Bug: \adjustspacing=1 does not disable expansion

Bug: \adjustspacing=1 does not disable expansion

[Henri Menke]

Dear devs,

The \adjustspacing register is described in the LuaTeX manual as
follows:

     When \adjustspacing has value 2, hz optimization will be applied to glyphs and kerns. When
     the value is 3, only glyphs will be treated. A value smaller than 2 disables this feature.

However, setting \adjustspacing=1 will only disable shrink but not
stretch.  Please find a minimal example example, where I have used
exaggerated values for shrink and stretch to emphasize the issue.  It
can be reproduced with both mtxrun --script plain and luatex with
luaotfload.sty.

I have already checked linebreak.c but add_to_widths looks innocuous and
properly checks the adjust_spacing parameter.

Cheers, Henri

---

%\input luaotfload.sty
\directlua{
   fonts.expansions.setups.default.stretch = 2000
   fonts.expansions.setups.default.shrink = 2000
}
\adjustspacing=1
\font\1="file:lmroman10-regular.otf:expansion=default"
\hsize=5em
\1 \input lorem
\bye
___________________________________________________________________________________
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://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Bug: \adjustspacing=1 does not disable expansion

[Henri Menke]

Possible patch (can be directly used with `git apply')

diff --git a/source/texk/web2c/luatexdir/tex/postlinebreak.c b/source/texk/web2c/luatexdir/tex/postlinebreak.c
index cbc77e556..9cd76b5fa 100644
--- a/source/texk/web2c/luatexdir/tex/postlinebreak.c
+++ b/source/texk/web2c/luatexdir/tex/postlinebreak.c
@@ -440,7 +440,7 @@ void ext_post_line_break(int paragraph_dir,
          }
          adjust_tail = adjust_head;
          pre_adjust_tail = pre_adjust_head;
-        if (adjust_spacing > 0) {
+        if (adjust_spacing > 1) {
              just_box = hpack(q, cur_width, cal_expand_ratio, paragraph_dir);
          } else {
              just_box = hpack(q, cur_width, exactly, paragraph_dir);

On 12/5/19 10:04 AM, Henri Menke wrote:
> Dear devs,
> 
> The \adjustspacing register is described in the LuaTeX manual as
> follows:
> 
>       When \adjustspacing has value 2, hz optimization will be applied to glyphs and kerns. When
>       the value is 3, only glyphs will be treated. A value smaller than 2 disables this feature.
> 
> However, setting \adjustspacing=1 will only disable shrink but not
> stretch.  Please find a minimal example example, where I have used
> exaggerated values for shrink and stretch to emphasize the issue.  It
> can be reproduced with both mtxrun --script plain and luatex with
> luaotfload.sty.
> 
> I have already checked linebreak.c but add_to_widths looks innocuous and
> properly checks the adjust_spacing parameter.
> 
> Cheers, Henri
> 
> ---
> 
> %\input luaotfload.sty
> \directlua{
>     fonts.expansions.setups.default.stretch = 2000
>     fonts.expansions.setups.default.shrink = 2000
> }
> \adjustspacing=1
> \font\1="file:lmroman10-regular.otf:expansion=default"
> \hsize=5em
> \1 \input lorem
> \bye
> 
___________________________________________________________________________________
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://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Bug: \adjustspacing=1 does not disable expansion

[Henri Menke]

It actually seems as if the documentation of LuaTeX is wrong here,
because the behaviour of `\adjustspacing=1' is compatible with
`\pdfadjustspacing=1` in pdfTeX.  From the pdfTeX manual:

     When \pdfadjustspacing is set to 1, font expansion is applied after
     TeX’s normal paragraph breaking routines have broken the paragraph
     into lines. In this case, line breaks are identical to standard TeX
     behavior.

So maybe just copy this paragraph to the LuaTeX manual.

On 12/5/19 1:34 PM, Henri Menke wrote:
> Possible patch (can be directly used with `git apply')
> 
> diff --git a/source/texk/web2c/luatexdir/tex/postlinebreak.c b/source/texk/web2c/luatexdir/tex/postlinebreak.c
> index cbc77e556..9cd76b5fa 100644
> --- a/source/texk/web2c/luatexdir/tex/postlinebreak.c
> +++ b/source/texk/web2c/luatexdir/tex/postlinebreak.c
> @@ -440,7 +440,7 @@ void ext_post_line_break(int paragraph_dir,
>            }
>            adjust_tail = adjust_head;
>            pre_adjust_tail = pre_adjust_head;
> -        if (adjust_spacing > 0) {
> +        if (adjust_spacing > 1) {
>                just_box = hpack(q, cur_width, cal_expand_ratio, paragraph_dir);
>            } else {
>                just_box = hpack(q, cur_width, exactly, paragraph_dir);
> 
> On 12/5/19 10:04 AM, Henri Menke wrote:
>> Dear devs,
>>
>> The \adjustspacing register is described in the LuaTeX manual as
>> follows:
>>
>>        When \adjustspacing has value 2, hz optimization will be applied to glyphs and kerns. When
>>        the value is 3, only glyphs will be treated. A value smaller than 2 disables this feature.
>>
>> However, setting \adjustspacing=1 will only disable shrink but not
>> stretch.  Please find a minimal example example, where I have used
>> exaggerated values for shrink and stretch to emphasize the issue.  It
>> can be reproduced with both mtxrun --script plain and luatex with
>> luaotfload.sty.
>>
>> I have already checked linebreak.c but add_to_widths looks innocuous and
>> properly checks the adjust_spacing parameter.
>>
>> Cheers, Henri
>>
>> ---
>>
>> %\input luaotfload.sty
>> \directlua{
>>      fonts.expansions.setups.default.stretch = 2000
>>      fonts.expansions.setups.default.shrink = 2000
>> }
>> \adjustspacing=1
>> \font\1="file:lmroman10-regular.otf:expansion=default"
>> \hsize=5em
>> \1 \input lorem
>> \bye
>>
___________________________________________________________________________________
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://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: Bug: \adjustspacing=1 does not disable expansion

[Hans Hagen]

On 12/5/2019 1:39 AM, Henri Menke wrote:
> It actually seems as if the documentation of LuaTeX is wrong here,
> because the behaviour of `\adjustspacing=1' is compatible with
> `\pdfadjustspacing=1` in pdfTeX.  From the pdfTeX manual:
> 
>      When \pdfadjustspacing is set to 1, font expansion is applied after
>      TeX’s normal paragraph breaking routines have broken the paragraph
>      into lines. In this case, line breaks are identical to standard TeX
>      behavior.
> 
> So maybe just copy this paragraph to the LuaTeX manual.
ok.

btw, Level 1 is rather useless and was more a variant to the at that 
time bitmap generated instances (which was the original idea: generate 
new fonts with mfm but that mode was dropped). Context doesn't support 
level 1 at all.

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | 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://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : http://contextgarden.net
___________________________________________________________________________________