tk-gif.py

#!python3.9


import itertools
import tkinter as tk

from pathlib import Path


class AnimatedGif(tk.Canvas):
    """
    Loads an GIF file and renders its frames
    using the Tk event loop.
    """
    def __init__(self, master=None, **kwargs):
        image = kwargs.pop('image')
        if isinstance(image, str):
            self._image_data = Path(image).read_bytes()
        elif isinstance(image, bytes):
            self._image_data = image
        else:
            raise TypeError(
                f'Unsupported type: {image!r}.' 
                f'Must be {str!r} or {bytes!r}'
            )
        
        self._gif_frames = None
        self._gif_frame_tags = None
        self._fps = 24
        
        super().__init__(master, **kwargs)
        self.config(highlightthickness=0)
        self._build_frames()
        self._configure_layers()
        self.after(1, self._loop_gif)
    
    
    def _configure_layers(self):
        frames = self._gif_frames
        tags = []
        self.configure(
            width=frames[0].width(),
            height=frames[0].height(),
        )
        for i, frame in enumerate(frames):
            tag = str(i)
            self.create_image(
                0, 0,
                image=frame,
                anchor=tk.NW,
                tags=tag,
            )
            tags.append(tag)
        self._gif_frame_tags = itertools.cycle(tags)
    
    
    def _loop_gif(self):
        self.tag_raise(
            next(self._gif_frame_tags)
        )
        self.after(self._fps, self._loop_gif)
        
    
    
    def _build_frames(self):
        #TODO: make this method faster!!
        frames = []
        for i in range(1000):
            try:
                frames.append(
                    tk.PhotoImage(
                        data=self._image_data, 
                        format=f'gif -index {i}'
                ))
            except tk.TclError as e:
                if 'no image data for this index' in str(e):
                    break
                raise e
        self._gif_frames = frames
    

def main():
    from urllib.request import urlopen
    url = (
        'https://upload.wikimedia.org/wikipedia/commons/2/'
        '2c/Rotating_earth_%28large%29.gif'
    )
    path = Path.home() / 'earth.gif'
    if not path.exists():
        path.write_bytes(urlopen(url).read())
    
    r = tk.Tk()
    Gif(r, image=str(path)).pack()
    r.mainloop()


if __name__ == '__main__':
    main()