"fake" space for better reflow

"fake" space for better reflow

[Ulrike Fischer]

If I compile a small document

\starttext
\input knuth

\stoptext


and then use in the adobe reader "view->zoom->reflow" I get as
result

Thus,Icametotheconclusionthatthedesignerofanewsystemmustnotonlybetheimplementerandfirstlarge--scaleuser;thedesignershoulda

I know it is due to the missing space glyph. With pdflatex I would
try to use \pdfinterwordspaceon but this primitive never found its
way into luatex. Is there any solution? (One that could be
translated to lualatex would be best).

-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

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Re: "fake" space for better reflow

[Hans Hagen]

On 11/30/2016 10:09 AM, Ulrike Fischer wrote:
> If I compile a small document
>
> \starttext
> \input knuth
>
> \stoptext
>
>
> and then use in the adobe reader "view->zoom->reflow" I get as
> result
>
> Thus,Icametotheconclusionthatthedesignerofanewsystemmustnotonlybetheimplementerandfirstlarge--scaleuser;thedesignershoulda

Cut and paste goes well so I think it's a bug in acrobat then.

> I know it is due to the missing space glyph. With pdflatex I would
> try to use \pdfinterwordspaceon but this primitive never found its
> way into luatex. Is there any solution? (One that could be
> translated to lualatex would be best).

One can write a filter that does it before shipout. Typically a case for 
callbacks.

Hans


-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
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Re: "fake" space for better reflow

[Ulrike Fischer]

Am Wed, 30 Nov 2016 12:45:17 +0100 schrieb Hans Hagen:

> On 11/30/2016 10:09 AM, Ulrike Fischer wrote:
>> If I compile a small document
>>
>> \starttext
>> \input knuth
>>
>> \stoptext
>>
>>
>> and then use in the adobe reader "view->zoom->reflow" I get as
>> result
>>
>> Thus,Icametotheconclusionthatthedesignerofanewsystemmustnotonlybetheimplementerandfirstlarge--scaleuser;thedesignershoulda
 
> Cut and paste goes well so I think it's a bug in acrobat then.

I'm not sure. Imho cut and paste use an heurisitic more or less
based on the size of the space (there are quite a number of
questions on tex.SX where the heuristic fails, e.g. in code
listings), while reflow seems to need glyphs. The speech of Ross
Moore on TUG14 seems to indicate that \pdfinterwordspaceon was
introduced in pdftex to get around this problem. 

http://river-valley.zeeba.tv/%E2%80%9Cfake-spaces%E2%80%9D-with-pdftex%E2%80%94best-of-both-worlds/

>> I know it is due to the missing space glyph. With pdflatex I would
>> try to use \pdfinterwordspaceon but this primitive never found its
>> way into luatex. Is there any solution? (One that could be
>> translated to lualatex would be best).
 
> One can write a filter that does it before shipout. Typically a case for 
> callbacks.

Well the main question is, what is the "does it" in this case.
pdftex inserts a space from a dummy.pdf. One use the fake space more
or less like this:

\pdfinterwordspaceon
\pdfmapline{=dummy-space <dummy-space.pfb}
\pdfglyphtounicode{space}{0020}
XXX YYY
\bye

But this doesn't sound like the correct way to go in a unicode/open
type world.  

(I'm also not quite if shipout is the correct time. Imho one would
probably avoid to add spaces e.g. in math).

-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/

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Re: "fake" space for better reflow

[Hans Hagen]

On 11/30/2016 5:58 PM, Ulrike Fischer wrote:
> Am Wed, 30 Nov 2016 12:45:17 +0100 schrieb Hans Hagen:
>
>> On 11/30/2016 10:09 AM, Ulrike Fischer wrote:
>>> If I compile a small document
>>>
>>> \starttext
>>> \input knuth
>>>
>>> \stoptext
>>>
>>>
>>> and then use in the adobe reader "view->zoom->reflow" I get as
>>> result
>>>
>>> Thus,Icametotheconclusionthatthedesignerofanewsystemmustnotonlybetheimplementerandfirstlarge--scaleuser;thedesignershoulda
>
>> Cut and paste goes well so I think it's a bug in acrobat then.
>
> I'm not sure. Imho cut and paste use an heurisitic more or less
> based on the size of the space (there are quite a number of
> questions on tex.SX where the heuristic fails, e.g. in code
> listings), while reflow seems to need glyphs. The speech of Ross
> Moore on TUG14 seems to indicate that \pdfinterwordspaceon was
> introduced in pdftex to get around this problem.
>
> http://river-valley.zeeba.tv/%E2%80%9Cfake-spaces%E2%80%9D-with-pdftex%E2%80%94best-of-both-worlds/

I assume that it just runs over the resulting list and replaces skips by 
spaces. One cannot in an earlier stage use spaces instead of skips 
simply because tex has a glue based model.

So, one can kick in some callback (before shipout) and  replace glue by 
space characters.

>>> I know it is due to the missing space glyph. With pdflatex I would
>>> try to use \pdfinterwordspaceon but this primitive never found its
>>> way into luatex. Is there any solution? (One that could be
>>> translated to lualatex would be best).
>
>> One can write a filter that does it before shipout. Typically a case for
>> callbacks.
>
> Well the main question is, what is the "does it" in this case.
> pdftex inserts a space from a dummy.pdf. One use the fake space more
> or less like this:
>
> \pdfinterwordspaceon
> \pdfmapline{=dummy-space <dummy-space.pfb}
> \pdfglyphtounicode{space}{0020}
> XXX YYY
> \bye

Well, just insert char 32 which is in most fonts ... (could even be a 
virtual char). We will not introduce such mechanisms in luatex, after 
all a macro package can decide for other criteria.

> But this doesn't sound like the correct way to go in a unicode/open
> type world.
>
> (I'm also not quite if shipout is the correct time. Imho one would
> probably avoid to add spaces e.g. in math).

One can recognize math. If context can do it (when a user enables it) 
... any macro package can ...

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
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___________________________________________________________________________________