bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

[akira]

In GNU Emacs 29.0.50 (build 1, aarch64-unknown-linux-gnu, GTK+ Version 3.24.30, cairo version 1.16.0)
Repository revision: ab5ee3e29e916d4009b301841e9780aad564a6a0
Repository branch: master
System Description: NixOS 22.05 (Quokka)

Configured using:
 'configure
 --prefix=/nix/store/0fiqa453abl4c1c28g0baqs9s274s7ff-emacs-pgtkgcc-20220103.0
 --disable-build-details --with-modules --with-x-toolkit=gtk3
 --with-cairo --with-xwidgets --with-native-compilation --with-pgtk'

Window manager: sway

Steps to reproduce:

- emacs -Q
- M-x xwidget-webkit-browse-url RET https://xkcd.com
- Hover mouse over the comic, there should be mousover text present

I also tested this on debian 11 under GNOME and observe the same
behavior. While emacs configured with the default with x+gtk3 the
mousover text works.

I also noticed that the cursor over "non-clickable" and non-text
elements is the I-beam cursor bar that is typically reserved for
hovering over select-able text elements. I would expect the cursor to be
the default mouse when hovering over, say, an image.

bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

[Akira Kyle]

Just tested mouseover on emacs with x+gtk3 on sway, and mouseover text
works there so I'm pretty confident this is an xwidget-webkit+pgtk
issue and not a sway issue.

Also while testing I noticed this warning: "Overriding existing
handler for signal 10. Set JSC_SIGNAL_FOR_GC if you want WebKit to use
a different signal"

Is this something to be concerned about? I don't know how emacs
internally handles SIGUSR1

bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Akira Kyle <akira@akirakyle.com> writes:

> Just tested mouseover on emacs with x+gtk3 on sway, and mouseover text
> works there so I'm pretty confident this is an xwidget-webkit+pgtk
> issue and not a sway issue.

By "mouseover text" you mean tooltips, correct?  Are you running Emacs
in Wayland or are you running it in Xwayland?

Thanks.

> Also while testing I noticed this warning: "Overriding existing
> handler for signal 10. Set JSC_SIGNAL_FOR_GC if you want WebKit to use
> a different signal"
>
> Is this something to be concerned about?

No, it's not.  It should be fixed once the JSC developers deliver on
their promise to provide an API to change the GC signal.

bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

[Akira Kyle]

On Mon, Jan 3, 2022 at 10:44 PM Po Lu <luangruo@yahoo.com> wrote:
>
> By "mouseover text" you mean tooltips, correct?  Are you running Emacs
> in Wayland or are you running it in Xwayland?
>

I think different people refer to them differently, so I think some do
call them tooltips. Concretely what I mean here is when the mouse
hovers over an html <img> tag with the title field set, there should
be a box that pops up next to the mouse with the value of that field
set. So hovering the mouse over <img src='img.png' title="value">
would display "value".

This issue is only on emacs --with-pgt. The mousover text works
correctly in emacs --with-x-toolkit=gtk3 under xwayland.

> > Is this something to be concerned about?
>
> No, it's not.  It should be fixed once the JSC developers deliver on
> their promise to provide an API to change the GC signal.
>

Great, thanks!

bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Akira Kyle <akira@akirakyle.com> writes:

> On Mon, Jan 3, 2022 at 10:44 PM Po Lu <luangruo@yahoo.com> wrote:
>>
>> By "mouseover text" you mean tooltips, correct?  Are you running Emacs
>> in Wayland or are you running it in Xwayland?
>>
>
> I think different people refer to them differently, so I think some do
> call them tooltips. Concretely what I mean here is when the mouse
> hovers over an html <img> tag with the title field set, there should
> be a box that pops up next to the mouse with the value of that field
> set. So hovering the mouse over <img src='img.png' title="value">
> would display "value".

> This issue is only on emacs --with-pgt. The mousover text works
> correctly in emacs --with-x-toolkit=gtk3 under xwayland.

Yes, but are you running it under Wayland, or is it running under X?

The PGTK port can run under both Wayland and X through GDK, and
different GDK backends behave very differently when it comes to
displaying tooltips from widgets inside offscreen windows.

IOW, what is the value of (pgtk-backend-display-class)?

Thanks.

bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

[Akira Kyle]

On Tue, Jan 4, 2022 at 12:22 AM Po Lu <luangruo@yahoo.com> wrote:
>
> > This issue is only on emacs --with-pgt. The mousover text works
> > correctly in emacs --with-x-toolkit=gtk3 under xwayland.
>
> Yes, but are you running it under Wayland, or is it running under X?
>
> The PGTK port can run under both Wayland and X through GDK, and
> different GDK backends behave very differently when it comes to
> displaying tooltips from widgets inside offscreen windows.
>
> IOW, what is the value of (pgtk-backend-display-class)?
>

Oh right, sorry for the confusion. It's when running under wayland so
the value of (pgtk-backend-display-class) is "GdkWaylandDisplay"

bug#53001: 29.0.50; xwidget-webkit: no mouseover text on pgtk

[Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Akira Kyle <akira@akirakyle.com> writes:

> Oh right, sorry for the confusion. It's when running under wayland so
> the value of (pgtk-backend-display-class) is "GdkWaylandDisplay"

Thanks, I see your problem here as well.
I will look into it.