Re: stackexchange question: sync html source and rendered buffers

[Kevin Ryde <user42_kevin@xxxxxxxxxxxx>]

Boruch Baum <boruch_baum@xxxxxxx> writes:
>
> 1] When opening an html source buffer, point should be at the position
> corresponding to point in the rendered buffer.

For tex comparison, I think whizzytex.el marks point in dvi output by
inserting macros in the source to show an overlay and command specials
for the advi viewer too.  Inserting in tex tends to be fragile because
it's hard to be sure the context is ok for arbitrary code.  The emacs
side has medium-hairy bits to jump out to a hopefully sane place.

> 2] When saving a modified source buffer, the rendered buffer should
> automatically refresh to reflect the edit.

Url like "buffer:Foo" or something to render buffer contents, not just
files etc, has come up before.  I think it was only a matter of getting
underneath the url reading.  Could be of interest again if displaying
stuff being edited.

> ...
> If that means that whenever one inserts / deletes  a single character
> at the beginning of the document, all characters need to be remapped,
> that strikes me as an undesirable cpu load.

whizzytex.el does a re-render on a single character, but in the
background so you keep editing more too.  Probably can't background very
much with emacs-w3m.