Re: "Final" version of tty child frames

[Gerd Möllmann]

Eli Zaretskii <eliz@gnu.org> writes:

> That's just how the cursor is hidden.  What I meant was the other
> problems Martin described, with moving the cursor:
>
>> In a fix I don't like I've put it on the first character on the right of
>> any child frame encountered.  But then the real point position will be
>> still hidden under the child frame.  So when you lean on C-f (in a
>> non-bidi context), the cursor immediately jumps to that position on the
>> right of any child frame but point still has to catch up with that
>> situation and only when it does that the cursor will continue moving.
>> Disconcerting and ugly.

Martin describes a case where he set w->cursor to a position _outside_
of the child frame, immediately to the right of it. As soon as be moves
the cursor "under" the child frame, it therefore appears to the right of
it. And it stays there with C-f, until it is no longer obscured by the
child frame.

Makes perfect sense to me, is the wrong thing to do, and he doesn't do
that anymore.

> In general, when w->cursor are all non-negative, the display engine
> believes that the cursor position corresponds to point, so violating
> that could cause problems elsewhere.  

And my question is where that is.

> At the very least, this should be prominently documented, and perhaps
> also some indication of that kept around, so that this abnormality
> could be easily detected if needed.
>
> IOW, let's not add one more subtle factoid into the display code, it
> has enough already.

Let's Martin decide if he wants to do more.