Standalone: Changing border mid-document

Question

I have a one-page standalone document:

\documentclass[border=1pt]{standalone}
\begin{document}
Lorem ipsum
\end{document}

I would like to create a command \removeborder that will, when placed between the \begin{document} and \end{document} commands, remove the border from this one-page document.

\documentclass[border=1pt]{standalone}
\newcommand{\removeborder}{???}
\begin{document}
\removeborder
Lorem Ipsum
\end{document}

While \standaloneconfig{border=0pt} (documented here) is similar to what I want, when put in place of the ???, it does not remove the border from the page. Unfortunately, I am rather restricted on which parts of this code I can modify, thus why I do not modify the \documentclass statement. The command \removeborder will always be called from within the page it should affect; I cannot simply define a \standaloneenv and place \removeborder before the environment is entered.

My question: What can I place in the ??? in the second code block to remove the border from this document?

Answer 1

The border values (one per side) are stored internally as \sa@border@left etc. by standalone. There are then applied (using \marginbox by my other package adjustbox) to the content box after the box is processed but before it is typeset. You can therefore change the values inside the content, however because it is grouped the changes will be lost at the end if the changes are not made global.

Note that the standard border is 0.50001 bp (big points, 72bp = 72.27pt), not 0 as this would visiually cut the text a little.

So the solution is:

\documentclass[border=1pt]{standalone}

\makeatletter
\newcommand{\removeborder}{%
    \global\def\sa@border@left{0.50001bp}%
    \global\let\sa@border@right\sa@border@left
    \global\let\sa@border@top\sa@border@left
    \global\let\sa@border@bottom\sa@border@left
}
\makeatother

\begin{document}
\removeborder
Lorem Ipsum
\end{document}

Answer 2

Here is a try.

With standalone class the start and the end of each page is clear (environment) and i think there is no automatic page break so one can add command that change border just before the page.

\documentclass[tikz,border=1cm]{standalone}
\makeatletter %save current values of border
\edef\mysaborders{\sa@border@left\space\sa@border@right\space\sa@border@top\space\sa@border@bottom}
\makeatother
\newcommand{\removeborder}{%
\standaloneconfig{border=0pt}}

\newcommand{\resetborder}{%
\standaloneconfig{border={\mysaborders}}}



\begin{document}
\begin{tikzpicture}
\fill[red!20](0,0) rectangle (3,3);
\end{tikzpicture}
\removeborder
\begin{tikzpicture}
\fill[red!60](0,0) rectangle (3,3);
\end{tikzpicture}

\begin{tikzpicture}
\fill[blue!60](0,0) rectangle (3,3);
\end{tikzpicture}

\resetborder
\begin{tikzpicture}
\fill[red!20](0,0) rectangle (3,3);
\end{tikzpicture}
\end{document}