This is done in as much of a drop-in fashion as possible. Note that
libvips does not support animated PNGs[^1], and as such this
conversion removes support for them as emoji; however, libvips
includes support for webp images, which future commits will take
advantage of.
This removes the MAX_EMOJI_GIF_SIZE limit, since that existed to work
around bugs in Pillow. MAX_EMOJI_GIF_FILE_SIZE_BYTES is fixed to
actually be 128KiB (not 128MiB, as it actually was), and is counted
_after_ resizing, since the point is to limit the amount of data
transfer to clients.
[^1]: https://github.com/libvips/libvips/discussions/2000
5dab6e9d31 began honoring the list of disposals for every frame.
Unfortunately, passing a list of disposals for a non-animated image
raises an exception:
```
File "zerver/lib/upload.py", line 212, in resize_emoji
image_data = resize_gif(im, size)
File "zerver/lib/upload.py", line 165, in resize_gif
frames[0].save(
File "[...]/PIL/Image.py", line 2212, in save
save_handler(self, fp, filename)
File "[...]/PIL/GifImagePlugin.py", line 605, in _save
_write_single_frame(im, fp, palette)
File "[...]/PIL/GifImagePlugin.py", line 506, in _write_single_frame
_write_local_header(fp, im, (0, 0), flags)
File "[...]/PIL/GifImagePlugin.py", line 647, in _write_local_header
disposal = int(im.encoderinfo.get("disposal", 0))
TypeError: int() argument must be a string, a bytes-like object or a
number, not 'list'
```
`check_add_realm_emoji` calls this as:
```
try:
is_animated = upload_emoji_image(image_file, emoji_file_name, a
uthor)
emoji_uploaded_successfully = True
finally:
if not emoji_uploaded_successfully:
realm_emoji.delete()
return None
# ...
```
This is equivalent to dropping _all_ exceptions silently. As such,
Zulip has silently rejected all non-animated images larger than 64x64
since 5dab6e9d31.
Adjust to only pass a single disposal if there are no additional
frames. Add a test for non-animated images, which requires also
fixing the incidental bug that all GIF images were being recorded as
animated, regardless of if they had more than 1 frame or not.
This additional logic to prevent resizing is certain circumstances
(file size, dimensions) is necessary because the pillow gif handling
code seems to be rather flaky with regards to handling gif color
palletes, causing broken gifs after resizing. The workaround is to
only resize when absolutely necessary (e.g. because the file is larger
than 128x128 or 128KB).
Fixes#10351.
Fixes the avatar/emoji part of #8177.
Does not address the issue with uploaded images, since we don't do
anything with them.
Also adds 3 images with different orientation exif tags to
test-images.
Alex Vandiver
Anders Kaseorg
Daniel Bradburn
Harshit Bansal
Shubham Padia
Nikhil Kumar Mishra
Eklavya Sharma