// Copyright 2014-2015 Yahoo! Inc.
// Copyrights licensed under the Mit License. See the accompanying LICENSE file for terms.
var assert = require('assert'),
PNGImage = require('pngjs-image'),
Promise = require('promise');
/**
* Blink-diff comparison class
*
* @constructor
* @class BlinkDiff
* @param {object} options
* @param {PNGImage|Buffer} options.imageA Image object of first image
* @param {string} options.imageAPath Path to first image
* @param {PNGImage|Buffer} options.imageB Image object of second image
* @param {string} options.imageBPath Path to second image
* @param {string} [options.imageOutputPath=undefined] Path to output image file
* @param {int} [options.imageOutputLimit=BlinkDiff.OUTPUT_ALL] Determines when an image output is created
* @param {string} [options.thresholdType=BlinkDiff.THRESHOLD_PIXEL] Defines the threshold of the comparison
* @param {int} [options.threshold=500] Threshold limit according to the comparison limit.
* @param {number} [options.delta=20] Distance between the color coordinates in the 4 dimensional color-space that will not trigger a difference.
* @param {int} [options.outputMaskRed=255] Value to set for red on difference pixel. 'Undefined' will not change the value.
* @param {int} [options.outputMaskGreen=0] Value to set for green on difference pixel. 'Undefined' will not change the value.
* @param {int} [options.outputMaskBlue=0] Value to set for blue on difference pixel. 'Undefined' will not change the value.
* @param {int} [options.outputMaskAlpha=255] Value to set for the alpha channel on difference pixel. 'Undefined' will not change the value.
* @param {float} [options.outputMaskOpacity=0.7] Strength of masking the pixel. 1.0 means that the full color will be used; anything less will mix-in the original pixel.
* @param {int} [options.outputShiftRed=255] Value to set for red on shifted pixel. 'Undefined' will not change the value.
* @param {int} [options.outputShiftGreen=165] Value to set for green on shifted pixel. 'Undefined' will not change the value.
* @param {int} [options.outputShiftBlue=0] Value to set for blue on shifted pixel. 'Undefined' will not change the value.
* @param {int} [options.outputShiftAlpha=255] Value to set for the alpha channel on shifted pixel. 'Undefined' will not change the value.
* @param {float} [options.outputShiftOpacity=0.7] Strength of masking the shifted pixel. 1.0 means that the full color will be used; anything less will mix-in the original pixel.
* @param {int} [options.outputBackgroundRed=0] Value to set for red as background. 'Undefined' will not change the value.
* @param {int} [options.outputBackgroundGreen=0] Value to set for green as background. 'Undefined' will not change the value.
* @param {int} [options.outputBackgroundBlue=0] Value to set for blue as background. 'Undefined' will not change the value.
* @param {int} [options.outputBackgroundAlpha=undefined] Value to set for the alpha channel as background. 'Undefined' will not change the value.
* @param {float} [options.outputBackgroundOpacity=0.6] Strength of masking the pixel. 1.0 means that the full color will be used; anything less will mix-in the original pixel.
* @param {object|object[]} [options.blockOut] Object or list of objects with coordinates of blocked-out areas.
* @param {int} [options.blockOutRed=0] Value to set for red on blocked-out pixel. 'Undefined' will not change the value.
* @param {int} [options.blockOutGreen=0] Value to set for green on blocked-out pixel. 'Undefined' will not change the value.
* @param {int} [options.blockOutBlue=0] Value to set for blue on blocked-out pixel. 'Undefined' will not change the value.
* @param {int} [options.blockOutAlpha=255] Value to set for the alpha channel on blocked-out pixel. 'Undefined' will not change the value.
* @param {float} [options.blockOutOpacity=1.0] Strength of masking the blocked-out pixel. 1.0 means that the full color will be used; anything less will mix-in the original pixel.
* @param {boolean} [options.copyImageAToOutput=true] Copies the first image to the output image before the comparison begins. This will make sure that the output image will highlight the differences on the first image.
* @param {boolean} [options.copyImageBToOutput=false] Copies the second image to the output image before the comparison begins. This will make sure that the output image will highlight the differences on the second image.
* @param {string[]} [options.filter=[]] Filters that will be applied before the comparison. Available filters are: blur, grayScale, lightness, luma, luminosity, sepia
* @param {boolean} [options.debug=false] When set, then the applied filters will be shown on the output image.
* @param {boolean} [options.composition=true] Should a composition be created to compare?
* @param {boolean} [options.composeLeftToRight=false] Create composition from left to right, otherwise let it decide on its own whats best
* @param {boolean} [options.composeTopToBottom=false] Create composition from top to bottom, otherwise let it decide on its own whats best
* @param {boolean} [options.hideShift=false] Hides shift highlighting by using the background color instead
* @param {int} [options.hShift=2] Horizontal shift for possible antialiasing
* @param {int} [options.vShift=2] Vertical shift for possible antialiasing
* @param {object} [options.cropImageA=null] Cropping for first image (default: no cropping)
* @param {int} [options.cropImageA.x=0] Coordinate for left corner of cropping region
* @param {int} [options.cropImageA.y=0] Coordinate for top corner of cropping region
* @param {int} [options.cropImageA.width] Width of cropping region (default: Width that is left)
* @param {int} [options.cropImageA.height] Height of cropping region (default: Height that is left)
* @param {object} [options.cropImageB=null] Cropping for second image (default: no cropping)
* @param {int} [options.cropImageB.x=0] Coordinate for left corner of cropping region
* @param {int} [options.cropImageB.y=0] Coordinate for top corner of cropping region
* @param {int} [options.cropImageB.width] Width of cropping region (default: Width that is left)
* @param {int} [options.cropImageB.height] Height of cropping region (default: Height that is left)
* @param {boolean} [options.perceptual=false] Turns perceptual comparison on
* @param {float} [options.gamma] Gamma correction for all colors
* @param {float} [options.gammaR] Gamma correction for red
* @param {float} [options.gammaG] Gamma correction for green
* @param {float} [options.gammaB] Gamma correction for blue
*
* @property {PNGImage} _imageA
* @property {PNGImage} _imageACompare
* @property {string} _imageAPath
* @property {PNGImage} _imageB
* @property {PNGImage} _imageBCompare
* @property {string} _imageBPath
* @property {PNGImage} _imageOutput
* @property {string} _imageOutputPath
* @property {int} _imageOutputLimit
* @property {string} _thresholdType
* @property {int} _threshold
* @property {number} _delta
* @property {int} _outputMaskRed
* @property {int} _outputMaskGreen
* @property {int} _outputMaskBlue
* @property {int} _outputMaskAlpha
* @property {float} _outputMaskOpacity
* @property {int} _outputShiftRed
* @property {int} _outputShiftGreen
* @property {int} _outputShiftBlue
* @property {int} _outputShiftAlpha
* @property {float} _outputShiftOpacity
* @property {int} _outputBackgroundRed
* @property {int} _outputBackgroundGreen
* @property {int} _outputBackgroundBlue
* @property {int} _outputBackgroundAlpha
* @property {float} _outputBackgroundOpacity
* @property {object[]} _blockOut
* @property {int} _blockOutRed
* @property {int} _blockOutGreen
* @property {int} _blockOutBlue
* @property {int} _blockOutAlpha
* @property {float} _blockOutOpacity
* @property {boolean} _copyImageAToOutput
* @property {boolean} _copyImageBToOutput
* @property {string[]} _filter
* @property {boolean} _debug
* @property {boolean} _composition
* @property {boolean} _composeLeftToRight
* @property {boolean} _composeTopToBottom
* @property {int} _hShift
* @property {int} _vShift
* @property {object} _cropImageA
* @property {int} _cropImageA.x
* @property {int} _cropImageA.y
* @property {int} _cropImageA.width
* @property {int} _cropImageA.height
* @property {object} _cropImageB
* @property {int} _cropImageB.x
* @property {int} _cropImageB.y
* @property {int} _cropImageB.width
* @property {int} _cropImageB.height
* @property {object} _refWhite
* @property {boolean} _perceptual
* @property {float} _gamma
* @property {float} _gammaR
* @property {float} _gammaG
* @property {float} _gammaB
*/
function BlinkDiff (options) {
this._imageA = options.imageA;
this._imageAPath = options.imageAPath;
assert.ok(options.imageAPath || options.imageA, "Image A not given.");
this._imageB = options.imageB;
this._imageBPath = options.imageBPath;
assert.ok(options.imageBPath || options.imageB, "Image B not given.");
this._imageOutput = null;
this._imageOutputPath = options.imageOutputPath;
this._imageOutputLimit = options.imageOutputLimit || BlinkDiff.OUTPUT_ALL;
// Pixel or Percent
this._thresholdType = options.thresholdType || BlinkDiff.THRESHOLD_PIXEL;
// How many pixels different to ignore.
this._threshold = options.threshold || 500;
this._delta = options.delta || 20;
this._outputMaskRed = options.outputMaskRed || 255;
this._outputMaskGreen = options.outputMaskGreen || 0;
this._outputMaskBlue = options.outputMaskBlue || 0;
this._outputMaskAlpha = options.outputMaskAlpha || 255;
this._outputMaskOpacity = options.outputMaskOpacity || 0.7;
this._outputBackgroundRed = options.outputBackgroundRed || 0;
this._outputBackgroundGreen = options.outputBackgroundGreen || 0;
this._outputBackgroundBlue = options.outputBackgroundBlue || 0;
this._outputBackgroundAlpha = options.outputBackgroundAlpha;
this._outputBackgroundOpacity = options.outputBackgroundOpacity || 0.6;
if (options.hideShift) {
this._outputShiftRed = this._outputBackgroundRed;
this._outputShiftGreen = this._outputBackgroundGreen;
this._outputShiftBlue = this._outputBackgroundBlue;
this._outputShiftAlpha = this._outputBackgroundAlpha;
this._outputShiftOpacity = this._outputBackgroundOpacity;
} else {
this._outputShiftRed = options.outputShiftRed || 200;
this._outputShiftGreen = options.outputShiftGreen || 100;
this._outputShiftBlue = options.outputShiftBlue || 0;
this._outputShiftAlpha = options.outputShiftAlpha || 255;
this._outputShiftOpacity = options.outputShiftOpacity || 0.7;
}
this._blockOut = options.blockOut || [];
if (typeof this._blockOut != 'object' && (this._blockOut.length !== undefined)) {
this._blockOut = [this._blockOut];
}
this._blockOutRed = options.blockOutRed || 0;
this._blockOutGreen = options.blockOutGreen || 0;
this._blockOutBlue = options.blockOutBlue || 0;
this._blockOutAlpha = options.blockOutAlpha || 255;
this._blockOutOpacity = options.blockOutOpacity || 1.0;
this._copyImageAToOutput = options.copyImageAToOutput || true;
this._copyImageBToOutput = options.copyImageBToOutput || false;
this._filter = options.filter || [];
this._debug = options.debug || false;
this._composition = options.composition || true;
this._composeLeftToRight = options.composeLeftToRight || false;
this._composeTopToBottom = options.composeTopToBottom || false;
this._hShift = options.hShift || 2;
this._vShift = options.vShift || 2;
this._cropImageA = options.cropImageA;
this._cropImageB = options.cropImageB;
// Prepare reference white
this._refWhite = this._convertRgbToXyz({c1: 1, c2: 1, c3: 1, c4: 1});
this._perceptual = options.perceptual || false;
this._gamma = options.gamma;
this._gammaR = options.gammaR;
this._gammaG = options.gammaG;
this._gammaB = options.gammaB;
}
/**
* Version of class
*
* @static
* @property version
* @type {string}
*/
BlinkDiff.version = require('./package.json').version;
/**
* Threshold-type for pixel
*
* @static
* @property THRESHOLD_PIXEL
* @type {string}
*/
BlinkDiff.THRESHOLD_PIXEL = 'pixel';
/**
* Threshold-type for percent of all pixels
*
* @static
* @property THRESHOLD_PERCENT
* @type {string}
*/
BlinkDiff.THRESHOLD_PERCENT = 'percent';
/**
* Unknown result of the comparison
*
* @static
* @property RESULT_UNKNOWN
* @type {int}
*/
BlinkDiff.RESULT_UNKNOWN = 0;
/**
* The images are too different
*
* @static
* @property RESULT_DIFFERENT
* @type {int}
*/
BlinkDiff.RESULT_DIFFERENT = 1;
/**
* The images are very similar, but still below the threshold
*
* @static
* @property RESULT_SIMILAR
* @type {int}
*/
BlinkDiff.RESULT_SIMILAR = 7;
/**
* The images are identical (or near identical)
*
* @static
* @property RESULT_IDENTICAL
* @type {int}
*/
BlinkDiff.RESULT_IDENTICAL = 5;
/**
* Create output when images are different
*
* @static
* @property OUTPUT_DIFFERENT
* @type {int}
*/
BlinkDiff.OUTPUT_DIFFERENT = 10;
/**
* Create output when images are similar or different
*
* @static
* @property OUTPUT_SIMILAR
* @type {int}
*/
BlinkDiff.OUTPUT_SIMILAR = 20;
/**
* Force output of all comparisons
*
* @static
* @property OUTPUT_ALL
* @type {int}
*/
BlinkDiff.OUTPUT_ALL = 100;
BlinkDiff.prototype = {
/**
* Runs the comparison with a promise
*
* @method runWithPromise
* @example
* var blinkDiff = BlinkDiff(...);
* blinkDiff.runWithPromise().then(function (result) {
* ...
* });
* @return {Promise}
*/
runWithPromise: function () {
return Promise.denodeify(this.run).call(this);
},
/**
* Runs the comparison in node-style
*
* @method run
* @example
* var blinkDiff = BlinkDiff(...);
* blinkDiff.run(function (err, result) {
* if (err) {
* throw err;
* }
*
* ...
* });
*
* @param {function} fn
*/
run: function (fn) {
var promise = Promise.resolve(), result;
PNGImage.log = function (text) {
this.log('ERROR: ' + text);
throw new Error('ERROR: ' + text);
}.bind(this);
promise.then(function () {
return this._loadImage(this._imageAPath, this._imageA);
}.bind(this)).then(function (imageA) {
this._imageA = imageA;
return this._loadImage(this._imageBPath, this._imageB);
}.bind(this)).then(function (imageB) {
var gamma, i, len, rect, color;
this._imageB = imageB;
// Crop images if requested
if (this._cropImageA) {
this._correctDimensions(this._imageA.getWidth(), this._imageA.getHeight(), this._cropImageA);
this._crop("Image-A", this._imageA, this._cropImageA);
}
if (this._cropImageB) {
this._correctDimensions(this._imageB.getWidth(), this._imageB.getHeight(), this._cropImageB);
this._crop("Image-B", this._imageB, this._cropImageB);
}
// Always clip
this._clip(this._imageA, this._imageB);
this._imageOutput = PNGImage.createImage(this._imageA.getWidth(), this._imageA.getHeight());
// Make a copy when not in debug mode
if (this._debug) {
this._imageACompare = this._imageA;
this._imageBCompare = this._imageB;
} else {
this._imageACompare = PNGImage.copyImage(this._imageA);
this._imageBCompare = PNGImage.copyImage(this._imageB);
}
// Block-out
color = {
red: this._blockOutRed,
green: this._blockOutGreen,
blue: this._blockOutBlue,
alpha: this._blockOutAlpha,
opacity: this._blockOutOpacity
};
for (i = 0, len = this._blockOut.length; i < len; i++) {
rect = this._blockOut[i];
// Make sure the block-out parameters fit
this._correctDimensions(this._imageACompare.getWidth(), this._imageACompare.getHeight(), rect);
this._imageACompare.fillRect(rect.x, rect.y, rect.width, rect.height, color);
this._imageBCompare.fillRect(rect.x, rect.y, rect.width, rect.height, color);
}
// Copy image to composition
if (this._copyImageAToOutput) {
this._copyImage(this._debug ? this._imageACompare : this._imageA, this._imageOutput);
} else if (this._copyImageBToOutput) {
this._copyImage(this._debug ? this._imageBCompare : this._imageB, this._imageOutput);
}
// Apply all filters
this._imageACompare.applyFilters(this._filter);
this._imageBCompare.applyFilters(this._filter);
// Gamma correction
if (this._gamma || this._gammaR || this._gammaG || this._gammaB) {
gamma = {
r: this._gammaR || this._gamma, g: this._gammaG || this._gamma, b: this._gammaB || this._gamma
};
}
// Comparison
result = this._compare(this._imageACompare, this._imageBCompare, this._imageOutput, this._delta, { // Output-Mask color
red: this._outputMaskRed,
green: this._outputMaskGreen,
blue: this._outputMaskBlue,
alpha: this._outputMaskAlpha,
opacity: this._outputMaskOpacity
}, { // Output-Shift color
red: this._outputShiftRed,
green: this._outputShiftGreen,
blue: this._outputShiftBlue,
alpha: this._outputShiftAlpha,
opacity: this._outputShiftOpacity
}, { // Background color
red: this._outputBackgroundRed,
green: this._outputBackgroundGreen,
blue: this._outputBackgroundBlue,
alpha: this._outputBackgroundAlpha,
opacity: this._outputBackgroundOpacity
}, this._hShift, this._vShift, this._perceptual, gamma);
// Create composition if requested
if (this._debug) {
this._imageOutput = this._createComposition(this._imageACompare, this._imageBCompare, this._imageOutput);
} else {
this._imageOutput = this._createComposition(this._imageA, this._imageB, this._imageOutput);
}
// Need to write to the filesystem?
if (this._imageOutputPath && this._withinOutputLimit(result.code, this._imageOutputLimit)) {
this._imageOutput.writeImage(this._imageOutputPath, function (err) {
if (err) {
fn(err);
} else {
this.log("Wrote differences to " + this._imageOutputPath);
fn(undefined, result);
}
}.bind(this));
} else {
fn(undefined, result);
}
}.bind(this)).then(null, function (err) {
console.error(err.stack);
fn(err);
});
},
/**
* Determines if result is within the output limit
*
* @method _withinOutputLimit
* @param {int} resultCode
* @param {int} outputLimit
* @return {boolean}
* @private
*/
_withinOutputLimit: function (resultCode, outputLimit) {
return this._convertResultCodeToRelativeValue(resultCode) <= outputLimit;
},
/**
* Converts the result-code to a relative value
*
* @method _convertResultCodeToRelativeValue
* @param {int} resultCode
* @return {int}
* @private
*/
_convertResultCodeToRelativeValue: function (resultCode) {
var valueMap = {
0: 0, 1: 10, 7: 20, 5: 30
};
return valueMap[resultCode] !== undefined ? valueMap[resultCode] : 0;
},
/**
* Creates a comparison image
*
* @method _createComposition
* @param {PNGImage} imageA
* @param {PNGImage} imageB
* @param {PNGImage} imageOutput
* @return {PNGImage}
* @private
*/
_createComposition: function (imageA, imageB, imageOutput) {
var width, height, image = imageOutput;
if (this._composition) {
width = Math.max(imageA.getWidth(), imageB.getWidth());
height = Math.max(imageA.getHeight(), imageB.getHeight());
if (((width > height) && !this._composeLeftToRight) || this._composeTopToBottom) {
image = PNGImage.createImage(width, height * 3);
imageA.getImage().bitblt(image.getImage(), 0, 0, imageA.getWidth(), imageA.getHeight(), 0, 0);
imageOutput.getImage().bitblt(image.getImage(), 0, 0, imageOutput.getWidth(), imageOutput.getHeight(), 0, height);
imageB.getImage().bitblt(image.getImage(), 0, 0, imageB.getWidth(), imageB.getHeight(), 0, height * 2);
} else {
image = PNGImage.createImage(width * 3, height);
imageA.getImage().bitblt(image.getImage(), 0, 0, imageA.getWidth(), imageA.getHeight(), 0, 0);
imageOutput.getImage().bitblt(image.getImage(), 0, 0, imageOutput.getWidth(), imageOutput.getHeight(), width, 0);
imageB.getImage().bitblt(image.getImage(), 0, 0, imageB.getWidth(), imageB.getHeight(), width * 2, 0);
}
}
return image;
},
/**
* Loads the image or uses the already available image
*
* @method _loadImage
* @param {string} path
* @param {PNGImage} image
* @return {PNGImage|Promise}
* @private
*/
_loadImage: function (path, image) {
if (image instanceof Buffer) {
return Promise.denodeify(PNGImage.loadImage)(image);
} else if ((typeof path === 'string') && !image) {
return Promise.denodeify(PNGImage.readImage)(path);
} else {
return image;
}
},
/**
* Copies one image into another image
*
* @method _copyImage
* @param {PNGImage} imageSrc
* @param {PNGImage} imageDst
* @private
*/
_copyImage: function (imageSrc, imageDst) {
imageSrc.getImage().bitblt(imageDst.getImage(), 0, 0, imageSrc.getWidth(), imageSrc.getHeight(), 0, 0);
},
/**
* Is the difference above the set threshold?
*
* @method isAboveThreshold
* @param {int} items
* @param {int} [total]
* @return {boolean}
*/
isAboveThreshold: function (items, total) {
if ((this._thresholdType === BlinkDiff.THRESHOLD_PIXEL) && (this._threshold <= items)) {
return true;
} else if (this._threshold <= (items / total)) {
return true;
}
return false;
},
/**
* Log method that can be overwritten to modify the logging behavior.
*
* @method log
* @param {string} text
*/
log: function (text) {
// Nothing here; Overwrite this to add some functionality
},
/**
* Has comparison passed?
*
* @method hasPassed
* @param {int} result Comparison result-code
* @return {boolean}
*/
hasPassed: function (result) {
return ((result !== BlinkDiff.RESULT_DIFFERENT) && (result !== BlinkDiff.RESULT_UNKNOWN));
},
/**
* Clips the images to the lower resolution of both
*
* @private
* @method _clip
* @param {PNGImage} imageA Source image
* @param {PNGImage} imageB Destination image
*/
_clip: function (imageA, imageB) {
var minWidth, minHeight;
if ((imageA.getWidth() != imageB.getWidth()) || (imageA.getHeight() != imageB.getHeight())) {
minWidth = imageA.getWidth();
if (imageB.getWidth() < minWidth) {
minWidth = imageB.getWidth();
}
minHeight = imageA.getHeight();
if (imageB.getHeight() < minHeight) {
minHeight = imageB.getHeight();
}
this.log("Clipping to " + minWidth + " x " + minHeight);
imageA.clip(0, 0, minWidth, minHeight);
imageB.clip(0, 0, minWidth, minHeight);
}
},
/**
* Crops the source image to the bounds of rect
*
* @method _crop
* @param {string} which Title of image to crop
* @param {PNGImage} image Source image
* @param {object} rect Values for rect
* @param {int} rect.x X value of rect
* @param {int} rect.y Y value of rect
* @param {int} rect.width Width value of rect
* @param {int} rect.height Height value of rect
* @private
*/
_crop: function (which, image, rect) {
this.log("Cropping " + which + " from " + rect.x + "," + rect.y + " by " + rect.width + " x " + rect.height);
image.clip(rect.x, rect.y, rect.width, rect.height);
},
/**
* Correcting area dimensions if necessary
*
* Note:
* Priority is on the x/y coordinates, and not on the size since the size will then be removed anyways.
*
* @method _correctDimensions
* @param {int} width
* @param {int} height
* @param {object} rect Values for rect
* @param {int} rect.x X value of rect
* @param {int} rect.y Y value of rect
* @param {int} rect.width Width value of rect
* @param {int} rect.height Height value of rect
* @private
*/
_correctDimensions: function (width, height, rect) {
// Set values if none given
rect.x = rect.x || 0;
rect.y = rect.y || 0;
rect.width = rect.width || width;
rect.height = rect.height || height;
// Check negative values
rect.x = Math.max(0, rect.x);
rect.y = Math.max(0, rect.y);
rect.width = Math.max(0, rect.width);
rect.height = Math.max(0, rect.height);
// Check dimensions
rect.x = Math.min(rect.x, width - 1); // -1 to make sure that there is an image
rect.y = Math.min(rect.y, height - 1);
rect.width = Math.min(rect.width, width - rect.x);
rect.height = Math.min(rect.height, height - rect.y);
},
/**
* Calculates the distance of colors in the 4 dimensional color space
*
* @method _colorDelta
* @param {object} color1 Values for color 1
* @param {int} color1.c1 First value of color 1
* @param {int} color1.c2 Second value of color 1
* @param {int} color1.c3 Third value of color 1
* @param {int} color1.c4 Fourth value of color 1
* @param {object} color2 Values for color 2
* @param {int} color2.c1 First value of color 2
* @param {int} color2.c2 Second value of color 2
* @param {int} color2.c3 Third value of color 2
* @param {int} color2.c4 Fourth value of color 2
* @return {number} Distance
* @private
*/
_colorDelta: function (color1, color2) {
var c1, c2, c3, c4;
c1 = Math.pow(color1.c1 - color2.c1, 2);
c2 = Math.pow(color1.c2 - color2.c2, 2);
c3 = Math.pow(color1.c3 - color2.c3, 2);
c4 = Math.pow(color1.c4 - color2.c4, 2);
return Math.sqrt(c1 + c2 + c3 + c4);
},
/**
* Gets the color of an image by the index
*
* @method _getColor
* @param {PNGImage} image Image
* @param {int} idx Index of pixel in image
* @param {boolean} [perceptual=false]
* @param {object} [gamma]
* @return {object} Color
* @private
*/
_getColor: function (image, idx, perceptual, gamma) {
var color;
color = {
c1: image.getRed(idx), c2: image.getGreen(idx), c3: image.getBlue(idx), c4: image.getAlpha(idx)
};
if (perceptual || gamma) {
color = this._correctGamma(color, gamma);
color = this._convertRgbToXyz(color);
color = this._convertXyzToCieLab(color);
}
return color;
},
/**
* Correct gamma and return color in [0, 1] range
*
* @method _correctGamma
* @param {object} color
* @param {object} [gamma]
* @return {{c1: number, c2: number, c3: number, c4: number}}
* @private
*/
_correctGamma: function (color, gamma) {
// Convert to range [0, 1]
var result = {
c1: color.c1 / 255, c2: color.c2 / 255, c3: color.c3 / 255, c4: color.c4
};
if (gamma || gamma.R !== undefined || gamma.G !== undefined || gamma.B !== undefined) {
if (gamma.R !== undefined) {
result.c1 = Math.pow(result.c1, gamma.R);
}
if (gamma.G !== undefined) {
result.c2 = Math.pow(result.c2, gamma.G);
}
if (gamma.B !== undefined) {
result.c3 = Math.pow(result.c3, gamma.B);
}
}
return result;
},
/**
* Converts the color from RGB to XYZ
*
* @method _convertRgbToXyz
* @param {object} color
* @return {object}
* @private
*/
_convertRgbToXyz: function (color) {
var result = {};
result.c1 = color.c1 * 0.4887180 + color.c2 * 0.3106803 + color.c3 * 0.2006017;
result.c2 = color.c1 * 0.1762044 + color.c2 * 0.8129847 + color.c3 * 0.0108109;
result.c3 = color.c2 * 0.0102048 + color.c3 * 0.9897952;
result.c4 = color.c4;
return result;
},
/**
* Converts the color from XYZ to CieLab
*
* @method _convertXyzToCieLab
* @param {object} color
* @return {object}
* @private
*/
_convertXyzToCieLab: function (color) {
var result = {}, c1, c2, c3;
function f (t) {
return (t > 0.00885645167904) ? Math.pow(t, 1 / 3) : 70.08333333333263 * t + 0.13793103448276;
}
c1 = f(color.c1 / this._refWhite.c1);
c2 = f(color.c2 / this._refWhite.c2);
c3 = f(color.c3 / this._refWhite.c3);
result.c1 = (116 * c2) - 16;
result.c2 = 500 * (c1 - c2);
result.c3 = 200 * (c2 - c3);
result.c4 = color.c4;
return result;
},
/**
* Calculates the lower limit
*
* @method _calculateLowerLimit
* @param {int} value
* @param {int} min
* @param {int} shift
* @return {int}
* @private
*/
_calculateLowerLimit: function (value, min, shift) {
return (value - shift) < min ? -(shift + (value - shift)) : -shift;
},
/**
* Calculates the upper limit
*
* @method _calculateUpperLimit
* @param {int} value
* @param {int} max
* @param {int} shift
* @return {int}
* @private
*/
_calculateUpperLimit: function (value, max, shift) {
return (value + shift) > max ? (max - value) : shift;
},
/**
* Checks if any pixel in the shift surrounding has a comparable color
*
* @method _shiftCompare
* @param {int} x
* @param {int} y
* @param {object} color
* @param {number} deltaThreshold
* @param {PNGImage} imageA
* @param {PNGImage} imageB
* @param {int} width
* @param {int} height
* @param {int} hShift
* @param {int} vShift
* @param {boolean} [perceptual=false]
* @param {object} [gamma]
* @return {boolean} Is pixel within delta found in surrounding?
* @private
*/
_shiftCompare: function (x, y, color, deltaThreshold, imageA, imageB, width, height, hShift, vShift, perceptual, gamma) {
var i, xOffset, xLow, xHigh, yOffset, yLow, yHigh, delta, color1, color2, localDeltaThreshold;
if ((hShift > 0) || (vShift > 0)) {
xLow = this._calculateLowerLimit(x, 0, hShift);
xHigh = this._calculateUpperLimit(x, width - 1, hShift);
yLow = this._calculateLowerLimit(y, 0, vShift);
yHigh = this._calculateUpperLimit(y, height - 1, vShift);
for (xOffset = xLow; xOffset <= xHigh; xOffset++) {
for (yOffset = yLow; yOffset <= yHigh; yOffset++) {
if ((xOffset != 0) || (yOffset != 0)) {
i = imageB.getIndex(x + xOffset, y + yOffset);
color1 = this._getColor(imageA, i, perceptual, gamma);
localDeltaThreshold = this._colorDelta(color, color1);
color2 = this._getColor(imageB, i, perceptual, gamma);
delta = this._colorDelta(color, color2);
if ((Math.abs(delta - localDeltaThreshold) < deltaThreshold) && (localDeltaThreshold > deltaThreshold)) {
return true;
}
}
}
}
}
return false;
},
/**
* Does a quick comparison between the supplied images
*
* @method _pixelCompare
* @param {PNGImage} imageA
* @param {PNGImage} imageB
* @param {PNGImage} imageOutput
* @param {number} deltaThreshold
* @param {int} width Width of image
* @param {int} height Height of image
* @param {object} outputMaskColor
* @param {int} [outputMaskColor.red]
* @param {int} [outputMaskColor.green]
* @param {int} [outputMaskColor.blue]
* @param {int} [outputMaskColor.alpha]
* @param {float} [outputMaskColor.opacity]
* @param {object} outputShiftColor
* @param {int} [outputShiftColor.red]
* @param {int} [outputShiftColor.green]
* @param {int} [outputShiftColor.blue]
* @param {int} [outputShiftColor.alpha]
* @param {float} [outputShiftColor.opacity]
* @param {object} backgroundColor
* @param {int} [backgroundColor.red]
* @param {int} [backgroundColor.green]
* @param {int} [backgroundColor.blue]
* @param {int} [backgroundColor.alpha]
* @param {float} [backgroundColor.opacity]
* @param {int} [hShift=0] Horizontal shift
* @param {int} [vShift=0] Vertical shift
* @param {boolean} [perceptual=false]
* @param {object} [gamma]
* @return {int} Number of pixel differences
* @private
*/
_pixelCompare: function (imageA, imageB, imageOutput, deltaThreshold, width, height, outputMaskColor, outputShiftColor, backgroundColor, hShift, vShift, perceptual, gamma) {
var difference = 0, i, x, y, delta, color1, color2;
for (x = 0; x < width; x++) {
for (y = 0; y < height; y++) {
i = imageA.getIndex(x, y);
color1 = this._getColor(imageA, i, perceptual, gamma);
color2 = this._getColor(imageB, i, perceptual, gamma);
delta = this._colorDelta(color1, color2);
if (delta > deltaThreshold) {
if (this._shiftCompare(x, y, color1, deltaThreshold, imageA, imageB, width, height, hShift, vShift, perceptual, gamma) && this._shiftCompare(x, y, color2, deltaThreshold, imageB, imageA, width, height, hShift, vShift, perceptual, gamma)) {
imageOutput.setAtIndex(i, outputShiftColor);
} else {
difference++;
imageOutput.setAtIndex(i, outputMaskColor);
}
} else {
imageOutput.setAtIndex(i, backgroundColor);
}
}
}
return difference;
},
/**
* Compares the two images supplied
*
* @method _compare
* @param {PNGImage} imageA
* @param {PNGImage} imageB
* @param {PNGImage} imageOutput
* @param {number} deltaThreshold
* @param {object} outputMaskColor
* @param {int} [outputMaskColor.red]
* @param {int} [outputMaskColor.green]
* @param {int} [outputMaskColor.blue]
* @param {int} [outputMaskColor.alpha]
* @param {float} [outputMaskColor.opacity]
* @param {object} outputShiftColor
* @param {int} [outputShiftColor.red]
* @param {int} [outputShiftColor.green]
* @param {int} [outputShiftColor.blue]
* @param {int} [outputShiftColor.alpha]
* @param {float} [outputShiftColor.opacity]
* @param {object} backgroundColor
* @param {int} [backgroundColor.red]
* @param {int} [backgroundColor.green]
* @param {int} [backgroundColor.blue]
* @param {int} [backgroundColor.alpha]
* @param {float} [backgroundColor.opacity]
* @param {int} [hShift=0] Horizontal shift
* @param {int} [vShift=0] Vertical shift
* @param {boolean} [perceptual=false]
* @param {object} [gamma]
* @return {object}
* @private
*/
_compare: function (imageA, imageB, imageOutput, deltaThreshold, outputMaskColor, outputShiftColor, backgroundColor, hShift, vShift, perceptual, gamma) {
var result = {
code: BlinkDiff.RESULT_UNKNOWN,
differences: undefined,
dimension: undefined,
width: undefined,
height: undefined
};
// Get some data needed for comparison
result.width = imageA.getWidth();
result.height = imageA.getHeight();
result.dimension = result.width * result.height;
// Check if identical
result.differences = this._pixelCompare(imageA, imageB, imageOutput, deltaThreshold, result.width, result.height, outputMaskColor, outputShiftColor, backgroundColor, hShift, vShift, perceptual, gamma);
// Result
if (result.differences == 0) {
this.log("Images are identical or near identical");
result.code = BlinkDiff.RESULT_IDENTICAL;
return result;
} else if (this.isAboveThreshold(result.differences, result.dimension)) {
this.log("Images are visibly different");
this.log(result.differences + " pixels are different");
result.code = BlinkDiff.RESULT_DIFFERENT;
return result;
} else {
this.log("Images are similar");
this.log(result.differences + " pixels are different");
result.code = BlinkDiff.RESULT_SIMILAR;
return result;
}
}
};
module.exports = BlinkDiff;
