[Openev-discuss] Re: OpenEV-CIETMap-S57

[Frank W. <war...@po...>]

s duclos wrote:
> 
> Hello Frank,
> 
> I'm following up on your mail of 15FEB01.
> 
> I can load/display S57 from gvtest now.
> The python part call gdal.GetLastErrorNo()
> in gvviewwindow.py and stop (openev 1.1.1).
> greping/objdump'ing doesn't help, this must be
> in CPL or there's some more magic with python.
> I'm new to this language.

Sylvain,

gdal.GetLastErrorNo() is from cpl.  The Python bindings for
CPL are within the GDAL module (gdal/pymod).  

> There is the loading part of s57 attribute/value pair
> that, I think, could go into the properties list.

Right!
 
> Also, to put in the properties of an S57 object,
> is a link to the rasterizing rule of the S52 DB.
> 
> The thing is that I'm not to eager to mess with
> OpenEV code directly. I would rather provide a
> plug-in of some sort. Maybe something in /contrib/...
> 
> Else, I would be forking OpenEV!
>
> But since you mentioned that CIETMap is doing
> something similar (forking & extending vector :)
> I thought that you might have an idea on how to switch
> the rendering machinery right above OpenGL.

Well, in the case of CIETMap, the basic vector rendering in
OpenEV is being improved rather than operating as a plugin. 
 
> I'm thinking of something like a dispatcher at the
> gvshapeslayer level.
> 
> A dispatcher would be needed also for the loading
> of attribute/value pair (not sure how, I have not
> trace match in that region.)
> 
> My goal here is to add capability to OpenEV without
> actually touching/disturbing OpenEV code it self!

OpenEV isn't inviolate!  I would prefer your changes be
done without changing the gvshapeslayer.c, but I don't mind
adding code to the OpenEV code base, and perhaps some 
configuration options to determine if S57 support should be
included if it introduces new dependencies. 
 
> I don't mind tearing the code apart to plug my stuff
> (I'm heading for gvS57layer.c as it is)
> but you might have a more sober approach on the
> drawing board to do just that :)

This is exactly how I would do it, a gvS57layer.c that overrides
gvshapeslayer.c stuff in a manner similar to appcurlayer.c.  

Would you like CVS commit access?  If so, I can put the question to
the existing OpenEV core team.  I believe our rule is that half or more of
the core team needs to agree to add new core team members (folks with commit
access).

Best regards,
 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, war...@po...
light and sound - activate the windows | http://pobox.com/~warmerda
and watch the world go round - Rush    | Geospatial Programmer for Rent