Introduce Toplevel::output()

This is a little helper that can be very convenient with our transition
from int-based screen ids to AbstractOutput.

As is, the main issue with int screen ids is that they are extremely
dynamic.

src/abstract_client.cpp

@@ -2047,7 +2047,7 @@ bool AbstractClient::isActiveFullScreen() const
     // according to NETWM spec implementation notes suggests
     // "focused windows having state _NET_WM_STATE_FULLSCREEN" to be on the highest layer.
     // we'll also take the screen into account
-    return ac && (ac == this || ac->screen() != screen()|| ac->allMainClients().contains(const_cast<AbstractClient*>(this)));
+    return ac && (ac == this || ac->output() != output()|| ac->allMainClients().contains(const_cast<AbstractClient*>(this)));
 }
 
 #define BORDER(which) \

src/activation.cpp

@@ -244,7 +244,7 @@ void Workspace::setActiveClient(AbstractClient* c)
         // activating a client can cause a non active fullscreen window to loose the ActiveLayer status on > 1 screens
         if (screens()->count() > 1) {
             for (auto it = m_allClients.begin(); it != m_allClients.end(); ++it) {
-                if (*it != active_client && (*it)->layer() == ActiveLayer && (*it)->screen() == active_client->screen()) {
+                if (*it != active_client && (*it)->layer() == ActiveLayer && (*it)->output() == active_client->output()) {
                     (*it)->updateLayer();
                 }
             }

src/layers.cpp

@@ -486,7 +486,7 @@ static Layer layerForClient(const X11Client *client)
         for (const X11Client *member : members) {
             if (member == client) {
                 continue;
-            } else if (member->screen() != client->screen()) {
+            } else if (member->output() != client->output()) {
                 continue;
             }
             if (member->layer() == ActiveLayer) {
@@ -709,7 +709,7 @@ void X11Client::restackWindow(xcb_window_t above, int detail, NET::RequestSource
             X11Client *c = qobject_cast<X11Client *>(*it);
 
             if (!c || !(  (*it)->isNormalWindow() && c->isShown(true) &&
-                    (*it)->isOnCurrentDesktop() && (*it)->isOnCurrentActivity() && (*it)->isOnScreen(screen()) ))
+                    (*it)->isOnCurrentDesktop() && (*it)->isOnCurrentActivity() && (*it)->isOnOutput(output()) ))
                 continue; // irrelevant clients
 
             if (*(it - 1) == other)

src/scripting/v3/clientmodel.cpp

@@ -6,7 +6,7 @@
 
 #include "clientmodel.h"
 #include "abstract_client.h"
-#include "screens.h"
+#include "abstract_output.h"
 #include "virtualdesktops.h"
 #include "workspace.h"
 
@@ -257,7 +257,7 @@ bool ClientFilterModel::filterAcceptsRow(int sourceRow, const QModelIndex &sourc
     }
 
     if (m_screenName.has_value()) {
-        if (screens()->name(client->screen()) != m_screenName) {
+        if (client->output()->name() != m_screenName) {
             return false;
         }
     }

src/toplevel.cpp

@@ -17,6 +17,7 @@
 #include "client_machine.h"
 #include "composite.h"
 #include "effects.h"
+#include "platform.h"
 #include "screens.h"
 #include "shadow.h"
 #include "shadowitem.h"
@@ -403,6 +404,11 @@ int Toplevel::screen() const
     return m_screen;
 }
 
+AbstractOutput *Toplevel::output() const
+{
+    return kwinApp()->platform()->findOutput(screen());
+}
+
 qreal Toplevel::screenScale() const
 {
     return m_screenScale;

src/toplevel.h

@@ -345,6 +345,7 @@ public:
     bool isOnOutput(AbstractOutput *output) const;
     bool isOnActiveScreen() const;
     int screen() const; // the screen where the center is
+    AbstractOutput *output() const;
     /**
      * The scale of the screen this window is currently on
      * @note The buffer scale can be different.

src/workspace.cpp

@@ -2207,7 +2207,7 @@ void Workspace::updateClientArea()
             }
         }
         StrutRects strutRegion = client->strutRects();
-        const QRect clientsScreenRect = KWin::screens()->geometry(client->screen());
+        const QRect clientsScreenRect = client->output()->geometry();
         for (auto strut = strutRegion.begin(); strut != strutRegion.end(); strut++) {
             *strut = StrutRect((*strut).intersected(clientsScreenRect), (*strut).area());
         }
@@ -2344,7 +2344,7 @@ QRect Workspace::clientArea(clientAreaOption opt, const QPoint& p, int desktop)
 
 QRect Workspace::clientArea(clientAreaOption opt, const Toplevel *window) const
 {
-    return clientArea(opt, window->frameGeometry().center(), window->desktop());
+    return clientArea(opt, window, window->output());
 }
 
 QRect Workspace::clientArea(clientAreaOption opt, const Toplevel *window, const AbstractOutput *output) const

src/xdgshellclient.cpp

@@ -655,7 +655,7 @@ StrutRect XdgToplevelClient::strutRect(StrutArea area) const
     }
 
     const QRect windowRect = frameGeometry();
-    const QRect outputRect = screens()->geometry(screen());
+    const QRect outputRect = output()->geometry();
 
     const bool left = windowRect.left() == outputRect.left();
     const bool right = windowRect.right() == outputRect.right();