Tue, 6 Apr 2010 15:10:49 +0200 письмо от Nils de Reus <nils.de.r...@ivm.vu.nl>:
> When I am getting a binary stored image from a database or as output from
> another process and I need to dynamically feed it into PIL, I usually resort
> to StringIO. The charm there is that I can simply use Image.open() and leave
> the hassle of figuring out the image header to PIL.
>
> import StringIO
> import Image
>
> ...
>
> cursor = connection.cursor()
> cursor.execute("SELECT file from table")
> row = cursor.fetchone()
>
> img_stringio_in = StringIO.StringIO( row[0] )
>
> img_full = Image.open( img_stringio_in )
>
> # You did not specify how you wanted to crop, so I leave defining the box
> parameter as an exercise to your imagination - but for the example I'll crop
> to the top-left 100x100 area.
>
> box = ( 0 , 0 , 100 , 100 )
>
> img_cropped = img_full.crop( box )
>
> Now you have a cropped image, and if I understand well, you want to write it
> back somehow into your database? Several different ways you could proceed
> now.. you could either dump a raw string with the toString function, or
> create another StringIO object and specify that as the file to save into
> using save() or one of the other means of saving the image, and dump that
> thing back into your database. Remember that if using the StringIO trick, you
> need to seek() back to the start after saving into it, like this:
>
> img_stringio_out = StringIO.StringIO()
> img_cropped.save( img_stringio_out, format="png" )
> img_stringio_out.seek( 0 )
>
> Otherwise, a later img_stringio_out.read() would return nothing, since the
> internal cursor would already be at EOF after the save()
>
> Kind regards,
> Nils
>
>
> >
> > I want to use PIL library for crop image on the fly. In my python script:
> >
> > cursor = connection.cursor()
> > cursor.execute("SELECT file from table");
> > row = cursor.fetchone();
> > filetype = imghdr.what(0,row[0]);
> > mimetype = 'image/' + filetype;
> > response = HttpResponse(row[0],mimetype = mimetype );
> >
> > How to correct use PIL library for read image to Image object and return
> > image after crop ?
> >
> > _______________________________________________
> > Image-SIG maillist - Image-SIG@python.org
> > http://mail.python.org/mailman/listinfo/image-sig
>
Thanks
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