Store AbstractOutput in Toplevel

Since AbstractOutput is used more than int screen ids in kwin, it's
worth storing AbstractOutput for better performance.

src/abstract_client.cpp

@@ -61,8 +61,8 @@ AbstractClient::AbstractClient()
 {
     connect(this, &AbstractClient::clientStartUserMovedResized,  this, &AbstractClient::moveResizedChanged);
     connect(this, &AbstractClient::clientFinishUserMovedResized, this, &AbstractClient::moveResizedChanged);
-    connect(this, &AbstractClient::clientStartUserMovedResized,  this, &AbstractClient::removeCheckScreenConnection);
-    connect(this, &AbstractClient::clientFinishUserMovedResized, this, &AbstractClient::setupCheckScreenConnection);
+    connect(this, &AbstractClient::clientStartUserMovedResized,  this, &AbstractClient::removeCheckOutputConnection);
+    connect(this, &AbstractClient::clientFinishUserMovedResized, this, &AbstractClient::setupCheckOutputConnection);
 
     connect(this, &AbstractClient::paletteChanged, this, &AbstractClient::triggerDecorationRepaint);
 
@@ -981,7 +981,7 @@ void AbstractClient::finishInteractiveMoveResize(bool cancel)
         }
         moveResize(moveResizeGeom);
     }
-    checkScreen(); // needs to be done because clientFinishUserMovedResized has not yet re-activated online alignment
+    checkOutput(); // needs to be done because clientFinishUserMovedResized has not yet re-activated online alignment
     if (output() != interactiveMoveResizeStartOutput()) {
         if (isFullScreen() || isElectricBorderMaximizing()) {
             updateGeometryRestoresForFullscreen(output());

src/toplevel.cpp

@@ -44,12 +44,10 @@ Toplevel::Toplevel()
     , effect_window(nullptr)
     , m_clientMachine(new ClientMachine(this))
     , m_wmClientLeader(XCB_WINDOW_NONE)
-    , m_screen(0)
     , m_skipCloseAnimation(false)
 {
-    connect(screens(), &Screens::changed, this, &Toplevel::checkScreen);
-    connect(screens(), &Screens::countChanged, this, &Toplevel::checkScreen);
-    setupCheckScreenConnection();
+    connect(screens(), &Screens::changed, this, &Toplevel::screenChanged);
+    setupCheckOutputConnection();
     connect(this, &Toplevel::bufferGeometryChanged, this, &Toplevel::inputTransformationChanged);
 
     // Only for compatibility reasons, drop in the next major release.
@@ -126,7 +124,7 @@ void Toplevel::copyToDeleted(Toplevel* c)
     m_clientMachine->setParent(this);
     m_wmClientLeader = c->wmClientLeader();
     opaque_region = c->opaqueRegion();
-    m_screen = c->m_screen;
+    m_output = c->m_output;
     m_skipCloseAnimation = c->m_skipCloseAnimation;
     m_internalFBO = c->m_internalFBO;
     m_internalImage = c->m_internalImage;
@@ -367,46 +365,44 @@ void Toplevel::deleteEffectWindow()
     effect_window = nullptr;
 }
 
-void Toplevel::checkScreen()
+void Toplevel::checkOutput()
 {
-    if (screens()->count() == 1) {
-        if (m_screen != 0) {
-            m_screen = 0;
-            Q_EMIT screenChanged();
-        }
-    } else {
-        const int s = screens()->number(frameGeometry().center());
-        if (s != m_screen) {
-            m_screen = s;
-            Q_EMIT screenChanged();
-        }
-    }
-    qreal newScale = screens()->scale(m_screen);
-    if (newScale != m_screenScale) {
-        m_screenScale = newScale;
-        Q_EMIT screenScaleChanged();
-    }
+    setOutput(kwinApp()->platform()->outputAt(frameGeometry().center()));
 }
 
-void Toplevel::setupCheckScreenConnection()
+void Toplevel::setupCheckOutputConnection()
 {
-    connect(this, &Toplevel::frameGeometryChanged, this, &Toplevel::checkScreen);
-    checkScreen();
+    connect(this, &Toplevel::frameGeometryChanged, this, &Toplevel::checkOutput);
+    checkOutput();
 }
 
-void Toplevel::removeCheckScreenConnection()
+void Toplevel::removeCheckOutputConnection()
 {
-    disconnect(this, &Toplevel::frameGeometryChanged, this, &Toplevel::checkScreen);
+    disconnect(this, &Toplevel::frameGeometryChanged, this, &Toplevel::checkOutput);
 }
 
 int Toplevel::screen() const
 {
-    return m_screen;
+    return kwinApp()->platform()->enabledOutputs().indexOf(m_output);
 }
 
 AbstractOutput *Toplevel::output() const
 {
-    return kwinApp()->platform()->findOutput(screen());
+    return m_output;
+}
+
+void Toplevel::setOutput(AbstractOutput *output)
+{
+    if (m_output != output) {
+        m_output = output;
+        Q_EMIT screenChanged();
+    }
+
+    qreal newScale = m_output->scale();
+    if (newScale != m_screenScale) {
+        m_screenScale = newScale;
+        Q_EMIT screenScaleChanged();
+    }
 }
 
 qreal Toplevel::screenScale() const

src/toplevel.h

@@ -346,6 +346,7 @@ public:
     bool isOnActiveOutput() const;
     int screen() const; // the screen where the center is
     AbstractOutput *output() const;
+    void setOutput(AbstractOutput *output);
     /**
      * The scale of the screen this window is currently on
      * @note The buffer scale can be different.
@@ -662,9 +663,9 @@ protected Q_SLOTS:
      * Checks whether the screen number for this Toplevel changed and updates if needed.
      * Any method changing the geometry of the Toplevel should call this method.
      */
-    void checkScreen();
-    void setupCheckScreenConnection();
-    void removeCheckScreenConnection();
+    void checkOutput();
+    void setupCheckOutputConnection();
+    void removeCheckOutputConnection();
     void setReadyForPainting();
 
 protected:
@@ -720,7 +721,7 @@ private:
     QRegion opaque_region;
     mutable QRegion m_shapeRegion;
     mutable bool m_shapeRegionIsValid = false;
-    int m_screen;
+    AbstractOutput *m_output = nullptr;
     bool m_skipCloseAnimation;
     quint32 m_surfaceId = 0;
     KWaylandServer::SurfaceInterface *m_surface = nullptr;

src/unmanaged.cpp

@@ -102,7 +102,7 @@ bool Unmanaged::track(xcb_window_t w)
     m_bufferGeometry = geo.rect();
     m_frameGeometry = geo.rect();
     m_clientGeometry = geo.rect();
-    checkScreen();
+    checkOutput();
     m_visual = attr->visual;
     bit_depth = geo->depth;
     info = new NETWinInfo(connection(), w, rootWindow(),

src/workspace.cpp

@@ -1213,7 +1213,13 @@ void Workspace::slotOutputEnabled(AbstractOutput *output)
 
 void Workspace::slotOutputDisabled(AbstractOutput *output)
 {
-    // TODO: Send clients on the given output to other outputs.
+    const auto stack = xStackingOrder();
+    for (Toplevel *toplevel : stack) {
+        if (toplevel->output() == output) {
+            toplevel->setOutput(kwinApp()->platform()->outputAt(toplevel->frameGeometry().center()));
+        }
+    }
+
     disconnect(output, &AbstractOutput::geometryChanged, this, &Workspace::desktopResized);
     desktopResized();
 }