Pillow/Scripts/gifmaker.py
Brian Crowell 37f22ebfcd py3k: Use string methods instead of string module
First, we go for the obvious stuff. The string module methods are gone in
3.0, so we translate them to the appropriate methods on the string class.
2013-01-10 08:42:49 -06:00

135 lines
2.9 KiB
Python

#
# 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 = <generate image i>
# 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
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])