Summary:
So far we didn't try to do high DPI on kwin internal windows, such as
the user context menu and tab bars and whatever.
Due to wayland scaling they were the correct phyiscal size but upscaled.
This patch fixes our QPA to enable Qt's high-dpi support.
BUG: 402853
Note icons are still low res. This is because the global
QGuiApplication::devicePixelRatio which is the max of all connected
screens is static for the duration of the app. QIcon uses this when
determining the DPR to use. This will require a Qt change.
Test Plan:
Ran at 2x on my normal DPI screen (as that's easier to see anything)
* User action menu is high DPI
* Window deco tooltips are still fine
* Tab switcher is high DPI
* Overlay in present windows Desktop grid are still ok
Reviewers: #kwin
Subscribers: zzag, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18042
This introduces an own QPA plugin for KWin. QtWayland's plugin is not
a good solution for KWin as QtWayland is meant for Wayland clients and
not for a Wayland server. Given that it makes more sense to have a very
minimal QPA plugin which supports the use cases we actually have.
With our own QPA plugin we should be able to improve the following
areas:
* no need to create Wayland server before QApplication
* Qt::BypassWindowManagerHint can be supported
* no workaround for creating OpenGL context in main thread
* sharing OpenGL context with Qt
* OpenGL context for Qt on libhybris backend
The plugin supports so far the following features:
* creating a QPlatformWindow using KWayland::Client (ShellSurface)
* creating a QPlatformBackingStore using a ShmPool
* creating a QPlatformOpenGLContext with Wayland::EGL
* or creating a QPlatformOpenGLContext which shares with KWin's scene
* creating a QPlatformScreen for each KWayland::Client::Output
* QPlatformNativeInterface compatible to QtWayland
