ipa中提取图片资源 png处理方法

ipa本身是一个zip文件改后缀后解压缩就能看到应用内使用的资源文件

其中png图片资源xcode打包的时候做了些手脚 具体怎么处理的这里不做解释

下边提供一个python脚本

from struct import *from zlib import *import statimport sysimport osdef getNormalizedPNG(filename):    pngheader = "\x89PNG\r\n\x1a\n"        file = open(filename, "rb")    oldPNG = file.read()    file.close()    if oldPNG[:8] != pngheader:        return None        newPNG = oldPNG[:8]        chunkPos = len(newPNG)        # For each chunk in the PNG file    while chunkPos < len(oldPNG):                # Reading chunk        chunkLength = oldPNG[chunkPos:chunkPos+4]        chunkLength = unpack(">L", chunkLength)[0]        chunkType = oldPNG[chunkPos+4 : chunkPos+8]        chunkData = oldPNG[chunkPos+8:chunkPos+8+chunkLength]        chunkCRC = oldPNG[chunkPos+chunkLength+8:chunkPos+chunkLength+12]        chunkCRC = unpack(">L", chunkCRC)[0]        chunkPos += chunkLength + 12        # Parsing the header chunk        if chunkType == "IHDR":            width = unpack(">L", chunkData[0:4])[0]            height = unpack(">L", chunkData[4:8])[0]        # Parsing the image chunk        if chunkType == "IDAT":            try:                # Uncompressing the image chunk                bufSize = width * height * 4 + height                chunkData = decompress( chunkData, -8, bufSize)                            except Exception, e:                # The PNG image is normalized                return None            # Swapping red & blue bytes for each pixel            newdata = ""            for y in xrange(height):                i = len(newdata)                newdata += chunkData[i]                for x in xrange(width):                    i = len(newdata)                    newdata += chunkData[i+2]                    newdata += chunkData[i+1]                    newdata += chunkData[i+0]                    newdata += chunkData[i+3]            # Compressing the image chunk            chunkData = newdata            chunkData = compress( chunkData )            chunkLength = len( chunkData )            chunkCRC = crc32(chunkType)            chunkCRC = crc32(chunkData, chunkCRC)            chunkCRC = (chunkCRC + 0x100000000) % 0x100000000        # Removing CgBI chunk         if chunkType != "CgBI":            newPNG += pack(">L", chunkLength)            newPNG += chunkType            if chunkLength > 0:                newPNG += chunkData            newPNG += pack(">L", chunkCRC)        # Stopping the PNG file parsing        if chunkType == "IEND":            break            return newPNGdef updatePNG(filename):    data = getNormalizedPNG(filename)    if data != None:        file = open(filename, "wb")        file.write(data)        file.close()        return True    return datadef getFiles(base):    global _dirs    global _pngs    if base == ".":        _dirs = []        _pngs = []            if base in _dirs:        return    files = os.listdir(base)    for  file in files:        filepath = os.path.join(base, file)        try:            st = os.lstat(filepath)        except os.error:            continue                if stat.S_ISDIR(st.st_mode):            if not filepath in _dirs:                getFiles(filepath)                _dirs.append( filepath )                        elif file[-4:].lower() == ".png":            if not filepath in _pngs:                _pngs.append( filepath )                if base == ".":        return _dirs, _pngsprint "-----------------------------------"print " iPhone PNG Images Normalizer v1.0"print "-----------------------------------"print " "print "[+] Searching PNG files...",dirs, pngs = getFiles(".")print "ok"if len(pngs) == 0:    print " "    print "[!] Alert: There are no PNG files found. Move this python file to the folder that contains the PNG files to normalize."    exit()    print " "print " -  %d PNG files were found at this folder (and subfolders)." % len(pngs)print " "while True:    normalize = raw_input("[?] Do you want to normalize all images (Y/N)? ").lower()    if len(normalize) > 0 and (normalize[0] == "y" or normalize[0] == "n"):        breaknormalized = 0if normalize[0] == "y":    for  ipng in xrange(len(pngs)):        perc = (float(ipng) / len(pngs)) * 100.0        print "%.2f%% %s" % (perc, pngs[ipng])        if updatePNG(pngs[ipng]):            normalized += 1print " "print "[+] %d PNG files were normalized." % normalized

可以把这些图片文件恢复成正常的png