platforms/wayland: Add initial HiDPI support

This can be useful for test purposes and for people who have HiDPI monitors.

plugins/platforms/wayland/egl_wayland_backend.cpp

@@ -50,8 +50,8 @@ EglWaylandOutput::EglWaylandOutput(WaylandOutput *output, QObject *parent)
 bool EglWaylandOutput::init(EglWaylandBackend *backend)
 {
     auto surface = m_waylandOutput->surface();
-    const QSize &size = m_waylandOutput->geometry().size();
-    auto overlay = wl_egl_window_create(*surface, size.width(), size.height());
+    const QSize nativeSize = m_waylandOutput->geometry().size() * m_waylandOutput->scale();
+    auto overlay = wl_egl_window_create(*surface, nativeSize.width(), nativeSize.height());
     if (!overlay) {
         qCCritical(KWIN_WAYLAND_BACKEND) << "Creating Wayland Egl window failed";
         return false;
@@ -71,19 +71,15 @@ bool EglWaylandOutput::init(EglWaylandBackend *backend)
     m_eglSurface = eglSurface;
 
     connect(m_waylandOutput, &WaylandOutput::sizeChanged, this, &EglWaylandOutput::updateSize);
-    connect(m_waylandOutput, &WaylandOutput::modeChanged, this, &EglWaylandOutput::updateMode);
+    connect(m_waylandOutput, &WaylandOutput::modeChanged, this, &EglWaylandOutput::updateSize);
 
     return true;
 }
 
-void EglWaylandOutput::updateSize(const QSize &size)
+void EglWaylandOutput::updateSize()
 {
-    wl_egl_window_resize(m_overlay, size.width(), size.height(), 0, 0);
-}
-
-void EglWaylandOutput::updateMode()
-{
-    updateSize(m_waylandOutput->geometry().size());
+    const QSize nativeSize = m_waylandOutput->geometry().size() * m_waylandOutput->scale();
+    wl_egl_window_resize(m_overlay, nativeSize.width(), nativeSize.height(), 0, 0);
 }
 
 EglWaylandBackend::EglWaylandBackend(WaylandBackend *b)
@@ -240,9 +236,7 @@ bool EglWaylandBackend::makeContextCurrent(EglWaylandOutput *output)
     }
 
     const QRect &v = output->m_waylandOutput->geometry();
-
-    //The output is in scaled coordinates
-    const qreal scale = 1;
+    const qreal scale = output->m_waylandOutput->scale();
 
     const QSize overall = screens()->size();
     glViewport(-v.x() * scale, (v.height() - overall.height() + v.y()) * scale,
@@ -324,13 +318,15 @@ void EglWaylandBackend::aboutToStartPainting(int screenId, const QRegion &damage
 
 void EglWaylandBackend::presentOnSurface(EglWaylandOutput *output, const QRegion &damage)
 {
-    output->m_waylandOutput->surface()->setupFrameCallback();
-    Compositor::self()->aboutToSwapBuffers();
+    WaylandOutput *waylandOutput = output->m_waylandOutput;
 
-    Q_EMIT output->m_waylandOutput->outputChange(damage);
+    waylandOutput->surface()->setupFrameCallback();
+    waylandOutput->surface()->setScale(waylandOutput->scale());
+    Compositor::self()->aboutToSwapBuffers();
+    Q_EMIT waylandOutput->outputChange(damage);
 
     if (supportsSwapBuffersWithDamage() && !output->m_damageHistory.isEmpty()) {
-        QVector<EGLint> rects = regionToRects(output->m_damageHistory.constFirst(), output->m_waylandOutput);
+        QVector<EGLint> rects = regionToRects(output->m_damageHistory.constFirst(), waylandOutput);
         eglSwapBuffersWithDamageEXT(eglDisplay(), output->m_eglSurface,
                                     rects.data(), rects.count()/4);
     } else {

plugins/platforms/wayland/egl_wayland_backend.h

@@ -34,8 +34,7 @@ public:
     ~EglWaylandOutput() override = default;
 
     bool init(EglWaylandBackend *backend);
-    void updateSize(const QSize &size);
-    void updateMode();
+    void updateSize();
 
 private:
     WaylandOutput *m_waylandOutput;

plugins/platforms/wayland/scene_qpainter_wayland_backend.cpp

@@ -86,6 +86,7 @@ void WaylandQPainterOutput::present(const QRegion &damage)
     auto s = m_waylandOutput->surface();
     s->attachBuffer(m_buffer);
     s->damage(damage);
+    s->setScale(m_waylandOutput->scale());
     s->commit();
 }
 
@@ -104,9 +105,9 @@ void WaylandQPainterOutput::prepareRenderingFrame()
     }
     m_buffer.clear();
 
-    const QSize size(m_waylandOutput->geometry().size());
+    const QSize nativeSize(m_waylandOutput->geometry().size() * m_waylandOutput->scale());
 
-    m_buffer = m_pool->getBuffer(size, size.width() * 4);
+    m_buffer = m_pool->getBuffer(nativeSize, nativeSize.width() * 4);
     if (!m_buffer) {
         qCDebug(KWIN_WAYLAND_BACKEND) << "Did not get a new Buffer from Shm Pool";
         m_backBuffer = QImage();
@@ -116,7 +117,7 @@ void WaylandQPainterOutput::prepareRenderingFrame()
     auto b = m_buffer.toStrongRef();
     b->setUsed(true);
 
-    m_backBuffer = QImage(b->address(), size.width(), size.height(), QImage::Format_RGB32);
+    m_backBuffer = QImage(b->address(), nativeSize.width(), nativeSize.height(), QImage::Format_RGB32);
     m_backBuffer.fill(Qt::transparent);
 //    qCDebug(KWIN_WAYLAND_BACKEND) << "Created a new back buffer for output surface" << m_waylandOutput->surface();
 }

plugins/platforms/wayland/wayland_backend.cpp

@@ -92,29 +92,30 @@ void WaylandCursor::installImage()
 {
     const QImage image = Cursors::self()->currentCursor()->image();
     if (image.isNull() || image.size().isEmpty()) {
-        doInstallImage(nullptr, QSize());
+        doInstallImage(nullptr, QSize(), 1);
         return;
     }
 
     auto buffer = m_backend->shmPool()->createBuffer(image).toStrongRef();
     wl_buffer *imageBuffer = *buffer.data();
-    doInstallImage(imageBuffer, image.size());
+    doInstallImage(imageBuffer, image.size(), image.devicePixelRatio());
 }
 
-void WaylandCursor::doInstallImage(wl_buffer *image, const QSize &size)
+void WaylandCursor::doInstallImage(wl_buffer *image, const QSize &size, qreal scale)
 {
     auto *pointer = m_backend->seat()->pointer();
     if (!pointer || !pointer->isValid()) {
         return;
     }
     pointer->setCursor(m_surface, image ? Cursors::self()->currentCursor()->hotspot() : QPoint());
-    drawSurface(image, size);
+    drawSurface(image, size, scale);
 }
 
-void WaylandCursor::drawSurface(wl_buffer *image, const QSize &size)
+void WaylandCursor::drawSurface(wl_buffer *image, const QSize &size, qreal scale)
 {
     m_surface->attachBuffer(image);
-    m_surface->damage(QRect(QPoint(0,0), size));
+    m_surface->setScale(scale);
+    m_surface->damageBuffer(QRect(QPoint(0, 0), size));
     m_surface->commit(Surface::CommitFlag::None);
     m_backend->flush();
 }
@@ -161,7 +162,7 @@ void WaylandSubSurfaceCursor::createSubSurface()
     m_subSurface->setMode(SubSurface::Mode::Desynchronized);
 }
 
-void WaylandSubSurfaceCursor::doInstallImage(wl_buffer *image, const QSize &size)
+void WaylandSubSurfaceCursor::doInstallImage(wl_buffer *image, const QSize &size, qreal scale)
 {
     if (!image) {
         delete m_subSurface;
@@ -171,7 +172,7 @@ void WaylandSubSurfaceCursor::doInstallImage(wl_buffer *image, const QSize &size
     createSubSurface();
     // cursor position might have changed due to different cursor hot spot
     move(input()->pointer()->pos());
-    drawSurface(image, size);
+    drawSurface(image, size, scale);
 }
 
 QPointF WaylandSubSurfaceCursor::absoluteToRelativePosition(const QPointF &position)
@@ -496,11 +497,12 @@ WaylandBackend::~WaylandBackend()
 
 void WaylandBackend::init()
 {
-    connect(m_registry, &Registry::compositorAnnounced, this,
-        [this](quint32 name) {
-            m_compositor->setup(m_registry->bindCompositor(name, 1));
+    connect(m_registry, &Registry::compositorAnnounced, this, [this](quint32 name, quint32 version) {
+        if (version < 4) {
+            qFatal("wl_compositor version 4 or later is required");
         }
-    );
+        m_compositor->setup(m_registry->bindCompositor(name, version));
+    });
     connect(m_registry, &Registry::subCompositorAnnounced, this,
         [this](quint32 name) {
             m_subCompositor->setup(m_registry->bindSubCompositor(name, 1));

plugins/platforms/wayland/wayland_backend.h

@@ -79,8 +79,8 @@ public:
 
 protected:
     void resetSurface();
-    virtual void doInstallImage(wl_buffer *image, const QSize &size);
-    void drawSurface(wl_buffer *image, const QSize &size);
+    virtual void doInstallImage(wl_buffer *image, const QSize &size, qreal scale);
+    void drawSurface(wl_buffer *image, const QSize &size, qreal scale);
 
     KWayland::Client::Surface *surface() const {
         return m_surface;
@@ -108,7 +108,7 @@ public:
 
 private:
     void changeOutput(WaylandOutput *output);
-    void doInstallImage(wl_buffer *image, const QSize &size) override;
+    void doInstallImage(wl_buffer *image, const QSize &size, qreal scale) override;
     void createSubSurface();
 
     QPointF absoluteToRelativePosition(const QPointF &position);