This lets the View have a desktop set to it and when drawing a Containment we pass in the effective desktop # being currently painted. The Containment is free to ignore this information, or it can try and cast the passed in options to a Containment::StyleOption to retrieve this information. This should be used for any per-desktop painting that happens (e.g. separate background per desktop) and opens the way to having View-per-Desktop for better composite manager support (think: desktop grid or cube where more than one desktop is simultaneously visible)

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=778239

applet.cpp

@@ -870,7 +870,6 @@ QColor Applet::color() const
 
 void Applet::paintWidget(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
 {
-    Q_UNUSED(widget)
     if (d->shadow && d->shadow->shadowedSize() != boundingRect().size()) {
         //kDebug() << "sizes are " << d->shadow->shadowedSize() << boundingRect().size();
         d->shadow->generate();
@@ -893,10 +892,14 @@ void Applet::paintWidget(QPainter *painter, const QStyleOptionGraphicsItem *opti
         if (widget && isContainment()) {
             // note that the widget we get is actually the viewport of the view, not the view itself
             View* v = qobject_cast<Plasma::View*>(widget->parent());
-            if (v && !v->drawWallpaper()) {
-                painter->restore();
-                return;
+            if (v && v->drawWallpaper()) { 
+                Containment::StyleOption coption(*option);
+                coption.desktop = v->effectiveDesktop();
+                paintInterface(painter, &coption, QRect(QPoint(0,0), d->contentSize(this).toSize()));
             }
+
+            painter->restore();
+            return;
         }
 
         //kDebug() << "paint interface of" << (QObject*) this;

containment.cpp

@@ -58,7 +58,7 @@ public:
         : q(c),
           formFactor(Planar),
           location(Floating),
-          screen(-1),
+          screen(-1), // no screen
           toolbox(0),
           type(Containment::NoContainmentType)
     {
@@ -90,6 +90,25 @@ public:
     Containment::Type type;
 };
 
+Containment::StyleOption::StyleOption()
+    : QStyleOptionGraphicsItem(),
+      desktop(-1)
+{
+
+}
+
+Containment::StyleOption::StyleOption(const Containment::StyleOption & other)
+    : QStyleOptionGraphicsItem(other),
+      desktop(other.desktop)
+{
+}
+
+Containment::StyleOption::StyleOption(const QStyleOptionGraphicsItem &other)
+    : QStyleOptionGraphicsItem(other),
+      desktop(-1)
+{
+}
+
 Containment::Containment(QGraphicsItem* parent,
                          const QString& serviceId,
                          uint containmentId)

containment.h

@@ -22,6 +22,7 @@
 
 #include <QtGui/QGraphicsItem>
 #include <QtGui/QWidget>
+#include <QtGui/QStyleOptionGraphicsItem>
 
 #include <kplugininfo.h>
 #include <ksharedconfig.h>
@@ -64,6 +65,16 @@ class PLASMA_EXPORT Containment : public Applet
     Q_OBJECT
 
     public:
+        class StyleOption : public QStyleOptionGraphicsItem
+        {
+            public:
+                explicit StyleOption();
+                explicit StyleOption(const StyleOption &other);
+                explicit StyleOption(const QStyleOptionGraphicsItem &other);
+
+                int desktop;
+        };
+
         typedef QList<Applet*> List;
         typedef QHash<QString, Applet*> Dict;
 

view.cpp

@@ -18,6 +18,9 @@
  */
 
 #include "view.h"
+
+#include <KWindowSystem>
+
 #include "corona.h"
 #include "containment.h"
 
@@ -31,7 +34,7 @@ class View::Private
 public:
     Private()
         : drawWallpaper(true),
-          screen(-1),
+          desktop(-1),
           containment(0)
     {
     }
@@ -41,7 +44,7 @@ public:
     }
 
     bool drawWallpaper;
-    int screen;
+    int desktop;
     Plasma::Containment *containment;
 };
 
@@ -58,6 +61,7 @@ View::View(Containment *containment, QWidget *parent)
     : QGraphicsView(parent),
       d(new Private)
 {
+    Q_ASSERT(containment);
     initGraphicsView();
     setScene(containment->scene());
     setContainment(containment);
@@ -91,15 +95,37 @@ void View::setScreen(int screen)
         }
 
         setContainment(corona->containmentForScreen(screen));
-    } else {
-        // reseting the screen who knows what.
-        d->screen = screen;
+        if (d->desktop < -1) {
+            // we want to set it to "all desktops" if we get ownership of
+            // a screen but don't have a desktop set
+            d->desktop = -1;
+        }
     }
 }
 
 int View::screen() const
 {
-    return d->screen;
+    return d->containment->screen();
+}
+
+void View::setDesktop(int desktop)
+{
+    // -1 == All desktops
+    if (desktop < -1 || desktop > KWindowSystem::numberOfDesktops() - 1) {
+        desktop = -1;
+    }
+
+    d->desktop = desktop;
+}
+
+int View::desktop() const
+{
+    return d->desktop;
+}
+
+int View::effectiveDesktop() const
+{
+    return d->desktop > -1 ? d->desktop : KWindowSystem::currentDesktop();
 }
 
 void View::setContainment(Containment *containment)
@@ -113,7 +139,6 @@ void View::setContainment(Containment *containment)
     }
 
     d->containment = containment;
-    d->screen = containment->screen();
     updateSceneRect();
     connect(containment, SIGNAL(geometryChanged()), this, SLOT(updateSceneRect()));
 }

view.h

@@ -68,6 +68,27 @@ public:
      */
     int screen() const;
 
+    /**
+     * Sets which virtual desktop this view is asociated with, if any.
+     *
+     * @arg desktop a valid desktop number, -1 for all desktops, less than -1 for none
+     */
+    void setDesktop(int desktop);
+
+    /**
+     * The virtual desktop this view is associated with
+     *
+     * @return the desktop number, -1 for all desktops and less than -1 for none
+     */
+    int desktop() const;
+
+    /**
+     * The virtual desktop this view is actually being viewed on
+     *
+     * @return the desktop number (always valid, never < 0)
+     */
+    int effectiveDesktop() const;
+
     /**
      * Sets the containment for this view, which will also cause the view
      * to track the geometry of the containment.