Re: [Pyobjc-dev] Passing objects between PyObjc and SWIG

[Kyle J. <osm...@gm...>]

On Thu, Mar 20, 2008 at 7:05 AM, Ronald Oussoren <ron...@ma...> wrote:
>
>  On 20 Mar, 2008, at 11:27, Kyle Johnson wrote:
>  > So basically, I need to code something which converts the PyObjc
>  > internal type to a SWIG-understandable internal type.
>
>  Those types are automaticly generated.
>
>  You can use the __cobject__() method on all Objective-C or
>  CoreFoundation objects to get a Python CObject that wraps the raw
>  pointer.  That might be easier to convert to something that swig might
>  understand.


Thank you for the info, Ronald. I think I'm going in the right
direction with this now.

I think there may be some wrapping still going on though with
__cobject__ as I'm getting invalid context errors from Core Graphics
(via Cairo).


I call the cairo function from Python like so:
ctx = NSGraphicsContext.currentContext().graphicsPort()
cairo.cairo_quartz_surface_create_for_cg_context(ctx.__cobject__(), 400, 400)


My wrapper code looks like this:

// definition of cairo function
cairo_surface_t *cairo_quartz_surface_create_for_cg_context
(CGContextRef cgContext, unsigned int width, unsigned int height);

// BEGIN: wrapper code (simplified)
CGContextRef arg1;
unsigned int arg2, arg3;
PyObject *obj0, *obj1, *obj2;

PyArg_ParseTuple(args,(char
*)"OOO:cairo_quartz_surface_create_for_cg_context",&obj0,&obj1,&obj2);
if( PyCObject_Check(obj0) ) {
    // !!! something is wrong here; either the void ptr returned isn't for
    // a CGContextRef or my typecasting/de-pointerizing is bad
    arg1 = *(CGContextRef *) PyCObject_AsVoidPtr(obj0);
} else {
    PyErr_SetString(PyExc_TypeError, "cgContext is not type PyCObject");
    return NULL;
}
// [...] code for obj1/arg2, obj2/arg3
result = cairo_quartz_surface_create_for_cg_context(arg1,arg2,arg3);

// END: wrapper code (simplified)



This shouldn't be a Cairo issue. I have a identical C/Objective-C copy
of my program working without a problem.

-- 
Kyle Johnson