RFR: IO cleanup

[Chris Colbert]

I think we should be aiming for as little C-code as possible in preference
for Cython, escpecially when you start talking about raising exceptions. By
using Cython, all of those questions you have are solved.

On Fri, Nov 5, 2010 at 1:27 PM, Maël Primet <mael.primet at gmail.com> wrote:

> Yes, and also it would be good if we'd specify clearly
> the correct way to treat image arrays:
> eg. how to load properly an array in the good type?
> should the algorithms automatically convert an array to  the  algorithm's
> required type, or should the algorithm fail if the data is not of the
> correct type (some algorithms have no reason to be run on integers / or real
> -valued  data, for instance).
> there should be an utility  function that do the transfer with as little
> copying as possible, yet it should be possible to force copy when the
> algorithms request it
> how do we transfer the arrays to C code ? should we transfer the array
> directly ? only the memory pointer and the size as is done now ? (but then
> we cannot call python code from C code, to do for instance an  FFT ) How do
> we  ensure the array is contiguous with as few copies as necessary ? How do
> we force a copy to be contiguous ?  etc
>
> and also: what is the  proper  way to raise an exception from C code,  etc.
>
> if you have any idea,
> it'd  be  welcome!
>
>
> On Fri, Nov 5, 2010 at 14:38, Chris Colbert <sccolbert at gmail.com> wrote:
>
>> btw, all your changes look good.
>>
>>
>> On Fri, Nov 5, 2010 at 9:29 AM, Chris Colbert <sccolbert at gmail.com>wrote:
>>
>>> Did we decided on a standard for which dtypes we will support?
>>>
>>> Some of the color conversions can be sped up in Cython with a lut (ala
>>> scivi), but we would need to write one func for each dtype.
>>>
>>> I am working on a webinar for image processing and am getting back into
>>> using th scikit, so there are some things I'm seeing during use that I would
>>> like to improve, but would require knowledge of what dtypes to support.
>>>
>>> Chris
>>>
>>> 2010/11/5 Stéfan van der Walt <stefan at sun.ac.za>
>>>
>>> Hi all,
>>>>
>>>> At the SciPy sprint (ages ago), Chris suggested that we clean up the
>>>> image loading API.  The following changes simplify `imread` by
>>>> removing the `dtype` argument.  This allows for simpler plugins.
>>>> Because `as_grey` is such a commonly used parameter, it is left in
>>>> place, but now works differently: after the image is loaded, the (new)
>>>> rgb2grey is simply performed on it.
>>>>
>>>> Please have a look at
>>>>
>>>> https://github.com/stefanv/scikits.image/compare/master...io_cleanup
>>>>
>>>> Regards
>>>> Stéfan
>>>>
>>>
>>>
>>
>
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