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Kuba Niegowski 2012-08-19 00:44:48 +02:00
commit 413c967aae
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.gitignore vendored Normal file
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node_modules
*.png

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LICENSE Normal file
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Copyright (c) 2012 Kuba Niegowski
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

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PNG.js
========
Options
--------
- `checkCRC` - `boolean` default: `true`
- `deflateChunkSize` - `int` default: 32 kB
- `deflateLevel` - `int` default: 9
- `filterType` - `int` default: -1 (auto)

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#!/usr/bin/env node
var fs = require('fs'),
PNG = require('../lib/png').PNG;
fs.readFile(process.argv[2], function(err, data) {
if (err) throw err;
var png = new PNG();
png.parse(data, function(err) {
if (err) console.log(err.stack);
for (var y = 0; y < png.height; y++) {
for (var x = 0; x < png.width; x++) {
var idx = (png.width * y + x) << 2;
// invert color
png.data[idx] = 255 - png.data[idx];
png.data[idx+1] = 255 - png.data[idx+1];
png.data[idx+2] = 255 - png.data[idx+2];
// and reduce opacity
png.data[idx+3] = png.data[idx+3] >> 1;
}
}
png.pipe(fs.createWriteStream(process.argv[3] || 'out.png'));
png.pack();
});
});

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#!/usr/bin/env node
var fs = require('fs'),
PNG = require('../lib/png').PNG;
var png = new PNG({
filterType: 4
}),
src = fs.createReadStream(process.argv[2]),
dst = fs.createWriteStream(process.argv[3] || 'out.png');
png.on('parsed', function() {
for (var y = 0; y < png.height; y++) {
for (var x = 0; x < png.width; x++) {
var idx = (png.width * y + x) << 2;
// invert color
png.data[idx] = 255 - png.data[idx];
png.data[idx+1] = 255 - png.data[idx+1];
png.data[idx+2] = 255 - png.data[idx+2];
// and reduce opacity
png.data[idx+3] = png.data[idx+3] >> 1;
}
}
png.pack();
});
src.pipe(png).pipe(dst);

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// Copyright (c) 2012 Kuba Niegowski
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
'use strict';
var util = require('util'),
zlib = require('zlib'),
events = require('events');
var Compress = module.exports = function(options) {
events.EventEmitter.call(this);
this._options = options;
options.deflateChunkSize = options.deflateChunkSize || 32 * 1024;
options.deflateLevel = options.deflateLevel || 9;
this._inflate = null;
};
util.inherits(Compress, events.EventEmitter);
Compress.prototype.prepareInflate = function(type) {
if (type != 0)
throw new Error('Unsupported compression method');
this._inflate = zlib.createInflate();
bufferStream(this._inflate, function(data) {
this._inflate = null;
this.emit('inflated', data);
}.bind(this));
this._inflate.on('error', this.emit.bind(this, 'error'));
};
Compress.prototype.writeInflate = function(data) {
this._inflate.write(data);
};
Compress.prototype.endInflate = function() {
this._inflate.end();
};
Compress.prototype.deflate = function(data) {
var deflate = zlib.createDeflate({
chunkSize: this._options.deflateChunkSize,
level: this._options.deflateLevel
});
bufferStream(deflate, function(data) {
this.emit('deflated', data);
}.bind(this));
deflate.on('error', this.emit.bind(this, 'error'));
deflate.end(data);
};
function bufferStream(stream, callback) {
var buffers = [],
length = 0;
stream.on('data', function(data) {
buffers.push(data);
length += data.length;
});
stream.on('end', function() {
callback(Buffer.concat(buffers, length));
});
return stream;
};

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// Copyright (c) 2012 Kuba Niegowski
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
'use strict';
var util = require('util'),
zlib = require('zlib'),
events = require('events');
var Filter = module.exports = function(options) {
events.EventEmitter.call(this);
this._options = options;
options.filterType = 'filterType' in options ? options.filterType : -1;
this._width = 0;
this._height = 0;
this._filters = {
0: this._filterNone.bind(this),
1: this._filterSub.bind(this),
2: this._filterUp.bind(this),
3: this._filterAvg.bind(this),
4: this._filterPaeth.bind(this)
};
};
util.inherits(Filter, events.EventEmitter);
Filter.prototype.prepare = function(width, height, type) {
if (type != 0)
throw new Error('Unsupported filter method');
this.width = width;
this.height = height;
};
Filter.prototype.unfilter = function(rawData) {
var pxLineLength = this.width << 2,
rawLineLength = pxLineLength + 1,
pxData = new Buffer(pxLineLength * this.height);
for (var y = 0; y < this.height; y++) {
var rawRowPos = rawLineLength * y + 1,
pxRowPos = y * pxLineLength,
pxUpRowPos = pxRowPos - pxLineLength,
filter = rawData[rawRowPos - 1];
if (filter == 0) {
rawData.copy(pxData, pxRowPos, rawRowPos, rawRowPos + pxLineLength);
} else if (filter == 1) {
for (var x = 0; x < pxLineLength; x++) {
var left = x >= 4 ? pxData[pxRowPos + x - 4] : 0;
pxData[pxRowPos + x] = rawData[rawRowPos + x] + left;
}
} else if (filter == 2) {
for (var x = 0; x < pxLineLength; x++) {
var up = y > 0 ? pxData[pxUpRowPos + x] : 0;
pxData[pxRowPos + x] = rawData[rawRowPos + x] + up;
}
} else if (filter == 3) {
for (var x = 0; x < pxLineLength; x++) {
var left = x >= 4 ? pxData[pxRowPos + x - 4] : 0,
up = y > 0 ? pxData[pxUpRowPos + x] : 0;
pxData[pxRowPos + x] = rawData[rawRowPos + x]
+ Math.floor((left + up) / 2);
}
} else if (filter == 4) {
for (var x = 0; x < pxLineLength; x++) {
var left = x >= 4 ? pxData[pxRowPos + x - 4] : 0,
up = y > 0 ? pxData[pxUpRowPos + x] : 0,
upLeft = x >= 4 && y > 0 ? pxData[pxUpRowPos + x - 4] : 0;
pxData[pxRowPos + x] = rawData[rawRowPos + x]
+ PaethPredictor(left, up, upLeft)
}
}
}
return pxData;
};
Filter.prototype.filter = function(pxData, width, height) {
var rawData = new Buffer(((width << 2) + 1) * height);
for (var y = 0; y < height; y++) {
// find best filter for this line (with lowest sum of values)
if (this._options.filterType == -1) {
var min = Infinity,
sel = 0;
for (var f in this._filters) {
var sum = this._filters[f](pxData, y, width, height, null);
if (sum < min) {
sel = f;
min = sum;
}
}
} else {
sel = this._options.filterType;
}
this._filters[sel](pxData, y, width, height, rawData);
}
return rawData;
};
Filter.prototype._filterNone = function(pxData, y, width, height, rawData) {
var pxRowLength = width << 2,
rawRowLength = pxRowLength + 1,
sum = 0;
if (!rawData) {
for (var x = 0; x < pxRowLength; x++)
sum += pxData[y * pxRowLength + x];
} else {
rawData[y * rawRowLength] = 0;
pxData.copy(rawData, rawRowLength * y + 1, pxRowLength * y, pxRowLength * (y + 1));
}
return sum;
};
Filter.prototype._filterSub = function(pxData, y, width, height, rawData) {
var pxRowLength = width << 2,
rawRowLength = pxRowLength + 1,
sum = 0;
if (rawData)
rawData[y * rawRowLength] = 1;
for (var x = 0; x < pxRowLength; x++) {
var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
val = pxData[y * pxRowLength + x] - left;
if (!rawData) sum += val;
else rawData[y * rawRowLength + 1 + x] = val;
}
return sum;
};
Filter.prototype._filterUp = function(pxData, y, width, height, rawData) {
var pxRowLength = width << 2,
rawRowLength = pxRowLength + 1,
sum = 0;
if (rawData)
rawData[y * rawRowLength] = 2;
for (var x = 0; x < pxRowLength; x++) {
var up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
val = pxData[y * pxRowLength + x] - up;
if (!rawData) sum += val;
else rawData[y * rawRowLength + 1 + x] = val;
}
return sum;
};
Filter.prototype._filterAvg = function(pxData, y, width, height, rawData) {
var pxRowLength = width << 2,
rawRowLength = pxRowLength + 1,
sum = 0;
if (rawData)
rawData[y * rawRowLength] = 3;
for (var x = 0; x < pxRowLength; x++) {
var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
val = pxData[y * pxRowLength + x] - ((left + up) >> 1);
if (!rawData) sum += val;
else rawData[y * rawRowLength + 1 + x] = val;
}
return sum;
};
Filter.prototype._filterPaeth = function(pxData, y, width, height, rawData) {
var pxRowLength = width << 2,
rawRowLength = pxRowLength + 1,
sum = 0;
if (rawData)
rawData[y * rawRowLength] = 4;
for (var x = 0; x < pxRowLength; x++) {
var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
upLeft = x >= 4 && y > 0 ? pxData[(y - 1) * pxRowLength + x - 4] : 0,
val = pxData[y * pxRowLength + x] - PaethPredictor(left, up, upLeft);
if (!rawData) sum += val;
else rawData[y * rawRowLength + 1 + x] = val;
}
return sum;
};
var PaethPredictor = function(left, above, upLeft) {
var p = left + above - upLeft,
pLeft = Math.abs(p - left),
pAbove = Math.abs(p - above),
pUpLeft = Math.abs(p - upLeft);
if (pLeft <= pAbove && pLeft <= pUpLeft) return left;
else if (pAbove <= pUpLeft) return above;
else return upLeft;
};

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// Copyright (c) 2012 Kuba Niegowski
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
'use strict';
var util = require('util'),
Stream = require('stream'),
Compress = require('./compress'),
Filter = require('./filter');
var signature = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
var TYPE_IHDR = 0x49484452;
var TYPE_IEND = 0x49454e44;
var TYPE_IDAT = 0x49444154;
var Parser = module.exports = function(options) {
Stream.call(this);
this._options = options;
options.checkCRC = options.checkCRC !== false;
this._hasIHDR = false;
this._hasIEND = false;
this._chunks = {};
this._chunks[TYPE_IHDR] = this._parseIHDR.bind(this);
this._chunks[TYPE_IEND] = this._parseIEND.bind(this);
this._chunks[TYPE_IDAT] = this._parseIDAT.bind(this);
this._compress = new Compress(options);
this._filter = new Filter(options);
this._initCompress();
};
util.inherits(Parser, Stream);
Parser.prototype._initCompress = function() {
this._compress.on('error', this.emit.bind(this, 'error'));
this._compress.on('deflated', this._packData.bind(this));
this._compress.on('inflated', function(data) {
this.emit('parsed', this._filter.unfilter(data));
}.bind(this));
};
Parser.prototype._parse = function(data) {
var idx = 0;
try {
// check PNG file signature
while (idx < signature.length) {
if (data[idx] != signature[idx]) {
throw new Error('Invalid file signature');
}
idx++;
}
//console.log('Signature is ok');
// iterate chunks
while (idx < data.length) {
idx = this._parseChunk(data, idx);
}
}
catch(err) {
this.emit('error', err);
}
};
Parser.prototype._pack = function(width, height, data) {
// Signature
this.emit('data', new Buffer(signature));
this.emit('data', this._packIHDR(width, height));
// filter pixel data
var data = this._filter.filter(data, width, height);
// compress it
this._compress.deflate(data);
};
Parser.prototype._packData = function(data) {
// console.log('deflate', data.length);
this.emit('data', this._packIDAT(data));
this.emit('data', this._packIEND());
this.emit('end');
};
Parser.prototype._parseChunk = function(data, idx) {
if (this._hasIEND)
throw new Error('Not expected chunk after IEND');
// chunk size (only content)
var length = data.readUInt32BE(idx);
idx += 4;
// chunk type
var type = data.readUInt32BE(idx),
ancillary = !!(data[idx] & 0x20), // or critical
priv = !!(data[idx+1] & 0x20), // or public
safeToCopy = !!(data[idx+3] & 0x20), // or unsafe
name = '';
for (var i = 0; i < 4; i++)
name += String.fromCharCode(data[idx+i]);
idx += 4;
// console.log('chunk ', name, length);
// calc CRC (of chunk type and content)
var calcCrc = crc32(data.slice(idx - 4, idx + length)),
content = data.slice(idx, idx + length);
idx += length;
// read CRC
var fileCrc = data.readInt32BE(idx);
idx += 4;
// and check CRC
if (this._options.checkCRC && calcCrc != fileCrc)
throw new Error('Crc error');
if (!this._hasIHDR && type != TYPE_IHDR)
throw new Error('Expected IHDR on beggining');
if (this._chunks[type]) {
this._chunks[type](content);
} else if (!ancillary)
throw new Error('Unsupported critical chunk type ' + name);
return idx;
};
Parser.prototype._packChunk = function(type, data) {
var len = (data ? data.length : 0),
buf = new Buffer(len + 12);
buf.writeUInt32BE(len, 0);
buf.writeUInt32BE(type, 4);
if (data) data.copy(buf, 8);
buf.writeInt32BE(crc32(buf.slice(4, buf.length - 4)), buf.length - 4);
return buf;
};
Parser.prototype._parseIHDR = function(data) {
var width = data.readUInt32BE(0),
height = data.readUInt32BE(4),
depth = data[8],
colorType = data[9], // 1 palette, 2 color, 4 alpha
compr = data[10],
filter = data[11],
interlace = data[12];
// console.log(' width', width, 'height', height,
// 'depth', depth, 'colorType', colorType,
// 'compr', compr, 'filter', filter, 'interlace', interlace
// );
if (depth != 8)
throw new Error('Unsupported bit depth');
if (colorType != 6)
throw new Error('Unsupported color type');
if (interlace != 0)
throw new Error('Unsupported interlace method');
this._compress.prepareInflate(compr);
this._filter.prepare(width, height, filter);
this._hasIHDR = true;
this.emit('metadata', width, height);
};
Parser.prototype._packIHDR = function(width, height) {
var buf = new Buffer(13);
buf.writeUInt32BE(width, 0);
buf.writeUInt32BE(height, 4);
buf[8] = 8;
buf[9] = 6; // colorType
buf[10] = 0; // compression
buf[11] = 0; // filter
buf[12] = 0; // interlace
return this._packChunk(TYPE_IHDR, buf);
};
Parser.prototype._parseIDAT = function(data) {
this._compress.writeInflate(data);
};
Parser.prototype._packIDAT = function(data) {
return this._packChunk(TYPE_IDAT, data);
};
Parser.prototype._parseIEND = function(data) {
// no more data to inflate
this._compress.endInflate();
this._hasIEND = true;
};
Parser.prototype._packIEND = function() {
return this._packChunk(TYPE_IEND, null);
};
// prepare crc table as in PNG Specification
var crcTable = [];
for (var i = 0; i < 256; i++) {
var c = i;
for (var j = 0; j < 8; j++) {
if (c & 1) {
c = 0xedb88320 ^ (c >>> 1);
} else {
c = c >>> 1;
}
}
crcTable[i] = c;
}
function crc32(buf) {
var crc = -1;
for (var i = 0; i < buf.length; i++) {
crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
}
return crc ^ -1;
}

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// Copyright (c) 2012 Kuba Niegowski
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
'use strict';
var util = require('util'),
Parser = require('./parser');
var PNG = exports.PNG = function(options) {
Parser.call(this, options);
this.width = options.width || 0;
this.height = options.height || 0;
this.data = this.width > 0 && this.height > 0
? new Buffer(4 * this.width * this.height) : null;
this.on('metadata', this._metadata.bind(this));
this.readable = this.writable = true;
this._buffers = [];
this._buffLen = 0;
this.on('parsed', function(data) {
this.data = data;
}.bind(this));
};
util.inherits(PNG, Parser);
PNG.prototype.pack = function() {
this._pack(this.width, this.height, this.data);
};
PNG.prototype.parse = function(data, callback) {
if (callback) {
var onParsed = null, onError = null;
this.once('parsed', onParsed = function(data) {
this.removeListener('error', onError);
this.data = data;
callback(null, this);
}.bind(this));
this.once('error', onError = function(err) {
this.removeListener('parsed', onParsed);
callback(err, null);
}.bind(this));
}
this._parse(data);
};
PNG.prototype.write = function(data) {
this._buffers.push(data);
this._buffLen += data.length;
};
PNG.prototype.end = function(data) {
if (data) this.write(data);
this._parse(Buffer.concat(this._buffers, this._buffLen));
this._buffers = [];
this._buffLen = 0;
};
PNG.prototype._metadata = function(width, height) {
this.width = width;
this.height = height;
this.data = null;
};

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{
"name": "pngjs",
"version": "0.1.0-alpha",
"description": "Simple PNG encoder/decoder",
"author": "Kuba Niegowski",
"contributors": [],
"homepage": "https://github.com/niegowski/node-pngjs/",
"keywords" : [
"png"
],
"engines": {
"node": "0.8.x"
},
"main": "./lib/png.js"
}