I expect it isn't much code, basically repackaging 8-bit bytes in 6-bit chars. Biggest q is 
probably the API - one cutesy idea is 
encoding convert{from,to} base64
:^)


Best regards, Richard Suchenwirth-Bauersachs  http://wiki.tcl.tk/RS


-----Urspr�ngliche Nachricht-----
Datum: Sat, 26 Apr 2008 09:04h
Von: "Donal K. Fellows" <donal.k.fellows@[...].uk> 
An: lluisgomez@[...].org
Kopie: tcl-core@[...].net
Betreff: Re: [TCLCORE] problem with image create photo


lluisgomez@[...].org wrote:
>  sorry if this is not the plae for this question, I don't found a  
>  tcl/tk users mailing list ... and i need hep with a strange problem ::

Strictly this isn't the right place; general user questions are best
directed to the newsgroup comp.lang.tcl (that's why you didn't find a
mailing list!) but it's an interesting one with some policy side pieces
to my answer which *are* on topic here. :-)

>  I'm using this command in my aplication
>     COLORGRID_SYS_VGUI3("image create photo img1223 -data {%s}\n",fdata);
>  where fdata is a const char* with a base64 encoded PNM image,

Not the most favoured way of doing it.

>  tk says:
>    "couldn't recognize image data"
>  If I do it with a base64 encoded GIF it works

That's because the GIF reader was specially hacked to support base64
encoded images. Fairly ugly, but made sense at the time! These days,
we'd not do that at all and instead direct people to the base64 decoder
available in tcllib.

>  hasn't tk built-in support for PNM images?

Yes, but only ones described as raw data. (In fact, I suspect we only
support the P6 and P5 subformats.) Alas, you can't include such raw data
just like that; we need a little more magic. See below...

>  any tips?

Apply what I said about base64 in tcllib and you get this:
   COLORGRID_SYS_VGUI3("package require base64;"
         "image create photo img1223 -data [base64::decode {%s}]\n",
         fdata);

Now the policy question for people on this list: should we generalize
the base64 reader so that all format readers (including those provided
by Img) pick up base64 support transparently?

Donal.

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