pngjs-image
Version:
JavaScript-based PNG image encoder, decoder, and manipulator
327 lines (283 loc) • 6.64 kB
JavaScript
// Copyright 2015 Yahoo! Inc.
// Copyrights licensed under the Mit License. See the accompanying LICENSE file for terms.
/**
* @class cHRM
* @module PNG
* @submodule PNGChunks
*/
module.exports = {
/**
* Gets the sequence
*
* @method getSequence
* @return {int}
*/
getSequence: function () {
return 200;
},
/**
* Gets the white-point x value
*
* @method getWhitePointX
* @return {float}
*/
getWhitePointX: function () {
return this._whitePointX || 1;
},
/**
* Sets the white-point x value
*
* @method setWhitePointX
* @param {float} value
*/
setWhitePointX: function (value) {
this._whitePointX = value;
},
/**
* Gets the white-point y value
*
* @method getWhitePointY
* @return {float}
*/
getWhitePointY: function () {
return this._whitePointY || 1;
},
/**
* Sets the white-point y value
*
* @method setWhitePointY
* @param {float} value
*/
setWhitePointY: function (value) {
this._whitePointY = value;
},
/**
* Gets the red x value
*
* @method getRedX
* @return {float}
*/
getRedX: function () {
return this._redX || 1;
},
/**
* Sets the red x value
*
* @method setRedX
* @param {float} value
*/
setRedX: function (value) {
this._redX = value;
},
/**
* Gets the red y value
*
* @method getRedY
* @return {float}
*/
getRedY: function () {
return this._redY || 1;
},
/**
* Sets the red y value
*
* @method setRedY
* @param {float} value
*/
setRedY: function (value) {
this._redY = value;
},
/**
* Gets the green x value
*
* @method getGreenX
* @return {float}
*/
getGreenX: function () {
return this._greenX || 1;
},
/**
* Sets the green x value
*
* @method setGreenX
* @param {float} value
*/
setGreenX: function (value) {
this._greenX = value;
},
/**
* Gets the green y value
*
* @method getGreenY
* @return {float}
*/
getGreenY: function () {
return this._greenY || 1;
},
/**
* Sets the green y value
*
* @method setGreenY
* @param {float} value
*/
setGreenY: function (value) {
this._greenY = value;
},
/**
* Gets the blue x value
*
* @method getBlueX
* @return {float}
*/
getBlueX: function () {
return this._blueX || 1;
},
/**
* Sets the blue x value
*
* @method setBlueX
* @param {float} value
*/
setBlueX: function (value) {
this._blueX = value;
},
/**
* Gets the blue y value
*
* @method getBlueY
* @return {float}
*/
getBlueY: function () {
return this._blueY || 1;
},
/**
* Sets the blue y value
*
* @method setBlueY
* @param {float} value
*/
setBlueY: function (value) {
this._blueY = value;
},
/**
* Parsing of chunk data
*
* Phase 1
*
* @method parse
* @param {BufferedStream} stream Data stream
* @param {int} length Length of chunk data
* @param {boolean} strict Should parsing be strict?
* @param {object} options Decoding options
*/
parse: function (stream, length, strict, options) {
// Validation
if (strict && (this.getFirstChunk(this.getType(), false) !== null)) {
throw new Error('Only one ' + this.getType() + ' is allowed in the data.');
}
if ((strict && (length !== 32)) || (length < 32)) {
throw new Error('The ' + this.getType() + ' chunk requires a length of 32 but got ' + length + '.');
}
this.setWhitePointX(stream.readUInt32BE() / 100000);
this.setWhitePointY(stream.readUInt32BE() / 100000);
this.setRedX(stream.readUInt32BE() / 100000);
this.setRedY(stream.readUInt32BE() / 100000);
this.setGreenX(stream.readUInt32BE() / 100000);
this.setGreenY(stream.readUInt32BE() / 100000);
this.setBlueX(stream.readUInt32BE() / 100000);
this.setBlueY(stream.readUInt32BE() / 100000);
},
/**
* Gathers chunk-data from decoded chunks
*
* Phase 5
*
* @static
* @method decodeData
* @param {object} data Data-object that will be used to export values
* @param {boolean} strict Should parsing be strict?
* @param {object} options Decoding options
*/
decodeData: function (data, strict, options) {
var chunks = this.getChunksByType(this.getType());
if (!chunks) {
return ;
}
if (strict && (chunks.length !== 1)) {
throw new Error('Not more than one chunk allowed for ' + this.getType() + '.');
}
data.volatile = data.volatile || {};
data.volatile.chromaticities = {
whitePointX: chunks[0].getWhitePointX(),
whitePointY: chunks[0].getWhitePointY(),
redX: chunks[0].getRedX(),
redY: chunks[0].getRedY(),
greenX: chunks[0].getGreenX(),
greenY: chunks[0].getGreenY(),
blueX: chunks[0].getBlueX(),
blueY: chunks[0].getBlueY()
};
},
/**
* Returns a list of chunks to be added to the data-stream
*
* Phase 1
*
* @static
* @method encodeData
* @param {Buffer} image Image data
* @param {object} options Encoding options
* @return {Chunk[]} List of chunks to encode
*/
encodeData: function (image, options) {
if (options.chromaticities) {
var chunk = this.createChunk(this.getType(), this.getChunks());
if (options.chromaticities.whitePointX !== undefined) {
chunk.setWhitePointX(options.chromaticities.whitePointX);
}
if (options.chromaticities.whitePointY !== undefined) {
chunk.setWhitePointY(options.chromaticities.whitePointY);
}
if (options.chromaticities.redX !== undefined) {
chunk.setRedX(options.chromaticities.redX);
}
if (options.chromaticities.redY !== undefined) {
chunk.setRedY(options.chromaticities.redY);
}
if (options.chromaticities.greenX !== undefined) {
chunk.setGreenX(options.chromaticities.greenX);
}
if (options.chromaticities.greenY !== undefined) {
chunk.setGreenY(options.chromaticities.greenY);
}
if (options.chromaticities.blueX !== undefined) {
chunk.setBlueX(options.chromaticities.blueX);
}
if (options.chromaticities.blueY !== undefined) {
chunk.setBlueY(options.chromaticities.blueY);
}
return [chunk];
} else {
return [];
}
},
/**
* Composing of chunk data
*
* Phase 4
*
* @method compose
* @param {BufferedStream} stream Data stream
* @param {object} options Encoding options
*/
compose: function (stream, options) {
stream.writeUInt32BE(this.getWhitePointX() * 100000);
stream.writeUInt32BE(this.getWhitePointY() * 100000);
stream.writeUInt32BE(this.getRedX() * 100000);
stream.writeUInt32BE(this.getRedY() * 100000);
stream.writeUInt32BE(this.getGreenX() * 100000);
stream.writeUInt32BE(this.getGreenY() * 100000);
stream.writeUInt32BE(this.getBlueX() * 100000);
stream.writeUInt32BE(this.getBlueY() * 100000);
}
};