RE: C-h r and Images

[Drew Adams]

> >> My motivation for the post was the thread in help list and a recurrent
> >> confusion between a frame and a window.
> >>
> >> It is easier to show
> >>   - a window
> >>   - a frame
> >>   - a minibuffer
> >>   - a header line
> >>   - a mode line
> >>
> >> with a single shot rather than explain it in Glossary.
> >
> > Great idea.  (Not either/or, of course.)
> 
> Something like http://www.emacswiki.org/emacs/DrewsEmacsWindowCallouts
> but in a plain vanilla `emacs -Q' rather than Drewmacs :-)

;-)  I had forgotten about that image (from Emacs 20).

> > What's more, it would be helpful to hyperlink directly to an explanation
> > of the term in question, rather than just saying "which see" or some such
> > English alternative to "q.v."
> 
> Linking directly to an explanation is possible with Info "anchors".

Is that done in TexInfo?  Should Emacs doc be doing that already?

If it were done, and then changes were made that break that xref, would
that problem be caught/detected, similarly to an ordinary broken xref?
E.g. is there a check or report about missing anchors that are xref'd?

How would that be done on parts of an image (which is just pixels)?
Can we do (the equivalent of) image maps, letting users, in effect,
click a callout (e.g., for "Mode Line"), to go to an appropriate part
of the manual for more info about it (e.g., `(emacs) Mode Line'), or to
provide a tooltip with a little related info?