[scikit-image] 回复：Re: imagepy new version

[Stefan van der Walt]

On Tue, 05 Jun 2018 11:32:19 +1000, Juan Nunez-Iglesias wrote:
> My understanding is that certain PyQt wrappers actually get around the
> GPL requirement, allowing you to link to it from BSD-licensed code.
>
> (Which is how things like Matplotlib and Spyder are BSD/MIT.)
> But, it's true: none of the Python GUI frameworks are perfect.

This issue has been discussed on the list before, and I am still
unconvinced that you can legally "get around" the GPL requirements.

It's a murky issue, complicated also by Qt's dual licensing model.  My
understanding is that you may distribute your code under whichever
license you choose, but that the binary product that results from
importing e.g. matplotlib + qt together is governed by the GPL.

The "workaround" is thus to postpone the instant at which linking occurs
(given that "import" is Python's way of linking).  What are the
implications of doing so?  Could a lawayer argue that, in spirit, the
GPL is being violated?

A different consideration is whether there is risk of legal trouble:
that risk is probably quite low, with Pyside2 / Qt at least.

Yet another issue is our responsibility to our users.  With patents,
e.g., our decision has been not to include any encumbered algorithms,
because there aren't very many good ways of protecting our users against
them (you copy/paste some skimage code from StackOverflow, run it, and
all of a sudden you've applied a patented algorithm on your
data—yikes!).  It is not clear how we should warn our users in this
case, or what exactly that warning should say.

Best regards,
Stéfan