reencode fonts with fonts.trigger

reencode fonts with fonts.trigger

[Ulrike Fischer]

Hello,

Khaled had another idea to manipulate (reencode) fonts: He suggested
to put a function in fonts.trigger. (Example below). I have some
questions regarding this example:

1. Is there a basic flaw in the idea?

2. Is the interface more or less stable or will it probably change
in the future?

If not
3. which tables/values in tfmdata must be copied/reassigned beside
the indices information? (There seem to be quite a lot informations
more than once in tfmdata. E.g. I find the boundingbox in two places
(descriptions and shared.otfdata.glyphs)). 

4. Which tables/values must be created if I try to move a char to a
place which is currently empty (like the "z" in the example)?

5. What is the recommanded lua-code to copy/reassign/remap the
tables?  Does a library or some helper functions exist which would
make it easier to move the tables around? 

  
\directlua{
 local function chess(tfmdata,value)
  if value then
   tfmdata.characters[122]={}

tfmdata.indices[75],tfmdata.indices[81],tfmdata.indices[122]=tfmdata.indices[81],tfmdata.indices[75],tfmdata.indices[81]
   table.tofile("filechess.lua", tfmdata, true) %show table 
  end
 end
 table.insert(fonts.triggers,"chess")
 fonts.initializers.base.otf.chess = chess
 fonts.initializers.node.otf.chess = chess
}

\font\test="file:SkakNew-Figurine.otf:chess=yes"

\starttext

\test KQzK

\stoptext

\bye

-- 
Ulrike Fischer 

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___________________________________________________________________________________

Re: reencode fonts with fonts.trigger

[Hans Hagen]

On 22-2-2011 4:22, Ulrike Fischer wrote:
> Hello,
>
> Khaled had another idea to manipulate (reencode) fonts: He suggested
> to put a function in fonts.trigger. (Example below). I have some
> questions regarding this example:
>
> 1. Is there a basic flaw in the idea?

When triggers are done, there are only empty entries in the characters 
table so swapping them has no effect. You can add info to them but some 
entries in them will be added when scaling takes place.

> 2. Is the interface more or less stable or will it probably change
> in the future?

the triggers interface will stay

> If not
> 3. which tables/values in tfmdata must be copied/reassigned beside
> the indices information? (There seem to be quite a lot informations
> more than once in tfmdata. E.g. I find the boundingbox in two places
> (descriptions and shared.otfdata.glyphs)).

they are the same (descriptions is the unicode ordering of glyphs but 
the subtables are shared, and best don't mess with those subtables as 
they can be shared as well)

you probably don't have to change anything else as tex only works with 
the tfm data (in node mode otf data is used but chess is unlikely to be 
influenced by node mode)


> 4. Which tables/values must be created if I try to move a char to a
> place which is currently empty (like the "z" in the example)?

see above, for tex only the tfmdata counts so no other data has to be 
created (unless you have kerns in which case you need to adapt all 
character entries that kern with that glyph)

> 5. What is the recommanded lua-code to copy/reassign/remap the
> tables?  Does a library or some helper functions exist which would
> make it easier to move the tables around?

For basemode reencoding you can use the changed subtable:

\starttext

\directlua{
     local function chess(tfmdata,value)
         if value then
             tfmdata.changed[75] = 81
             tfmdata.changed[81] = 75
         end
     end
     table.insert(fonts.triggers,"chess")
     fonts.initializers.base.otf.chess = chess
}

\start
     \font\TestA="file:SkakNew-Figurine.otf:chess=yes"  \TestA\char75 
\char81 \par
     \font\TestB="file:SkakNew-Figurine.otf:chess=no"   \TestB\char75 
\char81 \par
\stop

\stoptext

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: reencode fonts with fonts.trigger

[Hans Hagen]

On 22-2-2011 4:22, Ulrike Fischer wrote:
> Hello,
>
> Khaled had another idea to manipulate (reencode) fonts: He suggested
> to put a function in fonts.trigger. (Example below). I have some
> questions regarding this example:

I'll add the following to the luatex-fonts code. It demonstrates how to 
use postprocessing hooks. (It should work with the current code, unless 
you define multiple mapping of the same font, for which i've added a 
patch).

\startluacode
     local reencodings     = { }
     fonts.enc.reencodings = reencodings

     local function specialreencode(tfmdata,value)
         -- we forget about kerns as we assume symbols and we
         -- could issue a message if ther are kerns but it's
         -- a hack anyway so we odn't care too much here
         local encoding = value and reencodings[value]
         if encoding then
             local temp = { }
             local char = tfmdata.characters
             for k, v in next, encoding do
                 temp[k] = char[v]
             end
             for k, v in next, temp do
                 char[k] = temp[k]
             end
             -- if we use the font otherwise luatex gets confused so
             -- we return an additional hash value for fullname
             return string.format("reencoded:%s",value)
         end
     end

     local function reencode(tfmdata,value)
         tfmdata.postprocessors = tfmdata.postprocessors or { }
         table.insert(tfmdata.postprocessors,
             function(tfmdata)
                 return specialreencode(tfmdata,value)
             end
         )
     end

     table.insert(fonts.manipulators,"reencode")
     fonts.initializers.base.otf.reencode = reencode
\stopluacode

\startluacode
     fonts.enc.reencodings["mychess"] = {
         [75] = 81,
         [81] = 75,
     }
\stopluacode

\starttext

{\font\test=file:SkakNew-Figurine.otf at 50pt                  \test QK 
\par}
{\font\test=file:SkakNew-Figurine.otf:reencode=mychess at 50pt \test QK 
\par}

\stoptext


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: reencode fonts with fonts.trigger

[Ulrike Fischer]

Am Tue, 22 Feb 2011 18:05:58 +0100 schrieb Hans Hagen:


>> Khaled had another idea to manipulate (reencode) fonts: He suggested
>> to put a function in fonts.trigger. (Example below). I have some
>> questions regarding this example:

>> 1. Is there a basic flaw in the idea?
 
> When triggers are done, there are only empty entries in the characters 
> table so swapping them has no effect. You can add info to them but some 
> entries in them will be added when scaling takes place.

For which entries can this be a problem?


>> 5. What is the recommanded lua-code to copy/reassign/remap the
>> tables?  Does a library or some helper functions exist which would
>> make it easier to move the tables around?
> 
> For basemode reencoding you can use the changed subtable:
> 
> \starttext
> 
> \directlua{
>      local function chess(tfmdata,value)
>          if value then
>              tfmdata.changed[75] = 81
>              tfmdata.changed[81] = 75
>          end
>      end
>      table.insert(fonts.triggers,"chess")
>      fonts.initializers.base.otf.chess = chess
> }
> 
> \start
>      \font\TestA="file:SkakNew-Figurine.otf:chess=yes"  \TestA\char75 
> \char81 \par
>      \font\TestB="file:SkakNew-Figurine.otf:chess=no"   \TestB\char75 
> \char81 \par
> \stop
> 
> \stoptext

That works fine - even with luaotfload and latex (after I understood
that "basemode" means that I must call the font with "mode=base").
But curiously the dimens of the char change a bit in latex. E.g.
\showthe\fontcharwd reports without the reencoding 8.99998pt, and
9.0pt with the reencoding. In context I get in both cases 9.0pt.

Is it possible to swap (or set) the "tounicode" value at his time so
that copy&paste gives again a "K" for the king and a "Q" for the
queen?


-- 
Ulrike Fischer 

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: reencode fonts with fonts.trigger

[Ulrike Fischer]

Am Tue, 22 Feb 2011 20:29:48 +0100 schrieb Hans Hagen:


> I'll add the following to the luatex-fonts code. It demonstrates how to 
> use postprocessing hooks. (It should work with the current code, unless 
> you define multiple mapping of the same font, for which i've added a 
> patch).

The code didn't work with the context in miktex and a context from a
minimals about 3 month old (I got no errors but no reencoding
either). It worked fine with a current context. 

In latex/luaotfload I got at first an error ("enc" is nil). After I
added "if not fonts.enc then fonts.enc = { } end" it compiled but
didn't reencode. So I guess I will have to wait until luaotfload
gets updated before I can use this solution (which looks fine). 

But I wished they were some documentation about the general
structure of the font loading and processing and all this fields
(fonts.manipulators, fonts.triggers, tfmdata.postprocessors, ...).
Is there someone (beside yourself) who still understand the overall
picture?

-- 
Ulrike Fischer 

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: reencode fonts with fonts.trigger

[Hans Hagen]

On 23-2-2011 6:05, Ulrike Fischer wrote:

> But I wished they were some documentation about the general
> structure of the font loading and processing and all this fields
> (fonts.manipulators, fonts.triggers, tfmdata.postprocessors, ...).

There will be some documentation once it is stable enough. I also need 
to split off some code that is context specific in order to avoid confusion.

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________