Mapnik is an open source community creating a tool to enable to the craft of making beautiful maps. Working together collaboratively towards this goal is what makes it all possible and fun.
We host our code on github.com/mapnik and encourage anyone interested to fork the repository and provide pull requests or patches for things they want to see added.
If you just have a question about the code, or a feature you want to discuss then feel free to create a new issue.
## Code Philosophy
Look through the code to get an idea, and do not hesitate to ask questions.
Also read the design philosophy page for the motivations that lead to code decisions.
In general we use Boost, it makes more possible in C++. It is a big build time dependency (as in time to compile against and # of headers) but ultimately compiles to small object code and is very fast (particularly spirit). It also has no dependencies itself (it's really an extension to the C++ language) so requiring it is much easier than requiring a hard dependency that itself has other dependencies. This is a big reason that we prefer AGG to Cairo as our primary renderer. Also AGG, besides producing the best visual output, strikes an excellent balance between speed and thread safety by using very lightweight objects. Cairo not so much.
You will also notice that we don't use many of the standard geo libraries when we could. For instance we don't use GDAL, OGR, or GEOS anywhere in core, and only leverage them in optional plugins. We feel we can often write code that is faster and more thread safe than these libraries but that still does the job. If this ever changes we can adapt and start using these libraries or others as dependencies - nothing is nicer than standing on the shoulders of giants when it makes sense.
## License
Mapnik is licensed LGPL, which means that you are a free to use the code in any of your applications whether they be open source or not. It also means that if you contribute code to Mapnik that others are free to continue using Mapnik in the same way, even with your new additions. If you choose to redistribute an application using Mapnik just make sure to provide any source code modifications you make back to the community. For the actual details see the full LGPL license in the COPYING doc.
## Copyright
Mapnik is an open source project and will always be, proudly, an open source project. Your contributions to Mapnik should be motivated by (amount other things) your desire to contribute to a community effort and by the knowledge that your open code will stay that way.
Artem, as the founder and leader of the Mapnik project, is the primary copyright holder and therefore also the primary contact for any current or future license questions around Mapnik. It is important that the copyright holder is respected, trusted, and known to the community so maintaining copyright with Artem is key to maintaining the project as open source.
Therefore, convention is that all new files created by any core developers or patch
* Function definitions should not be separated from their arguments:
void foo(int a) { ... } // please
void foo (int a) { ... } // no
* Separate arguments by a single space:
void foo(int a, float b) // please
void foo(int a,float b) // no
* Space between operators:
if (a == b) // please
if(a==b) // no
* Braces should ideally be on a separate line:
if (a == b)
{
int z = 5;
// more...
}
### Other C++ style resources
Many also follow the useful [google](http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml) which mostly fits our style. However, Google obviously has to maintain a lot of aging codebases. Mapnik can move faster, so we don't follow all
of those style recommendations.
### Emacs helper
To auto-convert to the above syntax you can put this in an .emacs file:
