dired-mouse-drag-files

dired-mouse-drag-files

[Eli Zaretskii]

This feature is not universally available, but is doc string doesn't
say so (the manual does).

Moreover, setting the variable non-nil unconditionally shows a tooltip
on file names in Dired buffers saying that the user can drag the file
to another program, but that is only so on X; on other platforms it's
a misleading tooltip.

As an aside, changing the value of the variable doesn't affect the
Dired buffers that already exist, only those created afterwards, which
I think is not the best UX.

Can you please fix these issues?

Thanks.

Re: dired-mouse-drag-files

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> This feature is not universally available, but is doc string doesn't
> say so (the manual does).
>
> Moreover, setting the variable non-nil unconditionally shows a tooltip
> on file names in Dired buffers saying that the user can drag the file
> to another program, but that is only so on X; on other platforms it's
> a misleading tooltip.
>
> As an aside, changing the value of the variable doesn't affect the
> Dired buffers that already exist, only those created afterwards, which
> I think is not the best UX.
>
> Can you please fix these issues?

I will work on them ASAP, tho the idea is to have it universally
available by the time Emacs 29 is released.  (If nobody volunteers in a
week, I will try to find the time to implement it on NS.)

Thanks.

Re: dired-mouse-drag-files

[Eli Zaretskii]

> From: Po Lu <luangruo@yahoo.com>
> Cc: emacs-devel@gnu.org
> Date: Fri, 25 Mar 2022 22:06:54 +0800
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > This feature is not universally available, but is doc string doesn't
> > say so (the manual does).
> >
> > Moreover, setting the variable non-nil unconditionally shows a tooltip
> > on file names in Dired buffers saying that the user can drag the file
> > to another program, but that is only so on X; on other platforms it's
> > a misleading tooltip.
> >
> > As an aside, changing the value of the variable doesn't affect the
> > Dired buffers that already exist, only those created afterwards, which
> > I think is not the best UX.
> >
> > Can you please fix these issues?
> 
> I will work on them ASAP, tho the idea is to have it universally
> available by the time Emacs 29 is released.  (If nobody volunteers in a
> week, I will try to find the time to implement it on NS.)

At least for MS-Windows, I don't think this is a feasible goal, though
I'd be happy to be proven wrong.  I think we only support dragging
file names there, and only _into_ Emacs.

So some systems will probably never support this.

Re: dired-mouse-drag-files

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> At least for MS-Windows, I don't think this is a feasible goal, though
> I'd be happy to be proven wrong.  I think we only support dragging
> file names there, and only _into_ Emacs.
>
> So some systems will probably never support this.

I see, too bad.  Thanks for explaining.

Re: dired-mouse-drag-files

[Po Lu]

[You forgot to copy in the list, I did that for you this time.]

Justus-dev@Piater.name writes:

> What about Wayland?
>
> I don't think this should be too hard to implement (famous last words).
> Perhaps I'll give it a shot myself. Any advice?
>
> Best,
> Justus

It shouldn't be too hard, thanks!  First, rewrite pgtkselect.c to use
the low-level GDK selections API (the code translates very neatly from
X), since the GTK clipboard API is not very suitable for Emacs
drag-and-drop.  The file that needs work is pgtkselect.c.

Then, implement `x-begin-drag' using the GDK drag-and-drop system.  I
suggest running a nested event loop until the drop completes.

Most of the low level functions there are not much higher level than the
functions `x_dnd_get_target_window' and `x_set_dnd_targets' on X.

This documentation should be fairly helpful:

https://developer-old.gnome.org/gdk3/stable/gdk3-Drag-and-Drop.html
https://developer-old.gnome.org/gdk3/stable/gdk3-Selections.html