Animated GIFs in Safari

[kamenik]

This code generates simple animation, it looks well in chrome/firefox but it has broken background if shown in Safari. I am not able to tell, if it is problem of Pillow or Safari, could you loot at it please?

from io import BytesIO

from PIL import Image, ImageDraw, GifImagePlugin
from PIL.Image import Image as TImage

images = []

for i in range(1, 100):
    img = Image.new('RGBA', (500, 500))
    draw = ImageDraw.Draw(img)

    draw.rectangle((0, 0, 500, 500), fill=(0, 0, 64))
    draw.rectangle((100, 200 - (4 * i % 100), 400, 400), fill=(255, 255, 255))

    draw.rectangle((4 * i, 4 * i, 4 * i + 100, 4 * i + 100), fill=(255, 128, 0))

    img = img.convert("RGB")

    images.append(img)

img_io = BytesIO()

images[0].save(img_io, format="gif", save_all=True, append_images=images[1:], optimize=False, loop=0)
img_io.seek(0)
raw_bytes = img_io.getvalue()

with open('animgif.gif', 'wb') as f:
    f.write(raw_bytes)

OS: latest OpenSUSE Tumbleweed

Report:
--------------------------------------------------------------------
Pillow 10.3.0
Python 3.11.9 (main, Apr 08 2024, 06:18:15) [GCC]
--------------------------------------------------------------------
Python executable is /home/.../venv/bin/python
Environment Python files loaded from /home/.../venv
System Python files loaded from /usr
--------------------------------------------------------------------
Python Pillow modules loaded from /home/.../venv/lib64/python3.11/site-packages/PIL
Binary Pillow modules loaded from /home/.../lib64/python3.11/site-packages/PIL
--------------------------------------------------------------------
--- PIL CORE support ok, compiled for 10.3.0
--- TKINTER support ok, loaded 8.6
--- FREETYPE2 support ok, loaded 2.13.2
--- LITTLECMS2 support ok, loaded 2.16
--- WEBP support ok, loaded 1.3.2
--- WEBP Transparency support ok
--- WEBPMUX support ok
--- WEBP Animation support ok
--- JPEG support ok, compiled for libjpeg-turbo 3.0.2
--- OPENJPEG (JPEG2000) support ok, loaded 2.5.2
--- ZLIB (PNG/ZIP) support ok, loaded 1.3.1
--- LIBTIFF support ok, loaded 4.6.0
--- RAQM (Bidirectional Text) support ok, loaded 0.10.1, fribidi 1.0.14, harfbuzz 8.4.0
*** LIBIMAGEQUANT (Quantization method) support not installed
--- XCB (X protocol) support ok
--------------------------------------------------------------------

[radarhere]

If I change your save command to have a disposal of 1

images[0].save(img_io, format="gif", save_all=True, append_images=images[1:], optimize=False, loop=0, disposal=1)

then the resulting image looks the same in Safari and Chrome. Is that sufficient to solve your problem?

The GIF specification describes disposal of 1 as "Do not dispose. The graphic is to be left in place", and our default disposal of 0 as "No disposal specified. The decoder is not required to take any action".

It may not be a bug as such, but just a different interpretation of the specification.

[kamenik]

Ok, thank you for explanation ;).