[Image-SIG] Writting ppm files??

[Ashish Sethi]

well...I tried both ur suggestions but didnt give the desired results
1. First method gave me an all black image (i.e all x/16=0)
2. This method doesnt give me an image file as an outfile

Can u suggest how to work around this

On 8/19/08, Fredrik Lundh <fredrik at pythonware.com> wrote:
> Fredrik Lundh wrote:
>
> > looks like you could save yourself a lot of time and effort by first
> > checking if you can install:
> >
> > http://www.pythonware.com/products/pil/
>
> sorry, thought you'd posted this to c.l.python, and didn't see the "import"
> statement at first.
>
> >
> > > I am working with PPM/PGM/PBM file formats
> > > which have the basic format :-
> > >
> >
>
> > where line1= type of file(p1=PBM,p2=PGM,p3=PPM), line2=comment,
> > line3=dimension of the image (x and y length),line4=maximum value of
> > color( here 15 means 4 bit R,G,B data)
>
> not really -- the 15 means that the images contain data in the range 0-15.
> that fits in 4 bits, but since it's a text format, it isn't stored in 4
> bits.  far from it.
>
> why are you using PPM text files?  does the application your using really
> require that, or is this just something you thought would make things
> easier?
>
> if you're only interested in making sure that all RGB values in an image
> fits inside the 0-15 range, you can simply do:
>
>   im = Image.open(infile)
>   im = im.point(lambda x: x/16)
>   im.save(outfile)
>
> if you insist on writing this out as a text file, replace the "save" with a
> simple loop that uses the im.load() accessor.  something like this should
> work:
>
>   pix = im.load()
>
>   out = open(outfile, "w")
>   print >>out, "P2"
>   print >>out, "%d %d" % im.size
>   print >>out, "15"
>   for y in range(im.size[1]):
>       for x in range(im.size[0]):
>           r, g, b = pix[x, y]
>           print >>out, r, g, b,
>       print >>out
>   out.close()
>
> tweak as necessary.
>
>
> </F>
>
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