When a resize is driven client side we wait for the compositor to have a
chance to reconfigure us before submitting the next frame.
Using a blocking round trip caused an issue. Instead block isExposed and
trigger an expose event whilst a sync is in progress.
Qt's resizing is inherently synchronous. When an application calls
QWindow::setGeometry with a new size, we expect it to make that resize.
An expose event of the requested size will be generated.
Wayland is by default async, a client requests a size, and then will be
configured to that size, or potentially another size.
The simplest way to map the two APIs is to roundtrip when the client
wants to resize. This way we can guarantee that a call to
`setGeometry(); update()` will have the server configured size before
the paint.
In practice it's still not perfect due to other issues, but at least
will sort itself out within a frame.
This can be used to disambiguate the exclusive edge when the anchors are
on a corner (so there would be 2 candidates)
it's quite quick and dirty mostly to understand if we do want to push
for something along the lines
QWaylandLayerShellIntegration has virtual hooks for Xdg Activation.
This is important to hook up in layer shell because activation using
requestActivate in Qt will go through this path. It also means we have
support for us to drop the implementation in KWindowSystem in favour of
calling into Qt.
Without this when krunner expands, the frame after kwin will resize it
back to the last size the layer shell requested to be resized to.
To detect when we should not send an explicit size on window resize
events we check the anchors; if we're constrained on opposing edges we
want the compositor alone to set the size.
With QWaylandWindow::setShellIntegration(), it's possible to use
xdg-shell and layer-shell protocols in the same process. It's important
for plasmashell, where we want to use the layer shell protocol for
special surfaces such as the desktop background, and the xdg shell
protocol for dialogs.
In order to make a QWindow use the layer shell protocol, you need to
call LayerShellQt::Window::get() before the window is mapped.
