On Mon, Aug 24, 2020 at 4:20 PM Vlad Zahorodnii <vlad.zahorod...@kde.org> wrote: > > Howdy, > > As you probably know, surfaces created by plasmashell need to be treated > specially by the compositor. For example, notification windows must be > always on top, panels may go above and below normal windows. That's why > we use a proprietary protocol called plasma-shell for creating shell > surfaces that provide the functionality required by plasmashell. > > Unfortunately, there are technical issues with the plasma-shell protocol > that can be fixed only by rewriting the protocol from scratch. Luckily > for us, the sway community came up with a protocol called layer-shell > that a desktop environment could use in order to build components such > as panels, notifications, etc. The layer-shell protocol doesn't suffer > from the problems that we have with the plasma-shell protocol. > > The cool thing about is that with the layer-shell protocol it will be > possible to make applications such as latte-dock run across desktop > environments. > > Over the last a couple of weeks, I've been working on a layer-shell > protocol implementation in kwin. With the compositor side being almost > complete (it's still under code review), it's a good time to focus on > the client side. > > The biggest difference between the layer-shell protocol and the > plasma-shell protocol is that positioning is done in relative terms in > the former protocol. For example, instead of saying "please place me at > the specified position (x, y)," a client must say "please place me 10px > away from the left screen edge." Which brings us to the first problem: > we need to ditch specifying absolute window coordinates and transition > to relative positioning. Unfortunately, we cannot do it all at once, so > we need some way to smoothly transition between the two approaches. I > see several options: > > * Mimic absolute positioning via relative positioning. It's good as a > short-term solution, but imho, we need something better > * Introduce a Plasma::Dialog with relative positioning and start > gradually porting all plasma components to it > > The second problem is that we need to integrate the layer-shell protocol > in Qt in some way. Since plasmashell creates both normal windows and > special-purpose windows, we need to use **both** the xdg-shell and the > layer-shell protocol. It's not really clear how it can be achieved. > > The most ideal case is where Qt provides native support for the > layer-shell protocol out of the box. API-wise, plasmashell needs to set > the layer, the namespace, the margins, etc. Alternatively, we could fork > QtWayland QPA and extend it with features we need. Either way, we need > some changes in Qt in order to be able to use several shell surface > protocols simultaneously. > > Any ideas or thoughts on what the best way to integrate the layer-shell > protocol in plasma and Qt is? > > Cheers, > Vlad
I guess one way is by levarging QT_WAYLAND_SHELL_INTEGRATION plugin system, like maliit does. I don't know how this could be done per-window instead of per-process. The shell integration plugin could be implemented in Qt together with xdg-shell and ivi (see qtwayland/src/plugins/shellintegration). HTH, Aleix
