[Marble-devel] Overlays in the Marble Viewport

[Torsten Rahn]

Hi Christophe

On Friday 04 June 2010 12:01:07 Christophe Leske wrote:
> first of all, i would like to thank all the people that kindly helped me
> here the last months.
> Thorsten Rahn, Patrick Spendrin, Sylvain Pare and Jens-Michael Hofmann,
> as well as others.

Thanks for using Marble in your project and thanks a lot for contributing back 
by putting the experience you gained into techbase.kde.org! This is very helpful 
for us! :-)
 
> Since this is Marble-Devel, and I more interested in adapting Marble for
> customized projects, I was wondering if this is still the right place to
> ask questions about how to customize Marble? Is there any other forum or
> list which might be more suitable?

I definetely think this is the right place. marble-devel is for people who 
develop with Marble as well as for people who develop Marble itself.

> I am currently wondering how one can add overlays to the marble viewport
> (libMarbleWidget). I would like to add customized graphics to the
> viewport in order to "brand" the application for demonstration purposes.

You can either 

* overwrite the customPaint 

http://techbase.kde.org/Projects/Marble/MarbleGeoPainter

* or create a render plugin. As an example see:

/home/tackat/trunk/marble/src/plugins/render/test/

> Also, does the license under which the Marble Widget is published (I
> reckon it is the LPGL?)

Yes it is LGPL (2+).

> allow me to create customized applications using
> the widget and sell my work to cliens (either the created software as
> such, or the process of tailoring the software for the client)?

Yes, both of this is allowed as long as you do this within the terms of the 
license. In fact we have chosen the LGPL as a license to allow for commercial 
use and use in proprietary applications.

You should check the terms of the LGPL yourself.  For explanation there is also 
a Wikipedia article available at 
http://en.wikipedia.org/wiki/GNU_Lesser_General_Public_License

And of course it's also great if you sell your work based on Marble to clients 
as well as your services of tailoring the software for the client. In fact there 
are certainly quite a few Marble core developers who would like to do the same.

What we regard very important of course is that 

 * You contribute back: if you modify the Marble library itself then the LGPL 
asks you to provide the source code of the modifications back to the Marble 
project under the LGPL license. 
If you need to make changes to the Marble library itself which are supposed to 
be kept proprietary then a viable solution might be to create a plugin for 
Marble.  
  * You pay credits to the Marble project and its developers and you mention 
that Marble is licensed under the LGPL.

If you have more questions don't hesitate to ask :)

Regards,

Torsten

> Sorry if this is obvious, I am freelance developer working primarily
> under Windows and MacOS X, and not that much under Linux...
> 
> Greets,