%D \module
%D   [       file=page-sid,
%D        version=2000.10.20,
%D          title=\CONTEXT\ Page Macros,
%D       subtitle=Side Floats,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\writestatus{loading}{ConTeXt Page Macros / Side Floats}

\unprotect

%D These macro deal with side floats. We started with Daniel Comenetz macros as
%D published in TUGBoat Volume 14 (1993), No.\ 1: Anchored Figures at Either Margin.
%D I extended and patched the macros to suite our needs which results in a messy
%D module. Therefore, this module badly needs an update because it's now a mixture
%D of old and new macros.

% Interesting cases where it goes wrong:
%
% \placefigure[left]{}{} \dorecurse{3}{\input ward } {\par} \input ward
%
% Here we get an unwanted carried over hangindent and parindent. A solution is to
% associate it with the local par node instead. This is something to discuss with
% Taco as it could be a new luatex/mkiv feature: explicitly set par properties.

% Maybe I should just rewrite the lot.

\newdimen       \d_page_sides_height       % includes the topskip
\newdimen       \d_page_sides_width
\newdimen       \d_page_sides_hsize
\newdimen       \d_page_sides_vsize
\newdimen       \d_page_sides_vsize_reset  \d_page_sides_vsize_reset -\onepoint % could be a \let
\newdimen       \d_page_sides_progress
\newdimen       \d_page_sides_page_total
\newdimen       \d_page_sides_saved_depth

\newbox         \b_page_sides_bottom

\newcount       \c_page_sides_lines_done
\newcount       \c_page_sides_checks_done
\newcount       \c_page_sides_n_of_lines
\newcount       \c_page_sides_n_of_hang
\newconstant    \c_page_sides_float_type

\newconditional \c_page_sides_short        % needs checking .. best write this from scratch
\newconditional \c_page_sides_flag

\newdimen       \d_page_sides_shift
\newdimen       \d_page_sides_extrashift
\newdimen       \d_page_sides_leftshift
\newdimen       \d_page_sides_rightshift
\newdimen       \d_page_sides_leftskip
\newdimen       \d_page_sides_rightskip
\newdimen       \d_page_sides_maximum
\newdimen       \d_page_sides_topskip
\newdimen       \d_page_sides_bottomskip
\newdimen       \d_page_sides_downshift
\newdimen       \d_page_sides_pagetotal

\setnewconstant \c_page_sides_method \plusone   % 0=raw 1=safe (.99) 2=tight (-1pt)
\setnewconstant \c_page_sides_align  \zerocount

\def\page_sides_process_float_backspace  {\global\c_page_sides_float_type\plusone  \page_sides_handle_float}
\def\page_sides_process_float_leftedge   {\global\c_page_sides_float_type\plustwo  \page_sides_handle_float}
\def\page_sides_process_float_leftmargin {\global\c_page_sides_float_type\plusthree\page_sides_handle_float}
\def\page_sides_process_float_left       {\global\c_page_sides_float_type\plusfour \page_sides_handle_float}
\def\page_sides_process_float_right      {\global\c_page_sides_float_type\plusfive \page_sides_handle_float}
\def\page_sides_process_float_rightmargin{\global\c_page_sides_float_type\plussix  \page_sides_handle_float}
\def\page_sides_process_float_rightedge  {\global\c_page_sides_float_type\plusseven\page_sides_handle_float}
\def\page_sides_process_float_cutspace   {\global\c_page_sides_float_type\pluseight\page_sides_handle_float}
\def\page_sides_process_float_margin     {\global\c_page_sides_float_type\pluseight\page_sides_handle_float}

\newif\iftracesidefloats % public (might change)

\def\page_sides_floats_legend
  {\writestatus\m!floatblocks{anchor: orange, shift: red, box: green, dummy: blue, depth: magenta}%
   \glet\page_sides_floats_legenda\relax}

\installtextracker{floats.anchoring}
  {\page_sides_floats_legend
   \tracesidefloatstrue}
  {\tracesidefloatsfalse}

% end of public variables

\def\page_sides_apply_horizontal_shift
  {\ifdim\d_page_sides_maximum>\zeropoint
     \ifcase\c_page_sides_float_type
       % invalid
     \or
       % backspace
     \or
       \global\d_page_sides_shift\dimexpr
         -\d_page_sides_maximum
         -\rightorleftpageaction \leftedgedistance   \rightedgedistance
         -\rightorleftpageaction \leftmarginwidth    \rightmarginwidth
         -\rightorleftpageaction \leftmargindistance \rightmargindistance
         -\compensatedinnermakeupmargin
       \relax
     \or
       \global\d_page_sides_shift\dimexpr
         -\d_page_sides_maximum
         -\rightorleftpageaction \leftmargindistance \rightmargindistance
         -\compensatedinnermakeupmargin
       \relax
     \or
       % left
     \or
       % right
     \or
       \global\d_page_sides_shift\dimexpr
         -\d_page_sides_maximum
         -\rightorleftpageaction \leftmargindistance \rightmargindistance
         -\compensatedinnermakeupmargin
       \relax
     \or
       \global\d_page_sides_shift\dimexpr
         -\d_page_sides_maximum
         -\rightorleftpageaction \leftedgedistance   \rightedgedistance
         -\rightorleftpageaction \leftmarginwidth    \rightmarginwidth
         -\rightorleftpageaction \leftmargindistance \rightmargindistance
         -\compensatedinnermakeupmargin
       \relax
     \or
       % cutspace
     \fi
   \fi
   \ifdim\d_page_sides_shift=\zeropoint \relax
     \ifnum\c_page_sides_float_type=\plusfour
       \global\advance\d_page_sides_shift\d_page_sides_extrashift
       \global\d_page_sides_extrashift\zeropoint
     \else\ifnum\c_page_sides_float_type=\plusfive
       \global\advance\d_page_sides_shift\d_page_sides_extrashift
       \global\d_page_sides_extrashift\zeropoint
     \fi\fi
   \else
     \ifnum\c_page_sides_float_type<\plusfour
       \global\c_page_sides_float_type\plusfour
     \else\ifnum\c_page_sides_float_type>\plusfive
       \global\c_page_sides_float_type\plusfive
     \fi\fi
   \fi}

\def\page_sides_set_skips
  {\global\d_page_sides_rightskip\zeropoint
   \global\d_page_sides_leftskip \zeropoint
   \ifcase\c_page_sides_float_type
   \or % backspace
     \global\d_page_sides_leftskip\dimexpr
       +\rightorleftpageaction \backspace           \cutspace
       +\compensatedinnermakeupmargin
     \relax
   \or % leftedge
     \global\d_page_sides_leftskip\dimexpr
       +\rightorleftpageaction \leftmargindistance  \rightmargindistance
       +\rightorleftpageaction \leftmarginwidth     \rightmarginwidth
       +\rightorleftpageaction \leftedgedistance    \rightedgedistance
       +\compensatedinnermakeupmargin
     \relax
   \or % leftmargin
     \global\d_page_sides_leftskip\dimexpr
       +\rightorleftpageaction \leftmargindistance  \rightmargindistance
       +\compensatedinnermakeupmargin
     \relax
   \or % leftside
   \or % rightside
   \or % rightmargin
     \global\d_page_sides_rightskip\dimexpr
       +\rightorleftpageaction \rightmargindistance \leftmargindistance
       +\compensatedinnermakeupmargin
     \relax
   \or % rightedge
     \global\d_page_sides_rightskip\dimexpr
       +\rightorleftpageaction \rightmargindistance \leftmargindistance
       +\rightorleftpageaction \rightmarginwidth    \leftmarginwidth
       +\rightorleftpageaction \rightedgedistance   \leftedgedistance
       +\compensatedinnermakeupmargin
     \relax
   \or % cutspace
     \global\d_page_sides_rightskip\dimexpr
       +\rightorleftpageaction \cutspace            \backspace
       +\compensatedinnermakeupmargin
     \relax
   \fi
   \ifdim\d_page_sides_rightskip>\zeropoint \global\advance\d_page_sides_rightskip\rightskip \fi
   \ifdim\d_page_sides_leftskip >\zeropoint \global\advance\d_page_sides_leftskip \leftskip  \fi}

\def\page_sides_flush_floats
  {\par
   \ifdim\dimexpr\d_page_sides_vsize-\d_page_sides_bottomskip-\pagetotal\relax>\zeropoint % -\pagedepth
     \page_sides_flush_floats_progress
     \page_sides_flush_floats_after_next
   \fi
   \page_sides_flush_floats_reset}

\def\page_sides_flush_floats_text
  {\par
   \ifdim\dimexpr\d_page_sides_vsize-\d_page_sides_bottomskip-\pagetotal\relax>\zeropoint % -\pagedepth
     \page_sides_flush_floats_progress
     \page_sides_flush_floats_after_none
   \fi
   \page_sides_flush_floats_reset}

\def\page_sides_flush_floats_reset
  {\global\d_page_sides_vsize\d_page_sides_vsize_reset
   % also here if used at all \global\holdinginserts\zerocount
   \global\setfalse\c_page_sides_short
   \global\setfalse\c_page_sides_flag}

\unexpanded\def\doifelsesidefloat
  {\par
   \ifdim\dimexpr\d_page_sides_vsize-\pagetotal\relax>\zeropoint % -\pagedepth
     \expandafter\firstoftwoarguments
   \else
     \expandafter\secondoftwoarguments
   \fi}

\let\doifsidefloatelse\doifelsesidefloat

\installcorenamespace{sidefloatsteps}

\setvalue{\??sidefloatsteps\v!line  }{\strut}
\setvalue{\??sidefloatsteps\v!big   }{\strut}
\setvalue{\??sidefloatsteps\v!medium}{\halflinestrut} % was \halfstrut
\setvalue{\??sidefloatsteps\v!small }{\noheightstrut} % was \quarterstrut

% we don't officially know what kind of float we flush

\def\page_sides_flush_floats_tracer
  {\dontleavehmode
   \ruledhpack\bgroup\backgroundline[trace:b]{%
     \llap{\smash{\vrule\s!width4\points\s!height.4\points\s!depth.4\points}}%
     \ifnum\recurselevel=\plusone
       \llap{\smash{\smallinfofont\the\scratchdimen}\hskip.5\leftmargindistance}%
     \else\ifodd\recurselevel
       \llap{\smash{\smallinfofont\recurselevel}\hskip.5\leftmargindistance}%
     \fi\fi
     \page_sides_flush_floats_normal
     \kern\hsize
   \egroup}}

\def\page_sides_flush_floats_normal
  {\ifdim\scratchdimen>\htdp\strutbox
     \strut
   \else
     \m_pages_strut
   \fi}

% the \d_page_sides_bottomskip == \rootfloatparameter\c!sidespaceafter is embedded
% in the progression of the float

\def\page_sides_flush_floats_progress
  {\begingroup
   \let\page_sides_flush_floats\relax
   \edef\m_pages_strut
     {\ifcsname\??sidefloatsteps\rootfloatparameter\c!step\endcsname
        \lastnamedcs
      \else
        \noheightstrut
      \fi}%
   \forgetall
   \offinterlineskip
   \doloop
     {\scratchdimen\dimexpr\d_page_sides_vsize-\d_page_sides_bottomskip-\pagetotal-\pagedepth\relax
      \ifdim\scratchdimen>\onepoint % good enough, if we change it it will become a threshold
        \ifnum\recurselevel>\plushundred % safeguard, sort of deadcycles
          \exitloop
        \else\iftracesidefloats
          \page_sides_flush_floats_tracer\par
        \else
          \page_sides_flush_floats_normal\par
        \fi\fi
      \else
        \exitloop
      \fi}%
   \endgroup}

\def\page_sides_flush_floats_after_none
  {\ifdim\parskip>\zeropoint % why this test ?
     \ifdim\d_page_sides_bottomskip>\parskip
       \blank[\v!nowhite,\rootfloatparameter\c!sidespaceafter]%
     \fi
   \else
       \blank[\rootfloatparameter\c!sidespaceafter]%
   \fi}

\def\page_sides_flush_floats_blank#1% we need to deal with the distance
  {\ifdim\d_page_sides_bottomskip>\d_page_sides_topskip
     \blank[%
        \ifnum#1>\zerocount\v!nowhite,\fi
        \ifdim\d_page_sides_topskip   >\zeropoint-\rootfloatparameter\c!sidespacebefore,\fi % the next one
        \ifdim\d_page_sides_bottomskip>\zeropoint \rootfloatparameter\c!sidespaceafter  \fi
     ]%
   \else\ifdim\d_page_sides_bottomskip<\d_page_sides_topskip
     \blank[%
        \ifnum#1>\zerocount\v!nowhite,\fi
        \ifdim\d_page_sides_bottomskip>\zeropoint -\rootfloatparameter\c!sidespaceafter ,\fi
        \ifdim\d_page_sides_topskip   >\zeropoint  \rootfloatparameter\c!sidespacebefore \fi
     ]%
   \fi\fi}

\def\page_sides_flush_floats_after_next
  {\ifdim\parskip>\zeropoint % why this test ?
     \ifdim\d_page_sides_bottomskip>\parskip
       \page_sides_flush_floats_blank\plusone
     \fi
   \else
     \page_sides_flush_floats_blank\zerocount
   \fi}

\def\page_sides_check_floats_after_par
  {\page_sides_check_floats_indeed
   \ifdim\d_page_sides_pagetotal=\pagetotal \else
     \global\let\page_sides_check_floats\page_sides_check_floats_indeed
     \page_sides_flush_floats
     \global\c_page_sides_n_of_lines\zerocount % here !
   \fi}

\unexpanded\def\page_sides_flush_floats_after_par
  {\global\d_page_sides_pagetotal\pagetotal
   \global\let\page_sides_check_floats\page_sides_check_floats_after_par}

\unexpanded\def\page_sides_forget_floats
  {\global\d_page_sides_vsize\d_page_sides_vsize_reset
   \global\c_page_sides_n_of_lines\zerocount
   % also here if used at all \global\holdinginserts\zerocount
   \global\setfalse\c_page_sides_short
   \global\setfalse\c_page_sides_flag}

\let\page_otr_sides_pop_penalties \relax
\let\page_otr_sides_push_penalties\relax

\def\page_sides_restore_output_penalty
  {\ifnum\outputpenalty=\plustenthousand \else
     \penalty\outputpenalty
   \fi}

\def\page_sides_output_routine
  {\ifconditional\c_page_sides_short
     \page_sides_output_routine_yes
   \else
     \page_sides_output_routine_nop
   \fi}

\def\page_sides_output_routine_nop
  {\page_otr_command_side_float_output % otr specific
   \global\d_page_sides_vsize\d_page_sides_vsize_reset
   \global\c_page_sides_n_of_lines\zerocount
   % we can end up in fig lock, so \global\holdinginserts\zerocount here too ?
   \page_otr_sides_pop_penalties}

\def\page_sides_output_routine_yes % we need to rework this ... add pagediscards and such
  {\unvbox\normalpagebox % bah, and the discards?
% \pagediscards % not good
   \setbox\b_page_sides_bottom\lastbox
   \ifdim\wd\b_page_sides_bottom>\d_page_sides_hsize
     \penalty-201 % hm, i really need to write this from scatch
     \box\b_page_sides_bottom
   \else\ifvoid\b_page_sides_bottom
   \else
     \page_sides_restore_left_indent
     \ifdim\wd\b_page_sides_bottom<\d_page_sides_hsize
       \parskip\zeropoint
       %\noindent
       \ifinner\else
         \vadjust{\penalty\minusone}%
       \fi
       \global\advance\d_page_sides_hsize -\wd\b_page_sides_bottom
       \global\divide\d_page_sides_hsize \plustwo
       \hskip\d_page_sides_hsize % \kern
     \fi
     \box\b_page_sides_bottom
     \page_sides_restore_output_penalty
   \fi\fi
   % why was this \global\holdinginserts\zerocount
   \global\setfalse\c_page_sides_short}

\def\page_sides_restore_left_indent
  {\relax
   \ifnum\c_page_sides_float_type>\plusfour \else
     \parskip\zeropoint % here ?
     \ifdim\d_page_sides_width>\zeropoint % new, see prikkels
       \noindent
       \ifinner \else
         \vadjust{\penalty\minusone}%
       \fi
       \hskip\d_page_sides_width\relax % \kern
    %\else
    %  we have a margin or edge float
     \fi
   \fi}

\def\page_sides_relocate_float#1%
  {\global\setbox\floatbox\hpack
     {\ifnum\c_page_sides_float_type=\plusfour
        \kern\d_page_sides_leftshift
      \else\ifnum\c_page_sides_float_type=\plusone
        \kern\d_page_sides_leftshift
      \fi\fi
      \ifnum\c_page_sides_float_type>\plusfour
        \kern-\d_page_sides_extrashift
      \else
        \kern\d_page_sides_shift
      \fi
      \vbox{#1\ifnum\c_page_sides_align=\plusfour \removedepth \fi}%
      \ifnum\c_page_sides_float_type>\plusfour
        \kern\d_page_sides_shift
      \else
        \kern-\d_page_sides_extrashift
      \fi
      \ifnum\c_page_sides_float_type=\pluseight
        \kern\d_page_sides_rightshift
      \else\ifnum\c_page_sides_float_type=\plusfive
        \kern\d_page_sides_rightshift
      \fi\fi}}

\def\page_sides_apply_vertical_shift_normal
  {\global\setbox\floatbox\hpack % why extra box
     {\vpack
        {\vskip\privatescratchdimen
         \nointerlineskip
         \box\floatbox
         \ifnum\c_page_sides_align=\plusfive \vskip-\lineheight \fi}}}

\def\page_sides_apply_vertical_shift_traced
  {\global\setbox\floatbox\hpack % why extra box
     {\backgroundline[trace:r]{\ruledhpack{\vpack
        {\forgetall
         \hsize\wd\floatbox
         \vskip\privatescratchdimen
         \offinterlineskip
         \backgroundline[trace:g]{\ruledhpack{\box\floatbox}}\par
         \blackrule[\c!color=trace:s,\c!height=\d_page_sides_bottomskip,\c!depth=\zeropoint,\c!width=\hsize]%
         \vskip-\d_page_sides_bottomskip
         \ifnum\c_page_sides_align=\plusfive \vskip-\lineheight \fi}}}}}

\def\page_sides_apply_depth_normal
  {\global\setbox\floatbox\hpack
     {\lower\strutdp\box\floatbox}}

\def\page_sides_apply_depth_traced
  {\global\setbox\floatbox\hpack
     {\scratchdimen\wd\floatbox
      \lower\strutdp\box\floatbox
      \hskip-\scratchdimen
      \color[trace:m]
        {\vrule\s!height\zeropoint\s!depth\strutdp\s!width\scratchdimen}}}

\def\page_sides_apply_vertical_shift
  {\ifnum\c_page_sides_align=\plusfour
     \getnoflines{\ht\floatbox}%
     \privatescratchdimen\dimexpr\noflines\lineheight-\strutdp\relax
     \getrawnoflines\d_page_sides_topskip
     \advance\privatescratchdimen\noflines\lineheight
     % todo: maybe rounding problem here
     % \global\setbox\floatbox\hbox{\lower\lineheight\box\floatbox}%
     \iftracesidefloats
       \page_sides_apply_depth_traced
     \else
       \page_sides_apply_depth_normal
     \fi
     \ht\floatbox\privatescratchdimen
     \dp\floatbox\zeropoint
   \fi
   \ifcase\c_page_sides_align \else
     \global\d_page_sides_topskip\zeropoint
   \fi
   \privatescratchdimen
     \ifnum\c_page_sides_float_type<\plusfour
       \d_page_sides_topskip
     \else\ifnum\c_page_sides_float_type>\plusfive
       \d_page_sides_topskip
     \else
       \zeropoint
     \fi\fi
   % the top of the box is at the previous baseline
   \ifcase\c_page_sides_align
       % 0 normal
     \advance\privatescratchdimen\strutdp % or \openstrutdepth
   \or % 1 height
     \advance\privatescratchdimen\strutdp % or \openstrutdepth
   \or % 2 line
   \or % 3 depth
     \advance\privatescratchdimen\lineheight % or \openlineheight
     \advance\privatescratchdimen\strutdp    % or \openstrutdepth
   \or % 4 grid
     \privatescratchdimen\zeropoint
   \or
     \advance\privatescratchdimen\strutht % or \openstrutheight
   \fi
   % new
   \global\c_page_sides_lines_done\zerocount
   \ifnum\c_page_sides_n_of_lines>\zerocount
     \advance\privatescratchdimen\c_page_sides_n_of_lines\lineheight
   \fi
   \iftracesidefloats
     \page_sides_apply_vertical_shift_traced % uses \privatescratchdimen
   \else
     \page_sides_apply_vertical_shift_normal % uses \privatescratchdimen
   \fi
   \ifnum\c_page_sides_float_type<\plusfour
     \global\d_page_sides_topskip\zeropoint
   \else\ifnum\c_page_sides_float_type>\plusfive
     \global\d_page_sides_topskip\zeropoint
   \fi\fi
   \global\d_page_sides_downshift\zeropoint}

\def\page_sides_place_float
  {\ifnum\c_page_sides_float_type=\plusfour \kern\d_page_sides_topskip \fi
   \ifnum\c_page_sides_float_type=\plusfive \kern\d_page_sides_topskip \fi
   \d_page_sides_saved_depth\prevdepth
   \nointerlineskip
   \ifgridsnapping
     \page_sides_place_float_grid
   \else
     \page_sides_place_float_normal
   \fi
   \par
   \kern-\d_page_sides_height
   \penalty10001 % oeps, this will change
   \normalbaselines
   \prevdepth\d_page_sides_saved_depth}

\def\page_sides_place_float_normal
  {\page_sides_push_float_inline\firstofoneargument}

%D The following needs some more work .. consider this a quick hack. We probably
%D need an mkiv hanging grid option.

\def\page_sides_place_snap_to_grid#1%
  {\edef\p_grid{\floatparameter\c!grid}%
   \ifx\p_grid\empty\else
     \snaptogrid[\p_grid]%
   \fi
   \hbox{#1}}

\def\page_sides_place_float_grid
  {\getrawnoflines\d_page_sides_height % raw ?
   \d_page_sides_height\noflines\lineheight
   \page_sides_push_float_inline\page_sides_place_snap_to_grid}

\let\strc_floats_mark_par_as_free\relax

\def\page_sides_push_float_inline#1%
  {\begingroup
   \reseteverypar % needed !
   \parskip\zeropoint  % needed !
   \page_sides_set_skips
   \page_floats_report_total
   \relax
   \lefttoright % \textdir TLT\relax  % or \ifconditional\displaylefttoright below (more work)
   \strc_floats_mark_par_as_free
   \ifcase\c_page_sides_float_type
     % invalid
   \or % backspace
     \noindent#1{\llap{\rlap{\box\floatbox}\kern\d_page_sides_leftskip}}\hfill
   \or % leftedge
     \noindent#1{\llap{\box\floatbox\kern\d_page_sides_leftskip}}\hfill
   \or % leftmargin
     \noindent#1{\llap{\box\floatbox\kern\d_page_sides_leftskip}}\hfill
   \or % leftside
     \noindent#1{\box\floatbox}\hfill
   \or % rightside
     \hfill#1{\box\floatbox}%
   \or % rightmargin
     \hfill#1{\rlap{\kern\d_page_sides_rightskip\box\floatbox}}%
   \or % rightedge
     \hfill#1{\rlap{\kern\d_page_sides_rightskip\box\floatbox}}%
   \or % cutspace
     \hfill#1{\rlap{\kern\d_page_sides_rightskip\llap{\box\floatbox}}}%
   \fi
   \endgroup}

\def\page_sides_analyse_progress
  {\d_page_sides_progress\d_page_sides_vsize
   \ifconditional\c_page_sides_flag
     \advance\d_page_sides_progress-\d_page_sides_page_total
     \global\setfalse\c_page_sides_flag
   \else
     \advance\d_page_sides_progress-\pagetotal
     \advance\d_page_sides_progress-\pagedepth % new 2017-10-10
   \fi}

\def\page_sides_analyse_space
  {\global\settrue\c_page_sides_flag
   \global\d_page_sides_page_total \pagetotal % global
   \ifnum\c_page_sides_float_type<\plusfour
     \global\d_page_sides_width \zeropoint
   \else\ifnum\c_page_sides_float_type>\plusfive
     \global\d_page_sides_width\zeropoint
   \else
     \global\d_page_sides_width\dimexpr\wd\floatbox+\d_strc_floats_margin\relax
   \fi\fi
   \ifdim\d_page_sides_width<\zeropoint
     \global\d_page_sides_width\zeropoint
   \fi
   \global\d_page_sides_hsize \dimexpr\hsize-\d_page_sides_width\relax
   \global\d_page_sides_height\dimexpr\ht\floatbox+\dp\floatbox+\d_page_sides_topskip\relax
   \global\d_page_sides_vsize \dimexpr\d_page_sides_height+\d_page_sides_page_total\relax
   \scratchdimenone\d_page_sides_vsize
   \scratchdimentwo\pagegoal
   \relax
   \ifcase\c_page_sides_method
     % method 0 : raw
   \or
     % method 1 : safe (default)
     \scratchdimentwo .99\pagegoal
   \or
     % method 2 : tight
     \advance\scratchdimenone -\onepoint
   \fi
   \relax % really needed ! ! ! !
   \ifdim\scratchdimenone>\scratchdimentwo
     \global\setfalse\c_page_floats_room
   \else
     \ifdim\dimexpr\pagegoal-\d_page_sides_vsize\relax<\d_page_sides_bottomskip
      % just weird: \global\advance\d_page_sides_vsize \scratchdimenone
       \global\settrue\c_page_sides_short
       \page_otr_sides_push_penalties
       % why was this \global\holdinginserts\plusone
     \else
       \global\advance\d_page_sides_vsize \d_page_sides_bottomskip
       \global\advance\d_page_sides_vsize -\parskip % new 2017-10-10
       \global\setfalse\c_page_sides_short
     \fi
     \global\settrue\c_page_floats_room
   \fi}

% \unexpanded\def\fakenextstrutline
%   {\par
%    \begingroup
%    % overkill, done in \page_sides_inject_dummy_lines
%    \triggerpagebuilder
%    \reseteverypar
%    \forgetall
%    \dontleavehmode\hpack to \hsize{\strut\hss}\par
%    \clf_removelastline
%    % \pagetotal is still one line too much but pagedepth is ok
%    % but it seems to work
%    \endgroup}

\def\page_sides_prepare_space
  {%\fakenextstrutline % does more bad than good at page crossing
   \inhibitblank} % hm, why here .. gets obscured anyway

\def\page_sides_handle_float#1% grid (4) is rather experimental
  {\page_sides_prepare_space
   \page_sides_apply_horizontal_shift
   \page_sides_check_previous_float
   \page_sides_inject_dummy_lines
   \page_sides_relocate_float{#1}%
   \page_sides_apply_vertical_shift
   \page_sides_analyse_space
   \ifconditional\c_page_floats_room \else
     \page_otr_fill_and_eject_page
     \page_sides_analyse_space
     \page_sides_inject_dummy_lines
   \fi
   \page_sides_place_float
   \page_sides_check_floats_reset
   \ignorespaces} % not really needed

\def\page_sides_check_floats_indeed
  {\page_sides_analyse_progress
   \ifdim\d_page_sides_progress>\zeropoint
     \page_sides_check_floats_set
   \else
     \page_sides_check_floats_reset
   \fi
   \parskip\s_spac_whitespace_parskip}

\let\page_sides_check_floats\page_sides_check_floats_indeed

\unexpanded\def\page_sides_check_floats_tracer
  {\begingroup
   \hskip-\d_page_sides_width % kern
  %\llap{\smallinfofont\the\d_page_sides_progression\space=>\space\the\c_page_sides_n_of_hang\hskip.5\leftmargindistance}%
   \color[trace:o]%
     {\vrule\s!height.5\points\s!depth.5\points\s!width\d_page_sides_width
      \llap{\showstruts\strut\kern.25\bodyfontsize}}%
   \endgroup}

% \usemodule[art-01]
% \starttext
%     \definemeasure[MyHeight][3cm] \definemeasure[MyWidth][3cm]
%     \startbuffer
%         \input klein \par
%         \placefigure[left]{oeps}{\framed[width=\measure{MyWidth},height=\measure{MyHeight}]{}}
%         \dorecurse{4}{test\par} \dorecurse{3}{\input klein }\par
%         \placefigure[left]{oeps}{\framed[width=\measure{MyWidth},height=\measure{MyHeight}]{}}
%         \dorecurse{3}{\input klein }\par
%     \stopbuffer
%     \enabletrackers[floats.anchoring]
%     \setupfloats[step=small]
%     \setupheadertexts[width=\measure{MyWidth},height=\measure{MyHeight}]
%     \dostepwiserecurse {100} {120} {1} {
%         \definemeasure[MyWidth][#1pt]
%         \dostepwiserecurse {50} {300} {1} {
%             \definemeasure[MyHeight][##1pt]
%             \setupwhitespace[none]%
%             \getbuffer \page
%             \setupwhitespace[big]
%             \getbuffer \page
%         }
%     }
% \stoptext

% \setupfloats
%   [\c!sidethreshold=.5\strutdp] % set to "old" to check with old method

\newdimen\d_page_sides_progression

\unexpanded\def\page_sides_check_floats_set
  {\edef\p_sidethreshold{\floatparameter\c!sidethreshold}%
   \ifx\p_sidethreshold\v!old
     \d_page_sides_progression\dimexpr\d_page_sides_progress+\strutht-\roundingeps\relax
     \c_page_sides_n_of_hang\d_page_sides_progression
     \divide\c_page_sides_n_of_hang \baselineskip\relax
   \else
     \d_page_sides_progression
       \ifx\p_sidethreshold\empty
         \d_page_sides_progress
       \else
         \dimexpr\d_page_sides_progress-\p_sidethreshold\relax
       \fi
     \getnoflines\d_page_sides_progression
     \c_page_sides_n_of_hang\noflines
   \fi
   \ifnum\c_page_sides_n_of_hang>\zerocount
     % new from here (needs test case, old code)
     \ifcase\c_page_sides_n_of_lines
     \else
       \ifcase\c_page_sides_lines_done
         \global\c_page_sides_lines_done\c_page_sides_n_of_hang
       \else
         \privatescratchcounter\c_page_sides_lines_done
         \advance\privatescratchcounter-\c_page_sides_n_of_hang
         \global\advance\c_page_sides_n_of_lines-\privatescratchcounter
       \fi
     \fi
     % hm, when do we get the parshape branch? needs testing
     \ifnum\c_page_sides_n_of_lines>\zerocount
       \privatescratchtoks\emptytoks
       \privatescratchcounter\c_page_sides_n_of_lines
       \privatescratchdimen\dimexpr\hsize-\d_page_sides_width\relax
       \dorecurse\c_page_sides_n_of_lines
        %{\appendtoks \zeropoint \hsize \to \privatescratchtoks}%
         {\toksapp\privatescratchtoks{\zeropoint\hsize}}%
       \ifnum\c_page_sides_n_of_hang>\c_page_sides_n_of_lines
         \advance\c_page_sides_n_of_hang -\c_page_sides_n_of_lines\relax
         \advance\privatescratchcounter\c_page_sides_n_of_hang
         \dorecurse\c_page_sides_n_of_hang % weird, shouldn't that be scratchcounter
           {\ifnum\c_page_sides_float_type>\plusfour
             %\appendtoks \zeropoint         \privatescratchdimen \to \privatescratchtoks
              \toksapp\privatescratchtoks{\zeropoint\privatescratchdimen}%
            \else
             %\appendtoks \d_page_sides_width\privatescratchdimen \to \privatescratchtoks
              \toksapp\privatescratchtoks{\d_page_sides_width\privatescratchdimen}%
            \fi}%
       \fi
       \parshape
         \numexpr\privatescratchcounter+\plusone\relax
         \the\privatescratchtoks  % \privatescratchcounter
         \zeropoint \hsize % \plusone
       \relax
     \else
       % new till here
       \hangindent \ifnum\c_page_sides_float_type>\plusfour -\fi\d_page_sides_width
       \hangafter-\c_page_sides_n_of_hang
     \fi
   \fi
   \global\advance\c_page_sides_checks_done \plusone
   \iftracesidefloats
     \page_sides_check_floats_tracer
   \fi}

\unexpanded\def\page_sides_check_floats_reset
  {\global\c_page_sides_checks_done\zerocount}

\unexpanded\def\page_sides_synchronize_floats
  {\ifinner \else
     \page_sides_check_floats
   \fi}

\unexpanded\def\page_sides_check_previous_float
  {\page_sides_analyse_progress
   \ifdim\d_page_sides_progress>\zeropoint \relax
     \ifconditional\c_page_sides_short
       \global\setfalse\c_page_sides_short
       \page_otr_fill_and_eject_page
     \else
       \kern\d_page_sides_progress
     \fi
   \fi}

\def\page_sides_inject_dummy_lines_normal
  {\dorecurse\privatescratchcounter{\hpack to \hsize{\strut\hss}}}

\def\page_sides_inject_dummy_lines_traced
  {\dorecurse\privatescratchcounter{\ruledhpack{\backgroundline[trace:b]{\hpack to \hsize{\strut\hss}}}}}

\def\page_sides_inject_dummy_lines % so always one
  {\begingroup
   \privatescratchcounter\pageshrink
   \divide\privatescratchcounter \baselineskip
   \advance\privatescratchcounter \plusone
   \parskip\zeropoint
   \iftracesidefloats
     \page_sides_inject_dummy_lines_traced
   \else
     \page_sides_inject_dummy_lines_normal
   \fi
   \kern-\privatescratchcounter\baselineskip
   \penalty\zerocount
   \triggerpagebuilder
   \endgroup}

\def\adjustsidefloatdisplaylines % public, will change
  {\aftergroup\page_sides_adjust_display_lines}

\def\page_sides_adjust_display_lines
  {\par
   \noindent
   \ignorespaces}

%D We need to hook it into the other otr's. This code will be adapted once we rename
%D the callers. We use \type {\def} as they can be redefined! Some will become obsolete

\def\checksidefloat         {\page_sides_check_floats}
\def\flushsidefloats        {\page_sides_flush_floats_text}
\def\flushsidefloatsafterpar{\page_sides_flush_floats_after_par}
\def\forgetsidefloats       {\page_sides_forget_floats}
%def\synchronizesidefloats  {\page_sides_synchronize_floats}

\protect \endinput