Preliminary support for avoiding covering clients such as kicker

which want to be permanently visible.

I've used an XAtom called '_NET_AVOID_SPEC'. This of course can change
if need be. I think it's correct according to the wm spec, but the
wm spec seems to be empty on gnome.org, so who knows.

Windows can choose to be avoided by setting an XTextProperty
with one value, which can be either 'N', 'S', 'E', or 'W', according
to which screen edge they are anchored to.

kwin then sets its 'clientArea' rect appropriately, so that (in
  theory at least) clients will not enter this area in some circumstances,
such as when being mapped for the first time.

You can see that this actually works if you start lots of konsoles. They
don't appear over the panel. I don't know what happens if you move the
panel, but I presume things will be screwed up, because I haven't
looked at that yet.

If you maximise a window, it'll still fill the screen, because the
implementation of maximise in kwin/client.cpp doesn't take account
of the workspace's clientArea rect. This is easy to fix, but I've
been awake for too long, so I'll do it after 42 winks.

svn path=/trunk/kdebase/kwin/; revision=46772

client.cpp

@@ -320,9 +320,10 @@ bool WindowWrapper::x11Event( XEvent * e)
   Creates a client on workspace \a ws for window \a w.
  */
 Client::Client( Workspace *ws, WId w, QWidget *parent, const char *name, WFlags f )
-    : QWidget( parent, name, f | WStyle_Customize | WStyle_NoBorder )
+    : QWidget( parent, name, f | WStyle_Customize | WStyle_NoBorder ),
+      avoid_(false),
+      anchorEdge_(AnchorNorth)
 {
-
     wspace = ws;
     win = w;
     XWindowAttributes attr;
@@ -359,6 +360,56 @@ Client::Client( Workspace *ws, WId w, QWidget *parent, const char *name, WFlags
     if ( mainClient()->isSticky() )
 	setSticky( TRUE );
 
+    // Find out if we should be avoided.
+
+    // If this atom isn't set, set it now.
+    Atom avoidAtom = XInternAtom(qt_xdisplay(), "_NET_AVOID_SPEC", False);
+
+    XTextProperty avoidProp;
+
+    Status avoidStatus =
+        XGetTextProperty(qt_xdisplay(), w, &avoidProp, avoidAtom);
+
+    if (0 != avoidStatus) {
+
+        char ** avoidList;
+        int avoidListCount;
+
+        Status convertStatus =
+          XTextPropertyToStringList(&avoidProp, &avoidList, &avoidListCount);
+
+        if (0 != convertStatus) {
+
+          avoid_ = true;
+
+          if (avoidListCount != 1) {
+//            qDebug("Extra values in avoidance list. Ignoring.");
+          }
+
+          char * itemZero = avoidList[0];
+
+          switch (*itemZero) {
+
+            case 'N':
+              anchorEdge_ = AnchorNorth;
+              break;
+            case 'S':
+              anchorEdge_ = AnchorSouth;
+              break;
+            case 'E':
+              anchorEdge_ = AnchorEast;
+              break;
+            case 'W':
+              anchorEdge_ = AnchorWest;
+              break;
+            default:
+              anchorEdge_ = AnchorNorth;
+              break;
+          }
+
+          XFreeStringList(avoidList);
+        }
+    }
 }
 
 /*!
@@ -1848,7 +1899,6 @@ QCString Client::sessionId()
     return result;
 }
 
-
 NoBorderClient::NoBorderClient( Workspace *ws, WId w, QWidget *parent, const char *name )
     : Client( ws, w, parent, name )
 {

client.h

@@ -63,6 +63,9 @@ public:
     bool isTransient() const;
     Client* mainClient();
 
+    bool avoid() const { return avoid_; }
+    int anchorEdge() const { return anchorEdge_; }
+
     virtual bool windowEvent( XEvent * );
 
     void manage( bool isMapped = FALSE );
@@ -230,6 +233,9 @@ private:
     QPixmap miniicon_pix;
     QRect geom_restore;
     QRegion mask;
+
+    bool avoid_;
+    int anchorEdge_;
 };
 
 inline WId Client::window() const

workspace.cpp

@@ -247,6 +247,7 @@ void Workspace::init()
       inf.row = 0;
       cci.append(inf);
     }
+    updateClientArea();
 }
 
 Workspace::~Workspace()
@@ -339,6 +340,7 @@ bool Workspace::workspaceEvent( XEvent * e )
 		if ( addDockwin( e->xmaprequest.window ) )
 		    return TRUE;
 		c = clientFactory( this, e->xmaprequest.window );
+    updateClientArea();
 		if ( root != qt_xrootwin() ) {
 		    // TODO may use QWidget:.create
 		    XReparentWindow( qt_xdisplay(), c->winId(), root, 0, 0 );
@@ -500,7 +502,7 @@ QRect Workspace::geometry() const
  */
 QRect Workspace::clientArea() const
 {
-    return geometry(); // for now
+  return clientArea_;
 }
 
 
@@ -1312,6 +1314,54 @@ void Workspace::deskCleanup(CleanupType ct)
   }
 }
 
+/*!
+  Lowers the client \a c taking layers, transient windows and window
+  groups into account.
+ */
+void Workspace::lowerClient( Client* c )
+{
+  if ( !c )
+    return;
+
+  if ( c == desktop_client )
+    return; // deny
+
+  stacking_order.remove( c );
+  stacking_order.prepend( c );
+
+  // Not sure what this is doing. Disable for now.
+#if 0
+  ClientList saveset;
+
+  if ( c->transientFor() ) {
+
+    saveset.append( c );
+    Client* t = findClient( c->transientFor() );
+    Client* tmp;
+    while ( t && !saveset.contains( t ) && t->transientFor() ) {
+      tmp = findClient( t->transientFor() );
+      if ( !tmp )
+        break;
+      saveset.append( t );
+      t = tmp;
+    }
+    if ( t && !saveset.contains( t ) && t != desktop_client ) {
+      raiseClient( t );
+      return;
+    }
+  }
+
+  saveset.clear();
+  saveset.append( c );
+  raiseTransientsOf(saveset, c );
+#endif
+
+  XLowerWindow(qt_xdisplay(), c->winId());
+
+  propagateClients( TRUE );
+}
+
+
 /*!
   Raises the client \a c taking layers, transient windows and window
   groups into account.
@@ -2047,6 +2097,7 @@ void Workspace::slotResetAllClients()
         delete oldClient;
         newClient->manage( TRUE );
     }
+  updateClientArea();
 }
 
 /*!
@@ -2117,3 +2168,39 @@ SessionInfo* Workspace::takeSessionInfo( Client* c )
 
     return 0;
 }
+
+  void
+Workspace::updateClientArea()
+{
+  clientArea_ = geometry();
+
+  for (ClientList::ConstIterator it(clients.begin()); it != clients.end(); ++it)
+  {
+    if ((*it)->avoid()) {
+
+      switch (AnchorEdge((*it)->anchorEdge())) {
+
+        case AnchorNorth:
+          clientArea_
+            .setTop(QMAX(clientArea_.top(), (*it)->geometry().bottom()));
+          break;
+
+        case AnchorSouth:
+          clientArea_
+            .setBottom(QMIN(clientArea_.bottom(), (*it)->geometry().top()));
+          break;
+        
+        case AnchorEast:
+          clientArea_
+            .setRight(QMIN(clientArea_.right(), (*it)->geometry().left()));
+          break;
+        
+        case AnchorWest:
+          clientArea_
+            .setLeft(QMAX(clientArea_.left(), (*it)->geometry().right()));
+          break;
+      }
+    }
+  }
+}
+

workspace.h

@@ -23,6 +23,8 @@ class KGlobalAccel;
 
 typedef QValueList<Client*> ClientList;
 
+enum AnchorEdge { AnchorNorth, AnchorSouth, AnchorEast, AnchorWest };
+
 class DockWindow
 {
 public:
@@ -100,6 +102,7 @@ public:
     void doPlacement( Client* c );
     QPoint adjustClientPosition( Client* c, QPoint pos );
     void raiseClient( Client* c );
+    void lowerClient( Client* c );
 
     void clientHidden( Client*  );
 
@@ -234,6 +237,9 @@ private:
     Atom kwm_command;
 
     PluginMgr mgr;
+
+    void updateClientArea();
+    QRect clientArea_;
 };
 
 inline WId Workspace::rootWin() const