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

[Keyur S. <key...@ya...>]

Hi,

--- Joseph Koshy <jk...@Fr...> wrote:

> The protocol says very clearly that fonts in X are
> collections of
> glyph bitmaps indexed by a glyph index.  It states that
> the values
> used in text drawing requests are indices into the font.

It states that the values used in text drawing requests are
values used to index glyphs. This doesn't mean that these
are glyph indices. 

> It also states very clearly that 'character codes' (i.e
> code points of
> any character set) are not used in the protocol.
> 
> It states very clearly how the drawing requests are to
> place the
> bitmaps of the specified glyphs next to each other (i.e,
> it disallows
> reordering or substitution of glyphs).

Please give reference to each of above.

> There is a whole sub-standard (the X Logical Font
> Description) that is
> used by clients to select fonts with desired font
> encodings so that everything 'just works'.
> 
> This is one of the cornerstones of X's design.

XLFD (X Logical Font Description) is not just meant for
clients. It is also used by X library. When everything is
wrapped in X library then X client does not necessarily use
this XLFD.


> ks> Everywhere it says about "values" passed in the
> request. It
> ks> was left for implementation to decide what are these
> ks> "values". 
> 
> You are implying ambiguity in the specification where
> none exists.

You can send us pointers in X protocol specs where it is
_clearly_ mentioned that only glyph indices are used. I
have searched the specification but nowhere I have found
that only glyph indices are used and character codes should
not be used.

> If you had a question about this, you could have asked on
> the XFree86 lists.
> 
> I wonder what you are hoping to achieve by arguing about
> the X protocol on /this/ list:

This discussion will help us in deciding correct design of
bootable OS. When we have some doubts about other person's
idea then it is better to clarify that before moving
further in the design. This will only help all the people
to contribute towards better design.

And I remind you that only you raised questions about X
protocol, not me. I am just answering to your questions.

> - If there was really a doubt, you could have asked for
> clarification
>   from the rest of the X community; I see no mail from
> you on this
>   topic in the XFree86 archives.

I don't have any doubt. Doubt is in your mind. So I don't
see any need to raise this issue on XFree86 mailing list. 

> - You haven't run the test suite.

In one of my earlier mail I stated that older copy of IndiX
(which is on the website) breaks relationship with other
foreign languages. I have fixed the problem now and Pablo
Saratxaga (maintainer of Mandrake Linux) tested it on his
machine. IndiX was showing French without any problem. I'll
put the changes on the web.

> - A cursory search in the XFree86 archives for ``glyph
> indices'' or
>   other keywords would have revealed enough.

Also see 'man XDrawString'.It clearly states that
"character string" is passed in the function. I tell you
that X library doesn't convert these character codes into
glyph codes before sending them in the protocol request.

> The initial review of IndiX had been posted on
> <indic-computing-devel>
> to make public the rationale for why it wouldn't be
> bundled in the
> 'Bootable OS' sub-project.

When someone review my system publicly and posted his mail
in public list, then I reserve all the rights to defend my
system in public. I wonder why do you want to discuss this
topic off the list when it is very much connected to design
of Indic OS?

> As and when IndiX gets re-designed to be protocol
> compliant, we'll be happy to look at it again.

I can definately think about redesigning of IndiX once it
will be proved that it really breaks protocol. Remember
that you have safely ignored questions raised by Arun. You
have also decided to keep quiet on the issues like
XUtf8DrawString and XmbDrawString which we believe sends
character codes in X Protocol request. When you believe
that sending character codes breaks X protocol design then
you should prove that these functions really deal with
glyph codes and not character codes. You should also try to
write a small application to draw a string using some
Unicode encoded TrueType font and calling XDrawString16. If
you want, I can send a small program which I have tested.
It will show Indic characters on any X server not only
IndiX.

Instead of just saying what is there in X protocol, you
should also think about current implementation of XFree86.

Regards,
Keyur



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