Format a 'sectioned' counter individually

Question

I have a set of different types to include figure-like items in a document. These include a float (created by \SetupFloatingEnvironment), a non-float and full-page environments/commands.

While the non-float environment easily can share the counter and list of the basic float type through the \captionsetup, I had to go to some length with the full-page type: This doesn't have a real \caption but rather a text that is formatted like the caption. I then manually update the counter, write a) that 'caption' in the page header and b) manually create a toc entry.

Basically that works quite well, but when I'm in a context where the floating environments are numbered with the chapter number included I don't know how to mimick that in my manual caption.

So the question is: How can I determine the actual numbering options for floats (that the end user of my package may have changed individually)? And how can I reproduce that formatting for a custom caption and 'contentsline'?

Answer 1

In LaTeX, each counter defined by \newcounter{<counter>} is provided with an accompanying macro \the<counter> that defaults to \arabic{<counter>}. This allows users to step (or update) counters as expected, but have them linked to other counters when printing (for example, figure counters that include the chapter as well).

Instead of setting the counter using \arabic{<counter>} within your code, use \the<counter> instead, and redefine it in the following way, say:

\renewcommand{\the<counter>}{\the<othercounter>.\arabic{<counter>}}

This allows <counter> to inherit any formatting of the <othercounter>'s printing mechanism.

An alternative approach is to directly use \the<othercounter> to use its display properties, whatever they are.

Given a command \myfigure that wants to hook into the figure counter one could write:

\newcommand{\myfigure}{%
    \refstepcounter{figure}%
    \addcontentsline{lof}{figure}{\protect\numberline{\thefigure}{\ignorespaces #1\relax }}%
}

That way the contentsline uses the numbering of figure regardless of its formatting.