Re: "Final" version of tty child frames

[Gerd Möllmann]

Eli Zaretskii <eliz@gnu.org> writes:

>> Date: Thu, 16 Jan 2025 19:00:24 +0100
>> Cc: jared@finder.org, emacs-devel@gnu.org
>> From: martin rudalics <rudalics@gmx.at>
>> 
>> I attach what I have done so far.  It only handles LR text so far and
>> affects only the special case where W is the selected window and there
>> is a child frame on its frame.
>> 
>> I also attach a file tty-child-frames.el to be loaded with emacs -Q -nw.
>> With C-l and M-l make one or two child frames.  In the normal frame do
>> M-x info and scroll it if necessary so you an see a line which extends
>> past one of these frames.  On such a line lean on C-f and C-b - the
>> cursor should remain invisible as long as point is hidden by a child
>> frame and should reappear as soon as it is no more hidden.
>
> Did you try this with auto-hscroll-mode, both set to t and to
> current-line?  

If that leads to something being scrolled, we'll have built a desired
row to display the scrolled result, so that would not be a problematic
case if we check that the matrix used is the current matrix.

> What happens then if you move cursor with C-n and enter a line which
> is partially obscured by a child frame? Or if point becomes hidden
> because it enters the obscure part of the frame from above or below,
> not from left or from right?

>From a redisplay perspective, I'd say C-n, C-p, C-b, C-p lead all to the
same "PT given, find it in glyph row".

>
>> +  if (is_tty_selected && glyph->charpos > PT)
>> +    {
>> +      w->cursor.hpos = -1;
>> +      w->cursor.x = -1;
>> +    }
>
> Why do you need this test, and specifically the second part of the
> condition?

Good question. Something I overlooked.