[Marble-devel] LGPL license

[Torsten Rahn]

Hi Konrad,

Disclaimer: I'm not a lawyer, so don't take this as legal advice:

On Thursday, 18. August 2011 12:01:15 Konrad Enzensberger wrote:
> i like to use the marblewidget for a commercial development.
> because of some reasons it is not possible to have this development
> as opensource.

1.) If your proprietary code uses libmarblewidget without modification of 
libmarblewidget (and if it  links _dynamically_ against it) then the LGPL 
license allows for this.

2.) The LGPL does not allow you to modify the code of libmarblewidget without 
releasing the modifications under a free LGPL compatible license.

3.) You can however create a proprietary plugin for libmarblewidget without 
releasing the source. This is allowed by the LGPL.

So I guess the best solution is to put all your proprietary code into a 
proprietary Marble plugin that can be loaded via Marble's plugin 
infrastructure. If this requires changes to Marble's plugin infrastructure 
then you need to make those changes to the plugin infrastructure available 
under an LGPL compatible license. Your proprietary plugin can remain 
proprietary in this case.
 
> i hope you can answer me some questions regarding the lgpl license.
> 
> 1. i need to add some special classes to the marblewidget code.
>     Do i need to make this opensource ? ( i am afraid, this classes are not
> helpfull for others)

If these special classes are not part of your own Marble plugin and if they 
are modifications to libmarblewidget (or other LGPL code) then you need to 
license these special classes under an LGPL compatible license. You need to 
license them under an LGPL compatible license even if they are not helpful for 
others. 

> 2. i need to develope own plugins, but it is not possible to make this
> plugins opensource. is this possible?

Yes as long as possible modifications to libmarblewidget are provided under an 
LGPL compatible license. 
 
> 3. shipping my app along with own compiled marblewidget and the marble data
> stuff - what i have to add to not validate the marble license ?

If your app is proprietary and if it links against your own compilation of 
libmarblewidget (that honors the LGPL as described above) then we suggest to 
link dynamically against it. Linking statically without distributing the 
object files is not allowed by the LGPL since it doesn't allow the user for 
relinking to a different version of libmarblewidget.

Regarding the marble data stuff: we tried to keep the license of the data in 
the spirit of the LGPL so that Marble doesn't become a legal minefield.
Much of the data is licensed under the CC by SA, Public Domain or a BSD style 
license. 
However we still suggest to check/verify the license of the data.  This is 
especially true for the Terms of Use for Online Services which might change at 
any point. 

> at last, one developement question:
> for my development, i need to add several thousands objects to the map.
> from what i can see on marblewidget code, currently you do not support
> QGraphicsScene/QGraphicsItem/QGraphicsView , right ? Do you plan to add
> this in future ?

Konstantin Oblaukhov is working on a GeoGraphicsScene for Marble's 
GeoGraphicsItems. This would allow you to create and manage a big number
of GeoGraphicsItems. It's not compatible with QGraphicsView however.

We currently have no plans to use QGraphicsView/QGraphicsScene/QGraphicsItem 
since it is limited to cartesian 2D views.
Marble's GeoGraphicsItems are based on the same basic concept of QGraphicsView 
but allow for geospatial coordinates. Marble's GeographicsItems just use an 
API that is similar to the QGraphicsView framework but are not supposed to be 
used in combination with QGraphicsView. 

Feel free to ask any further questions.

Best Regards,

Torsten

> 
> thanks for support, konrad