%%
%% This is file `bidihl.sty'.
%%
%% ___________________________________________
%% Copyright © 2015 Vafa Khalighi <persian-tex@tug.org>
%%
%% It may be distributed and/or modified under the LaTeX Project Public License,
%% version 1.3c or higher (your choice). The latest version of
%% this license is at: http://www.latex-project.org/lppl.txt
%%
%% This work is “author-maintained” (as per LPPL maintenance status)
%% by Vafa Khalighi.
%%
%%
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{bidihl}[2015/07/07 v0.1c Experimental bidi-aware text highlighting]
%% Load color package and define highlighting color
\RequirePackage{color}
\definecolor{bidihlcolor}{rgb}{1,1,0} % yellow
%% Register Declaration
\newdimen\bidihl@line@thickness \bidihl@line@thickness.4pt
\newdimen\bidihl@pixel \bidihl@pixel0.1pt
\newdimen\bidihl@height \newdimen\bidihl@depth
\newcount\bidihl@spacefactor
\newif\ifbidihl@nospace
%% User Interface and Initialization
\def\bidihl{\bidihl@highlight{\dp\strutbox}{\ht\strutbox}}
\def\bidihl@line#1#2#3#4{\begingroup \let\\\bidihlnewline
\ifdim#1<\z@ \bidihl@height#3\relax
\else \bidihl@height#2\relax \fi
\bidihl@depth-\bidihl@height
\ifdim\bidihl@height<\z@ \advance\bidihl@depth\bidihl@line@thickness
\else \advance\bidihl@height\bidihl@line@thickness \fi
\bidihl@nospacetrue
\ifvmode\leavevmode\fi \bidihl@spacefactor\spacefactor
\def\@tempa{#4 }\edef\@tempb{\noexpand\@nil\space}%
\expandafter\expandafter\expandafter\bidihl@wordloop
\expandafter\@tempa\@tempb
\endgroup \bidihl@aftergroup}
\def\bidihl@highlight#1#2#3{\begingroup \let\\\bidihlnewline
\bidihl@depth#1\relax
\bidihl@height#2\relax
\bidihl@nospacetrue
\ifvmode\leavevmode\fi \bidihl@spacefactor\spacefactor
\def\@tempa{#3 }\edef\@tempb{\noexpand\@nil\space}%
\expandafter\expandafter\expandafter\bidihl@wordloop
\expandafter\@tempa\@tempb
\endgroup \bidihl@aftergroup}
%% Processing Word Elements
\def\bidihl@wordloop{\bidihl@ifbgroup\bidihl@wordblock\bidihl@iwordloop}
\def\bidihl@ifbgroup#1#2{\let\@tempa#1\let\@tempb#2\futurelet\@tempc\bidihl@ifnc}
\def\bidihl@ifnc{\ifx\@tempc\bgroup \let\next\@tempa \else\let\next\@tempb \fi
\next}
\def\bidihl@wordblock#1{\bidihl@spaceskip
\def\bidihl@theword{#1}\bidihl@putword \bidihl@nospacetrue
\bidihl@wordloop}
\def\bidihl@iwordloop#1 {\def\@tempa{#1}\ifx\@tempa\@nnil \let\next\bidihl@end
\else\ifx\@tempa\empty \else
\bidihl@spaceskip
\def\bidihl@theword{}\bidihl@charloop#1\@nil\fi
\bidihl@nospacefalse \let\next\bidihl@wordloop \fi
\next}
\def\bidihl@charloop{\bidihl@ifbgroup\bidihl@charblock\bidihl@icharloop}
\def\bidihl@charblock#1{\bidihl@putword
\def\bidihl@theword{#1}\bidihl@putword
\bidihl@charloop}
\def\bidihl@icharloop#1{\def\@tempa{#1}%
\ifx\@tempa\@nnil \bidihl@putword \let\next\relax
\else\ifx\bidihlspace#1\relax \bidihl@putword \let\next\bidihl@space
\else\ifx\bidihlnewline#1\relax \bidihl@putword \let\next\bidihl@newline
\else\edef\bidihl@theword{\bidihl@theword#1}%
\let\next\bidihl@charloop \fi\fi\fi \next}
\def\bidihlspace{\PackageError{bidihl}%
{\string\bidihlspace\space cannot be used here.}%
{\string\bidihlspace\space can be used only in the argument of
\string\bidihl.}}
\def\bidihlnewline{\PackageError{bidihl}%
{\string\bidihlnewline\space cannot be used here.}%
{\string\bidihlnewline\space can be used only in the argument of
\string\bidihl.}}
%% Interword Spacing
\def\bidihl@spaceskip{\ifbidihl@nospace\else
\ifdim\spaceskip=\z@
\@tempdima\fontdimen3\font\relax
\multiply\@tempdima\bidihl@spacefactor \divide\@tempdima\@m
\@tempdimb\fontdimen4\font\relax \multiply\@tempdimb\@m
\divide\@tempdimb\bidihl@spacefactor
\@tempskipa\fontdimen2\font plus\@tempdima minus\@tempdimb\relax
\else
\edef\@tempa{\the\spaceskip\space @ @ @ @ }%
\expandafter\bidihl@setspaceskip\@tempa\@nil
\fi
\ifnum\bidihl@spacefactor<2000\else
\ifdim\xspaceskip=\z@ \advance\@tempskipa\fontdimen7\font
\else \@tempskipa\xspaceskip
\fi\fi
\bidihl@skip\@tempskipa \fi}
\def\bidihl@setspaceskip#1 #2 #3 #4 #5 #6\@nil{\@tempdima\z@ \@tempdimb\z@
\def\@tempa{#2}\def\@tempb{#3}%
\ifx\@tempa\bidihl@plus \@tempdima#3\def\@tempa{#4}\def\@tempb{#5}\fi
\ifx\@tempa\bidihl@minus \@tempdimb\@tempb\relax\fi
\multiply\@tempdima\bidihl@specefactor \divide\@tempdima\@m
\multiply\@tempdimb\@m \divide\bidihl@spacefactor
\@tempskipa#1 plus\@tempdima minus\@tempdimb\relax}
\def\@tempa#1 #2 #3 #4 #5\@nil{\def\bidihl@plus{#2}\def\bidihl@minus{#4}}
\@tempskipa1pt plus 2pt minus 3pt
\expandafter\@tempa\the\@tempskipa\@nil
%% Draw highlight text
\def\bidihl@putword{\setbox\@tempboxa\hbox{\bidihl@theword
\global\bidihl@spacefactor\spacefactor}%
\@tempdima\wd\@tempboxa
\if@RTL%
\box\@tempboxa
{\color{bidihlcolor}\llap{\vrule\@height\bidihl@height\@depth\bidihl@depth\@width\@tempdima}}%
\else
{\color{bidihlcolor}\rlap{\vrule\@height\bidihl@height\@depth\bidihl@depth\@width\@tempdima}}%
\box\@tempboxa
\fi
\def\bidihl@theword{}}
\def\bidihl@skip#1{%
\if@RTL%
\leaders\hb@xt@\bidihl@pixel{\hss{\color{bidihlcolor}\vrule\@height\bidihl@height\@depth\bidihl@depth}\hss}%
\hskip#1\relax%
\else%
{\color{bidihlcolor}\leaders\hrule\@height\bidihl@height\@depth\bidihl@depth\hskip#1\relax}%
\fi}
%% Explicit Spacing and Line Breaking
\def\bidihl@space{\@ifstar\bidihl@sspace\bidihl@ispace}
\def\bidihl@sspace#1{\vrule width\z@\nobreak\bidihl@skip{#1}\bidihl@charloop}
\def\bidihl@ispace#1{\@tempskipa#1\relax
\@ifstar{\@tempswafalse\bidihl@iispace}{\@tempswatrue\bidihl@iispace}}
\def\bidihl@iispace{\@ifnextchar[%]
{\bidihl@penalty}%
{\bidihl@skip\@tempskipa \bidihl@charloop}}
\def\bidihl@penalty[#1]{\@tempcnta#1\relax
\if@tempswa
\ifnum\@tempcnta<\z@ \@tempcnta-\@tempcnta \fi
\ifcase\@tempcnta \or
\@tempcnta\@lowpenalty \or
\@tempcnta\@medpenalty \or
\@tempcnta\@highpenalty \else
\@tempcnta\@M \fi
\ifnum#1<\z@ \@tempcnta-\@tempcnta \fi \fi
\penalty\@tempcnta \bidihl@skip\@tempskipa \bidihl@charloop}
\def\bidihl@newline{\@ifstar{\bidihl@skip{0pt plus1fil}\break \bidihl@charloop}%
{\hfil \break \bidihl@charloop}}
%% Finalization
\def\bidihl@end{\xdef\bidihl@aftergroup{\spacefactor\number\bidihl@spacefactor\relax}}
\endinput
%%
%% End of file `bidihl.sty'.