bug#7390: 24.0.50; pos-col-row gives incorrect row

[Eli Zaretskii]

> From: Chong Yidong <cyd@stupidchicken.com>
> Cc: Drew Adams <drew.adams@oracle.com>, 7390@debbugs.gnu.org
> Date: Sat, 13 Nov 2010 16:44:04 -0500
> 
> Chong Yidong <cyd@stupidchicken.com> writes:
> 
> > I've checked a fix for picture-mouse-set-point into the emacs-23 branch.
> 
> Hmm; I took a closer look at your fix, and it doesn't seem quite right.
> If you make an abnormally tall header-line, e.g.
> 
> (setq header-line-format (propertize "foo" 'face '(:height 5.0)))
> 
> then this new code gives the wrong value.

That's expected: posn-col-row is documented to return an
approximation, based on the assumption that all the lines are of the
canonical height.  Your example breaks that assumption.  Similar
problems will happen if one of the lines above the mouse click uses an
unusually large font.