Implement DesktopThumbnailItem as a collection of window thumbnails

The main motivation behind this change is to refactor scene code in
order to allow us set WindowItem visibility upfront before compositing
starts.

src/effects.cpp

@@ -121,8 +121,6 @@ EffectsHandlerImpl::EffectsHandlerImpl(Compositor *compositor, Scene *scene)
     , fullscreen_effect(nullptr)
     , m_compositor(compositor)
     , m_scene(scene)
-    , m_desktopRendering(false)
-    , m_currentRenderedDesktop(0)
     , m_effectLoader(new EffectLoader(this))
     , m_trackingCursorChanges(0)
 {
@@ -376,22 +374,6 @@ void EffectsHandlerImpl::paintScreen(int mask, const QRegion &region, ScreenPain
     }
 }
 
-void EffectsHandlerImpl::paintDesktop(int desktop, int mask, QRegion region, ScreenPaintData &data)
-{
-    if (desktop < 1 || desktop > numberOfDesktops()) {
-        return;
-    }
-    m_currentRenderedDesktop = desktop;
-    m_desktopRendering = true;
-    // save the paint screen iterator
-    EffectsIterator savedIterator = m_currentPaintScreenIterator;
-    m_currentPaintScreenIterator = m_activeEffects.constBegin();
-    effects->paintScreen(mask, region, data);
-    // restore the saved iterator
-    m_currentPaintScreenIterator = savedIterator;
-    m_desktopRendering = false;
-}
-
 void EffectsHandlerImpl::postPaintScreen()
 {
     if (m_currentPaintScreenIterator != m_activeEffects.constEnd()) {

src/effects.h

@@ -61,10 +61,6 @@ public:
     ~EffectsHandlerImpl() override;
     void prePaintScreen(ScreenPrePaintData &data, std::chrono::milliseconds presentTime) override;
     void paintScreen(int mask, const QRegion &region, ScreenPaintData &data) override;
-    /**
-     * Special hook to perform a paintScreen but just with the windows on @p desktop.
-     */
-    void paintDesktop(int desktop, int mask, QRegion region, ScreenPaintData &data);
     void postPaintScreen() override;
     void prePaintWindow(EffectWindow *w, WindowPrePaintData &data, std::chrono::milliseconds presentTime) override;
     void paintWindow(EffectWindow *w, int mask, const QRegion &region, WindowPaintData &data) override;
@@ -204,21 +200,6 @@ public:
      */
     bool blocksDirectScanout() const;
 
-    /**
-     * @returns Whether we are currently in a desktop rendering process triggered by paintDesktop hook
-     */
-    bool isDesktopRendering() const
-    {
-        return m_desktopRendering;
-    }
-    /**
-     * @returns the desktop currently being rendered in the paintDesktop hook.
-     */
-    int currentRenderedDesktop() const
-    {
-        return m_currentRenderedDesktop;
-    }
-
     KWaylandServer::Display *waylandDisplay() const override;
 
     bool animationsSupported() const override;
@@ -367,8 +348,6 @@ private:
     QHash<QByteArray, qulonglong> m_managedProperties;
     Compositor *m_compositor;
     Scene *m_scene;
-    bool m_desktopRendering;
-    int m_currentRenderedDesktop;
     QList<Effect *> m_grabbedMouseEffects;
     EffectLoader *m_effectLoader;
     int m_trackingCursorChanges;

src/scene.cpp

@@ -602,11 +602,6 @@ void Scene::paintWindow(SceneWindow *w, int mask, const QRegion &region)
     effects->paintWindow(effectWindow(w), mask, region, data);
 }
 
-void Scene::paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data)
-{
-    static_cast<EffectsHandlerImpl *>(effects)->paintDesktop(desktop, mask, region, data);
-}
-
 // the function that'll be eventually called by paintWindow() above
 void Scene::finalPaintWindow(EffectWindowImpl *w, int mask, const QRegion &region, WindowPaintData &data)
 {
@@ -766,14 +761,8 @@ void SceneWindow::resetPaintingEnabled()
     if (toplevel->isDeleted()) {
         disable_painting |= PAINT_DISABLED_BY_DELETE;
     }
-    if (static_cast<EffectsHandlerImpl *>(effects)->isDesktopRendering()) {
-        if (!toplevel->isOnDesktop(static_cast<EffectsHandlerImpl *>(effects)->currentRenderedDesktop())) {
-            disable_painting |= PAINT_DISABLED_BY_DESKTOP;
-        }
-    } else {
-        if (!toplevel->isOnCurrentDesktop()) {
-            disable_painting |= PAINT_DISABLED_BY_DESKTOP;
-        }
+    if (!toplevel->isOnCurrentDesktop()) {
+        disable_painting |= PAINT_DISABLED_BY_DESKTOP;
     }
     if (!toplevel->isOnCurrentActivity()) {
         disable_painting |= PAINT_DISABLED_BY_ACTIVITY;

src/scene.h

@@ -202,8 +202,6 @@ public:
     virtual SurfaceTexture *createSurfaceTextureX11(SurfacePixmapX11 *pixmap);
     virtual SurfaceTexture *createSurfaceTextureWayland(SurfacePixmapWayland *pixmap);
 
-    virtual void paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data);
-
     QMatrix4x4 renderTargetProjectionMatrix() const;
     QRect renderTargetRect() const;
     void setRenderTargetRect(const QRect &rect);

src/scenes/opengl/scene_opengl.cpp

@@ -152,15 +152,6 @@ void SceneOpenGL::paintBackground(const QRegion &region)
     }
 }
 
-void SceneOpenGL::paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data)
-{
-    const QRect r = region.boundingRect();
-    glEnable(GL_SCISSOR_TEST);
-    glScissor(r.x(), geometry().size().height() - r.y() - r.height(), r.width(), r.height());
-    KWin::Scene::paintDesktop(desktop, mask, region, data);
-    glDisable(GL_SCISSOR_TEST);
-}
-
 void SceneOpenGL::paintOffscreenQuickView(OffscreenQuickView *w)
 {
     GLTexture *t = w->bufferAsTexture();

src/scenes/opengl/scene_opengl.h

@@ -64,7 +64,6 @@ public:
 protected:
     void paintBackground(const QRegion &region) override;
     QMatrix4x4 transformation(int mask, const ScreenPaintData &data) const;
-    void paintDesktop(int desktop, int mask, const QRegion &region, ScreenPaintData &data) override;
     void paintOffscreenQuickView(OffscreenQuickView *w) override;
 
     void paintSimpleScreen(int mask, const QRegion &region) override;

src/scripting/CMakeLists.txt

@@ -1,3 +1,5 @@
+add_subdirectory(v2)
+
 if (KWIN_BUILD_KCMS)
     set(kcm_kwin4_genericscripted_SRCS genericscriptedconfig.cpp)
     qt_add_dbus_interface(kcm_kwin4_genericscripted_SRCS ${kwin_effects_dbus_xml} kwineffects_interface)

src/scripting/scripting.cpp

@@ -641,7 +641,6 @@ KWin::Scripting::Scripting(QObject *parent)
 
 void KWin::Scripting::init()
 {
-    qmlRegisterType<DesktopThumbnailItem>("org.kde.kwin", 2, 0, "DesktopThumbnailItem");
     qmlRegisterType<WindowThumbnailItem>("org.kde.kwin", 2, 0, "ThumbnailItem");
     qmlRegisterType<DBusCall>("org.kde.kwin", 2, 0, "DBusCall");
     qmlRegisterType<ScreenEdgeItem>("org.kde.kwin", 2, 0, "ScreenEdgeItem");

src/scripting/thumbnailitem.cpp

@@ -440,89 +440,4 @@ void WindowThumbnailItem::updateOffscreenTexture()
     update();
 }
 
-DesktopThumbnailItem::DesktopThumbnailItem(QQuickItem *parent)
-    : ThumbnailItemBase(parent)
-{
-}
-
-int DesktopThumbnailItem::desktop() const
-{
-    return m_desktop;
-}
-
-void DesktopThumbnailItem::setDesktop(int desktop)
-{
-    desktop = qBound<int>(1, desktop, VirtualDesktopManager::self()->count());
-    if (m_desktop != desktop) {
-        m_desktop = desktop;
-        invalidateOffscreenTexture();
-        Q_EMIT desktopChanged();
-    }
-}
-
-QImage DesktopThumbnailItem::fallbackImage() const
-{
-    return QImage();
-}
-
-QRectF DesktopThumbnailItem::paintedRect() const
-{
-    return centeredSize(boundingRect(), screens()->size());
-}
-
-void DesktopThumbnailItem::invalidateOffscreenTexture()
-{
-    update();
-}
-
-void DesktopThumbnailItem::updateOffscreenTexture()
-{
-    if (m_acquireFence) {
-        return;
-    }
-
-    const QRect geometry = screens()->geometry();
-    QSize textureSize = geometry.size();
-    if (sourceSize().width() > 0) {
-        textureSize.setWidth(sourceSize().width());
-    }
-    if (sourceSize().height() > 0) {
-        textureSize.setHeight(sourceSize().height());
-    }
-
-    m_devicePixelRatio = window()->devicePixelRatio();
-    textureSize *= m_devicePixelRatio;
-
-    if (!m_offscreenTexture || m_offscreenTexture->size() != textureSize) {
-        m_offscreenTexture.reset(new GLTexture(GL_RGBA8, textureSize));
-        m_offscreenTexture->setFilter(GL_LINEAR);
-        m_offscreenTexture->setWrapMode(GL_CLAMP_TO_EDGE);
-        m_offscreenTexture->setYInverted(true);
-        m_offscreenTarget.reset(new GLFramebuffer(m_offscreenTexture.data()));
-    }
-
-    GLFramebuffer::pushFramebuffer(m_offscreenTarget.data());
-    glClearColor(0.0, 0.0, 0.0, 0.0);
-    glClear(GL_COLOR_BUFFER_BIT);
-
-    QMatrix4x4 projectionMatrix;
-    projectionMatrix.ortho(geometry);
-    ScreenPaintData data(projectionMatrix);
-
-    // The thumbnail must be rendered using kwin's opengl context as VAOs are not
-    // shared across contexts. Unfortunately, this also introduces a latency of 1
-    // frame, which is not ideal, but it is acceptable for things such as thumbnails.
-    const int mask = Scene::PAINT_WINDOW_TRANSFORMED | Scene::PAINT_SCREEN_TRANSFORMED;
-    Scene *scene = Compositor::self()->scene();
-    scene->paintDesktop(m_desktop, mask, infiniteRegion(), data);
-    GLFramebuffer::popFramebuffer();
-
-    // The fence is needed to avoid the case where qtquick renderer starts using
-    // the texture while all rendering commands to it haven't completed yet.
-    m_acquireFence = glFenceSync(GL_SYNC_GPU_COMMANDS_COMPLETE, 0);
-
-    // We know that the texture has changed, so schedule an item update.
-    update();
-}
-
 } // namespace KWin

src/scripting/thumbnailitem.h

@@ -128,28 +128,4 @@ private:
     bool m_dirty = false;
 };
 
-class DesktopThumbnailItem : public ThumbnailItemBase
-{
-    Q_OBJECT
-    Q_PROPERTY(int desktop READ desktop WRITE setDesktop NOTIFY desktopChanged)
-
-public:
-    explicit DesktopThumbnailItem(QQuickItem *parent = nullptr);
-
-    int desktop() const;
-    void setDesktop(int desktop);
-
-Q_SIGNALS:
-    void desktopChanged();
-
-protected:
-    QImage fallbackImage() const override;
-    QRectF paintedRect() const override;
-    void invalidateOffscreenTexture() override;
-    void updateOffscreenTexture() override;
-
-private:
-    int m_desktop = 1;
-};
-
 } // namespace KWin

src/scripting/v2/CMakeLists.txt

@@ -0,0 +1,6 @@
+# SPDX-FileCopyrightText: 2022 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+install(DIRECTORY qml/
+        DESTINATION ${KDE_INSTALL_QMLDIR}/org/kde/kwin.2)

src/scripting/v2/qml/DesktopThumbnailItem.qml

@@ -0,0 +1,41 @@
+/*
+    SPDX-FileCopyrightText: 2022 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+
+    SPDX-License-Identifier: GPL-2.0-or-later
+*/
+
+import QtQuick 2.12
+import org.kde.kwin 2.0 as KWinComponents
+
+Item {
+    id: root
+
+    property int desktop: 1
+
+    // These unused properties exist for compatibility reasons.
+    property real brightness: 1
+    property real saturation: 1
+    property Item clipTo: null
+
+    Item {
+        id: container
+        anchors.centerIn: parent
+        width: workspace.virtualScreenSize.width
+        height: workspace.virtualScreenSize.height
+        scale: Math.min(parent.width / container.width, parent.height / container.height)
+
+        Repeater {
+            model: KWinComponents.ClientModel {
+                exclusions: KWinComponents.ClientModel.OtherActivitiesExclusion
+            }
+
+            KWinComponents.ThumbnailItem {
+                client: model.client
+                x: model.client.x
+                y: model.client.y
+                z: model.client.stackingOrder
+                visible: (model.client.desktop === -1 || model.client.desktop === root.desktop) && !model.client.minimized
+            }
+        }
+    }
+}

src/scripting/v2/qml/qmldir

@@ -0,0 +1,7 @@
+# SPDX-FileCopyrightText: 2022 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
+#
+# SPDX-License-Identifier: CC0-1.0
+
+module org.kde.kwin
+
+DesktopThumbnailItem 2.0 DesktopThumbnailItem.qml