[Image-SIG] Array to Image transformations

[Carlos da Silva Santos]

There are currently two PEPs related to this kind of problem. One is
lead by Travis Oliphant of numpy and is about establishing a buffer
protocol for data interchange. The second one is specifically related
to passing image data between applications/toolkits.

http://www.python.org/dev/peps/pep-3118/
http://www.python.org/dev/peps/pep-0368/

So I guess in the near future we will get rid of string conversions.

Carlos

On Wed, Feb 27, 2008 at 6:23 AM, Frédéric Mantegazza
<frederic.mantegazza at gbiloba.org> wrote:
> On mardi 26 février 2008, Joao S. O. Bueno wrote:
>
>  > On Thu 21 Feb 2008 05:47:22 Sahar Vilan wrote:
>
>  > > Can anyone help me with transformation from numpy array to image (at
>  > > PIL library)?
>  > > I want to change an array (at numpy) into an image (at Image) in order
>  > > to rotate the image and save it in standard image format.
>  >
>
> > Sorry for the long delay.
>  > These convertions in python among data and image representation indeed
>  > require some experimentation.
>  >
>  > (In my todo list, wiht low priority, I have a python module that would
>  > seamlessly translate image data across various image handling
>  > bindings/ibraries and numerical types).
>  >
>  > Fortunatey, in this case it is rather simple:
>  >
>  > For numpy.array -> python image, you do something like:
>  >
>  > a = numpy.array ("\x0"  (WIDTH  * HEIGHT  * 3), "B")
>  > #code to create imag data inside array
>  > # (...)
>  > i  = Image.new("RGB", (WIDTH, HEIGHT))
>  >
>  > i.fromstring(a.tostring())
>  > i.save(filename)
>
>  Hello,
>
>  I'm also very interested by such features, because I think it could be a
>  nice way to use color management libraries. For example, the little cms
>  python wrapper could handle arrays (which it does not yet), and then, PIL
>  could convert image from/to arrays.
>
>  > i.fromstring(a.tostring())
>
>  What is the performances of such transformations?
>
>  --
>    Frédéric
>
>    http://www.gbiloba.org
>
>
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