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Henning Hraban Ramm schrieb am 08.09.2023 um 12:22:
Hi, for an involved image placement (full page image starting each chapter, several stacked elements), I’d like an environment that accepts key-value arguments, like
\startMyFigure[page=left,title={My caption}] \externalfigure[dummy]… \stopMyFigure
I don’t think that a real float makes sense, even if the interface looks similar, since it’s always a full page in a fixed place, I need no numbering and can place the caption myself.
Does it make sense to use \definestartstop? How would I “plugin“ the argument handling?
Or should I better define start and stop separately?
\def\startMyFigure[#1]{ % e.g. use utilities.parsers.settings_to_hash(#1) } \def\stopMyFigure{}
Probably I’ll need to catch the content (\externalfigure, might become more) and use it in a \setlayer – so perhaps something like
\definebuffer[MyFigure] \define\stopMyFigure{% \setlayer[page]{\getMyFigure}}} }
? But then I don’t know how to handle the arguments.
Probably it makes most sense to do it in Lua, like
\startluacode interfaces.implement { name = "startMyFigure", public = true, arguments = {"hash",}, actions = function(h, a) -- … end, } \stopluacode
But I didn’t find how to do environments.
When you just need an environment with a optional argument to pass user values you can use the userdata environment but be aware that you have some limitations (like verbatim) because the mechanism uses a buffer to store the content. For images (and other content) which are placed on a separate page at the start of a chapter you can use the pageinjection mechanism which was added for this purpose. Wolfgang