# jch - hacked summer 2003 to read frames.
#
# The Python Imaging Library
# $Id: gifmaker.py,v 1.1 2003/09/13 01:31:44 jch Exp $
#
# convert sequence format to GIF animation
#
# history:
#       97-01-03 fl     created
#
# Copyright (c) Secret Labs AB 1997.  All rights reserved.
# Copyright (c) Fredrik Lundh 1997.
#
# See the README file for information on usage and redistribution.
#

import Image, ImageChops
import string
import ImagePalette

from GifImagePlugin import getheader, getdata

def bumpname(filename, pos):
    if pos == 0:
        pos = len(filename)-5
    digit = string.find(string.digits, filename[pos])
    #print "digit %d pos %d\n"%(digit, pos)
    if digit >= 0 and digit < 9:
        return filename[0:pos]+string.digits[digit+1]+filename[pos+1:len(filename)]
    elif digit == 9 and pos > 1:
        temp = filename[0:pos]+string.digits[0]+filename[pos+1:len(filename)]
        return bumpname(temp, pos-1)
    else:
        return "noway"

# --------------------------------------------------------------------
# sequence iterator
class image_sequence:
    def __init__(self, filename):
        self.filename = filename
    def __getitem__(self, ix):
        try:
            im = Image.open(self.filename)
        except IOError:
            print "can not open "+self.filename
            raise IndexError # end of sequence
        im.palette = self.palette
        tim = im.convert("P")
        tim.thumbnail((200,200))
        self.filename = bumpname(self.filename, 0)
        print self.filename
        return tim

    def setPalette(self, palette):
        self.palette = palette
        
# --------------------------------------------------------------------
# straightforward delta encoding

def makedelta(fp, sequence):
    """Convert list of image frames to a GIF animation file"""

    frames = 0

    previous = None

    for im in sequence:

        #
        # FIXME: write graphics control block before each frame

        if not previous:

            # global header
            for s in getheader(im) + getdata(im):
                fp.write(s)

        else:

            # delta frame
            delta = ImageChops.subtract_modulo(im, previous)

            bbox = delta.getbbox()

            if bbox:

                # compress difference
                for s in getdata(im.crop(bbox), offset = bbox[:2]):
                    fp.write(s)

            else:
                # FIXME: what should we do in this case?
                pass

        previous = im.copy()

        frames = frames + 1

    fp.write(";")

    return frames

# --------------------------------------------------------------------
# main hack

def compress(infile, outfile,palette):

    # open input image, and force loading of first frame
    im = Image.open(infile)

    # open output file
    fp = open(outfile, "wb")

    seq = image_sequence(infile)
    seq.setPalette(palette)

    makedelta(fp, seq)

    fp.close()


if __name__ == "__main__":

    import sys

    if len(sys.argv) < 3:
        print "Usage: gifmaker frameNNNN.jpg outfile.gif [haspalette.gif]"
        print "concatenate all consecutive frames into a gif animation"
        sys.exit(1)

    palette = 0
        
    if len(sys.argv) > 3:
        im = Image.open(sys.argv[3])
        im.load()
        palette = im.palette
        
    compress(sys.argv[1], sys.argv[2], palette)