Re: [Pyobjc-dev] VTK bindings

[b.bum <bb...@ma...>]

On Dec 2, 2003, at 1:12 AM, Carlos Phillips wrote:
> 2003-12-02 03:30:46.165 Simple1[1541] PyObjCPointer created: at  
> 0x6d16080 of type  
> {vtkRenderer={?={?={?=^^?i}C{vtkTimeStamp=^^? 
> L}^{vtkSubjectHelper}}^{vtkAssemblyPath}^{vtkPropCollection}iIff^{vtkPr 
> opCollection}^{vtkActor2DCollection}^{vtkWindow}[3f][4f][2f][2f][2f][2i 
> ][2i][3f][3f][4f]}^{vtkCamera}^{vtkLight}^{vtkLightCollection}^{vtkCull 
> erCollection}^{vtkActorCollection}^{vtkVolumeCollection}[3f]^{vtkRender 
> Window}ffiii*{vtkTimeStamp=^^? 
> L}fii^^{vtkProp}i^^{vtkAssemblyPath}iii[6f]f}8@0:4

Like Bob said, once a PyObjCPointer is created, you are generally out  
of luck.  PyObjC transparently bridged Objective-C.  In this case, you  
are asking it to transparently bridge a relatively complex C data type.

Having had a look at the article, I see three methods like this....

-(vtkRenderer *)renderer;
-(vtkRenderWindow *)renderWindow;
-(vtkRenderWindowInteractor *)renderWindowInteractor;

... invoking the first would cause the above message to be produced.

The problem is that you are passing a C structure reference across the  
bridge into the Python world.   This is an edge case that is generally  
hard to handle.

One solution would be to create a class for each c structure.  Then,  
implement a method that returns an instance of the class that contains  
the structure.  Each class would have instance methods that would  
get/set the data found within the C structure-- the vtkRenderer *, for  
example.

b.bum