Adding a clip property to the ThumbnailItem

By default clip is enabled. This means that if the thumbnail would
overlap the "parent" window, it does not get rendered at all. If set
to false it will always be rendered. This is required for window strip
where the complete screen width is used, so overlap does not matter.

scene.cpp

@@ -419,8 +419,8 @@ void Scene::paintWindow(Window* w, int mask, QRegion region, WindowQuadList quad
         } else {
             thumbMask |= PAINT_WINDOW_TRANSLUCENT;
         }
-        if (x < wImpl->x() || x + size.width() > wImpl->x() + wImpl->width() ||
-            y < wImpl->y() || y + size.height() > wImpl->y() + wImpl->height()) {
+        if (item->isClip() && (x < wImpl->x() || x + size.width() > wImpl->x() + wImpl->width() ||
+            y < wImpl->y() || y + size.height() > wImpl->y() + wImpl->height())) {
             // don't render windows outside the containing window.
             // TODO: improve by spliting out the window quads which do not fit
             continue;

tabbox/qml/window_strip.qml

@@ -78,6 +78,7 @@ Item {
                 wId: windowId
                 width: parent.width - closeButtonContainer.width - 20
                 height: thumbnailListView.height - 40
+                clip: false
                 anchors.centerIn: parent
                 MouseArea {
                     anchors.fill: parent

thumbnailitem.cpp

@@ -35,6 +35,7 @@ namespace KWin
 ThumbnailItem::ThumbnailItem(QDeclarativeItem* parent)
     : QDeclarativeItem(parent)
     , m_wId(0)
+    , m_clip(true)
     , m_parent(QWeakPointer<EffectWindowImpl>())
 {
     setFlags(flags() & ~QGraphicsItem::ItemHasNoContents);
@@ -81,6 +82,12 @@ void ThumbnailItem::setWId(qulonglong wId)
     emit wIdChanged(wId);
 }
 
+void ThumbnailItem::setClip(bool clip)
+{
+    m_clip = clip;
+    emit clipChanged(clip);
+}
+
 void ThumbnailItem::effectWindowAdded()
 {
     // the window might be added before the EffectWindow is created

thumbnailitem.h

@@ -34,6 +34,7 @@ class ThumbnailItem : public QDeclarativeItem
 {
     Q_OBJECT
     Q_PROPERTY(qulonglong wId READ wId WRITE setWId NOTIFY wIdChanged SCRIPTABLE true)
+    Q_PROPERTY(bool clip READ isClip WRITE setClip NOTIFY clipChanged SCRIPTABLE true)
 public:
     ThumbnailItem(QDeclarativeItem *parent = 0);
     virtual ~ThumbnailItem();
@@ -42,15 +43,21 @@ public:
         return m_wId;
     }
     void setWId(qulonglong wId);
+    bool isClip() const {
+        return m_clip;
+    }
+    void setClip(bool clip);
     virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
 Q_SIGNALS:
     void wIdChanged(qulonglong wid);
+    void clipChanged(bool clipped);
 private Q_SLOTS:
     void init();
     void effectWindowAdded();
 private:
     void findParentEffectWindow();
     qulonglong m_wId;
+    bool m_clip;
     QWeakPointer<EffectWindowImpl> m_parent;
 };