On 5/22/2020 18:18, Hans Hagen wrote:

On 5/23/2020 12:03 AM, Hans Hagen wrote:

...

On 5/22/2020 11:22 AM, context@vivaldi.net wrote:

...

Hello,

is it possible to get somehow the width of the "material" (box?) of the current line which is "ready" to be typeset?

See the case:

---- \starttext

   some text

   pqrs % Here I need to get width (or content) of the text from the begin of the current line,         % i.e. width of the text "pqrs".         % (Depending of the width I will decide what to do later.)

\stoptext ----

I am too laical to know how to "inject" TeX workflow or whether to access LuaTeX internals (nodes?) to get the desired information.

- Is it possible somehow? Too easy ...

\startluacode      function document.whatever()          context(nodes.hpack(tex.getnest().head.next).width)      end \stopluacode

\unexpanded\def\widthuptohere{\dimexpr\ctxlua{document.whatever()}sp\relax}

\starttext

     \dorecurse {10} {          snippet #1\scratchdimen\widthuptohere\ has \the\scratchdimen\ width\par      }

\stoptext

but still you have to wikify it ... maybe i'll make it a low level helper (but than you also need to wikify that because i have no clue where to explain it) Actually, one needs to flush a bit

\startluacode     function document.whatever()         local h = nodes.hpack(tex.getnest().head.next)         local w = h.width         h.list = nil         nodes.free(h)         context(w)     end \stopluacode

\unexpanded\def\widthuptohere{\dimexpr\ctxlua{document.whatever()}sp\relax}

\starttext

    \dorecurse {10} {         snippet #1\scratchdimen\widthuptohere\ has \the\scratchdimen\ width\par     }

\stoptext

not that it matters much, because it's unlikely that you leak more than a dozen nodes in a run.

Hans

If the OP simply wants the width of a string, one can use \setwidthof#1\to#2. \define\String{pqrs} \setwidthof{\String}\to\Wdth \String\ is \Wdth\ wide. \setwidthof{{\tfb\em\String}}\to\Wdth {\tfb\em\String} is \Wdth\ wide. I do not know if that is different from the width of the same string unboxed from the paragraph. There may be some adjustments made in justification, expansion, and such that are not treated. -- Rik

On 5/22/2020 19:49, Rik Kabel wrote:

If the OP simply wants the width of a string, one can use \setwidthof#1\to#2.

\define\String{pqrs} \setwidthof{\String}\to\Wdth \String\ is \Wdth\ wide.

\setwidthof{{\tfb\em\String}}\to\Wdth {\tfb\em\String} is \Wdth\ wide.

I do not know if that is different from the width of the same string unboxed from the paragraph. There may be some adjustments made in justification, expansion, and such that are not treated.

Correcting my post (thank you, Floris), the format is a bit different than I had written. The following works: \starttext \define\String{pqrs} \setwidthof\String\to\WdthA {\String} is \WdthA\ wide. \define\String{\tfx\em pqrs} \setwidthof\String\to\WdthB {\String} is \WdthB\ wide. \define\String{\ss pqrs} \setwidthof\String\to\WdthC {\String} is \WdthC\ wide. \stoptext Giving: -- Rik