That patch works to address make-frame's respect for text-pixels, at least
on NS (the only platform I tested).

Now to address the clone-frame implementation to respect pixelwise, and/or
as you suggested, perhaps a formal frame parameter resize-pixelwise. If we
adopt the change I proposed it could be used in Emacs 30 or 31 since this
is a bug (but not a regression). If we go for resize-pixelwise, it'll be
31, right?

On Wed, Dec 11, 2024 at 4:38 AM martin rudalics <rudalics@gmx.at> wrote:

>  > Somewhere in the bowels
>  > of frame.c, et.al., is an issue where text-pixels behaves differently
> than
>  > set-frame-size which is reliable on NS where make-frame using
> text-pixels
>  > is incorrect by the vertical scroll bar width. GTK it's off, too, but I
>  > didn't analyze that further.
>
> If you mean that with
>
> (progn
>    (setq frame-resize-pixelwise t)
>    (make-frame '((width . (text-pixels . 800)))))
>
> then
>
> (frame-text-width)
>
> evaluates to 784, please try the attached patch.
>
> Thanks, martin