# Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies).

# All rights reserved.

# This component and the accompanying materials are made available

# under the terms of "Eclipse Public License v1.0"

# which accompanies this distribution, and is available

# at the URL "http://www.eclipse.org/legal/epl-v10.html".

#

# Initial Contributors:

# Nokia Corporation - initial contribution.

#

# Contributors:

#

# Description:

#

"""

Reference Image

Class representing test images and results of comparing it against reference images.

"""

import os

import os.path

from string import *

from PIL import Image, ImageChops, ImageOps, ImageStat, ImageFilter

from sets import Set

import shutil

# Relative path for reference images

KRefPath = "\\ref\\"

# Relative path for test images

KTestPath = "\\test\\"

# Compare test with reference images by pixel and pyramid difference; generate diff images

class RefImage:

    # Change the value to tune the passing limit for pyramid diff

    PYRAMID_PASS_LIMIT = 10

    # Change the value to tune the passing limit for pixel diff

    PIXEL_DIFF_PASS_LIMIT = 2

    # These are the types of differences that can be tested.

    PIXEL_DIFF = 1

    DIFF_SCORE = 2

    PYRAMID_DIFF = 3

    # @param aRefFile The reference images

    # @param aTestFile The test images

    # @param aBaseDir The base directory of reference and test images

    # @param aSource The distinctive part of the expected diff image name

    def __init__(self, aRefFile, aTestFile, aBaseDir, aSource):

        self.source     = aSource

        self.refFile    = aRefFile

        self.testFile   = aTestFile

        self.baseDir    = aBaseDir

        self.targetImage  = os.path.basename(aRefFile)

        self.maxDiff      = -1

        self.diffScore    = -1

        self.pyramidDiffs = None

        self.refImageCache  = None

        self.testFileCache  = None

        self.cachedTestFile = None

        self.cachedDiff   = None

        self.diffImages   = None

        self.diffsInUse   = Set([self.PIXEL_DIFF,self.PYRAMID_DIFF])

    # Read in reference images

    def _getImage(self):

        if not self.refImageCache:

            self.refImageCache = Image.open(self.baseDir + KRefPath + self.refFile)

            print "ref image: ", self.refFile

        return self.refImageCache

    # Read in test images

    def _getTestee(self):

        if not self.testFileCache:

            self.testFileCache = Image.open(self.baseDir + KTestPath + self.testFile)

            print "test image: ", self.testFile

        return self.testFileCache  

    # Get absolute value of the difference between test and reference images

    def _getDiff(self):

         self.cachedDiff = ImageChops.difference(self._getImage(), self._getTestee())

         return self.cachedDiff

    # Get pyramid levels of an image.

    # Returns a set of successively low-pass filtered images, resized by 1/2, 1/4, 1/8 respectivly.

    # @param aImage The image as the source to get pyramid levels

    # @return A set of 3 images scaled at 1/2, 1/4, and 1/8

    def _genPyramidLevels(self, aImage):

        # Create a 3X3 convolution kernel.

        # Gaussian image smoothing kernel, approximated by 3x3 convolution filter.

        # A convolution is a weighted average of all the pixels in some neighborhood of a given pixel.

        # The convolution kernel values are the weights for the average.

        kernel = ImageFilter.Kernel((3, 3), [.75, .9, .75, .9, 1, .9, .75, .9, .75])

        source = aImage

        res = []

        while len(res) < 3:

            srcSize = source.size

            # Mirror borders.

            temp = Image.new("RGBA", (srcSize[0]+2, srcSize[1]+2))

            temp.paste(source, (1, 1))

            # .crop returns a rectangular region from the current image. Passed: left, upper, right, and lower pixel coordinate.

            # .paste to upper-left corner.

            # left, top, right, bottom

            # Add a one pixel border around the image, so the center of the 3x3 convolution filter starts on the corner pixel of the image. 

            temp.paste(source.crop((1, 0, 1, srcSize[1]-1)), (0, 1))

            temp.paste(source.crop((0, 1, srcSize[1]-1, 1)), (1, 0))

            temp.paste(source.crop((srcSize[0]-2, 0, srcSize[0]-2, srcSize[1]-1)), (srcSize[0]+1, 1))

            temp.paste(source.crop((0, srcSize[1]-2, srcSize[1]-1, srcSize[1]-2)), (1, srcSize[1]+1))

            # Resize the filtered image to 0.5 size, via. 2x2 linear interpolation.

            filtered = temp.filter(kernel).crop((1, 1, srcSize[0], srcSize[1])).resize((srcSize[0]/2, srcSize[1]/2), Image.BILINEAR)

            source = filtered

            res.append(filtered)

        return res

    # Compute difference values between test and reference images

    #

    # - Generate mask image (3x3 max/min differences)

    # - Generate pyramid reference images (1/2, 1/4, 1/8 low-pass filtered and scaled).

    # - Generate pyramid test      images (1/2, 1/4, 1/8 low-pass filtered and scaled).

    # - Generate pyramid mask      images (1/2, 1/4, 1/8 low-pass filtered and scaled).

    # - Weight the mask according to level.

    # - For each level:

    #   - Get absolute difference image between reference and test.

    #   - Multiply absolute difference with inverted mask at that level

    # - Take maximum pixel value at each level as the pyramid difference.

    #

    # See: http://www.pythonware.com/library/pil/handbook/index.htm

    #

    def compPyramidDiff(self):

        ref = self._getImage()

        testee = self._getTestee()

        #if testee.size != ref.size:

        #	file.write("WARNING: The reference image has different dimension from the testee image")

        # maskImage is the difference between min and max pixels within a 3x3 pixel environment in the reference image.

        maskImage = ImageChops.difference(ref.filter(ImageFilter.MinFilter(3)), ref.filter(ImageFilter.MaxFilter(3)))

        # generate low-pass filtered pyramid images.

        refLevels = self._genPyramidLevels(ref)

        refL1 = refLevels[0]

        refL2 = refLevels[1]

        refL3 = refLevels[2]

        testLevels = self._genPyramidLevels(testee)

        testL1 = testLevels[0]

        testL2 = testLevels[1]

        testL3 = testLevels[2]

        maskLevels = self._genPyramidLevels(maskImage)

        # Apply weighting factor to masks at levels 1, 2, and 3.

        maskL1 = Image.eval(maskLevels[0], lambda x: 5*x)

        maskL2 = Image.eval(maskLevels[1], lambda x: 3*x)

        maskL3 = Image.eval(maskLevels[2], lambda x: 2*x)

        # Generate a pixel difference image between reference and test.

        # Multiply the difference image with the inverse of the mask.

        #   Mask inverse (out = MAX - image):

        #     So, areas of regional (3x3) similarity thend to MAX and differences tend to 0x00.

        #   Multiply (out = image1 * image2 / MAX:

        #     Superimposes two images on top of each other. If you multiply an image with a solid black image,

        #     the result is black. If you multiply with a solid white image, the image is unaffected.

        #   This has the effect of accentuating any test/reference differences where there is a small

        #   regional difference in the reference image.

        diffL1 = ImageChops.difference(refL1, testL1)

        diffL1 = ImageChops.multiply(diffL1, ImageChops.invert(maskL1))

        diffL2 = ImageChops.difference(refL2, testL2)

        diffL2 = ImageChops.multiply(diffL2, ImageChops.invert(maskL2))

        diffL3 = ImageChops.difference(refL3, testL3)

        diffL3 = ImageChops.multiply(diffL3, ImageChops.invert(maskL3))

        # So now the difference images are a grey-scale image that are brighter where differences

        # between the reference and test images were detected in regions where there was little 

        # variability in the reference image.

        # Get maxima for all bands at each pyramid level, and take the maximum value as the pyramid value.

        # stat.extrema (Get min/max values for each band in the image).

        self.pyramidDiffs = [

            max(map(lambda (x): x[1], ImageStat.Stat(diffL1).extrema)),

            max(map(lambda (x): x[1], ImageStat.Stat(diffL2).extrema)),

            max(map(lambda (x): x[1], ImageStat.Stat(diffL3).extrema))

        ]

        print "self.pyramidDiffs = ", self.pyramidDiffs

    # Compute max diff of pixel difference  

    def compMaxDiff(self):

        self.maxDiff = max(map(lambda (x): x[1], ImageStat.Stat(self._getDiff()).extrema))

    # Compute diff score

    # @param file A log file to store error messages

    def compDiffScore(self, file):

        self.diffScore = 0

        ref = self._getImage()

        testee = self._getTestee()

        if testee.size != ref.size:

            file.write("WARNING: Reference image from source has different dimension than the testee image")

            #raise ValueError("Reference image from source has different dimension than the testee image")

        # If a difference exists...

        if self.maxDiff != 0:      

            # Filter images for min and max pixel (dark and light) values within 5x5 environment.                  

            refMin = ref.filter(ImageFilter.MinFilter(5))

            refMax = ref.filter(ImageFilter.MaxFilter(5))

            testMin = testee.filter(ImageFilter.MinFilter(5))

            testMax = testee.filter(ImageFilter.MaxFilter(5))

            # make the min and max filter images a bit darker and lighter, respectively.

            refMin = Image.eval(refMin, lambda x: x - 4)

            refMax = Image.eval(refMax, lambda x: x + 4)

            testMin = Image.eval(testMin, lambda x: x - 4)

            testMax = Image.eval(testMax, lambda x: x + 4)

            refRefHist = ref.histogram()

            testRefHist = testee.histogram()

            # Calculate difference score.

            # Check for darkness in reference image.

            # Generate an image of the darkest pixels when comparing the 5x5 max filtered and lightened reference image against the test image.

            # If the pixel colour histogram of the generated image is different from the test image histogram, increase the difference score.

            if (ImageChops.darker(refMax, testee).histogram() != testRefHist):

                self.diffScore += 1

            # Check for lightness in reference image.

            if (ImageChops.lighter(refMin, testee).histogram() != testRefHist):

                self.diffScore += 1

            # Check for darkness in test image.

            if (ImageChops.darker(testMax, ref).histogram() != refRefHist):

                self.diffScore += 1

            #  Check for lightness in test image.

            if (ImageChops.lighter(testMin, ref).histogram() != refRefHist):

                self.diffScore += 1

        print "self.diffScore: ", self.diffScore

    # Generate test results

    # @param file A log file to store error messages

    def pyramidValue (self):

      return self.pyramidDiffs[2]

    def passed(self, file, aThresholdValue):

        if aThresholdValue == -1:

            aThresholdValue = self.PYRAMID_PASS_LIMIT

        if self.pyramidDiffs:

            return self.pyramidValue() <= aThresholdValue

        elif self.maxDiff >= 0:

            return self.maxDiff <= self.PIXEL_DIFF_PASS_LIMIT

        elif self.maxDiff < 0:

            warningMsg = "WARNING: Differences were not computed for the test image " + self.testFile + " against its reference image<br>"

            print warningMsg;

            if file: file.write(warningMsg);

            return True

        else:

            assert False

            return False

    # Make diff images

    # @param aDestDir

    def makeDiffImages(self, aDestDir):

        diffBands = list(self._getDiff().split())

        assert (len(diffBands) == 3 or len(diffBands) == 1)

        diffs = {}

        baseDiffName = "Diff_" + self.source +  "_" + self.targetImage

        # Invert the diffs.

        for i in range(len(diffBands)):

        #for i in range(4):

	        diffBands[i] = ImageChops.invert(diffBands[i])

        temp = ["R", "G", "B"]

        for i in range(len(diffBands)):

	        name = temp[i] + baseDiffName

        # Highlight the differing pixels

        if not self.PYRAMID_DIFF in self.diffsInUse and not self.DIFF_SCORE in self.diffsInUse:

           	diffBands[i] = Image.eval(diffBands[i], lambda x: (x / (255 - self.PIXEL_DIFF_PASS_LIMIT)) * 255)

		# Following line commented as we don't need to save bitmaps for the separate R,G or B channels.

        #diffBands[i].save(aDestDir + name, "BMP")

        diffs[temp[i]] = name

        if len(diffBands) == 3:

        	rgbDiff = ImageChops.darker(diffBands[0], ImageChops.darker(diffBands[1], diffBands[2]))

        else:

        	rgbDiff = diffBands[0]

        rgbDiffName = "RGB" + baseDiffName 

        rgbDiff.save(aDestDir + rgbDiffName, "BMP")

        diffs["RGB"] = rgbDiffName

    	self.diffImages = diffs

    	return diffs

    # Print test results to command line    

    # @param file A log file to store error messages

    def printResult(self, file, aThresholdValue):

        print "test result: ", self.passed(file, aThresholdValue), "maxDiff: ", self.maxDiff

    # Get test results

    # @param file A log file to store error messages

    def getResult(self, file, aThresholdValue):

        return self.passed(file, aThresholdValue);

    # Get current puramid result value.

    def getPyramidResultValue(self):

        if self.pyramidDiffs:

            return self.pyramidValue()

        return 255

    # Get diff images

    def getDiffImages(self):

        assert self.diffImages != None

        return self.diffImages

    # Disable a diff test

    # @param diff Holds either self.PIXEL_DIFF,self.PYRAMID_DIFF or both when the tester wants to disable either or both of the diff tests 

    def disableDiff(self, diff):

        self.diffsInUse.discard(diff)

    # Enabld a diff test

    # @param diff Holds either self.PIXEL_DIFF,self.PYRAMID_DIFF or both when the tester wants to enable either or both of the diff tests

    def enableDiff(self, diff):

        self.diffsInUse.add(diff)

    # Set diffs

    # @param diffs Either self.PIXEL_DIFF,self.PYRAMID_DIFF or both when the tester wants to set either or both of the diff tests

    def setDiffs(self, diffs):

        self.diffsInUse = (diffs)

    # Compute difference according to the values in self.diffsInUse

    # @param file A log file to store error messages

    def computeDifferences(self, file):

        if self.PIXEL_DIFF in self.diffsInUse:

            self.compMaxDiff()

        if self.DIFF_SCORE in self.diffsInUse:

            self.compDiffScore(file)

        if self.PYRAMID_DIFF in self.diffsInUse:

            self.compPyramidDiff()