Re: "Final" version of tty child frames

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>> Date: Tue, 22 Oct 2024 06:46:15 +0200
>> 
>> I have (re-)created the scratch/tty-child-frames branch today, which
>> contains the code for child frames on ttys, based on a recent master.
>> 
>> I'm a happy user of this for a while now with corfu, vertico +
>> vertico-posframe + consult, transient + transient-posframe,
>> which-key + which-key-posframe. And my current todo list is now empty,
>> so here it is.
>
> Is there a way to test the feature without using corfu?  If so, can
> you suggest some simple Lisp to see if the child frames work in a
> build of this branch?

Thanks for taking a look.

Something built-in you could try is show-paren-mode with
show-paren-context-when-offscreen set to 'child-frame. Not very useful,
but it should display a child frame at (0,0) of a window.

Or maybe

(defun my-make-child ()
  (interactive)
  (make-frame `((parent-frame . ,(selected-frame))
		(background-color . "gray10")
		(foreground-color . "white")
		(internal-border-width . 1)
		(top . 15)
		(left . 40)
		(width . 80)
		(height . 25))))

which is not really the use case I have in mind but anyway.

>> Disclaimer: As I mentioned already in other contexts, I don't want to
>> be the maintainer of anything, for personal reasons.
>> 
>> Have fun!
>
> Does this compile cleanly for you?  I get gobs of warnings like this:

Yes it does, with clang.

>   dispnew.c: In function ‘gui_update_window_end’:
>   dispnew.c:4495:34: warning: potential null pointer dereference [-Wnull-dereference]
>    4495 |       hlinfo->mouse_face_beg_row = hlinfo->mouse_face_beg_col = -1;
> 	|       ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> This seems to be because you've changed the definition of
> MOUSE_HL_INFO to be this:
>
>   #   define MOUSE_HL_INFO(F)                                     \
>     (FRAME_WINDOW_P (F)                                           \
>     ? (FRAME_OUTPUT_DATA (F)                                      \
>        ? &FRAME_DISPLAY_INFO (F)->mouse_highlight                 \
>        : NULL)                                                    \
>      : &(F)->output_data.tty->display_info->mouse_highlight)
>
> I don't understand the need for this NULL there.  What is its purpose,
> and what will we lose by going back to the original definition?  I
> believe that NULL is what's causing these warnings.

It probably crept in when I ported this. I can remove that if you want.