I am writing a new package that does not use tikz but uses the standard latex2e picture environment. I am pleased that I could get the needed graphics without tikz. This means when the general public uses the package, it will not impose a tikz dependency on them (which is big and can have side-effects).
The problem is that objects need to be placed in absolute positions independant from other text on the page and without affecting other objects, like fold marks on a letter.
A similar question was answered:
It’s not a great answer because it relies on importing an external package (tikzpagenodes). We should not have to pull in the whole tikz infrastructure just to (for example) place a fold mark on a page. This is my starting attempt:
\setlength{\unitlength}{1mm}
\begin{ocg}{foldmarks}{fm}{on}\color{red}
\noindent\hspace{\dimexpr(-\oddsidemargin-1in)}\begin{picture}(0,0)
\put(0,0){hello, this is the origin!}
\end{picture}
\end{ocg}
The “h” in “hello” is rightfully against the far left edge of the paper. It’s ugly that I had to subtract off a left margin and an arbitrary 1 inch (which is hard-coded into the page layout), but it works for the horizontal. Doing the same with a negative \vspace{} (e.g. \vspace{\dimexpr(-\footskip-1in)}) has no effect, so a bottom margin or footer is forced.
How can this be overcome without using tikz?