For any given class and its specified page layout, I'd like to be able to combine (sum or subtract) a subset of the page dimensions, to obtain a length to work with, without specifying absolute values.
For example: I'd like to set the width of a figure equal to \textwidth + \marginparsep + \marginparwidth
I don't have a MWE yet, because I'm trying to figure out if this is possible somehow.
This is related, but applicable only to KOMA
\newlength\widthw \setlength{\widthw}{\textwidth+\marginparsep+\marginparwidth}– Alessandro Cuttin Dec 11 '17 at 16:08calcpackage Ulrike's version uses (e)tex primitive arithmetic so does not need any particular packages. – David Carlisle Dec 11 '17 at 21:40scrextendexists and can be used with several other classes, e.g, the standard classes. So the example there does also work, e.g., with\documentclass{book}\usepackage{scrextend}. – Schweinebacke Dec 12 '17 at 08:46