bug#55696: 28.1; eshell fails to respect text-scale-increase

[Jim Porter]

On 5/28/2022 8:43 PM, Jeff Kowalski wrote:
> To reproduce:
>
> emacs -Q
>
> M-x eshell
> ls /etc  # to get a listing of many files
>
> Note at this point, the listing is well-wrapped to the width of the 
> window.  Now,
>
> M-x text-scale-increase
> ls /etc
>
> At this point, the listing is very poorly wrapped.  It appears to ignore 
> the increased width of the font relative to the width of the window

Thanks for the bug report. I think this patch fixes things. I added 
`window-max-lines' as the Y-axis correspondent to the X-axis version 
`window-max-chars-per-line'; maybe there's a function for this already, 
but I didn't see one after a bit of searching.

Note that the values of $LINES and $COLUMNS are sometimes different now, 
even without text-scale-increase. I think this new behavior is more in 
line with what people (and programs) would actually expect; they're the 
sizes that would actually be visible without any scrolling.

However, these differences could be surprising to people. For example, 
in a terminal, $COLUMNS might normally be 80, but within Emacs/Eshell, 
it would be 79 (subtracting one to account for the reserved continuation 
glyph). Maybe we want to do something different so that it remains 80...

0001-Account-for-remapped-faces-in-COLUMNS-and-LINES-in-E.patch
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