gif_qr.py

#!/usr/bin/python2

import os
import qrtools
import sys
from PIL import Image

__author__ = "Maki from _PRIME_"
__version__ = "1.0"


def analyseImage(path):
    '''
    Pre-process pass over the image to determine the mode (full or additive).
    Necessary as assessing single frames isn't reliable. Need to know the mode
    before processing all frames.

    @param path: path to GIF file

    @type path: C{GIF}

    @raise path: Check if the file exists

    @return: This function returns a dictionnary that contains the image files.
    '''
    try:
        im = Image.open(path)
        results = {
            'size': im.size,
            'mode': 'full',
        }
        try:
            while True:
                if im.tile:
                    tile = im.tile[0]
                    update_region = tile[1]
                    update_region_dimensions = update_region[2:]
                    if update_region_dimensions != im.size:
                        results['mode'] = 'partial'
                        break
                im.seek(im.tell() + 1)
        except EOFError:
            pass

        return results
    except IOError:
        print("Wrong file name")


def processImage(path):
    '''
    Iterate the GIF, extracting each frame and decode qr code on
    each extracted file.

    @param path: Path to GIF file

    @type path: C{GIF}

    @raise path: Check the file type
    @raise path: Check for end of file

    @return: This function returns nothing, it just write
    each frame of the GIF as a PNG file on disk.
    '''
    try:
        mode = analyseImage(path)['mode']
        flag = []

        im = Image.open(path)

        i = 0
        p = im.getpalette()
        last_frame = im.convert('RGBA')

        try:
            while True:
                # You can uncomment the line below to get more verbosity
                # print("saving {0} ({1}) frame {2}, {3} {4}".format(path, mode, i, im.size, im.tile))
                # If the GIF uses local colour tables, each frame will
                # have its own palette.
                # If not, we need to apply the global palette to the new frame.
                if not im.getpalette():
                    im.putpalette(p)

                new_frame = Image.new('RGBA', im.size)

                # Is this file a "partial"-mode GIF where frames
                # update a region of a different size to the entire image?
                # If so, we need to construct the new frame by pasting
                # it on top of the preceding frames.
                if mode == 'partial':
                    new_frame.paste(last_frame)

                # Will set frame name, example : if toto.gif in
                # input then toto-0.png, toto-1.png etc...
                png_file = '%s-%d.png' % (''.join(os.path.basename(path).split('.')[:-1]), i)
                new_frame.paste(im, (0, 0), im.convert('RGBA'))
                new_frame.save(png_file, 'PNG')

                # QR Code decoder
                qr = qrtools.QR()
                qr.decode(png_file)
                flag.append(qr.data)

                print(''.join(flag))

                i += 1
                last_frame = new_frame
                im.seek(im.tell() + 1)
        except EOFError:
            pass

    except TypeError:
        print("Wrong file type")


def cleanDir():
    '''
    Directory cleaner, this function will delete all png file in
    the current directory.
    '''
    filelist = [f for f in os.listdir(".") if f.endswith(".png")]
    for f in filelist:
        os.remove(f)


def showHelp():
    print("\
    This script will split a GIF File in frames and decode the QR Code inside it. \n \
    Frames will be stored in the current folder as png files and delete with the cleanDir function.\n  \
    \n \
    Usage: gif_qr.py <file.gif> \
    ")

if __name__ == "__main__":
    if len(sys.argv) > 1:
        gif_file = sys.argv[1]
        processImage(gif_file)
        # Comment the function below to keep PNG file
        cleanDir()
    else:
        showHelp()