[Pyobjc-dev] Variable-length array argument

[Orestis M. <or...@or...>]

Hello,

I'm trying to call NSBitmapImageRep getPixel:atX:y:. The issue is that  
the signature is like this:
- (void)getPixel:(NSUInteger[])pixelData atX:(NSInteger)x y:(NSInteger)y

And expects a pointer to an array, which is variable in length as it  
depends on the type of the bitmap representation. Here's the things  
I've tried:

  * Passing None: exceptions.TypeError: Need explict buffer for  
variable-length array argument
  * Passing objc.NULL: works but doesn't return anything :/
  * Passing lists/strings: exceptions.ValueError: argument 0 must be  
None or objc.NULL
  * Passing an array.array('i'): exceptions.ValueError: type mismatch  
between array.array of i and and C array of I8i12i16
  * Passing an array.array('I'): bus error
  * Passing an array.array('I'), but initialised to size 100 with  
zeroes: exceptions.SystemError: NULL result without error in  
PyObject_Call

I've run out of things to try. So far as I can trace the code, I need  
to pass something that is accepted by PyObject_AsWriteBuffer, and can  
also be converted to this complex c array by PyObjC_PythonToCArray.  
Any pointers on how I can do that?

Thanks,
Orestis
--
or...@or...
http://orestis.gr/