Re: Display-relative coordinates

[Eli Zaretskii]

> Date: Fri, 29 Jul 2016 08:38:19 -0700 (PDT)
> From: Drew Adams <address@hidden>
> Cc: address@hidden
> 
> > You don't tell what location of the character cells you take
> > as its coordinates.
> 
> I did say that I measured to the bottom of the cursor (block).

The y-coordinate of a character cell is for its left-top corner, not
the bottom.  Otherwise, how could the first line have the y-coordinate
of zero?

> > You also say that the height of a character is 12 pixels, but
> > the default height of a line in "emacs -Q" is 16, not 12.
> 
> I believe I measured it.  Measuring it again now: 12 pixels for
> a char.  And in 1/10 pt, face `default' has height 102.  (And no,
> char height does not include interline height.)

There's no "interline height" (a.k.a. "line spacing") in the default
face.  And characters don't have the same height in a font, so "12
pixels for a char" is a meaningless utterance.

> I mentioned char height only to let you know that I measured to
> the bottom of the cursor (as I said).  If you want to instead
> use the bottom of the cursor on the previous line (so as to
> include the interline height), and you want to use 16, then
> 420 - 16 = 404, instead of the 420 - 12 = 408 that I reported
> using char height.  Still not the same as 354.  Again, perhaps
> I'm missing something.

You most definitely are, but we will never know what that is.

> > Maybe you could go line by line starting at the first line of the
> > window, show the pixel coordinates of the first (leftmost) character
> > on that line, and then tell which part(s) of the results don't look
> > correct to you.
> 
> Sorry, I'm done with this.

And I'm done answering your questions, because each time I try, I end
up wasting my time, when you unilaterally decide to stop bothering.