\input ptb-utils
\input pdfGraphics/ptb-colors

\_checkloaded{colorboxes}

\newbox\_contentbox
\newbox\_splitbox

\def\_spaceleft{%
    \ifdim\pagetotal=\z@%
        \dimexpr\vsize - \topskip\relax%
    \else%
        \dimexpr \pagegoal - \pagetotal - \topskip\relax%
    \fi%
}

\newif\if_recheck
\newif\if_lastbox
\newif\if_firstbox
\def\_getsplitdim#1{%
    \ifdim\dimexpr\_spaceleft-#1\relax>\ht\_contentbox%
        \edef\_splitdim{\the\ht\_contentbox}%
        \_recheckfalse%
        \_lastboxtrue%
    \else%
        \_lastboxfalse%
        \ifdim\dimexpr\_spaceleft-#1\relax>\z@%
            \edef\_splitdim{\the\dimexpr\_spaceleft-#1\relax}%
            \_recheckfalse%
        \else
            \if_recheck%
                \vfil\break\vfilneg%
                \_recheckfalse%
            \else%
                \null\par%
                \_rechecktrue%
            \fi%
            \_getsplitdim{#1}%
        \fi%
    \fi%
}

%   Splits the content box to fit into pages.
%   #1: Total vertical buffer
%   #2: Output routine for new box
\def\__splitcontentbox#1#2#3#4#5{
    \unless\ifvoid\_contentbox%
        \_getsplitdim{#1}%
        \setbox\_splitbox = \vsplit\_contentbox to\_splitdim\relax%
        \setbox0=\vbox{%
            \if_firstbox%
                \if_lastbox%
                    #2%
                \else%
                    #3%
                \fi%
            \else%
                \if_lastbox%
                    #5%
                \else%
                    #4%
                \fi%
            \fi%
        }%
        \vbox to\z@{\copy0\vss}%
        \kern\ht0\relax\penalty\z@%
        \_firstboxfalse%
        \__splitcontentbox{#1}{#2}{#3}{#4}{#5}%
    \fi%
}
\def\_splitcontentbox#1#2#3#4#5{{%
    \splittopskip=\z@%
    \boxmaxdepth=\z@%
    \offinterlineskip%
    \_firstboxtrue%
    \__splitcontentbox{#1}{#2}{#3}{#4}{#5}%
}}

\def\_ppbuf{0pt}
\def\_bppbox#1#2#3[#4]{%
    \_getdotsnlines#4\_nul%
    \def\_colorcontentboxT{%
        \hbox{\curvedcolorbox{#2}{#1}{\_setcolor{}{#3}\box\_splitbox}{#4}}%
    }%
    \def\_colorcontentboxS{%
        \hbox{\curvedcolorbox{#2}{#1}{\_setcolor{}{#3}\box\_splitbox}%
            {_X\_linel\_dottl\_linet\_dottr\_liner X}%
        }%
    }%
    \def\_colorcontentboxM{%
        \hbox{\curvedcolorbox{#2}{#1}{\_setcolor{}{#3}\box\_splitbox}%
            {_X\_linel X_X\_liner X}%
        }%
    }%
    \def\_colorcontentboxE{%
        \hbox{\curvedcolorbox{#2}{#1}{\_setcolor{}{#3}\box\_splitbox}%
            {\_lineb\_dotbl\_linel X_X\_liner\_dotbr}%
        }%
    }%
    \par%
    \kern\_ppbuf\relax%
    \null\par% Move the kern from recent contributions to MVL
    \setbox\_contentbox=\vbox\bgroup%
        \hsize=\dimexpr\hsize-\_actual_curve_buf * 2\relax%
}

\def\bppbox#1#2#3{%
    \_ifnextchar[ {\_bppbox{#1}{#2}{#3}}{\_bppbox{#1}{#2}{#3}[-.-.-.-.]}%
}

\def\eppbox{%
    \egroup%
    \_splitcontentbox{2\_actual_curve_buf}%
        \_colorcontentboxT\_colorcontentboxS\_colorcontentboxM\_colorcontentboxE%
    \vskip\_ppbuf\relax%
}

\def\pprulewd{2.5pt}
\def\pprulevbuf{5pt}
\def\pprulehbuf{7pt}

\def\blinedppbox#1#2#3{%
    \def\_colorcontentbox{{%
        \setbox0=\hbox{{\_setcolor{}{#2}\vrule width\pprulewd\relax}\kern\pprulehbuf\vbox{\kern\pprulevbuf\_setcolor{}{#3}\box\_splitbox\kern\pprulevbuf}\kern\pprulehbuf}%
        \hbox{{\_setcolor{}{#1}\vrule height\ht0 width\wd0 depth\dp0}\kern-\wd0\box0}%
    }}%
    \par\kern\_ppbuf\relax%
    \null\par%
    \setbox\_contentbox=\vbox\bgroup%
        \hsize=\dimexpr\hsize-\pprulewd - \pprulehbuf * 2\relax%
}
\def\elinedppbox{%
    \egroup%
    \_splitcontentbox{2\dimexpr\pprulevbuf\relax}%
        \_colorcontentbox\_colorcontentbox\_colorcontentbox\_colorcontentbox%
    \vskip\_ppbuf\relax%
}