# # The Python Imaging Library # $Id$ # # 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. # # # For special purposes, you can import this module and call # the makedelta or compress functions yourself. For example, # if you have an application that generates a sequence of # images, you can convert it to a GIF animation using some- # thing like the following code: # # import Image # import gifmaker # # sequence = [] # # # generate sequence # for i in range(100): # im = # sequence.append(im) # # # write GIF animation # fp = open("out.gif", "wb") # gifmaker.makedelta(fp, sequence) # fp.close() # # Alternatively, use an iterator to generate the sequence, and # write data directly to a socket. Or something... # from PIL import Image, ImageChops import string from PIL.GifImagePlugin import getheader, getdata # -------------------------------------------------------------------- # sequence iterator class image_sequence: def __init__(self, im): self.im = im def __getitem__(self, ix): try: if ix: self.im.seek(ix) return self.im except EOFError: raise IndexError # end of sequence # -------------------------------------------------------------------- # 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): # open input image, and force loading of first frame im = Image.open(infile) im.load() # open output file fp = open(outfile, "wb") seq = image_sequence(im) makedelta(fp, seq) fp.close() if __name__ == "__main__": import sys if len(sys.argv) < 3: print "GIFMAKER -- create GIF animations" print "Usage: gifmaker infile outfile" sys.exit(1) compress(sys.argv[1], sys.argv[2])