PanoTools NG:
Re: PTViewer Licensing Question
dmgalpha 2007-Sep-19 22:39:20
--- In #removed#, Fulvio Senore <mailing@...> wrote:
>
>
>
> hd_de_2000 ha scritto:
> > --- In #removed#, Fulvio Senore <mailing@> wrote:
> >
> >> Carl von Einem ha scritto:
> >>
> >>> Another important change of license conditions came with
ptviewer 2.1
> >>> <http://www.panotools.org/mailarchive/msg/7621#msg7621>
> >>> "GNU-License applies to all extensions of PTViewer, including the
> >>> QTVR-extension PTMViewer."
> >>>
> >>>
> >> I have always been curious about this: PTViewer is licensed under
the
> >> GPL, but I think that an applet is conceptually similar to a plugin:
> >> something that under Windows is implemented as a DLL. The browser
links
> >> to the plugin or to the applet.
> >> It seems that the GLP requires that code linking to a GPL
software must
> >> be open-source: to solve this problem there is the LGPL that lets
> >> proprietary software link to the library.
> >>
> >> So, strictly speaking, Internet Explorer should not be allowed to
use
> >> PTViewer. Maybe PTViewer should have been released under the LGPL.
> >>
> >> Does anybody have more information about this?
> >>
> >>
> >
> > Hi Fulvio,
> >
> > you can link and use GPL-software in any way you wish! Restrictions
> > only apply if you _distribute_ the software. Then you have to also
> > distribute (or otherwise make available) the sources. The user of the
> > applet may run it on any Java Runtime he/she wishes, be it open source
> > or not!
> >
> > Using the PTViewer applet on a website or CD obviously qualifies as
> > distribution. Using GPL-d applets then requires to either offer the
> > sources from your site or supply a download link to some place
> > offering the sources. For _unmodified_ versions of PTViewer I have
> > waived this particular requirement, so that you can just use it
> > without any further action.
> >
> > As soon as changes are made to the applet (like changing the class
> > name etc) the full requirements of the GPL apply and you must supply
> > the modified sources together with the applet.
> >
> > Best regards
> >
> > Helmut Dersch
> >
> Hi Helmut,
>
> thank you for your information. I do not know the terms of the GPL very
> well, so I did not know those things.
>
> As you might know, I have released a modified version of PTViewer,
based
> on your code. To me, users of my version of PTViewer can use the applet
> as they like, and I am not interested in requiring anything from them:
> no aknowledgement, no link to my site.
Software licensed under the GPL cannot have this type of requirements
(they are known as advertisement clauses). So even if you wanted, you
cannot require a link to your site.
I am not sure what version of the GPL applies (I haven't been able to
find the actual source of the PTviewer, only its jar file--sorry I am
java illiterate). For instance, if it is version 2, then you are
required, once you start distributing your changes, to provide the
entire sources. The Free Software Foundation recommends to distribute
the sources next to the "binary" (in this case the compiled java applet).
>
> Do I need to write this in my website, or am I bound to your terms of
> license, so I do not need to explain anything?
>
>
> Fulvio Senore
>
I believe this is a simple, straightforward case because you
acknowledge that your modifications of PTviewer are a derivative work
of the original (I am not taking here about it inclusion on a CD or
website, just the software itself, as an independent product).
In that case the requirements are simple: you need to relicense under
the same license you received it, and you need to make the sources
available. for the specific details check section 3 of the GPL
http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
This might also clarify the issue. This is from the GPL FAQ, from the FSF:
http://www.gnu.org/licenses/old-licenses/gpl-2.0-faq.html#SourceAndBinar...
Can I put the binaries on my Internet server and put the source on
a different Internet site?
The GPL says you must offer access to copy the source code
"from the same place"; that is, next to the binaries. However, if you
make arrangements with another site to keep the necessary source code
available, and put a link or cross-reference to the source code next
to the binaries, we think that qualifies as "from the same place".
Note, however, that it is not enough to find some site that
happens to have the appropriate source code today, and tell people to
look there. Tomorrow that site may have deleted that source code, or
simply replaced it with a newer version of the same program. Then you
would no longer be complying with the GPL requirements. To make a
reasonable effort to comply, you need to make a positive arrangement
with the other site, and thus ensure that the source will be available
there for as long as you keep the binaries available.
--daniel
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