Re: SVG widget in GNU Emacs

[Po Lu]

Akira Kyle <ak@akirakyle.com> writes:

> I'd be curious to see anyone in the past several years on a GNU/linux
> system that actually uses xwidgets given that last I checked it
> suffered from a rather severe flickering bug. I know people on macOS
> regularly use it, especially since the popular homebrew-emacs-plus
> formula enables it.

If I understand correctly, Fedora Core builds Emacs with xwidgets
enabled by default.

> If you do figure out the flickering problem, I'd be very interested in
> were the bug is. Last year I tried tracking it down to no avail. I
> think I started to suspect it was a bug somewhere between the way GTK
> handles offscreen rendering and the way emacs tries to take control of
> GTK's event loop.

The flickering problem is not a real problem here, I think.  My theory
is that it can be fixed by moving the display to a separate X window,
instead of a GtkDrawingArea.

(Perhaps by using `gdk_window_ensure_native' on the drawing area's
window, but I'm unsure if that approach still works on GTK 3 as it did
on GTK+ 2.)

> I don't think it currently is, or ever will be, a technical problem.
> The xwayland devs have made sure of that. I think its more of a
> perception problem as wayland becomes adopted and users see apps
> requiring xwayland as increasingly "unmaintained", "legacy" apps. I've
> certainly seen such questions come up with newcomers, especially when
> it comes to users on HiDPI displays so users can see a tangible
> difference in the default font rendering between xwayland and native
> wayland apps.

Does Xwayland not support HiDPI displays?

> Exactly why I think for the sake of future compatibility with GTK 4,
> it's best not to rely on off-screen rendering.

If future compatibility with GTK 4 is really such a concern, we should
not even be using cairo.