[Tutor] problem in converting pixel data to image file

[Tomaz Bevec]

Ashish,

I don't know that much about image processing, but I think you should check into the Image Magick convert utility.  You might be trying to re-invent the wheel.  I have used Image Magick to good effect for the batch processing and conversion of images in a non-python setting.  You can spawn a process from within your python code to take advantage of this program.

Image Magick convert: (scroll down to see options)
(http://www.imagemagick.org/script/convert.php)

--Tomaz




--- On Mon, 8/18/08, Lie Ryan <lie.1296 at gmail.com> wrote:

> From: Lie Ryan <lie.1296 at gmail.com>
> Subject: Re: [Tutor] problem in converting pixel data to image file
> To: tutor at python.org
> Date: Monday, August 18, 2008, 3:41 AM
> > Message: 3
> > Date: Mon, 18 Aug 2008 14:30:08 +0530
> > From: "Ashish Sethi"
> <ashishbitsgoa at gmail.com>
> > Subject: [Tutor] problem in converting pixel data to
> image file
> > To: tutor at python.org
> > Message-ID:
> >        
> <edb5c69c0808180200g62b34859j7441d4587d82276b at mail.gmail.com>
> > Content-Type: text/plain; charset="utf-8"
> > 
> > Hi all,
> > I have a problem in converting the pixel data (read
> from a string and
> > written to a file using fromstring command in PIL ).
> > The file handle of this file is called buffer. Now,
> when I tried to
> > open the
> > file as an image file but it didnt work.
> 
> What is the format of the image you want to open? PIL
> doesn't support
> all image format in the world (of course), but the most
> common ones are
> supported. fromstring, by default, assumes that the string
> you're
> passing it is in raw format (i.e. the definition of raw
> format is
> explained PIL's documentation)
> 
> > Then I read the documentation of PIL and found this
> written about
> > fromstring
> > function
> > "Note that this function decodes pixel data, not
> entire images. If you
> > have an entire image in a string, wrap it in a
> *StringIO *object, and
> > use
> > *open *to load it."
> 
> StringIO is simply a wrapper around string to make it have
> a file-like
> interface (since Python uses Duck Typing principle, if an
> object has the
> same members a file-object have, like read(), write(),
> readlines(), etc
> python should not differentiate them)
> 
> > so i wrote the following code....
> > 
> > file = StringIO.StringIO(buffer)
> > img = Image.open(file)
> > img.save(file, 'JPEG')
> > 
> > *Error:*
> > img = Image.open(file)
> >   File
> "/home/rahhal/python/lib/python2.4/site-packages/PIL/Image.py",
> > line
> > 1745, in open
> >     raise IOError("cannot identify image
> file")
> > IOError: cannot identify image file
> 
> PIL is it cannot identify what format the original image is
> in, either
> you pass explicitly what format the original file is in, or
> (at the
> worst case) you create (or search whether one is available
> on the
> internet) your own decoder.
> 
> PS: List of image format supported by PIL (you can also
> find it in PIL's
> documentation):
> BMP
> BUFR (identify only)
> CUR (read only)
> DCX (read only)
> EPS (write-only)
> FITS (identify only)
> FLI, FLC (read only)
> FPX (read only)
> GBR (read only)
> GD (read only)
> GIF
> GRIB (identify only)
> HDF5 (identify only)
> ICO (read only)
> IM
> IMT (read only)
> IPTC/NAA (read only)
> JPEG
> MCIDAS (read only)
> MIC (read only)
> MPEG (identify only)
> MSP
> PALM (write only)
> PCD (read only)
> PCX
> PDF (write only)
> PIXAR (read only)
> PNG
> PPM
> PSD (read only)
> SGI (read only)
> SPIDER
> TGA (read only)
> TIFF
> WAL (read only)
> WMF (identify only)
> XBM
> XPM (read only)
> XV Thumbnails 
> 
> > Can any one please help in solving my problem??
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