sphinxpackageboxes.sty

%% COLORED BOXES
%
% change this info string if making any custom modification
\ProvidesPackage{sphinxpackageboxes}[2022/07/04 v5.1.0 advanced colored boxes]

% Currently, this file only provides a replacement to the \spx@verb@fcolorbox
% of sphinxlatexliterals.sty which will draw boxes with a frame having
% rounded corners, and a background color.
%
% It needs \sphinxverbatimsep, \sphinxverbatimborder and a new parameter
% \sphinxverbatimradius
%
% Executes \RequirePackage for:
%
% - pict2e.  Ideally we would need a recent version of this package which
%   allows dimensional arguments to its \moveto, \lineto, etc...
%   but we add ourselves some wrapper to facilitate the usage.


% MEMO: we have also successfully tested usage of tcolorbox's \tcbox but
% decided to use pict2e.sty for the following reasons:
% 1- an order of magnitude faster for what we want to do,
% 2- orders of magnitude smaller dependency (tcolorbox uses the pgf TeX
%    framework)
% 3- possibility to accomplish already quite fancy boxes with pict2e
%    (and the additional coding as contributed here).

% In this first installment, the caption and continuation hints of code-blocks
% are done exactly as formerly; only difference is in the rounded corrners.
% The space occupied is same, if nothing else is changed.

\IfFileExists{pict2e.sty}
   {\RequirePackage{pict2e}}
   {\PackageWarningNoLine{sphinx}{%
       The package pict2e is required for rounded boxes.\MessageBreak
       It does not seem to be available on your system.\MessageBreak
       The verbatimradius setting will thus be ignored}%
    \AtEndDocument{\PackageWarningNoLine{sphinx}{%
       I issued a warning which may have gotten lost in the\MessageBreak
       gigantic console output: pict2e.sty was not found,\MessageBreak
       and verbatimradius has been ignored}}\endinput}

% First we define some wrapper to be able to use arguments being (only)
% dimensions or dimensional expressions.  The \unitlength will always be 1pt.
\def\spx@moveto(#1,#2)%
   {\expanded{\noexpand\moveto(\strip@pt\dimexpr#1,\strip@pt\dimexpr#2)}}
\def\spx@lineto(#1,#2)%
   {\expanded{\noexpand\lineto(\strip@pt\dimexpr#1,\strip@pt\dimexpr#2)}}
% attention we use here [2] always; and there are two more mandatory
% arguments, angles, we don't need to worry about them here.
\def\spx@circlearc#1#2#3{\expanded{\noexpand\circlearc[2]%
    {\strip@pt\dimexpr#1}{\strip@pt\dimexpr#2}{\strip@pt\dimexpr#3}}%
}

% TODO: add top right bottom left padding possibilities.
\long\def\spx@verb@fcolorbox #1#2#3{%
  % Prepare a box with the contents and reserved space for framing.
  \setbox\tw@\hbox{\kern\dimexpr\sphinxverbatimborder+\sphinxverbatimsep\relax
                  {#3}\kern\dimexpr\sphinxverbatimborder+\sphinxverbatimsep\relax}%
    \ht\tw@ \dimexpr\ht\tw@+\sphinxverbatimsep+\sphinxverbatimborder\relax
    \dp\tw@ \dimexpr\dp\tw@+\sphinxverbatimsep+\sphinxverbatimborder\relax
  \vbox{%
% Prepare a macro for path to be inserted in a picture environment for stroke
% and fill; the path will be redefined for each of fill or stroke.  This macro
% does nothing yet.
\def\spx@dopath{%
  \spx@moveto(\sphinxverbatimradius,\z@)% \z@ not 0 as our \spx@moveto is quite dumb
  \spx@lineto(\wd\tw@-\sphinxverbatimborder-\sphinxverbatimradius,\z@)%
  \spx@circlearc{\wd\tw@-\sphinxverbatimborder-\sphinxverbatimradius}%
                {\sphinxverbatimradius}%
                {\sphinxverbatimradius}{-90}{0}%
  \spx@lineto(\wd\tw@-\sphinxverbatimborder,\ht\tw@+\dp\tw@-\sphinxverbatimborder-\sphinxverbatimradius)%
  \spx@circlearc{\wd\tw@-\sphinxverbatimborder-\sphinxverbatimradius}
                {\ht\tw@+\dp\tw@-\sphinxverbatimborder-\sphinxverbatimradius}%
                {\sphinxverbatimradius}{0}{90}%
  \spx@lineto(\sphinxverbatimradius,\ht\tw@+\dp\tw@-\sphinxverbatimborder)%
  \spx@circlearc{\sphinxverbatimradius}%
                {\ht\tw@+\dp\tw@-\sphinxverbatimborder-\sphinxverbatimradius}%
                {\sphinxverbatimradius}{90}{180}%
  \spx@lineto(\z@,\sphinxverbatimradius)%
  \spx@circlearc{\sphinxverbatimradius}{\sphinxverbatimradius}{\sphinxverbatimradius}{180}{270}%
}% end of definition of \spx@dopath
%
        #1% continuation hint attached above frame
        % there will be a small "\lineskip" space here from TeX
        % draw frame border _latest_ to avoid pdf viewer issue
        % be careful not to cause "color push + contents + color pop"
% MEMO: when pict2e doth a path stroke, the path is in the middle of the line
% width, i.e. the line extends by half its width to the exterior of the filled
% path.  This explains some 0.5 things below.
        \hbox{\setlength{\unitlength}{1pt}% attention to space token here
              \begin{picture}(\wd\tw@,\ht\tw@+\dp\tw@)%
                             (-.5\sphinxverbatimborder,-.5\sphinxverbatimborder)%
              \color{VerbatimColor}% color for background
              \spx@dopath\fillpath
              \color{VerbatimBorderColor}% color for border
\ifspx@opt@verbatimwithframe % even with \sphinxverbatimborder set to 0pt, the
                             % stroke will produce a visible contour, so we
                             % must explicitly exclude doing it.
              \linethickness{\sphinxverbatimborder}%
              \spx@dopath\strokepath
\fi
              \end{picture}}%
        % now the contents
        \kern-\dimexpr\ht\tw@+\dp\tw@\relax
        \copy\tw@ % attention that #2 will need \wd\tw@
        \nointerlineskip
        % TODO: add some \lineskip glue here, this is all in a \vbox so can't split
        #2% continuation hint attached below frame
       }% end of \vbox
}%

\endinput