enable dragging from desktop to panel

note: there's no visual feedback before you release the mouse button, and there's no way to drag back to the desktop.

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=770333

applethandle.cpp

@@ -19,6 +19,7 @@
 
 #include "applethandle_p.h"
 
+#include <QApplication>
 #include <QtGui/QGraphicsSceneMouseEvent>
 #include <QtGui/QLinearGradient>
 #include <QtGui/QPainter>
@@ -31,6 +32,7 @@
 #include <cmath>
 #include <math.h>
 
+#include "plasma/view.h"
 #include "applet.h"
 #include "containment.h"
 #include "corona.h"
@@ -328,6 +330,27 @@ void AppletHandle::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
                     Phase::self()->animateItem(m_applet, Phase::Disappear);
                 }
                 break;
+            case MoveButton: {
+                //find out if we were dropped on a panel or something
+                QWidget *w = QApplication::topLevelAt(event->screenPos());
+                kDebug() << "move to widget" << w;
+                if (w) {
+                    Plasma::View *v = qobject_cast<Plasma::View *>(w);
+                    if (v) {
+                        Containment *c = v->containment();
+                        //XXX the dashboard view won't give us a containment. if it did, this could
+                        //break shit.
+                        if (c && c != m_containment) {
+                            //we actually have been dropped on another containment, so move there
+                            //we have a screenpos, we need a scenepos
+                            //FIXME how reliable is this transform?
+                            QPoint pos = v->mapFromGlobal(event->screenPos());
+                            switchContainment(c, v->mapToScene(pos));
+                        }
+                    }
+                }
+                break;
+            }
             default:
                 break;
         }
@@ -378,17 +401,9 @@ void AppletHandle::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
                     if (containments[i]->sceneBoundingRect().contains(event->scenePos())) {
                         // add the applet to the new containment
                         // and take it from the old one
-                        QPointF scenePosition = scenePos();
                         //kDebug() << "moving to other containment with position" << pos() << event->scenePos();
                         //kDebug() << "position before reparenting" << pos() << scenePos();
-                        m_containment = containments[i];
-                        //m_containment->addChild(m_applet);
-                        //setParentItem(containments[i]);
-                        m_containment->addApplet(m_applet);
-                        setParentItem(m_containment);
-                        m_applet->setParentItem(this);
-                        setPos(m_containment->mapFromScene(scenePosition));
-                        update();
+                        switchContainment(containments[i], scenePos());
                         break;
                     }
                 }
@@ -493,6 +508,31 @@ void AppletHandle::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
     }
 }
 
+//pos relative to scene
+void AppletHandle::switchContainment(Containment *containment, const QPointF &pos)
+{
+    Applet *applet=m_applet;
+    switch (containment->containmentType()) {
+        case Containment::PanelContainment:
+            kDebug() << "panel";
+            //we need to fully disassociate the applet and handle, then kill the handle
+            forceDisappear(); //takes care of event filter and killing handle
+            m_applet=0; //make sure we don't try to act on the applet again
+            applet->disconnect(this); //make sure the applet doesn't tell us to do anything
+            containment->addApplet(applet, containment->mapFromScene(pos));
+            break;
+        default: //FIXME assuming everything else behaves like desktop
+            kDebug() << "desktop";
+            m_containment = containment;
+            containment->addApplet(m_applet);
+            setParentItem(containment);
+            m_applet->setParentItem(this);
+            setPos(containment->mapFromScene(pos));
+            //setPos(pos);
+    }
+    update();
+}
+
 QVariant AppletHandle::itemChange(GraphicsItemChange change, const QVariant &value)
 {
     if (change == ItemPositionHasChanged && m_applet) {

applethandle_p.h

@@ -74,6 +74,12 @@ class AppletHandle : public QObject, public QGraphicsItem
         void calculateSize();
         ButtonType mapToButton(const QPointF &point) const;
         void forceDisappear();
+        /**
+         * move our applet to another containment
+         * @param containment the containment to move to
+         * @param pos the (scene-relative) position to place it at
+         */
+        void switchContainment(Containment *containment, const QPointF &pos);
 
         QRectF m_rect;
         ButtonType m_pressedButton;

containment.cpp

@@ -404,63 +404,9 @@ Applet* Containment::addApplet(const QString& name, const QVariantList& args, ui
         applet = new Applet;
     }
 
-    switch (containmentType()) {
-    case PanelContainment:
-    {
-        //panels don't want backgrounds, which is important when setting geometry
-        applet->setDrawStandardBackground(false);
-
-        // Calculate where the user wants the applet to go before adding it
-        int index = -1;
-        QPointF position = appletGeometry.topLeft();
-        BoxLayout *l = dynamic_cast<BoxLayout *>(layout());
-        if (!delayInit && l && position != QPointF(-1, -1)) {
-            foreach (Applet *existingApplet, d->applets) {
-                if (formFactor() == Horizontal) {
-                    qreal middle = (existingApplet->geometry().left() +
-                            existingApplet->geometry().right()) / 2.0;
-                    // Applets are checked in order so there is no need to check
-                    // if the position is equal to or greater than the applet's
-                    // leftmost point. This also allows for dropping in the gap
-                    // between applets.
-                    if (position.x() < middle) {
-                        index = l->indexOf(existingApplet);
-                        break;
-                    } else if (position.x() <= existingApplet->geometry().right()) {
-                        index = l->indexOf(existingApplet) + 1;
-                        break;
-                    }
-                } else {
-                    qreal middle = (existingApplet->geometry().top() +
-                            existingApplet->geometry().bottom()) / 2.0;
-                    if (position.y() < middle) {
-                        index = l->indexOf(existingApplet);
-                        break;
-                    } else if (position.y() <= existingApplet->geometry().bottom()) {
-                        index = l->indexOf(existingApplet) + 1;
-                        break;
-                    }
-                }
-            }
-        }
-
-        addApplet(applet);
-        prepareApplet(applet, delayInit);
-
-        // Reposition the applet after adding has been done
-        if (index != -1) {
-            l->insertItem(index, l->takeAt(l->indexOf(applet)));
-            d->applets.removeAll(applet);
-            d->applets.insert(index, applet);
-        }
-
-        break;
-    }
-
-    default:
-        addApplet(applet);
-        prepareApplet(applet, delayInit);
+    addApplet(applet, appletGeometry.topLeft(), delayInit);
 
+    if (containmentType() != PanelContainment) {
         //kDebug() << "adding applet" << applet->name() << "with a default geometry of" << appletGeometry << appletGeometry.isValid();
         if (appletGeometry.isValid()) {
             applet->setGeometry(appletGeometry);
@@ -484,6 +430,106 @@ Applet* Containment::addApplet(const QString& name, const QVariantList& args, ui
     return applet;
 }
 
+//pos must be relative to the containment already. use mapfromscene.
+//what we're trying to do here for panels is make the applet go to the requested position,
+//or somewhere close to it, and get integrated properly into the containment as if it were created
+//there.
+void Containment::addApplet(Applet *applet, const QPointF &pos, bool dontInit)
+{
+    if (!applet) {
+        kDebug() << "adding null applet!?!";
+        return;
+    }
+
+    Containment *currentContainment = applet->containment();
+    int index = -1;
+
+    if (containmentType() == PanelContainment) {
+        //panels don't want backgrounds, which is important when setting geometry
+        applet->setDrawStandardBackground(false);
+
+        // Calculate where the user wants the applet to go before adding it
+        //so long as this isn't a new applet with a delayed init
+        if (! dontInit || (currentContainment && currentContainment != this)) {
+            index = indexAt(pos);
+        }
+    }
+
+    if (currentContainment && currentContainment != this) {
+        applet->removeSceneEventFilter(currentContainment);
+        KConfigGroup oldConfig = applet->config();
+        applet->resetConfigurationObject();
+        currentContainment->d->applets.removeAll(applet);
+        addChild(applet);
+
+        // now move the old config to the new location
+        KConfigGroup c = config().group("Applets").group(QString::number(applet->id()));
+        oldConfig.reparent(&c);
+    } else {
+        addChild(applet);
+    }
+
+    d->applets << applet;
+
+    connect(applet, SIGNAL(destroyed(QObject*)),
+            this, SLOT(appletDestroyed(QObject*)));
+
+    if (containmentType() == PanelContainment) {
+        // Reposition the applet after adding has been done
+        if (index != -1) {
+            BoxLayout *l = dynamic_cast<BoxLayout *>(layout());
+            l->insertItem(index, l->takeAt(l->indexOf(applet)));
+            d->applets.removeAll(applet);
+            d->applets.insert(index, applet);
+        }
+    } else {
+        //FIXME if it came from a panel its bg was disabled
+        //maybe we should expect the applet to handle that on a constraint update?
+
+        //should we really do this? hell, do we have any business playing with the geometry of
+        //non-panel applets at all?
+        if (pos != QPointF(-1, -1)) {
+            applet->setPos(pos);
+        }
+    }
+    prepareApplet(applet, dontInit); //must at least flush constraints
+}
+
+//containment-relative pos... right?
+int Containment::indexAt(const QPointF &pos) const
+{
+    if (pos == QPointF(-1, -1)) {
+        return -1;
+    }
+    BoxLayout *l = dynamic_cast<BoxLayout *>(layout());
+    if (l) {
+        foreach (Applet *existingApplet, d->applets) {
+            if (formFactor() == Horizontal) {
+                qreal middle = (existingApplet->geometry().left() +
+                        existingApplet->geometry().right()) / 2.0;
+                // Applets are checked in order so there is no need to check
+                // if the position is equal to or greater than the applet's
+                // leftmost point. This also allows for dropping in the gap
+                // between applets.
+                if (pos.x() < middle) {
+                    return l->indexOf(existingApplet);
+                } else if (pos.x() <= existingApplet->geometry().right()) {
+                    return l->indexOf(existingApplet) + 1;
+                }
+            } else {
+                qreal middle = (existingApplet->geometry().top() +
+                        existingApplet->geometry().bottom()) / 2.0;
+                if (pos.y() < middle) {
+                    return l->indexOf(existingApplet);
+                } else if (pos.y() <= existingApplet->geometry().bottom()) {
+                    return l->indexOf(existingApplet) + 1;
+                }
+            }
+        }
+    }
+    return -1;
+}
+
 void Containment::prepareApplet(Applet *applet, bool delayInit)
 {
     if (delayInit) {
@@ -549,33 +595,6 @@ bool Containment::regionIsEmpty(const QRectF &region, Applet *ignoredApplet) con
     return true;
 }
 
-void Containment::addApplet(Applet *applet)
-{
-    Containment *currentContainment = applet->containment();
-    if (currentContainment && currentContainment != this) {
-        applet->removeSceneEventFilter(currentContainment);
-        KConfigGroup oldConfig = applet->config();
-        applet->resetConfigurationObject();
-        currentContainment->d->applets.removeAll(applet);
-        addChild(applet);
-
-        // now move the old config to the new location
-        KConfigGroup c = config().group("Applets").group(QString::number(applet->id()));
-        oldConfig.reparent(&c);
-    } else {
-        addChild(applet);
-    }
-
-    d->applets << applet;
-
-    if (currentContainment) {
-        applet->installSceneEventFilter(this);
-    }
-
-    connect(applet, SIGNAL(destroyed(QObject*)),
-            this, SLOT(appletDestroyed(QObject*)));
-}
-
 void Containment::appletDestroyed(QObject* object)
 {
     // we do a static_cast here since it really isn't an Applet by this

containment.h

@@ -183,9 +183,17 @@ class PLASMA_EXPORT Containment : public Applet
         void clearApplets();
 
         /**
-         * add existing applet to this containment
+         * add existing applet to this containment at pos
+         * @param pos the containment-relative position
+         * @param dontInit if true, init() will not be called on the applet
          */
-        void addApplet(Applet * applet);
+        void addApplet(Applet *applet, const QPointF &pos = QPointF(-1, -1), bool dontInit = true);
+
+        /**
+         * @return the index to insert an applet at if you want it near the point pos.
+         * @param pos the containment-relative position
+         */
+        virtual int indexAt(const QPointF &pos) const;
 
         /**
          * Sets the physical screen this Containment is associated with.