bug#60585: 30.0.50; global-text-scale-adjust shrinks window (was not before), was: Re: bug#52493: 29.0.50; Setting Inconsolata up in init.el makes default face rendered wrong

[martin rudalics]

> And it does have a thumb when the buffer is taller than the
> window. Sometimes the thumb gets bigger and sometimes smaller,
> though. That's a little odd. Perhaps it works off the number of
> visible characters rather than lines.

Interesting.  I've never seen such behavior.

> InconsolataLGC:
>
> (set-face-attribute 'default nil :family "InconsolataLGC")
>
> (gdb) p font->average_width
> $1 = 21
> (gdb) p font_ascent
> $2 = 37
> (gdb) p font_descent
> $3 = 8
>
> (set-face-attribute 'default nil :height 110)
>
> (gdb) p font->average_width
> $7 = 17
> (gdb) p font_ascent
> $8 = 31
> (gdb) p font_descent
> $9 = 6
>
> Now the reverse:
>
> (set-face-attribute 'default nil :height 110)
>
> (gdb) p font->average_width
> $10 = 15
> (gdb) p font_ascent
> $11 = 25
> (gdb) p font_descent
> $12 = 5
>
> (set-face-attribute 'default nil :family "InconsolataLGC")
>
> (gdb) p font->average_width
> $13 = 17
> (gdb) p font_ascent
> $14 = 31
> (gdb) p font_descent
> $15 = 6
>
> (I did restart Emacs between tries, just not GDB.)
>
> Inconsolata LGC:
>
> All exactly the same. Omitted to save space.

There's one thing that we haven't checked yet and I don't know how to do
that.  When you evaluate :height first you get a line height of 30 which
scaling should reduce to 15 without loss.  When you evaluate :family
first you scale twice with a loss.  I have no idea whether this has any
impact.  You can try whether either of the following

(progn
  (set-face-attribute 'default nil :family "Inconsolata LGC")
  (set-face-attribute 'default nil :height 110))

(progn
  (set-face-attribute 'default nil :height 110)
  (set-face-attribute 'default nil :family "Inconsolata LGC"))

causes a different shrinking behavior but I doubt that it will reveal
anything useful.  So I ran out of ideas ...

martin