So I wrote a LaTeX package that would give me full-page floats: https://tex.stackexchange.com/a/84312/13450
Unfortunately, it introduces hard page breaks.
\documentclass[a5paper]{memoir}
\usepackage{picturepage}
\usepackage{mwe}
\begin{document}
\blindtext\blindtext
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam
lobortis facilisis sem. Nullam nec mi et neque pharetra sollicitudin.
Praesent imperdiet mi nec ante. Donec ullamcorper, felis non sodales
commodo, lectus velit ultrices augue, a dignissim nibh lectus
placerat pede. Vivamus nunc nunc, molestie ut, ultricies vel, semper
in, velit. Ut porttitor. Praesent in sapien. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit. Duis fringilla tristique neque.
Sed interdum libero ut metus. Pellentesque placerat. Nam rutrum
augue a leo. Morbi sed elit sit amet ante lobortis sollicitudin. Praesent
blandit blandit mauris. Praesent lectus tellus, aliquet aliquam,
luctus a, egestas a, turpis. Mauris lacinia lorem sit amet ipsum.
Nunc quis urna dictum turpis accumsan semper. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis sem.
Nullam nec mi et neque pharetra sollicitudin. Praesent imperdiet
mi nec ante. Donec ullamcorper, felis non sodales commodo, lectus
velit ultrices augue, a dignissim nibh lectus placerat pede. Vivamus
nunc nunc, molestie ut, ultricies vel, semper in, velit. Ut porttitor.
Praesent in sapien. Lorem ipsum dolor sit amet, consectetuer
adipiscing elit. Duis fringilla tristique neque. Sed interdum libero
ut metus. Pellentesque placerat. Nam rutrum augue a leo. Morbi
sed elit sit amet ante lobortis sollicitudin. Praesent blandit blandit
mauris. Praesent lectus tellus, aliquet aliquam, luctus a, egestas a,
turpis. Mauris lacinia lorem sit amet ipsum. Nunc quis urna dictum
turpis accumsan semper.
\picturepage{example-image-a}{Full-page image.}{fig:a}
\blindtext\blindtext
\blindtext\blindtext\blindtext\blindtext
\end{document}
So this obviously introduces an ugly page break (pages after the image not shown).
Now usually, \afterpage is perfect for these kinds of cases.
\documentclass[a5paper]{memoir}
\usepackage{picturepage}
\usepackage{mwe}
\usepackage{afterpage}
\begin{document}
\blindtext\blindtext
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam
lobortis facilisis sem. Nullam nec mi et neque pharetra sollicitudin.
Praesent imperdiet mi nec ante. Donec ullamcorper, felis non sodales
commodo, lectus velit ultrices augue, a dignissim nibh lectus
placerat pede. Vivamus nunc nunc, molestie ut, ultricies vel, semper
in, velit. Ut porttitor. Praesent in sapien. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit. Duis fringilla tristique neque.
Sed interdum libero ut metus. Pellentesque placerat. Nam rutrum
augue a leo. Morbi sed elit sit amet ante lobortis sollicitudin. Praesent
blandit blandit mauris. Praesent lectus tellus, aliquet aliquam,
luctus a, egestas a, turpis. Mauris lacinia lorem sit amet ipsum.
Nunc quis urna dictum turpis accumsan semper. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis sem.
Nullam nec mi et neque pharetra sollicitudin. Praesent imperdiet
mi nec ante. Donec ullamcorper, felis non sodales commodo, lectus
velit ultrices augue, a dignissim nibh lectus placerat pede. Vivamus
nunc nunc, molestie ut, ultricies vel, semper in, velit. Ut porttitor.
Praesent in sapien. Lorem ipsum dolor sit amet, consectetuer
adipiscing elit. Duis fringilla tristique neque. Sed interdum libero
ut metus. Pellentesque placerat. Nam rutrum augue a leo. Morbi
sed elit sit amet ante lobortis sollicitudin. Praesent blandit blandit
mauris. Praesent lectus tellus, aliquet aliquam, luctus a, egestas a,
turpis. Mauris lacinia lorem sit amet ipsum. Nunc quis urna dictum
turpis accumsan semper.
\afterpage{\picturepage{example-image-a}{Full-page image.}{fig:a}}
\blindtext\blindtext
\blindtext\blindtext\blindtext\blindtext
\end{document}
For some reason I haven't been able to figure out, at least with memoir, this usage of \afterpage utterly ruins the page following the \picturepage.
Now, going back to a more manual approach, one could notice that LaTeX breaks the first page after "amet ipsum." So introducing the page break there will of course make two paragraphs out of one. But as long as this fact could be visually concealed, this would be a workable solution (not a good one, let alone a beautiful one ... but it'll do). Unfortunately, I don't know how to tell LaTeX that it should just typeset the first half of the paragraph as it used to. The second one is a simple matter of \noindent:
\documentclass[a5paper]{memoir}
\usepackage{picturepage}
\usepackage{mwe}
\begin{document}
\blindtext\blindtext
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam
lobortis facilisis sem. Nullam nec mi et neque pharetra sollicitudin.
Praesent imperdiet mi nec ante. Donec ullamcorper, felis non so-
dales commodo, lectus velit ultrices augue, a dignissim nibh lectus
placerat pede. Vivamus nunc nunc, molestie ut, ultricies vel, sem-
per in, velit. Ut porttitor. Praesent in sapien. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit. Duis fringilla tristique neque.
Sed interdum libero ut metus. Pellentesque placerat. Nam rutrum
augue a leo. Morbi sed elit sit amet ante lobortis sollicitudin. Prae-
sent blandit blandit mauris. Praesent lectus tellus, aliquet aliquam,
luctus a, egestas a, turpis. Mauris lacinia lorem sit amet ipsum.
\picturepage{example-image-a}{Full-page image.}{fig:a}
\noindent Nunc quis urna dictum turpis accumsan semper. Lorem ipsum dolor
sit amet, consectetuer adipiscing elit. Etiam lobortis facilisis sem.
Nullam nec mi et neque pharetra sollicitudin. Praesent imperdiet
mi nec ante. Donec ullamcorper, felis non sodales commodo, lectus
velit ultrices augue, a dignissim nibh lectus placerat pede. Vivamus
nunc nunc, molestie ut, ultricies vel, semper in, velit. Ut portti-
tor. Praesent in sapien. Lorem ipsum dolor sit amet, consectetuer
adipiscing elit. Duis fringilla tristique neque. Sed interdum libero
ut metus. Pellentesque placerat. Nam rutrum augue a leo. Morbi
sed elit sit amet ante lobortis sollicitudin. Praesent blandit blandit
mauris. Praesent lectus tellus, aliquet aliquam, luctus a, egestas a,
turpis. Mauris lacinia lorem sit amet ipsum. Nunc quis urna dictum
turpis accumsan semper.
\blindtext\blindtext
\blindtext\blindtext\blindtext\blindtext
\end{document}
So as I hope you are able to see (and as it is expected behaviour), the last line of the paragraph before the page break is no longer justified, thus destroying the impression of a coherent paragraph over the two pages.
How do I get LaTeX to typeset that last paragraph before the page break as it did before, without the ragged-right last line? Of course, if you have any idea how my problem might be solved at any other point, especially by fixing the afterpage behaviour, that'd be at least as appreciated.
Apologies if this seems too specific to my messed up picturepage package or not minimal enough because I'm using this huge chunk of code but I felt it would be better to provide a decent motivation instead of just asking "How do I split a paragraph but I don't want afterpage because reasons!"
memoirclass is used but not if thearticleclass is used.memoiris so huge that it's probably hard to pinpoint what part exactly is to blame.\afterpageis to blame. This is a relatively new feature of thegeometrypackage so maybe nobody noticed this bug yet.\afterpage{\newgeometry{textheight=\paperheight,textwidth=\paperwidth}\null\restoregeometry}will already produce a similar behaviour, adding a\clearpageafter\restoregeometrywill mess the page up exactly as my package does.atbegshipackage would be useful? I used it to do something similar here... (Haven't tested this withmemoirclass, maybe it has the same problems.)\picturepageto\AtBeginShipoutNext, I get aNot in outer par modeerror :/