From: "Ara.T.Howard" <ahoward@...>
Date: 2004-02-24T13:34:57+09:00
Subject: Re: TkPhotoImage :data=>buf

On Tue, 24 Feb 2004, Hidetoshi NAGAI wrote:

> Hi, 
> 
> From: "Ara.T.Howard" <Ara.T.Howard@noaa.gov>
> Subject: TkPhotoImage :data=>buf
> Date: Sun, 22 Feb 2004 02:44:51 +0900
> Message-ID: <Pine.LNX.4.44.0402211035300.27847-100000@fattire.ngdc.noaa.gov>
> > does anyone know if this is simply a limitation of the gif formatted images?
> 
> It's a bug. I understand the reason og the trouble.  But it may be a little
> difficalt to fix. 
> 
> The bug depends on string interchange between Ruby and Tk interpreter. To
> avoid the trouble of the difference of encoding between the interpreters,
> current Ruby/Tk converts encoding of strings automatically. Usually it will
> be convenient for Ruby/Tk users. Therefore, when treats a binary string
> (especially, includes null bytes), the data is garbled. 
> 
> To fix the bug, I'll have to edit tcltklib.c and TkVariable class, and add a
> new class "Tk::BinaryString" which is a subclass of Tk::EncodedString class.
> A Tk::EncodedString instance is a string with encoding information. By
> creating a Tk::BinaryString instance (has a special encoding 'binary') for a
> binary string, Ruby/Tk recognizes that the string never be converted and
> never be terminated by a null byte. 
> 
> Although this strategy may trouble Ruby/Tk users, it will be an actual and
> reasonable solution. I think so. Probably I'll have to change the
> implementation of TkVariable class.  My only worry is en-bugging by side
> effects.
> 
> Please wait for a good news about this.  It will not be far-off. 

thanks for the detailed reply!

if you you introduced the Tk::BinaryString class, and only used it when
':buf=>data' was used - that shouldn't cause any bugs should it?

thanks again.

-a
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