[Dev-luatex] keeping in sync with pdftex changes

[Hans Hagen]

On 1/11/2021 6:12 PM, Ulrike Fischer wrote:

> (It is not an very important change. The one case in LaTeX where it
> really mattered has been resolve by adjusting the box levels. I only
> mentioned it here too, so that you can consider it. The ability to
> stop a running link is much more needed.)
After updating pdftex i tested that feature (somewhat stupid example as 
we don't use this link command in context):

\pdfobjcompresslevel0
\pdfcompresslevel0

\starttext

test [\pdfrunninglinkoff
     [\pdfstartlink goto page 2 {}whatever page 1\pdfendlink]%
\pdfrunninglinkon] test

\vskip1cm

\pdfrunninglinkoff
     [\pdfstartlink goto page 2 {}whatever page 2\pdfendlink]%
\pdfrunninglinkon

\vskip1cm

[\pdfstartlink goto page 2 {}whatever \pdfrunninglinkoff 
page\pdfrunninglinkon 3\pdfendlink]%

\vskip1cm

[\pdfstartlink goto page 2 {}whatever

before \pdfrunninglinkoff page \pdfrunninglinkon after

whatever \pdfendlink]

\vskip1cm

[\pdfstartlink goto page 2 {}whatever

\pdfrunninglinkoff page \pdfrunninglinkon

whatever \pdfendlink]

\vskip1cm

[\pdfstartlink goto page 2 {}whatever

yes \pdfrunninglinkoff page \vadjust{also no} \vadjust pre {also yes} 
page \par no \pdfrunninglinkon

whatever \pdfendlink]

\page

here

\stoptext

so, this flag is somewhat unpredictable in the sense that it influences 
the next box at the upper level and has no effect in the middle or 
preceding (either or not migrated) boxes inside the setting. I looked at 
the pdftex source and it's not hard to implement (which also explains 
the above behavioir) and we don't need to document it.

Hans



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