Hans,
thank you.
By your and Max's answers, I understand that
there must be box.glueset for the glues in the box.list to actually work.
Best regards
Huang Fusyong(黄复雄)
Hans Hagen via ntg-context <ntg-context@ntg.nl> 于2022年11月11日周五 18:52写道：
>
> On 11/11/2022 10:53 AM, Max Chernoff via ntg-context wrote:
> > Hi,
> >
> >> I want to simulate \hss in lua end in ConTeXt/luametatex environment.
> >> For example,
> >>
> >> ```ConTeXt
> >> a{\raise 1.5ex\hbox to 0pt{\hss b}}c
> >> ```
> >
> >> And in lua, I do as follows(part of my app seen in attachment):
> >
> > Your code doesn't compile as is. I think that this is the same thing
> > though:
> >
> > \starttext
> > \startluacode
> > local a = node.new"glyph"
> > a.char = string.byte("a")
> > a.font = font.current()
> >
> > local b = node.new"glyph"
> > b.char = string.byte("b")
> > b.font = font.current()
> >
> > local c = node.new"glyph"
> > c.char = string.byte("c")
> > c.font = font.current()
> >
> > local hss = node.new("glue")
> > hss.stretch = 65536
> > hss.stretchorder = 2
> > hss.shrink = 65536
> > hss.shrinkorder = 2
> > hss.width = 0
> > b = node.insertbefore(b, b, hss)
> >
> > local box = node.new("hlist", "box")
> > box.head = b
> > box.width = 0
> > box.shift = -tex.sp("1ex")
> >
> > tex.forcehmode()
> > node.write(a + box + c)
> > \stopluacode
> > \stoptext
> >
> >> And got 'b' on top of 'c' in pdf as follows:
> >>
> >> ```pdf
> >> b
> >> ac
> >> ```
> >
> > The \hss isn't the problem here. The problem is actually with the box.
> > When you manually make the \hbox like that, I think (although I could be
> > wrong) that you're bypassing all of TeX's glue calculations. You should
> > probably use "node.hpack" instead:
> >
> > \starttext
> > \startluacode
> > local a = node.new"glyph"
> > a.char = string.byte("a")
> > a.font = font.current()
> >
> > local b = node.new"glyph"
> > b.char = string.byte("b")
> > b.font = font.current()
> >
> > local c = node.new"glyph"
> > c.char = string.byte("c")
> > c.font = font.current()
> >
> > local hss = node.new("glue")
> > hss.stretch = 65536
> > hss.stretchorder = 2
> > hss.shrink = 65536
> > hss.shrinkorder = 2
> > hss.width = 0
> >
> > local box = node.hpack(hss + b, "exactly", 0)
> > box.shift = -tex.sp("1ex")
> >
> > tex.forcehmode()
> > a.next = box
> > box.next = c
> > node.write(a)
> > \stopluacode
> > \stoptext
> indeed, an dafter that you can check it
>
> box.glueorder : 2
> box.glueset : 6.6683349609375
> box.gluesign : 2
>
> which will be applied (in the backend) to glues
>
> 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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