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add ability to write gamma chunks

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This commit is contained in:
Luke Page 2015-08-05 17:00:37 +01:00
parent bf5ae3c54e
commit ff9d322a36
4 changed files with 14 additions and 5 deletions
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12
lib/packer.js
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@ -43,12 +43,16 @@ var Packer = module.exports = function(options) {
util.inherits(Packer, Stream);
Packer.prototype.pack = function(data, width, height) {
Packer.prototype.pack = function(data, width, height, gamma) {
// Signature
this.emit('data', new Buffer(constants.PNG_SIGNATURE));
this.emit('data', this._packIHDR(width, height));
if (gamma) {
this.emit('data', this._packGAMA(gamma));
}
// filter pixel data
//TODO {}
var filter = new Filter(width, height, 4, 8, false, this._options, {});
@ -88,6 +92,12 @@ Packer.prototype._packChunk = function(type, data) {
return buf;
};
Packer.prototype._packGAMA = function(gamma) {
var buf = new Buffer(4);
buf.writeUInt32BE(Math.floor(gamma * 100000), 0); // TODO constant
return this._packChunk(constants.TYPE_gAMA, buf);
};
Packer.prototype._packIHDR = function(width, height) {
var buf = new Buffer(13);

2
lib/parser.js
View file

@ -270,7 +270,7 @@ Parser.prototype._handleGAMA = function(length) {
Parser.prototype._parseGAMA = function(data) {
this._crc.write(data);
this.gamma(data.readUInt32BE(0) / 100000);
this.gamma(data.readUInt32BE(0) / 100000); //TODO constant
this._handleChunkEnd();
};

2
lib/png.js
View file

@ -71,7 +71,7 @@ PNG.sync = PNGSync;
PNG.prototype.pack = function() {
process.nextTick(function() {
this._packer.pack(this.data, this.width, this.height);
this._packer.pack(this.data, this.width, this.height, this.gamma);
}.bind(this));
return this;

3
test/convert-images.js
View file

@ -51,7 +51,7 @@ module.exports = function(done) {
} else {
var outpng = new PNG();
//PNG.adjustGamma(png);
outpng.gamma = png.gamma;
outpng.data = png.data;
outpng.width = png.width;
outpng.height = png.height;
@ -76,7 +76,6 @@ module.exports = function(done) {
if (expectedError) {
console.log("Async: Error expected, parsed fine ..", file);
}
//this.adjustGamma();
this.pack()
.pipe(