implement showingDesktop by raising desktop window

This is an alternative approach suggested by the
NETWM spec.
The advantage is, that windows are not minimized
at all what apparently lead to some confusion
about the nature of the mode (which was abused
to tidy up) and a secret config key to allow for
that unrelated behavior.
Instead the ShowDesktopIsMinimizeAll key is removed
and replaced by a dedicated script + shortcut.

Bonus: less code to remember "minimized" windows =)

client.cpp

@@ -990,12 +990,12 @@ void Client::updateVisibility()
         return;
     }
     if (isManaged())
-        resetShowingDesktop(true);
+        resetShowingDesktop();
     internalShow();
 }
 
 
-void Client::resetShowingDesktop(bool keep_hidden)
+void Client::resetShowingDesktop()
 {
     if (isDock() || !workspace()->showingDesktop())
         return;
@@ -1006,7 +1006,7 @@ void Client::resetShowingDesktop(bool keep_hidden)
             break;
 
     if (!belongs_to_desktop)
-        workspace()->resetShowingDesktop(keep_hidden);
+        workspace()->setShowingDesktop(false);
 }
 
 /**

client.h

@@ -717,7 +717,7 @@ private:
     bool processDecorationButtonPress(int button, int state, int x, int y, int x_root, int y_root,
                                       bool ignoreMenu = false);
     Client* findAutogroupCandidate() const;
-    void resetShowingDesktop(bool keep_hidden);
+    void resetShowingDesktop();
 
 protected:
     virtual void debug(QDebug& stream) const;

layers.cpp

@@ -827,7 +827,7 @@ Layer Client::layer() const
 Layer Client::belongsToLayer() const
 {
     if (isDesktop())
-        return DesktopLayer;
+        return workspace()->showingDesktop() ? AboveLayer : DesktopLayer;
     if (isSplash())          // no damn annoying splashscreens
         return NormalLayer; // getting in the way of everything else
     if (isDock()) {

manage.cpp

@@ -603,7 +603,7 @@ bool Client::manage(xcb_window_t w, bool isMapped)
             }
         }
 
-        resetShowingDesktop(false);
+        resetShowingDesktop();
 
         if (isOnCurrentDesktop() && !isMapped && !allow && (!session || session->stackingOrder < 0))
             workspace()->restackClientUnderActive(this);

workspace.cpp

@@ -113,7 +113,6 @@ Workspace::Workspace(bool restore)
     , force_restacking(false)
     , x_stacking_dirty(true)
     , showing_desktop(false)
-    , block_showing_desktop(0)
     , was_user_interaction(false)
     , session_saving(false)
     , block_focus(0)
@@ -550,7 +549,6 @@ void Workspace::removeClient(Client* c)
     desktops.removeAll(c);
     x_stacking_dirty = true;
     attention_chain.removeAll(c);
-    showing_desktop_clients.removeAll(c);
     Group* group = findGroup(c->window());
     if (group != NULL)
         group->lostLeader();
@@ -849,7 +847,6 @@ void Workspace::slotCurrentDesktopChanged(uint oldDesktop, uint newDesktop)
 
 void Workspace::updateClientVisibilityOnDesktopChange(uint oldDesktop, uint newDesktop)
 {
-    ++block_showing_desktop;
     ObscuringWindows obs_wins;
     for (ToplevelList::ConstIterator it = stacking_order.constBegin();
             it != stacking_order.constEnd();
@@ -879,9 +876,8 @@ void Workspace::updateClientVisibilityOnDesktopChange(uint oldDesktop, uint newD
         if (c->isOnDesktop(newDesktop) && c->isOnCurrentActivity())
             c->updateVisibility();
     }
-    --block_showing_desktop;
     if (showingDesktop())   // Do this only after desktop change to avoid flicker
-        resetShowingDesktop(false);
+        setShowingDesktop(false);
 }
 
 void Workspace::activateClientOnNewDesktop(uint desktop)
@@ -956,7 +952,6 @@ void Workspace::updateCurrentActivity(const QString &new_activity)
     // TODO: Q_ASSERT( block_stacking_updates == 0 ); // Make sure stacking_order is up to date
     StackingUpdatesBlocker blocker(this);
 
-    ++block_showing_desktop; //FIXME should I be using that?
     // Optimized Desktop switching: unmapping done from back to front
     // mapping done from front to back => less exposure events
     //Notify::raise((Notify::Event) (Notify::DesktopChange+new_desktop));
@@ -997,10 +992,9 @@ void Workspace::updateCurrentActivity(const QString &new_activity)
             c->updateVisibility();
     }
 
-    --block_showing_desktop;
     //FIXME not sure if I should do this either
     if (showingDesktop())   // Do this only after desktop change to avoid flicker
-        resetShowingDesktop(false);
+        setShowingDesktop(false);
 
     // Restore the focus on this desktop
     --block_focus;
@@ -1206,68 +1200,12 @@ void Workspace::setShowingDesktop(bool showing)
 {
     rootInfo()->setShowingDesktop(showing);
     showing_desktop = showing;
-    ++block_showing_desktop;
-    if (showing_desktop) {
-        showing_desktop_clients.clear();
-        ++block_focus;
-        ToplevelList cls = stackingOrder();
-        // Find them first, then minimize, otherwise transients may get minimized with the window
-        // they're transient for
-        for (ToplevelList::ConstIterator it = cls.constBegin();
-                it != cls.constEnd();
-                ++it) {
-            Client *c = qobject_cast<Client*>(*it);
-            if (!c) {
-                continue;
-            }
-            if (c->isOnCurrentActivity() && c->isOnCurrentDesktop() && c->isShown(true) && !c->isSpecialWindow())
-                showing_desktop_clients.prepend(c);   // Topmost first to reduce flicker
-        }
-        for (ClientList::ConstIterator it = showing_desktop_clients.constBegin();
-                it != showing_desktop_clients.constEnd();
-                ++it)
-            (*it)->minimize();
-        --block_focus;
-        if (Client* desk = findDesktop(true, VirtualDesktopManager::self()->current()))
+    if (Client* desk = findDesktop(true, VirtualDesktopManager::self()->current())) {
+        desk->updateLayer();
+        lowerClient(desk);
+        if (showing_desktop)
             requestFocus(desk);
-    } else {
-        for (ClientList::ConstIterator it = showing_desktop_clients.constBegin();
-                it != showing_desktop_clients.constEnd();
-                ++it)
-            (*it)->unminimize();
-        if (showing_desktop_clients.count() > 0)
-            requestFocus(showing_desktop_clients.first());
-        showing_desktop_clients.clear();
     }
-    --block_showing_desktop;
-}
-
-/**
- * Following Kicker's behavior:
- * Changing a virtual desktop resets the state and shows the windows again.
- * Unminimizing a window resets the state but keeps the windows hidden (except
- * the one that was unminimized).
- * A new window resets the state and shows the windows again, with the new window
- * being active. Due to popular demand (#67406) by people who apparently
- * don't see a difference between "show desktop" and "minimize all", this is not
- * true if "showDesktopIsMinimizeAll" is set in kwinrc. In such case showing
- * a new window resets the state but doesn't show windows.
- */
-void Workspace::resetShowingDesktop(bool keep_hidden)
-{
-    if (block_showing_desktop > 0)
-        return;
-    rootInfo()->setShowingDesktop(false);
-    showing_desktop = false;
-    ++block_showing_desktop;
-    if (!keep_hidden) {
-        for (ClientList::ConstIterator it = showing_desktop_clients.constBegin();
-                it != showing_desktop_clients.constEnd();
-                ++it)
-            (*it)->unminimize();
-    }
-    showing_desktop_clients.clear();
-    --block_showing_desktop;
 }
 
 void Workspace::disableGlobalShortcutsForClient(bool disable)

workspace.h

@@ -277,7 +277,6 @@ public:
     void setCurrentScreen(int new_screen);
 
     void setShowingDesktop(bool showing);
-    void resetShowingDesktop(bool keep_hidden);
     bool showingDesktop() const;
 
     void sendPingToWindow(xcb_window_t w, xcb_timestamp_t timestamp);   // Called from Client::pingWindow()
@@ -535,8 +534,6 @@ private:
     ClientList attention_chain;
 
     bool showing_desktop;
-    ClientList showing_desktop_clients;
-    int block_showing_desktop;
 
     GroupList groups;