ba = tb[ti + 3], br = tb[ti], bg = tb[ti + 1], bb = tb[ti + 2];
+				if (fa == ba && fr == br && fg == bg && fb == bb) { tb[ti] = 0; tb[ti + 1] = 0; tb[ti + 2] = 0; tb[ti + 3] = 0; }
+				else { tb[ti] = fr; tb[ti + 1] = fg; tb[ti + 2] = fb; tb[ti + 3] = fa; }
+			}
+			else if (mode == 3) {	// check if can be blended
+				var fa = sb[si + 3], fr = sb[si], fg = sb[si + 1], fb = sb[si + 2];
+				var ba = tb[ti + 3], br = tb[ti], bg = tb[ti + 1], bb = tb[ti + 2];
+				if (fa == ba && fr == br && fg == bg && fb == bb) continue;
+				//if(fa!=255 && ba!=0) return false;
+				if (fa < 220 && ba > 20) return false;
+			}
+		}
+	return true;
+}
+
+
+UPNG.encode = function (bufs, w, h, ps, dels, forbidPlte) {
+	if (ps == null) ps = 0;
+	if (forbidPlte == null) forbidPlte = false;
+
+	var nimg = UPNG.encode.compress(bufs, w, h, ps, false, forbidPlte);
+	UPNG.encode.compressPNG(nimg, -1);
+
+	return UPNG.encode._main(nimg, w, h, dels);
+}
+
+UPNG.encodeLL = function (bufs, w, h, cc, ac, depth, dels) {
+	var nimg = { ctype: 0 + (cc == 1 ? 0 : 2) + (ac == 0 ? 0 : 4), depth: depth, frames: [] };
+
+	var bipp = (cc + ac) * depth, bipl = bipp * w;
+	for (var i = 0; i < bufs.length; i++)
+		nimg.frames.push({ rect: { x: 0, y: 0, width: w, height: h }, img: new Uint8Array(bufs[i]), blend: 0, dispose: 1, bpp: Math.ceil(bipp / 8), bpl: Math.ceil(bipl / 8) });
+
+	UPNG.encode.compressPNG(nimg, 4);
+
+	return UPNG.encode._main(nimg, w, h, dels);
+}
+
+UPNG.encode._main = function (nimg, w, h, dels) {
+	var crc = UPNG.crc.crc, wUi = UPNG._bin.writeUint, wUs = UPNG._bin.writeUshort, wAs = UPNG._bin.writeASCII;
+	var offset = 8, anim = nimg.frames.length > 1, pltAlpha = false;
+
+	var leng = 8 + (16 + 5 + 4) + (9 + 4) + (anim ? 20 : 0);
+	if (nimg.ctype == 3) {
+		var dl = nimg.plte.length;
+		for (var i = 0; i < dl; i++) if ((nimg.plte[i] >>> 24) != 255) pltAlpha = true;
+		leng += (8 + dl * 3 + 4) + (pltAlpha ? (8 + dl * 1 + 4) : 0);
+	}
+	for (var j = 0; j < nimg.frames.length; j++) {
+		var fr = nimg.frames[j];
+		if (anim) leng += 38;
+		leng += fr.cimg.length + 12;
+		if (j != 0) leng += 4;
+	}
+	leng += 12;
+
+	var data = new Uint8Array(leng);
+	var wr = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
+	for (var i = 0; i < 8; i++) data[i] = wr[i];
+
+	wUi(data, offset, 13); offset += 4;
+	wAs(data, offset, "IHDR"); offset += 4;
+	wUi(data, offset, w); offset += 4;
+	wUi(data, offset, h); offset += 4;
+	data[offset] = nimg.depth; offset++;  // depth
+	data[offset] = nimg.ctype; offset++;  // ctype
+	data[offset] = 0; offset++;  // compress
+	data[offset] = 0; offset++;  // filter
+	data[offset] = 0; offset++;  // interlace
+	wUi(data, offset, crc(data, offset - 17, 17)); offset += 4; // crc
+
+	// 9 bytes to say, that it is sRGB
+	wUi(data, offset, 1); offset += 4;
+	wAs(data, offset, "sRGB"); offset += 4;
+	data[offset] = 1; offset++;
+	wUi(data, offset, crc(data, offset - 5, 5)); offset += 4; // crc
+
+	if (anim) {
+		wUi(data, offset, 8); offset += 4;
+		wAs(data, offset, "acTL"); offset += 4;
+		wUi(data, offset, nimg.frames.length); offset += 4;
+		wUi(data, offset, 0); offset += 4;
+		wUi(data, offset, crc(data, offset - 12, 12)); offset += 4; // crc
+	}
+
+	if (nimg.ctype == 3) {
+		var dl = nimg.plte.length;
+		wUi(data, offset, dl * 3); offset += 4;
+		wAs(data, offset, "PLTE"); offset += 4;
+		for (var i = 0; i < dl; i++) {
+			var ti = i * 3, c = nimg.plte[i], r = (c) & 255, g = (c >>> 8) & 255, b = (c >>> 16) & 255;
+			data[offset + ti + 0] = r; data[offset + ti + 1] = g; data[offset + ti + 2] = b;
+		}
+		offset += dl * 3;
+		wUi(data, offset, crc(data, offset - dl * 3 - 4, dl * 3 + 4)); offset += 4; // crc
+
+		if (pltAlpha) {
+			wUi(data, offset, dl); offset += 4;
+			wAs(data, offset, "tRNS"); offset += 4;
+			for (var i = 0; i < dl; i++)  data[offset + i] = (nimg.plte[i] >>> 24) & 255;
+			offset += dl;
+			wUi(data, offset, crc(data, offset - dl - 4, dl + 4)); offset += 4; // crc
+		}
+	}
+
+	var fi = 0;
+	for (var j = 0; j < nimg.frames.length; j++) {
+		var fr = nimg.frames[j];
+		if (anim) {
+			wUi(data, offset, 26); offset += 4;
+			wAs(data, offset, "fcTL"); offset += 4;
+			wUi(data, offset, fi++); offset += 4;
+			wUi(data, offset, fr.rect.width); offset += 4;
+			wUi(data, offset, fr.rect.height); offset += 4;
+			wUi(data, offset, fr.rect.x); offset += 4;
+			wUi(data, offset, fr.rect.y); offset += 4;
+			wUs(data, offset, dels[j]); offset += 2;
+			wUs(data, offset, 1000); offset += 2;
+			data[offset] = fr.dispose; offset++;	// dispose
+			data[offset] = fr.blend; offset++;	// blend
+			wUi(data, offset, crc(data, offset - 30, 30)); offset += 4; // crc
+		}
+
+		var imgd = fr.cimg, dl = imgd.length;
+		wUi(data, offset, dl + (j == 0 ? 0 : 4)); offset += 4;
+		var ioff = offset;
+		wAs(data, offset, (j == 0) ? "IDAT" : "fdAT"); offset += 4;
+		if (j != 0) { wUi(data, offset, fi++); offset += 4; }
+		for (var i = 0; i < dl; i++) data[offset + i] = imgd[i];
+		offset += dl;
+		wUi(data, offset, crc(data, ioff, offset - ioff)); offset += 4; // crc
+	}
+
+	wUi(data, offset, 0); offset += 4;
+	wAs(data, offset, "IEND"); offset += 4;
+	wUi(data, offset, crc(data, offset - 4, 4)); offset += 4; // crc
+
+	return data.buffer;
+}
+
+UPNG.encode.compressPNG = function (out, filter) {
+	for (var i = 0; i < out.frames.length; i++) {
+		var frm = out.frames[i], nw = frm.rect.width, nh = frm.rect.height;
+		var fdata = new Uint8Array(nh * frm.bpl + nh);
+		frm.cimg = UPNG.encode._filterZero(frm.img, nh, frm.bpp, frm.bpl, fdata, filter);
+	}
+}
+
+
+
+UPNG.encode.compress = function (bufs, w, h, ps, forGIF, forbidPlte) {
+	//var time = Date.now();
+	if (forbidPlte == null) forbidPlte = false;
+
+	var ctype = 6, depth = 8, alphaAnd = 255
+
+	for (var j = 0; j < bufs.length; j++) {  // when not quantized, other frames can contain colors, that are not in an initial frame
+		var img = new Uint8Array(bufs[j]), ilen = img.length;
+		for (var i = 0; i < ilen; i += 4) alphaAnd &= img[i + 3];
+	}
+	var gotAlpha = (alphaAnd != 255);
+
+	//console.log("alpha check", Date.now()-time);  time = Date.now();
+
+	var brute = gotAlpha && forGIF;		// brute : frames can only be copied, not "blended"
+	var frms = UPNG.encode.framize(bufs, w, h, forGIF, brute);
+	//console.log("framize", Date.now()-time);  time = Date.now();
+
+	var cmap = {}, plte = [], inds = [];
+
+	if (ps != 0) {
+		var nbufs = []; for (var i = 0; i < frms.length; i++) nbufs.push(frms[i].img.buffer);
+
+		var abuf = UPNG.encode.concatRGBA(nbufs, forGIF), qres = UPNG.quantize(abuf, ps);
+		var cof = 0, bb = new Uint8Array(qres.abuf);
+		for (var i = 0; i < frms.length; i++) {
+			var ti = frms[i].img, bln = ti.length; inds.push(new Uint8Array(qres.inds.buffer, cof >> 2, bln >> 2));
+			for (var j = 0; j < bln; j += 4) { ti[j] = bb[cof + j]; ti[j + 1] = bb[cof + j + 1]; ti[j + 2] = bb[cof + j + 2]; ti[j + 3] = bb[cof + j + 3]; } cof += bln;
+		}
+
+		for (var i = 0; i < qres.plte.length; i++) plte.push(qres.plte[i].est.rgba);
+		//console.log("quantize", Date.now()-time);  time = Date.now();
+	}
+	else {
+		// what if ps==0, but there are <=256 colors?  we still need to detect, if the palette could be used
+		for (var j = 0; j < frms.length; j++) {  // when not quantized, other frames can contain colors, that are not in an initial frame
+			var frm = frms[j], img32 = new Uint32Array(frm.img.buffer), nw = frm.rect.width, ilen = img32.length;
+			var ind = new Uint8Array(ilen); inds.push(ind);
+			for (var i = 0; i < ilen; i++) {
+				var c = img32[i];
+				if (i != 0 && c == img32[i - 1]) ind[i] = ind[i - 1];
+				else if (i > nw && c == img32[i - nw]) ind[i] = ind[i - nw];
+				else {
+					var cmc = cmap[c];
+					if (cmc == null) { cmap[c] = cmc = plte.length; plte.push(c); if (plte.length >= 300) break; }
+					ind[i] = cmc;
+				}
+			}
+		}
+		//console.log("make palette", Date.now()-time);  time = Date.now();
+	}
+
+	var cc = plte.length; //console.log("colors:",cc);
+	if (cc <= 256 && forbidPlte == false) {
+		if (cc <= 2) depth = 1; else if (cc <= 4) depth = 2; else if (cc <= 16) depth = 4; else depth = 8;
+		if (forGIF) depth = 8;
+	}
+
+	for (var j = 0; j < frms.length; j++) {
+		var frm = frms[j], nx = frm.rect.x, ny = frm.rect.y, nw = frm.rect.width, nh = frm.rect.height;
+		var cimg = frm.img, cimg32 = new Uint32Array(cimg.buffer);
+		var bpl = 4 * nw, bpp = 4;
+		if (cc <= 256 && forbidPlte == false) {
+			bpl = Math.ceil(depth * nw / 8);
+			var nimg = new Uint8Array(bpl * nh);
+			var inj = inds[j];
+			for (var y = 0; y < nh; y++) {
+				var i = y * bpl, ii = y * nw;
+				if (depth == 8) for (var x = 0; x < nw; x++) nimg[i + (x)] = (inj[ii + x]);
+				else if (depth == 4) for (var x = 0; x < nw; x++) nimg[i + (x >> 1)] |= (inj[ii + x] << (4 - (x & 1) * 4));
+				else if (depth == 2) for (var x = 0; x < nw; x++) nimg[i + (x >> 2)] |= (inj[ii + x] << (6 - (x & 3) * 2));
+				else if (depth == 1) for (var x = 0; x < nw; x++) nimg[i + (x >> 3)] |= (inj[ii + x] << (7 - (x & 7) * 1));
+			}
+			cimg = nimg; ctype = 3; bpp = 1;
+		}
+		else if (gotAlpha == false && frms.length == 1) {	// some next "reduced" frames may contain alpha for blending
+			var nimg = new Uint8Array(nw * nh * 3), area = nw * nh;
+			for (var i = 0; i < area; i++) { var ti = i * 3, qi = i * 4; nimg[ti] = cimg[qi]; nimg[ti + 1] = cimg[qi + 1]; nimg[ti + 2] = cimg[qi + 2]; }
+			cimg = nimg; ctype = 2; bpp = 3; bpl = 3 * nw;
+		}
+		frm.img = cimg; frm.bpl = bpl; frm.bpp = bpp;
+	}
+	//console.log("colors => palette indices", Date.now()-time);  time = Date.now();
+
+	return { ctype: ctype, depth: depth, plte: plte, frames: frms };
+}
+UPNG.encode.framize = function (bufs, w, h, forGIF, brute) {
+	var frms = [];
+	for (var j = 0; j < bufs.length; j++) {
+		var cimg = new Uint8Array(bufs[j]), cimg32 = new Uint32Array(cimg.buffer);
+
+		var nx = 0, ny = 0, nw = w, nh = h, blend = 0;
+		if (j != 0 && !brute) {
+			var tlim = (forGIF || j == 1 || frms[frms.length - 2].dispose == 2) ? 1 : 2, tstp = 0, tarea = 1e9;
+			for (var it = 0; it < tlim; it++) {
+				var pimg = new Uint8Array(bufs[j - 1 - it]), p32 = new Uint32Array(bufs[j - 1 - it]);
+				var mix = w, miy = h, max = -1, may = -1;
+				for (var y = 0; y < h; y++) for (var x = 0; x < w; x++) {
+					var i = y * w + x;
+					if (cimg32[i] != p32[i]) {
+						if (x < mix) mix = x; if (x > max) max = x;
+						if (y < miy) miy = y; if (y > may) may = y;
+					}
+				}
+				var sarea = (max == -1) ? 1 : (max - mix + 1) * (may - miy + 1);
+				if (sarea < tarea) {
+					tarea = sarea; tstp = it;
+					if (max == -1) { nx = ny = 0; nw = nh = 1; }
+					else { nx = mix; ny = miy; nw = max - mix + 1; nh = may - miy + 1; }
+				}
+			}
+
+			var pimg = new Uint8Array(bufs[j - 1 - tstp]);
+			if (tstp == 1) frms[frms.length - 1].dispose = 2;
+
+			var nimg = new Uint8Array(nw * nh * 4), nimg32 = new Uint32Array(nimg.buffer);
+			UPNG._copyTile(pimg, w, h, nimg, nw, nh, -nx, -ny, 0);
+			if (UPNG._copyTile(cimg, w, h, nimg, nw, nh, -nx, -ny, 3)) {
+				UPNG._copyTile(cimg, w, h, nimg, nw, nh, -nx, -ny, 2); blend = 1;
+			}
+			else {
+				UPNG._copyTile(cimg, w, h, nimg, nw, nh, -nx, -ny, 0); blend = 0;
+			}
+			cimg = nimg;
+		}
+		else cimg = cimg.slice(0);	// img may be rewrited further ... don't rewrite input
+		frms.push({ rect: { x: nx, y: ny, width: nw, height: nh }, img: cimg, blend: blend, dispose: brute ? 1 : 0 });
+	}
+	return frms;
+}
+
+UPNG.encode._filterZero = function (img, h, bpp, bpl, data, filter) {
+	if (filter != -1) {
+		for (var y = 0; y < h; y++) UPNG.encode._filterLine(data, img, y, bpl, bpp, filter);
+		return pako["deflate"](data);
+	}
+	var fls = [];
+	for (var t = 0; t < 5; t++) {
+		if (h * bpl > 500000 && (t == 2 || t == 3 || t == 4)) continue;
+		for (var y = 0; y < h; y++) UPNG.encode._filterLine(data, img, y, bpl, bpp, t);
+		fls.push(pako["deflate"](data)); if (bpp == 1) break;
+	}
+	var ti, tsize = 1e9;
+	for (var i = 0; i < fls.length; i++) if (fls[i].length < tsize) { ti = i; tsize = fls[i].length; }
+	return fls[ti];
+}
+UPNG.encode._filterLine = function (data, img, y, bpl, bpp, type) {
+	var i = y * bpl, di = i + y, paeth = UPNG.decode._paeth
+	data[di] = type; di++;
+
+	if (type == 0) for (var x = 0; x < bpl; x++) data[di + x] = img[i + x];
+	else if (type == 1) {
+		for (var x = 0; x < bpp; x++) data[di + x] = img[i + x];
+		for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] - img[i + x - bpp] + 256) & 255;
+	}
+	else if (y == 0) {
+		for (var x = 0; x < bpp; x++) data[di + x] = img[i + x];
+
+		if (type == 2) for (var x = bpp; x < bpl; x++) data[di + x] = img[i + x];
+		if (type == 3) for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] - (img[i + x - bpp] >> 1) + 256) & 255;
+		if (type == 4) for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] - paeth(img[i + x - bpp], 0, 0) + 256) & 255;
+	}
+	else {
+		if (type == 2) { for (var x = 0; x < bpl; x++) data[di + x] = (img[i + x] + 256 - img[i + x - bpl]) & 255; }
+		if (type == 3) {
+			for (var x = 0; x < bpp; x++) data[di + x] = (img[i + x] + 256 - (img[i + x - bpl] >> 1)) & 255;
+			for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] + 256 - ((img[i + x - bpl] + img[i + x - bpp]) >> 1)) & 255;
+		}
+		if (type == 4) {
+			for (var x = 0; x < bpp; x++) data[di + x] = (img[i + x] + 256 - paeth(0, img[i + x - bpl], 0)) & 255;
+			for (var x = bpp; x < bpl; x++) data[di + x] = (img[i + x] + 256 - paeth(img[i + x - bpp], img[i + x - bpl], img[i + x - bpp - bpl])) & 255;
+		}
+	}
+}
+
+UPNG.crc = {
+	table: (function () {
+		var tab = new Uint32Array(256);
+		for (var n = 0; n < 256; n++) {
+			var c = n;
+			for (var k = 0; k < 8; k++) {
+				if (c & 1) c = 0xedb88320 ^ (c >>> 1);
+				else c = c >>> 1;
+			}
+			tab[n] = c;
+		}
+		return tab;
+	})(),
+	update: function (c, buf, off, len) {
+		for (var i = 0; i < len; i++)  c = UPNG.crc.table[(c ^ buf[off + i]) & 0xff] ^ (c >>> 8);
+		return c;
+	},
+	crc: function (b, o, l) { return UPNG.crc.update(0xffffffff, b, o, l) ^ 0xffffffff; }
+}
+
+
+UPNG.quantize = function (abuf, ps) {
+	var oimg = new Uint8Array(abuf), nimg = oimg.slice(0), nimg32 = new Uint32Array(nimg.buffer);
+
+	var KD = UPNG.quantize.getKDtree(nimg, ps);
+	var root = KD[0], leafs = KD[1];
+
+	var planeDst = UPNG.quantize.planeDst;
+	var sb = oimg, tb = nimg32, len = sb.length;
+
+	var inds = new Uint8Array(oimg.length >> 2);
+	for (var i = 0; i < len; i += 4) {
+		var r = sb[i] * (1 / 255), g = sb[i + 1] * (1 / 255), b = sb[i + 2] * (1 / 255), a = sb[i + 3] * (1 / 255);
+
+		//  exact, but too slow :(
+		var nd = UPNG.quantize.getNearest(root, r, g, b, a);
+		//var nd = root;
+		//while(nd.left) nd = (planeDst(nd.est,r,g,b,a)<=0) ? nd.left : nd.right;
+
+		inds[i >> 2] = nd.ind;
+		tb[i >> 2] = nd.est.rgba;
+	}
+	return { abuf: nimg.buffer, inds: inds, plte: leafs };
+}
+
+UPNG.quantize.getKDtree = function (nimg, ps, err) {
+	if (err == null) err = 0.0001;
+	var nimg32 = new Uint32Array(nimg.buffer);
+
+	var root = { i0: 0, i1: nimg.length, bst: null, est: null, tdst: 0, left: null, right: null };  // basic statistic, extra statistic
+	root.bst = UPNG.quantize.stats(nimg, root.i0, root.i1); root.est = UPNG.quantize.estats(root.bst);
+	var leafs = [root];
+
+	while (leafs.length < ps) {
+		var maxL = 0, mi = 0;
+		for (var i = 0; i < leafs.length; i++) if (leafs[i].est.L > maxL) { maxL = leafs[i].est.L; mi = i; }
+		if (maxL < err) break;
+		var node = leafs[mi];
+
+		var s0 = UPNG.quantize.splitPixels(nimg, nimg32, node.i0, node.i1, node.est.e, node.est.eMq255);
+		var s0wrong = (node.i0 >= s0 || node.i1 <= s0);
+		//console.log(maxL, leafs.length, mi);
+		if (s0wrong) { node.est.L = 0; continue; }
+
+
+		var ln = { i0: node.i0, i1: s0, bst: null, est: null, tdst: 0, left: null, right: null }; ln.bst = UPNG.quantize.stats(nimg, ln.i0, ln.i1);
+		ln.est = UPNG.quantize.estats(ln.bst);
+		var rn = { i0: s0, i1: node.i1, bst: null, est: null, tdst: 0, left: null, right: null }; rn.bst = { R: [], m: [], N: node.bst.N - ln.bst.N };
+		for (var i = 0; i < 16; i++) rn.bst.R[i] = node.bst.R[i] - ln.bst.R[i];
+		for (var i = 0; i < 4; i++) rn.bst.m[i] = node.bst.m[i] - ln.bst.m[i];
+		rn.est = UPNG.quantize.estats(rn.bst);
+
+		node.left = ln; node.right = rn;
+		leafs[mi] = ln; leafs.push(rn);
+	}
+	leafs.sort(function (a, b) { return b.bst.N - a.bst.N; });
+	for (var i = 0; i < leafs.length; i++) leafs[i].ind = i;
+	return [root, leafs];
+}
+
+UPNG.quantize.getNearest = function (nd, r, g, b, a) {
+	if (nd.left == null) { nd.tdst = UPNG.quantize.dist(nd.est.q, r, g, b, a); return nd; }
+	var planeDst = UPNG.quantize.planeDst(nd.est, r, g, b, a);
+
+	var node0 = nd.left, node1 = nd.right;
+	if (planeDst > 0) { node0 = nd.right; node1 = nd.left; }
+
+	var ln = UPNG.quantize.getNearest(node0, r, g, b, a);
+	if (ln.tdst <= planeDst * planeDst) return ln;
+	var rn = UPNG.quantize.getNearest(node1, r, g, b, a);
+	return rn.tdst < ln.tdst ? rn : ln;
+}
+UPNG.quantize.planeDst = function (est, r, g, b, a) { var e = est.e; return e[0] * r + e[1] * g + e[2] * b + e[3] * a - est.eMq; }
+UPNG.quantize.dist = function (q, r, g, b, a) { var d0 = r - q[0], d1 = g - q[1], d2 = b - q[2], d3 = a - q[3]; return d0 * d0 + d1 * d1 + d2 * d2 + d3 * d3; }
+
+UPNG.quantize.splitPixels = function (nimg, nimg32, i0, i1, e, eMq) {
+	var vecDot = UPNG.quantize.vecDot;
+	i1 -= 4;
+	var shfs = 0;
+	while (i0 < i1) {
+		while (vecDot(nimg, i0, e) <= eMq) i0 += 4;
+		while (vecDot(nimg, i1, e) > eMq) i1 -= 4;
+		if (i0 >= i1) break;
+
+		var t = nimg32[i0 >> 2]; nimg32[i0 >> 2] = nimg32[i1 >> 2]; nimg32[i1 >> 2] = t;
+
+		i0 += 4; i1 -= 4;
+	}
+	while (vecDot(nimg, i0, e) > eMq) i0 -= 4;
+	return i0 + 4;
+}
+UPNG.quantize.vecDot = function (nimg, i, e) {
+	return nimg[i] * e[0] + nimg[i + 1] * e[1] + nimg[i + 2] * e[2] + nimg[i + 3] * e[3];
+}
+UPNG.quantize.stats = function (nimg, i0, i1) {
+	var R = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+	var m = [0, 0, 0, 0];
+	var N = (i1 - i0) >> 2;
+	for (var i = i0; i < i1; i += 4) {
+		var r = nimg[i] * (1 / 255), g = nimg[i + 1] * (1 / 255), b = nimg[i + 2] * (1 / 255), a = nimg[i + 3] * (1 / 255);
+		//var r = nimg[i], g = nimg[i+1], b = nimg[i+2], a = nimg[i+3];
+		m[0] += r; m[1] += g; m[2] += b; m[3] += a;
+
+		R[0] += r * r; R[1] += r * g; R[2] += r * b; R[3] += r * a;
+		R[5] += g * g; R[6] += g * b; R[7] += g * a;
+		R[10] += b * b; R[11] += b * a;
+		R[15] += a * a;
+	}
+	R[4] = R[1]; R[8] = R[2]; R[9] = R[6]; R[12] = R[3]; R[13] = R[7]; R[14] = R[11];
+
+	return { R: R, m: m, N: N };
+}
+UPNG.quantize.estats = function (stats) {
+	var R = stats.R, m = stats.m, N = stats.N;
+
+	// when all samples are equal, but N is large (millions), the Rj can be non-zero ( 0.0003.... - precission error)
+	var m0 = m[0], m1 = m[1], m2 = m[2], m3 = m[3], iN = (N == 0 ? 0 : 1 / N);
+	var Rj = [
+		R[0] - m0 * m0 * iN, R[1] - m0 * m1 * iN, R[2] - m0 * m2 * iN, R[3] - m0 * m3 * iN,
+		R[4] - m1 * m0 * iN, R[5] - m1 * m1 * iN, R[6] - m1 * m2 * iN, R[7] - m1 * m3 * iN,
+		R[8] - m2 * m0 * iN, R[9] - m2 * m1 * iN, R[10] - m2 * m2 * iN, R[11] - m2 * m3 * iN,
+		R[12] - m3 * m0 * iN, R[13] - m3 * m1 * iN, R[14] - m3 * m2 * iN, R[15] - m3 * m3 * iN
+	];
+
+	var A = Rj, M = UPNG.M4;
+	var b = [0.5, 0.5, 0.5, 0.5], mi = 0, tmi = 0;
+
+	if (N != 0)
+		for (var i = 0; i < 10; i++) {
+			b = M.multVec(A, b); tmi = Math.sqrt(M.dot(b, b)); b = M.sml(1 / tmi, b);
+			if (Math.abs(tmi - mi) < 1e-9) break; mi = tmi;
+		}
+	//b = [0,0,1,0];  mi=N;
+	var q = [m0 * iN, m1 * iN, m2 * iN, m3 * iN];
+	var eMq255 = M.dot(M.sml(255, q), b);
+
+	return {
+		Cov: Rj, q: q, e: b, L: mi, eMq255: eMq255, eMq: M.dot(b, q),
+		rgba: (((Math.round(255 * q[3]) << 24) | (Math.round(255 * q[2]) << 16) | (Math.round(255 * q[1]) << 8) | (Math.round(255 * q[0]) << 0)) >>> 0)
+	};
+}
+UPNG.M4 = {
+	multVec: function (m, v) {
+		return [
+			m[0] * v[0] + m[1] * v[1] + m[2] * v[2] + m[3] * v[3],
+			m[4] * v[0] + m[5] * v[1] + m[6] * v[2] + m[7] * v[3],
+			m[8] * v[0] + m[9] * v[1] + m[10] * v[2] + m[11] * v[3],
+			m[12] * v[0] + m[13] * v[1] + m[14] * v[2] + m[15] * v[3]
+		];
+	},
+	dot: function (x, y) { return x[0] * y[0] + x[1] * y[1] + x[2] * y[2] + x[3] * y[3]; },
+	sml: function (a, y) { return [a * y[0], a * y[1], a * y[2], a * y[3]]; }
+}
+
+UPNG.encode.concatRGBA = function (bufs, roundAlpha) {
+	var tlen = 0;
+	for (var i = 0; i < bufs.length; i++) tlen += bufs[i].byteLength;
+	var nimg = new Uint8Array(tlen), noff = 0;
+	for (var i = 0; i < bufs.length; i++) {
+		var img = new Uint8Array(bufs[i]), il = img.length;
+		for (var j = 0; j < il; j += 4) {
+			var r = img[j], g = img[j + 1], b = img[j + 2], a = img[j + 3];
+			if (roundAlpha) a = (a & 128) == 0 ? 0 : 255;
+			if (a == 0) r = g = b = 0;
+			nimg[noff + j] = r; nimg[noff + j + 1] = g; nimg[noff + j + 2] = b; nimg[noff + j + 3] = a;
+		}
+		noff += il;
+	}
+	return nimg.buffer;
+}
+
+module.exports = UPNG;

src/lib/ReedSolomonDecoder.js

@@ -1,3 +1,4 @@
+var GF256 = require('./GF256')
 var GF256Poly = require('./GF256Poly')
 
 module.exports = function ReedSolomonDecoder(field) {

test/node.js

@@ -0,0 +1,12 @@
+var imgDecode = require('../server')
+
+
+imgDecode.decodeQRFile('./img/out.bmp').then(console.log)
+imgDecode.decodeQRFile('./img/out.jpg').then(console.log,console.error)
+imgDecode.decodeQRFile('./img/out.png').then(console.log,console.error)
+imgDecode.decodeQRFile('./img/out.gif').then(console.log,console.error)
+imgDecode.decodeQRFile('./img/dt.gif').then(console.log,console.error)
+imgDecode.decodeQRFile('./img/dt1.gif').then(console.log,console.error)
+
+//动态img
+