[Image-SIG] proper type of image objects

[Fredrik Lundh]

On Mon, Apr 13, 2009 at 5:01 AM, Guy K. Kloss <g.kloss at massey.ac.nz> wrote:
>
> Hi,
>
> I'm currently working on extending the ctypes based LCMS bindings, and I want
> to support PIL image types natively inside the doTransform() method on a
> Transform object.
>
> Anyway, for that task I need to distinguish between different valid object
> types for the input buffer to decide which action to take. For NumPy arrays
> that works nicely, but I don't know how to distinguish properly whether I'm
> dealing with a PIL.Image type object. Below you can find some of the
> tinkerings of the "obvious" candidates.
>
> So far it seems as if only the last one gives me a viable option, but it
> doesn't strike me as being very pythonic, elegant or even clean in the code.
>
> Any suggestions?
>
> Guy
>
>
> >>> type(a_numpy_array)
> <type 'numpy.ndarray'>
> >>> isinstance(a_numpy_array, numpy.ndarray)
> True
> >>> type(a_pil_image)
> <type 'instance'>
> >>> isinstance(a_pil_image, instance)
> [...]
> NameError: name 'instance' is not defined
> >>> isinstance(inImage, PIL.Image)
> [...]
> TypeError: isinstance() arg 2 must be a class, type, or tuple of classes and
> types

>>> PIL.Image
<module 'PIL.Image' from 'PIL\Image.pyc'>
>>> PIL.Image.Image
<class PIL.Image.Image at 0x00C5D720>
>>> isinstance(inImage, PIL.Image.Image)
True
>>> PIL.Image.isImageType(inImage)
True

</F>