While @tarleb’s answer is surely the best (except that it specifies a
wrong amount of vertical space), here is a “simpler” (by some measure)
but more hacky (in LaTeX terms at least) solution which optionally uses a Pandoc Lua filter or a LaTeX hack but avoids loading another LaTeX package.
We want the LaTeX source to look something like this:
\hypertarget{level-4-heading}{%
\paragraph{Level 4 heading}\label{level-4-heading}}
\hfill
Lorem ipsum dolor sit amet.
This LaTeX looks awful, but if you don’t need to keep or share the LaTeX
source it does what you probably want: a space between the level 4
heading and the paragraph after it equal to the space between a level 3
heading and the paragraph after it.
![Level 4 heading with paragraph break]()
Here is how it works: since a \hfill on a line on its own is about as
close as you can get to an empty paragraph in LaTeX you get a first
paragraph — the one running in with the heading — containing only
horizontal white space until the end of the line, and then immediately
after a new paragraph — the actual first paragraph after the heading —
with just a normal paragraph space between it and the heading. This
probably also upsets LaTeX’s idea about what a \paragraph should be
like as little as possible.
The “manual” way to do this is as follows:
#### Level 4 heading
````{=latex}
\hfill
````
Lorem ipsum dolor sit amet.
This uses Pandoc’s relatively new raw markup syntax — the “code block”
is actually a raw LaTeX block — but it looks even more awful than the
resulting LaTeX source! It is also a tedious chore to have to insert
this after every level 4 heading. In other words you want to insert that
raw LaTeX automatically, and that can be done with a Lua filter:
--[======================================================================[
latex-h4-break.lua - Pandoc filter to get break after a level 4 heading.
Usage:
$ pandoc --lua-filter latex-h4-break.lua input.md -o output.pdf
--]======================================================================]
-- create it once, use it many times!
local hfill_block = pandoc.RawBlock('latex', '\\hfill')
function Header (elem)
if 4 == elem.level then
return { elem, hfill_block }
else -- ignore headings at other levels!
return nil
end
end
However you can also do a simple LaTeX hack in a header-includes
metadata block to get the same effect:
---
header-includes:
- |
``` {=latex}
\let\originAlParaGraph\paragraph
\renewcommand{\paragraph}[1]{\originAlParaGraph{#1} \hfill}
```
---
#### Level 4 heading
Lorem ipsum dolor sit amet.
This works by first creating an “alias” of the \paragraph command and
then redefining the \paragraph command itself, using the alias in the
new definition so that now wherever the LaTeX source created by Pandoc
contains \paragraph{Foo} it is if it instead had contained
\paragraph{Foo} \hfill which does what we want with zero extra
dependencies! (In case you wonder the wacky spelling of the “aliased”
command is to minimize the risk that it collides with anything which
already exists, since the TeX \let command doesn’t check for that. We
certainly don’t want to overwrite any existing command!)
NOTE: If you really should want more or less space than a normal
paragraph break after the heading just add an appropriate \vspace
command after the \hfill: \hfill \vspace{-0.5\parskip}.
