Re: Weird godown, dorecurse, colors and page-fitting interaction

[Hans Hagen <pragma@wxs.nl>]

Adam Lindsay wrote:

> Hi all,
>
> What's happening here?
>
> \setupcolors[state=start]
> \starttext
> \startTEXpage
> \dorecurse{2}{abc\godown[0pt]}
> \stopTEXpage
> \startTEXpage
> \startcolor[yellow]
> \dorecurse{2}{abc\godown[0pt]}
> \stopcolor
> \stopTEXpage
> \stoptext
>
a long story ... to which ttp wizzard taco might want to add comment

ok, a fix first (missing \fi)

\def\godown[#1]%
  {\relax
   \ifhmode\endgraf\fi
   \ifvmode\nointerlineskip\vskip#1\relax\fi}

what you observe is some interference; the fitting page macros use 
framed and when you set width and height to fit, it will use the 
reshaperr to determine the width; this mechanism fails as soon as nodes 
show up that cannot be \un-whatevered or \last-whatevered; also, some 
mechanisms have as side effect that they force the box to have a width 
of \hsize

question for taco: how difficult would it be to have something:

   \squeezebox\scratchbox

where the result is a box with a width equal to the max(natural width of 
lines)

(that way we could replace the reshaper and get around those interfering 
and blocking nodes)

you may see some of the side effects when you play with:

\starttext

\setupcolors[state=start]

\startTEXpage
\dorecurse{2}{abc\godown[0pt]}
\stopTEXpage

\startTEXpage[foregroundcolor=yellow]
\dorecurse{2}{abc\godown[0pt]}
\stopTEXpage

\startTEXpage
\startcolor[red]\dorecurse{2}{abc\godown[0pt]}\stopcolor
\stopTEXpage

\startTEXpage[width=fixed]
\startcolor[green]\dorecurse{2}{abc\godown[0pt]}\stopcolor
\stopTEXpage

\startTEXpage[width=fixed]
\dorecurse{2}{\startcolor[cyan]abc\stopcolor\godown[0pt]}
\stopTEXpage

\startTEXpage
\dorecurse{2}{\startcolor[magenta]abc\stopcolor\godown[0pt]}
\stopTEXpage

\startTEXpage
\vbox{\startcolor[blue]\dorecurse{2}{abc\godown[0pt]}\stopcolor}
\stopTEXpage

\stoptext

so, there is no real solution unless you use the foreground color or box 
things yourself

Hans