title: How do I toggle between a Vertical and a Horizontal split in vimdiff?
body: <p><a href="http://vimdoc.sourceforge.net/htmldoc/options.html#%27diffopt%27" rel="noreferrer">I already know</a> how to use the <code>diffopt</code> variable to start diff mode with horizontal/vertical splits but not how to toggle between the two when I already have two files open for comparison.</p>
  
  <p>I tried the accepted answer found in <a href="https://stackoverflow.com/questions/1269603/to-switch-from-vertical-split-to-horizontal-split-fast-in-vim">this older post</a>, but to no avail. The Ctrl+W commands didn't work for me. Perhaps because I'm running gVim in Windows-friendly mode?</p>