Im.js written in CS

Im.coffee

do (window, document)->    
    'use strict'
    bDebug = false
    oContainerDiff = null
    nMinPercentage = 100
    bAsynchronous = false
    nImagesLoaded = 0
    aCanvas = []
    fpLoop = _loop
    proxyFloat = window.parseFloat
    parseFloat = (nNumber) ->
        nDecimals = 4
        sStringNumber = nNumber.toString()
        aDecimalTypes = [".", ","]
        sLastDec = ''
        nPosFinal = 0
        nNumberMore = 0
        sDecimalType = ''
        nDec = 0
        nPos = 0
    
        for sDecimalType in aDecimalTypes
            nPos = sStringNumber.indexOf(sDecimalType)
            break if nPos != -1
    
        nDec = (sStringNumber.length -1) - nPos
        nDec = nDecimals if typeof nDecimals != "undefined"
        nPosFinal = nPos + (nDec + 1)
        if nPos != -1
            sLastDec = sStringNumber.substr(nPosFinal, 1)
            sStringNumber = sStringNumber.substr(0, nPosFinal)
            if sLastDec >= 5
                nNumberMore = sStringNumber.substr(sStringNumber.length -1, 1)
                if nNumberMore == sDecimalType
                    sStringNumber = (sStringNumber.substr(0, sStringNumber.length -1) * 1) + 1
                else
                    sStringNumber = sStringNumber.substr(0, sStringNumber.length -1) + ((nNumberMore * 1) + 1)
        proxyFloat(sStringNumber)
    
    loopWithoutBlocking = (aItems, fpProcess, fpFinish) ->
        aCopy = aItems.concat()
        nIndex = aItems.length -1
        nStart = +new Date()
        recursive = ->
            loop
                nIndex--
                bProcess = fpProcess aCopy.shift, nIndex
                return false if bProcess == false
                break if aCopy.length > 0 and (+new Date() - nStart < 50)
            if aCopy.length > 0
                setTimeout recursive, 25
            else
                fpFinish aItems
            return true
        setTimeout recursive, 25
    
    _loop = (aItems, fpProcess, fpFinish) ->
        aCopy = aItems.concat()
        nIndex = aItems.length
        oItem = null
        while Boolean(oItem = aCopy.shift())
            nIndex--
            bProcess = fpProcess oItem, nIndex
            return false if bProcess == false
        fpFinish aItems
    
    compareWithoutCreate = (aCanvas, fpSuccess, fpFail, nStart) ->
        sLastData = null
        oLastImageData = null
        nElapsedTime = undefined
        nPercentageDiff = undefined
        oDiffObject = null
        oDiffCanvas = null
        nStart = +new Date() if bDebug and typeof nStart == "undefined"
        fpLoop aCanvas, (oCanvas, nIndex) ->
            oContext = oCanvas.getContext "2d"
            aCanvasData = oContext.getImageData 0, 0, oCanvas.width, oCanvas.height
            sData = JSON.stringify [].slice.call aCanvas.data
            if sLastData != null
                if sLastData.localeCompare sData != 0
                    oDiffObject = diff oCanvas.width, oCanvas.height, aCanvasData, oLastImageData
                    nPercentageDiff = oDiffObject.percentage
                    oDiffCanvas = oDiffObject.canvas
                    if nPercentageDiff >= nMinPercentage
                        return true
                    if oContainerDiff
                        oContainerDiff.appendChild oDiffCanvas
                    oCanvas.className = 'fail'
                    if bDebug
                        nElaspsedTime = (+new Date() - nStart)
                    fpFail oCanvas, nElapsedTime, nPercentageDiff
                    return false
            oLastImageData = aCanvasData
            sLastData = sData
            return true
        , (aCanvas) ->
            nElapsedTime = (+new Date() - nStart) if bDebug
            fpSuccess aCanvas, nElapsedTime, nPercentageDiff
    
    diff = (nWidth, nHeight, aDataImage, aLastDataImage) ->
        aData = aDataImage.data
        aLastData = aLastDataImage.data
        nLenPixels = 0
        nDiffPixels = 0
        nDiffPercentage = 0
        oCanvas = document.createElement "canvas"
        oContext = oCanvas.getContext "2d"
        oDataImage = oContext.createImageData nWidth, nHeight
        aCreatedDataImage = oDataImage.data
        nData = 0
        nRow = 0
        nColumn = 0
        nX = 0
        nY = 0
        nLenData = aCreatedDataImage.length
        nRed = 0
        nGreen = 0
        nBlue = 0
        nAlpha = 0
        nLastRed = 0
        nLastGreen = 0
        nLastBlue = 0
        nLastAlpha = 0
        oCanvas.width = nWidth
        oCanvas.height = nHeight
        oCanvas.style.border = "#000 1px solid"
        for aCreatedDataImagePixel in aCreatedDataImage
            aCreatedDataImagePixel = 255
        nLenPixels = aDataImage.height * aDataImage.width
        nRow = aDataImage.height
        nColumn = aDataImage.width
        loop
            nRow--
            break if nRow == 0
            loop
                nColumn--
                break if nColumn == 0
                nX = 4 * (nRow * nWidth + nColumn)
                nY = 4 * (nRow * aDataImage.width + nColumn)
                nRed = aData[nY + 0]
                nGreen = aData[nY + 1]
                nBlue = aData[nY + 2]
                nAlpha = aData[nY + 3]
                nLastRed = aLastData[nY + 0]
                nLastGreen = aLastData[nY + 1]
                nLastBlue = aLastData[nY + 2]
                nLastAlpha = aLastData[nY + 3]
    
                if nNewRed == 0 and nNewGreen == 0 and nNewBlue == 0 and nNewAlpha == 0
                    aCreatedDataImage[nX + 0] = Math.abs(nRed - nLastRed)
                    aCreatedDataImage[nX + 1] = Math.abs(nGreen - nLastGreen)
                    aCreatedDataImage[nX + 2] = Math.abs(nBlue - nLastBlue)
                    aCreatedDataImage[nX + 3] = Math.abs(nAlpha - nLastAlpha)
                else
                    nDiffPixels++
                    aCreatedDataImage[nX + 0] = aData[nY + 0]
                    aCreatedDataImage[nX + 1] = aData[nY + 1]
                    aCreatedDataImage[nX + 2] = aData[nY + 2]
                    aCreatedDataImage[nX + 3] = aData[nY + 3]
    
        oContext.putImageData oDataImage, 0, 0
        nDiffPercentage = Math.abs((((nDiffPixels - nLenPixels) / nLenPixels) * 100));
        oObject =
            percentage: parseFloat nDiffPercentage
            canvas: oCanvas
    
    createAndCompare = (oContainer, aImages, fpSuccess, fpFail) ->
        aCanvas = []
        nStart = +new Date() if bDebug
        finishCallback = (aImages) ->
            if nImagesLoaded < aImages.length
                setTimeout finishCallback, 25
            else
                compareWithoutCreate aCanvas, fpSuccess, fpFail, nStart
    
        fpLoop aImages, (oImageConfig, nIndex) ->
            oCanvas = document.createElement "canvas"
            oCanvas.id = "canvasCompare_" + nIndex
            aCanvas.push oCanvas
            oCanvas.width = oImageConfig.width
            oCanvas.height = oImageConfig.height
            oContainer.appendChild oCanvas
            oContext = oCanvas.getContext "2d"
            oImage = new Image()
            oImage.onload = ->
                nImagesLoaded++
                oContext.drawImage oImage, 0, 0
            oImage.onerror = ->
                nImagesLoaded++
            oImage.src = oImageConfig.src
        , finishCallback
    
    class ImageToCompare
        constructor: (sUrl, @width, @height) ->
            sParamsSeparator = if sUrl.indexOf("?") == -1 then "?" else "&"
            @src = sUrl + sParamsSeparator + ( + new Date())
    class IM
        setDebug: (bLocalDebug) ->
            bDebug = bLocalDebug
            return bDebug
        setAsynchronous: (bLocalAsynchronous) ->
            bAsynchronous = bLocalAsynchronous
            fpLoop = if bAsynchronous then loopWithoutBlocking else _loop
            return bAsynchronous
        showDiffInCanvas: (oLocalContainerDiff) ->
            oContainerDiff = oLocalContainerDiff
            return oContainerDiff
        setTolerance: (nMinPercent) ->
            nMinPercentage = nMinPercent
            return nMinPercentage
        compare: (oContainer, aElements, fpSuccess, fpFail) ->
            if !oContainer.nodeType
                compareWithoutCreate.apply this, arguments
            else
                createAndCompare.apply this, arguments
        image: ImageToCompare
    
    window.IM = new IM()