From fa69a979c9fca3e45d048ee67593dc48fb5b0847 Mon Sep 17 00:00:00 2001
From: Jason Stubbs <jasonbstubbs@gmail.com>
Date: Sat, 22 Dec 2007 12:32:55 +0000
Subject: [PATCH] Try to place unpositioned applets in areas that aren't
 occupied using a very simple placement policy.

BUG: 154122

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=751607
---
 containment.cpp | 59 +++++++++++++++++++++++++++++++++++++++++--------
 containment.h   |  3 +++
 2 files changed, 53 insertions(+), 9 deletions(-)

diff --git a/containment.cpp b/containment.cpp
index 6ee4b2dd3..217350894 100644
--- a/containment.cpp
+++ b/containment.cpp
@@ -417,15 +417,7 @@ Applet* Containment::addApplet(const QString& name, const QVariantList& args, ui
         applet->setGeometry(QRectF(appletGeometry.topLeft(),
                                    applet->sizeHint()));
     } else if (geometry().isValid()) {
-        //TODO: Make sure new applets don't overlap with existing ones
-        // Center exactly:
-        QSizeF size = applet->sizeHint();
-        qreal appletWidth = size.width();
-        qreal appletHeight = size.height();
-        qreal width = geometry().width();
-        qreal height = geometry().height();
-        //kDebug() << "measuring geometry with" << appletWidth << appletHeight << width << height;
-        applet->setGeometry(QRectF(QPointF((width / 2) - (appletWidth / 2), (height / 2) - (appletHeight / 2)), size));
+        applet->setGeometry(geometryForApplet(applet));
     }
 
     //kDebug() << applet->name() << "sizehint:" << applet->sizeHint() << "geometry:" << applet->geometry();
@@ -443,6 +435,55 @@ Applet* Containment::addApplet(const QString& name, const QVariantList& args, ui
     return applet;
 }
 
+QRectF Containment::geometryForApplet(Applet *applet) const
+{
+    // first try the top left of the containment
+    QRectF placement = QRectF(geometry().topLeft(), applet->sizeHint());
+    if (regionIsEmpty(placement, applet)) {
+        return placement;
+    }
+
+    QList<Applet *> otherApplets = d->applets;
+    otherApplets.removeAll(applet);
+
+    // Then below existing applets
+    foreach (Applet *otherApplet, otherApplets) {
+        placement.moveTo(otherApplet->pos() + QPointF(0, otherApplet->size().height()));
+        if (!geometry().contains(placement)) {
+            continue;
+        }
+        if (regionIsEmpty(placement, applet)) {
+            return placement;
+        }
+    }
+
+    // Then to the right
+    foreach (Applet *otherApplet, otherApplets) {
+        placement.moveTo(otherApplet->pos() + QPointF(otherApplet->size().width(), 0));
+        if (!geometry().contains(placement)) {
+            continue;
+        }
+        if (regionIsEmpty(placement, applet)) {
+            return placement;
+        }
+    }
+
+    // Otherwise place it in the centre of the screen
+    placement.moveLeft(geometry().width() / 2 + placement.width() / 2);
+    placement.moveTop(geometry().height() / 2 + placement.height() / 2);
+    return placement;
+}
+
+bool Containment::regionIsEmpty(const QRectF &region, Applet *ignoredApplet) const
+{
+    foreach (Applet *applet, d->applets) {
+        if (applet != ignoredApplet && applet->geometry().intersects(region)) {
+            return false;
+        }
+    }
+    return true;
+}
+
 void Containment::addApplet(Applet *applet)
 {
     Containment *currentContainment = applet->containment();
diff --git a/containment.h b/containment.h
index 714ceb13b..86a0f0958 100644
--- a/containment.h
+++ b/containment.h
@@ -314,6 +314,9 @@ class PLASMA_EXPORT Containment : public Applet
         void destroyApplet();
 
     private:
+        QRectF geometryForApplet(Applet *applet) const;
+        bool regionIsEmpty(const QRectF &region, Applet *ignoredApplet=0) const;
+
         Q_DISABLE_COPY(Containment)
 
         class Private;