gifwriter.py

import subprocess
import os

from scipy.misc import imsave


class GifWriter(object):

    def __init__(self, temp_format, dest_gif):
        try:
            subprocess.check_call(
                ['convert'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        except OSError:
            raise Exception('imagemagick is required for gif support')
        except subprocess.CalledProcessError:
            pass

        self.temp_format = temp_format
        self.dest_gif = dest_gif
        self.temp_filenames = []
        self.closed = False

    def append(self, image):
        if self.closed:
            raise Exception('GifWriter is already closed')
        filename = self.temp_format % len(self.temp_filenames)
        self.temp_filenames.append(filename)
        imsave(filename, image)

    def close(self):
        subprocess.check_call(['convert', '-delay', '2', '-loop', '0'] +
                              self.temp_filenames + [self.dest_gif])
        for filename in self.temp_filenames:
            os.unlink(filename)
        self.closed = True