[Qgis-developer] geos c api note

[Martin Dobias]

Hi Jurgen,

On 8/15/08, Jürgen E. Fischer <jef at norbit.de> wrote:
> Hi Martin,
>
> On Wed, 13. Aug 2008 at 17:05:44 +0530, Martin Dobias wrote:
> > i'd like to say that in my opinion it would cause pain to switch to
> > geos c api now before 1.0 release. there are more reasons:
>
> > - we shouldn't force users to use some very new version of geos
>
> Is that really a big issue?  We need tons of dependencies.  I don't
> think using a current GEOS version is going to be a significant extra
> effort for now, if someone is willing to go though the hassle of
> building QGIS at all.

Well, very recent library versions cause problems mostly for linux
users which usually use packages from distros and manual installation
of the libs discourages quite a lot

> > - may bring new bugs
>
> That's true for almost every change.

Yes, so why to do this work just before the release?


> > - this is my biggest concern - we'd like to do many changes in
> > geometry handling after 1.0 release and geos c api doesn't have
> > support of many features that we will need so that might result in
> > going back to geos c++ api.
>
> Apparently the C++ API is not the recommended interface (see
> http://download.osgeo.org/geos/doxygen/).  Note: on Windows there ure
> only DLLs for the C-API.  Unless you use the static library there is no
> available C++-API at all.

You're right. I'm aware of the issues. On windows we have to build
many deps by ourselves so building also geos is not such a problem.
The thing about c++ api not being recommended is really something that
we should avoid in long term. But doing it now just kills the
development effort I (and others) would like to give to enhance qgis.


> So I think we should target the C-API and extend it if necessary in
> cooperation with the geos folks.

Indeed. However I would prefer the cooperation in way that first we
list what we need, they make the necessary changes and then we can
switch to C api.


Regards
Martin