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138 lines
3.0 KiB
Python
138 lines
3.0 KiB
Python
#!/usr/bin/env python
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#
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# The Python Imaging Library
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# $Id$
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#
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# convert sequence format to GIF animation
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#
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# history:
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# 97-01-03 fl created
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#
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# Copyright (c) Secret Labs AB 1997. All rights reserved.
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# Copyright (c) Fredrik Lundh 1997.
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#
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# See the README file for information on usage and redistribution.
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#
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#
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# For special purposes, you can import this module and call
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# the makedelta or compress functions yourself. For example,
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# if you have an application that generates a sequence of
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# images, you can convert it to a GIF animation using some-
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# thing like the following code:
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#
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# import Image
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# import gifmaker
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#
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# sequence = []
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#
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# # generate sequence
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# for i in range(100):
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# im = <generate image i>
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# sequence.append(im)
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#
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# # write GIF animation
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# fp = open("out.gif", "wb")
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# gifmaker.makedelta(fp, sequence)
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# fp.close()
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#
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# Alternatively, use an iterator to generate the sequence, and
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# write data directly to a socket. Or something...
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#
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from __future__ import print_function
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from PIL import Image, ImageChops
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from PIL.GifImagePlugin import getheader, getdata
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# --------------------------------------------------------------------
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# sequence iterator
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class image_sequence:
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def __init__(self, im):
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self.im = im
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def __getitem__(self, ix):
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try:
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if ix:
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self.im.seek(ix)
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return self.im
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except EOFError:
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raise IndexError # end of sequence
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# --------------------------------------------------------------------
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# straightforward delta encoding
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def makedelta(fp, sequence):
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"""Convert list of image frames to a GIF animation file"""
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frames = 0
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previous = None
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for im in sequence:
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#
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# FIXME: write graphics control block before each frame
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if not previous:
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# global header
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for s in getheader(im) + getdata(im):
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fp.write(s)
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else:
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# delta frame
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delta = ImageChops.subtract_modulo(im, previous)
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bbox = delta.getbbox()
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if bbox:
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# compress difference
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for s in getdata(im.crop(bbox), offset = bbox[:2]):
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fp.write(s)
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else:
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# FIXME: what should we do in this case?
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pass
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previous = im.copy()
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frames = frames + 1
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fp.write(";")
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return frames
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# --------------------------------------------------------------------
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# main hack
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def compress(infile, outfile):
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# open input image, and force loading of first frame
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im = Image.open(infile)
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im.load()
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# open output file
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fp = open(outfile, "wb")
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seq = image_sequence(im)
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makedelta(fp, seq)
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fp.close()
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if __name__ == "__main__":
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import sys
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if len(sys.argv) < 3:
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print("GIFMAKER -- create GIF animations")
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print("Usage: gifmaker infile outfile")
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sys.exit(1)
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compress(sys.argv[1], sys.argv[2])
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