[gdal-dev] pass gdal dataset as an argument from Python to C

[Shawn Gong]

Thank you both Sean and Even.


SWIG is too complicated for me, and I will find a work around.

Shawn

________________________________
From: Even Rouault [even.rouault at spatialys.com]
Sent: November-27-17 2:10 PM
To: gdal-dev at lists.osgeo.org
Cc: Sean Gillies; Shawn Gong
Subject: Re: [gdal-dev] pass gdal dataset as an argument from Python to C


On lundi 27 novembre 2017 11:46:50 CET Sean Gillies wrote:

> I believe it's possible, yes, but it will be challenging. I'm not aware of

> anybody else doing this.

>

> In

> https://github.com/OSGeo/gdal/blob/trunk/gdal/swig/python/extensions/gdal_wr

> ap.cpp you can see examples of C++ functions that access the GDAL objects

> referenced by Python objects. This isn't a stable public API by any means,

> and therefore I hesitate to recommend it. Maybe Even would be able to

> comment more on how much support there is for the SWIG-generated C++ Python

> classes.

>



Yes should be doable by "importing" some SWIG_ methods from gdal_wrap.cpp. This might be

fragile in case the SWIG_ wrapping structures evolve.



Interesting bits:



SWIGINTERN PyObject *_wrap_Dataset_RasterXSize_get(PyObject *SWIGUNUSEDPARM(self), PyObject *args) {

PyObject *resultobj = 0; int bLocalUseExceptionsCode = bUseExceptions;

GDALDatasetShadow *arg1 = (GDALDatasetShadow *) 0 ;

void *argp1 = 0 ;

int res1 = 0 ;

PyObject * obj0 = 0 ;

int result;

if (!PyArg_ParseTuple(args,(char *)"O:Dataset_RasterXSize_get",&obj0)) SWIG_fail;

res1 = SWIG_ConvertPtr(obj0, &argp1,SWIGTYPE_p_GDALDatasetShadow, 0 | 0 );

if (!SWIG_IsOK(res1)) {

SWIG_exception_fail(SWIG_ArgError(res1), "in method '" "Dataset_RasterXSize_get" "', argument " "1"" of type '" "GDALDatasetShadow *""'");

}

arg1 = reinterpret_cast< GDALDatasetShadow * >(argp1);

....

}



(GDALDatasetShadow* is an alias of GDALDataset*)



static PyMethodDef SwigMethods[] = {

{ (char *)"Dataset_RasterXSize_get", _wrap_Dataset_RasterXSize_get, METH_VARARGS, (char *)"Dataset_RasterXSize_get(Dataset self) -> int"},

}





--

Spatialys - Geospatial professional services

http://www.spatialys.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20171127/d37fe410/attachment-0001.html>