Bug 1906512

pyglet itself has:

    # Fallback: PIL
    try:
        from pyglet.image.codecs import pil
        add_encoders(pil)
        add_decoders(pil)
    except ImportError:
        pass

    # Fallback: PNG loader (slow)
    try:
        from pyglet.image.codecs import png
        add_encoders(png)
        add_decoders(png)
    except ImportError:
        pass

sympy has:

    if fmt == "png":
        from pyglet.image.codecs.png import PNGImageDecoder
        img = image.load(fname, decoder=PNGImageDecoder())
    else:
        raise ValueError("pyglet preview works only for 'png' files.")


I guess this works:

    from pyglet.image.codecs.pil import PILImageDecoder
    img = image.load(fname, decoder=PILImageDecoder())

And should support more file types, even. However, this is all only assumptions, I don't know pyglet/sympy internals, just passing by.

> However, this is all only assumptions, I don't know pyglet/sympy internals, just passing by.

Verified that it works: https://bugzilla.redhat.com/show_bug.cgi?id=1906363#c1

It is enough to let Pyglet choose an appropriate decoder with:

    img = image.load(fname)

I see no reason to force a specific decoder, and the Pyglet docs even discourage it "unless your application has to work around specific deficiences in an operating system decoder"[0].

[0] https://pyglet.readthedocs.io/en/latest/programming_guide/image.html?highlight=PILImageDecoder#loading-an-image

I checked that this works for sympy; see https://src.fedoraproject.org/rpms/sympy/pull-request/3

This bug appears to have been reported against 'rawhide' during the Fedora 34 development cycle.
Changing version to 34.

I've (finally) added a note with a link to the Pyglet docs to the spec file.
I don't know of a better place to put it: a README for the RPM would not be much more discoverable, and I'd need to write one to put a note in it :)


Thanks for getting in touch!