RE: mode line: 1) indicate region size, if active; 2) highlight column # if > limit

[Drew Adams]

> > 3. The line and column indicator is highlighted (red, in image) when the
> > cursor passes a user-defined limit. (This version still uses the
> > (line#,column#) format.)
>
> I like this idea -- make it nice and clear when you pop over the
> 70th/80th column. Could you be a bit more precise with the semantics?
> i) Will it highlight just the col number if you pass the col limit,
> and just the row number if you pass the row limit, and both if both,
> or does it just highlight both co-ordinates when either exceeds the
> limit? I think I'd prefer the former here.
> ii) What does it do in the case of line-number-mode and/or
> column-number-mode being off?

See the code; it's pretty simple:
http://www.emacswiki.org/cgi-bin/wiki/modeline-posn.el.

The only intention is to highlight the column number. I see no reason for a
line (i.e. row) limit, do you?

Highlighting occurs when the cursor column passes a user-defined limit (a
user option, with default value 70, not necessarily `fill-column').

The code I use highlights the column number indicator, if only column-number
mode is on. It highlights the whole pair (line, col), if both line-number
mode and column-number mode are on. It does not highlight the line number,
if only line-number mode is on.

Perhaps the code could be tweaked to highlight only the column number when
both line number mode and column number mode are on, but I'm not bothered by
the extra line-number highlighting, personally.