Re: [Indic-computing-devel] Re: NCST Indix Examined

[<fpo...@ba...>]

> The distinction between characters and glyphs is
> important even for
> Latin scripts.  Consider ligatures and diacritical marks;
> some Latin
> encodings have separate character codes for the
> diacritical marks; a
> "c" and a "cedilla" (two code points) together can have
a
> different
> glyph in these languages.  Similarly "f", "f" and
"i"
> combine to form
> a distinct glyph "ffi".

Since I am the writer/language police:)

I noticed the phrase "Latin scripts". Are you talking about Western Latin 8859-1 and its various cousins (8859-2, 3, 4etc.) ?

JUST for clarification. 

> 
> The X protocol was explicitly designed NOT to support
> these kinds of
> transformations.

> with meanings ranging from the visual
> representation (the letterform), the 'abstract' character
> itself, the
> code point assigned to the character in a given encoding,
> a specific
> glyph in a font, etc.  The exact meaning is usually clear
> from the context.

May I suggest that it often isn't? That is what is driving my literal mind completely around the semantical bend: it is not always made clear what the writers are referring to. Just a personal observation.

 Maybe it might be an idea to clarify Xlib and X Protocol documentation on this point and take more recent developments in Unicode/ISCII etc. into account?

> 
> Nowhere does the X11 protocol specification say that
> 'character codes'
> are to be used in text drawing requests.  In fact, it
> EXPLICITLY
> states that the semantics of character `codes' are NOT to
> be honored by the X server.

>It says that X protocol does no translation of character
>sets. It doesn't mean that characters 'codes' are not to be
>honored by the X server. 

So which one is it? A translation of character sets into....glyphs is  - to my knowledge at least - the task of the font rendering software used by the X server. what I don't understand is what an X client does. Just display the glyphs? I am not sure what "honoring character codes" would mean here. Are you talking about character set codes or glyph sets?

>X protocol also doesn't EXPLICITLY
>says that glyph codes have to be passed in the request.
>Everywhere it says about "values" passed in the request. It
>was left for implementation to decide what are these
>"values". Actually at that time, there was no distinction
>between character codes and glyph codes.

Yes, there was. But there wasn't a terribly urgent need for software developers at the time to pay any attention to the distinction.

> 
> If you change this, you'll end up with some other
> "protocol", not the
> X protocol.  This new graphics "protocol" is however:

>The client will simply pass the Unicode
>value of the character "KA" in XDrawString16 call and the
>font renderer will take care of it. You can try this out by
>writing a simple application to draw glyph for character
>"KA" from some Unicode encoded Indic font.

Interesting. I am beginning to understand what is going on here.

So does the passing of character codes (or whatever is meant by this) break the X protocol?

Confused again

-Frank