diff --git a/example/piechart/main.cpp b/example/piechart/main.cpp
index d60cb4d..74d2315 100644
--- a/example/piechart/main.cpp
+++ b/example/piechart/main.cpp
@@ -26,9 +26,6 @@ int main(int argc, char *argv[])
     series->enableClickExplodes(true);
     series->enableHoverHighlight(true);
 
-    foreach (QPieSlice*s, series->slices())
-        qDebug() << s->angle() << s->span() << s->percentage();
-
     QChartView* chartView =  new QChartView(&window);
     chartView->setRenderHint(QPainter::Antialiasing);
     chartView->addSeries(series);
diff --git a/src/piechart/piepresenter.cpp b/src/piechart/piepresenter.cpp
index 49e9408..9e5f4fd 100644
--- a/src/piechart/piepresenter.cpp
+++ b/src/piechart/piepresenter.cpp
@@ -2,8 +2,12 @@
 #include "piepresenter.h"
 #include "pieslice.h"
 #include "qpieslice.h"
+#include "pieslicelabel.h"
+#include "qpieseries.h"
+#include <qmath.h>
 #include <QDebug>
-#include <QTime>
+#include <QFontMetrics>
+
 
 QTCOMMERCIALCHART_BEGIN_NAMESPACE
 
@@ -15,6 +19,12 @@ PiePresenter::PiePresenter(QGraphicsItem *parent, QPieSeries *series)
     connect(series, SIGNAL(changed(const QPieSeries::ChangeSet&)), this, SLOT(handleSeriesChanged(const QPieSeries::ChangeSet&)));
     connect(series, SIGNAL(sizeFactorChanged()), this, SLOT(updateGeometry()));
     connect(series, SIGNAL(positionChanged()), this, SLOT(updateGeometry()));
+
+    if (m_series->count()) {
+        QPieSeries::ChangeSet changeSet;
+        changeSet.appendAdded(m_series->m_slices);
+        handleSeriesChanged(changeSet);
+    }
 }
 
 PiePresenter::~PiePresenter()
@@ -22,7 +32,7 @@ PiePresenter::~PiePresenter()
     // slices deleted automatically through QGraphicsItem
 }
 
-void PiePresenter::paint(QPainter *, const QStyleOptionGraphicsItem *, QWidget *)
+void PiePresenter::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
 {
     // TODO: paint shadows for all components
     // - get paths from items & merge & offset and draw with shadow color?
@@ -35,19 +45,17 @@ void PiePresenter::handleSeriesChanged(const QPieSeries::ChangeSet& changeSet)
     //qDebug() << "  changed: " << changeSet.changed();
     //qDebug() << "  removed: " << changeSet.removed();
 
-    // ignore changeset when there are no visual slices
-    // changeset might not be valid about the added slices
-    if (m_slices.count() == 0) {
-        foreach (QPieSlice* s, m_series->m_slices)
-            addSlice(s);
-        return;
-    }
+    foreach (QPieSlice* s, changeSet.added())
+        addSlice(s);
+
+    foreach (QPieSlice* s, changeSet.changed())
+        updateSlice(s);
 
     foreach (QPieSlice* s, changeSet.removed())
         deleteSlice(s);
 
-    foreach (QPieSlice* s, changeSet.added())
-        addSlice(s);
+    // every change possibly changes the actual pie size
+    updateGeometry();
 }
 
 void PiePresenter::handleDomainChanged(const Domain& domain)
@@ -58,15 +66,17 @@ void PiePresenter::handleDomainChanged(const Domain& domain)
 void PiePresenter::handleGeometryChanged(const QRectF& rect)
 {
     m_rect = rect;
+    prepareGeometryChange();
     updateGeometry();
 }
 
 void PiePresenter::updateGeometry()
 {
-    prepareGeometryChange();
+    if (!m_rect.isValid() || m_rect.isEmpty())
+        return;
 
+    // calculate maximum rectangle for pie
     QRectF pieRect = m_rect;
-
     if (pieRect.width() < pieRect.height()) {
         pieRect.setWidth(pieRect.width() * m_series->sizeFactor());
         pieRect.setHeight(pieRect.width());
@@ -77,6 +87,7 @@ void PiePresenter::updateGeometry()
         pieRect.moveCenter(m_rect.center());
     }
 
+    // position the pie rectangle
     switch (m_series->position()) {
         case QPieSeries::PiePositionTopLeft: {
             pieRect.setHeight(pieRect.height() / 2);
@@ -106,12 +117,43 @@ void PiePresenter::updateGeometry()
             break;
     }
 
+    // calculate how much space we need around the pie rectangle (labels & exploding)
+    qreal delta = 0;
+    qreal pieRadius = pieRect.height() / 2;
+    foreach (QPieSlice* s, m_series->m_slices) {
+
+        // calculate the farthest point in the slice from the pie center
+        qreal centerAngle = s->angle() + (s->angleSpan() / 2);
+        qreal len = pieRadius + s->labelArmLength() + s->explodeDistance();
+        QPointF dp(qSin(centerAngle*(PI/180)) * len, -qCos(centerAngle*(PI/180)) * len);
+        QPointF p = pieRect.center() + dp;
+
+        // TODO: consider the label text
+
+        // calculate how much the radius must get smaller to fit that point in the base rectangle
+        qreal dt = m_rect.top() - p.y();
+        if (dt > delta) delta = dt;
+        qreal dl = m_rect.left() - p.x();
+        if (dl > delta) delta = dl;
+        qreal dr = p.x() - m_rect.right();
+        if (dr > delta) delta = dr;
+        qreal db = p.y() - m_rect.bottom();
+        if (db > delta) delta = db;
+
+        //if (!m_rect.contains(p)) qDebug() << s->label() << dt << dl << dr << db << "delta" << delta;
+    }
+
+    // shrink the pie rectangle so that everything outside it fits the base rectangle
+    pieRect.adjust(delta, delta, -delta, -delta);
+
+    // update slices
     if (m_pieRect != pieRect) {
         m_pieRect = pieRect;
-        //qDebug() << "PiePresenter::updateGeometry()" << m_pieRect;
+        //qDebug() << "PiePresenter::updateGeometry()" << m_rect << m_pieRect;
         foreach (PieSlice* s, m_slices.values()) {
             s->setPieRect(m_pieRect);
             s->updateGeometry();
+            s->update();
         }
     }
 }
@@ -121,8 +163,7 @@ void PiePresenter::addSlice(QPieSlice* sliceData)
     //qDebug() << "PiePresenter::addSlice()" << sliceData;
 
     if (m_slices.keys().contains(sliceData)) {
-        //qWarning() << "PiePresenter::addSlice(): slice already exists!" << sliceData;
-        Q_ASSERT(0);
+        Q_ASSERT(0); // TODO: how to handle this nicely?
         return;
     }
 
@@ -135,22 +176,33 @@ void PiePresenter::addSlice(QPieSlice* sliceData)
     m_slices.insert(sliceData, slice);
 
     // connect signals
-    connect(sliceData, SIGNAL(changed()), slice, SLOT(handleSliceDataChanged()));
     connect(slice, SIGNAL(clicked()), sliceData, SIGNAL(clicked()));
     connect(slice, SIGNAL(hoverEnter()), sliceData, SIGNAL(hoverEnter()));
     connect(slice, SIGNAL(hoverLeave()), sliceData, SIGNAL(hoverLeave()));
 }
 
+void PiePresenter::updateSlice(QPieSlice* sliceData)
+{
+    //qDebug() << "PiePresenter::updateSlice()" << sliceData;
+
+    if (!m_slices.contains(sliceData)) {
+        Q_ASSERT(0); // TODO: how to handle this nicely?
+        return;
+    }
+
+    m_slices[sliceData]->updateData(sliceData);
+}
+
 void PiePresenter::deleteSlice(QPieSlice* sliceData)
 {
     //qDebug() << "PiePresenter::deleteSlice()" << sliceData;
 
-    if (m_slices.contains(sliceData))
-        delete m_slices.take(sliceData);
-    else {
-        // nothing to remove
-        Q_ASSERT(0); // TODO: remove before release
+    if (!m_slices.contains(sliceData)) {
+        Q_ASSERT(0); // TODO: how to handle this nicely?
+        return;
     }
+
+    delete m_slices.take(sliceData);
 }
 
 #include "moc_piepresenter.cpp"
diff --git a/src/piechart/piepresenter.h b/src/piechart/piepresenter.h
index a3348f9..9004a15 100644
--- a/src/piechart/piepresenter.h
+++ b/src/piechart/piepresenter.h
@@ -9,6 +9,8 @@ class QGraphicsItem;
 QTCOMMERCIALCHART_BEGIN_NAMESPACE
 class PieSlice;
 
+#define PI 3.14159265 // TODO: is this defined in some header?
+
 class PiePresenter : public QObject, public ChartItem
 {
     Q_OBJECT
@@ -33,6 +35,7 @@ public Q_SLOTS:
 
 private:
     void addSlice(QPieSlice* sliceData);
+    void updateSlice(QPieSlice* sliceData);
     void deleteSlice(QPieSlice* sliceData);
 
 private:
diff --git a/src/piechart/pieslice.cpp b/src/piechart/pieslice.cpp
index bb241c3..9893cfc 100644
--- a/src/piechart/pieslice.cpp
+++ b/src/piechart/pieslice.cpp
@@ -11,9 +11,6 @@
 
 QTCOMMERCIALCHART_BEGIN_NAMESPACE
 
-#define PI 3.14159265
-#define EXPLODE_OFFSET 20
-
 QPointF offset(qreal angle, qreal length)
 {
     qreal dx = qSin(angle*(PI/180)) * length;
@@ -25,8 +22,9 @@ PieSlice::PieSlice(QGraphicsItem* parent)
     :QGraphicsObject(parent),
     m_slicelabel(new PieSliceLabel(this)),
     m_angle(0),
-    m_span(0),
-    m_isExploded(false)
+    m_angleSpan(0),
+    m_isExploded(false),
+    m_explodeDistance(0)
 {
     setAcceptHoverEvents(true);
     setAcceptedMouseButtons(Qt::LeftButton);
@@ -76,24 +74,27 @@ void PieSlice::setPieRect(QRectF rect)
 
 void PieSlice::updateGeometry()
 {
+    if (!m_pieRect.isValid() || m_pieRect.isEmpty())
+        return;
+
     prepareGeometryChange();
 
     // calculate center angle
-    qreal centerAngle = m_angle + (m_span/2);
+    qreal centerAngle = m_angle + (m_angleSpan/2);
 
     // adjust rect for exploding
     QRectF rect = m_pieRect;
-    rect.adjust(EXPLODE_OFFSET, EXPLODE_OFFSET, -EXPLODE_OFFSET ,-EXPLODE_OFFSET);
     if (m_isExploded) {
-        QPointF d = offset((centerAngle), EXPLODE_OFFSET);
-        rect.translate(d.x(), d.y());
+        qreal dx = qSin(centerAngle*(PI/180)) * m_explodeDistance;
+        qreal dy = -qCos(centerAngle*(PI/180)) * m_explodeDistance;
+        rect.translate(dx, dy);
     }
 
     // update slice path
     // TODO: draw the shape so that it might have a hole in the center
     QPainterPath path;
     path.moveTo(rect.center());
-    path.arcTo(rect, -m_angle + 90, -m_span);
+    path.arcTo(rect, -m_angle + 90, -m_angleSpan);
     path.closeSubpath();
     m_path = path;
 
@@ -103,24 +104,19 @@ void PieSlice::updateGeometry()
     m_slicelabel->setArmStartPoint(edgeCenter);
     m_slicelabel->setArmAngle(centerAngle);
     m_slicelabel->updateGeometry();
+    m_slicelabel->update();
 
     //qDebug() << "PieSlice::updateGeometry" << m_slicelabel->text() << boundingRect() << m_angle << m_span;
 }
 
-void PieSlice::handleSliceDataChanged()
-{
-    QPieSlice *slice = qobject_cast<QPieSlice*>(sender());
-    Q_ASSERT(slice);
-    updateData(slice);
-}
-
 void PieSlice::updateData(const QPieSlice* sliceData)
 {
     // TODO: compare what has changes to avoid unneccesary geometry updates
 
     m_angle = sliceData->angle();
-    m_span = sliceData->span();
+    m_angleSpan = sliceData->angleSpan();
     m_isExploded = sliceData->isExploded();
+    m_explodeDistance = sliceData->explodeDistance(); // TODO: expose to public API
     m_pen = sliceData->pen();
     m_brush = sliceData->brush();
 
@@ -128,11 +124,10 @@ void PieSlice::updateData(const QPieSlice* sliceData)
     m_slicelabel->setText(sliceData->label());
     m_slicelabel->setPen(sliceData->labelPen());
     m_slicelabel->setFont(sliceData->labelFont());
-    m_slicelabel->setArmLength(sliceData->labelArmLenght());
+    m_slicelabel->setArmLength(sliceData->labelArmLength());
 
     updateGeometry();
     update();
-    m_slicelabel->update();
 }
 
 #include "moc_pieslice.cpp"
diff --git a/src/piechart/pieslice.h b/src/piechart/pieslice.h
index 8a67e72..aca1f3f 100644
--- a/src/piechart/pieslice.h
+++ b/src/piechart/pieslice.h
@@ -36,11 +36,13 @@ Q_SIGNALS:
     void hoverLeave();
 
 public Q_SLOTS:
-    void handleSliceDataChanged();
     void setPieRect(QRectF rect);
     void updateGeometry();
     void updateData(const QPieSlice *sliceData);
 
+public:
+    PieSliceLabel* label() { return m_slicelabel; }
+
 private:
     PieSliceLabel* m_slicelabel;
 
@@ -48,8 +50,10 @@ private:
     QPainterPath m_path;
 
     qreal m_angle;
-    qreal m_span;
+    qreal m_angleSpan;
+
     bool m_isExploded;
+    qreal m_explodeDistance;
 
     QPen m_pen;
     QBrush m_brush;
diff --git a/src/piechart/qpieseries.cpp b/src/piechart/qpieseries.cpp
index 0a94f51..690556c 100644
--- a/src/piechart/qpieseries.cpp
+++ b/src/piechart/qpieseries.cpp
@@ -2,6 +2,7 @@
 #include "qpieslice.h"
 #include "piepresenter.h"
 #include "pieslice.h"
+#include <QFontMetrics>
 #include <QDebug>
 
 QTCOMMERCIALCHART_BEGIN_NAMESPACE
@@ -12,6 +13,12 @@ void QPieSeries::ChangeSet::appendAdded(QPieSlice* slice)
         m_added << slice;
 }
 
+void QPieSeries::ChangeSet::appendAdded(QList<QPieSlice*> slices)
+{
+    foreach (QPieSlice* s, slices)
+        appendAdded(s);
+}
+
 void QPieSeries::ChangeSet::appendChanged(QPieSlice* slice)
 {
     if (!m_changed.contains(slice))
@@ -114,7 +121,7 @@ QPieSlice* QPieSeries::add(qreal value, QString name)
 void QPieSeries::remove(QPieSlice* slice)
 {
     if (!m_slices.removeOne(slice)) {
-        Q_ASSERT(0); // TODO: remove before release
+        Q_ASSERT(0); // TODO: how should this be reported?
         return;
     }
 
@@ -263,7 +270,7 @@ void QPieSeries::updateDerivativeData()
         m_total += s->value();
 
     // we must have some values
-    Q_ASSERT(m_total > 0); // TODO
+    Q_ASSERT(m_total > 0); // TODO: is this the correct way to handle this?
 
     // update slice attributes
     qreal sliceAngle = m_pieStartAngle;
@@ -278,8 +285,8 @@ void QPieSeries::updateDerivativeData()
         }
 
         qreal sliceSpan = m_pieSpan * percentage;
-        if (s->m_span != sliceSpan) {
-            s->m_span = sliceSpan;
+        if (s->m_angleSpan != sliceSpan) {
+            s->m_angleSpan = sliceSpan;
             changed = true;
         }
 
diff --git a/src/piechart/qpieseries.h b/src/piechart/qpieseries.h
index 65e3e72..977af05 100644
--- a/src/piechart/qpieseries.h
+++ b/src/piechart/qpieseries.h
@@ -32,6 +32,7 @@ public:
     {
     public:
         void appendAdded(QPieSlice* slice);
+        void appendAdded(QList<QPieSlice*> slices);
         void appendChanged(QPieSlice* slice);
         void appendRemoved(QPieSlice* slice);
 
@@ -67,13 +68,6 @@ public:
 
     QList<QPieSlice*> slices() const { return m_slices; }
 
-    // TODO: find slices?
-    // QList<QPieSlice*> findByValue(qreal value);
-    // ...
-
-    // TODO: sorting slices?
-    // void sort(QPieSeries::SortByValue)
-
     void setSizeFactor(qreal sizeFactor);
     qreal sizeFactor() const { return m_sizeFactor; }
 
@@ -86,6 +80,17 @@ public:
     void enableClickExplodes(bool enable);
     void enableHoverHighlight(bool enable);
 
+    // TODO: find slices?
+    // QList<QPieSlice*> findByValue(qreal value);
+    // ...
+
+    // TODO: sorting slices?
+    // void sort(QPieSeries::SortByValue|label|??)
+
+    // TODO: general graphics customization
+    // setDrawStyle(2d|3d)
+    // setDropShadows(bool)
+
 Q_SIGNALS:
     void changed(const QPieSeries::ChangeSet& changeSet);
     void clicked(QPieSlice* slice);
@@ -94,12 +99,11 @@ Q_SIGNALS:
     void sizeFactorChanged();
     void positionChanged();
 
-private Q_SLOTS: // should be private and not in the interface
+private Q_SLOTS: // TODO: should be private and not visible in the interface at all
     void sliceChanged();
     void sliceClicked();
     void sliceHoverEnter();
     void sliceHoverLeave();
-
     void toggleExploded(QPieSlice* slice);
     void highlightOn(QPieSlice* slice);
     void highlightOff(QPieSlice* slice);
diff --git a/src/piechart/qpieslice.cpp b/src/piechart/qpieslice.cpp
index 595575a..55c14b4 100644
--- a/src/piechart/qpieslice.cpp
+++ b/src/piechart/qpieslice.cpp
@@ -2,18 +2,20 @@
 
 QTCOMMERCIALCHART_BEGIN_NAMESPACE
 
-#define DEFAULT_PEN_COLOR        Qt::black
-#define DEFAULT_BRUSH_COLOR      Qt::white
-#define DEFAULT_LABEL_ARM_LENGTH 50
+#define DEFAULT_PEN_COLOR         Qt::black
+#define DEFAULT_BRUSH_COLOR       Qt::white
+#define DEFAULT_LABEL_ARM_LENGTH  50
+#define DEFAULT_EXPOLODE_DISTANCE 20
 
 QPieSlice::QPieSlice(QObject *parent)
     :QObject(parent),
     m_value(0),
     m_isLabelVisible(true),
     m_isExploded(false),
+    m_explodeDistance(DEFAULT_EXPOLODE_DISTANCE),
     m_percentage(0),
     m_angle(0),
-    m_span(0),
+    m_angleSpan(0),
     m_pen(DEFAULT_PEN_COLOR),
     m_brush(DEFAULT_BRUSH_COLOR),
     m_labelPen(DEFAULT_PEN_COLOR),
@@ -28,9 +30,10 @@ QPieSlice::QPieSlice(qreal value, QString label, bool labelVisible, QObject *par
     m_label(label),
     m_isLabelVisible(labelVisible),
     m_isExploded(false),
+    m_explodeDistance(DEFAULT_EXPOLODE_DISTANCE),
     m_percentage(0),
     m_angle(0),
-    m_span(0),
+    m_angleSpan(0),
     m_pen(DEFAULT_PEN_COLOR),
     m_brush(DEFAULT_BRUSH_COLOR),
     m_labelPen(DEFAULT_PEN_COLOR),
@@ -64,6 +67,11 @@ bool QPieSlice::isExploded() const
     return m_isExploded;
 }
 
+qreal QPieSlice::explodeDistance() const
+{
+    return m_explodeDistance;
+}
+
 qreal QPieSlice::percentage() const
 {
     return m_percentage;
@@ -74,9 +82,9 @@ qreal QPieSlice::angle() const
     return m_angle;
 }
 
-qreal QPieSlice::span() const
+qreal QPieSlice::angleSpan() const
 {
-    return m_span;
+    return m_angleSpan;
 }
 
 QPen QPieSlice::pen() const
@@ -99,7 +107,7 @@ QFont QPieSlice::labelFont() const
     return m_labelFont;
 }
 
-qreal QPieSlice::labelArmLenght() const
+qreal QPieSlice::labelArmLength() const
 {
     return m_labelArmLength;
 }
@@ -136,6 +144,14 @@ void QPieSlice::setExploded(bool exploded)
     }
 }
 
+void QPieSlice::setExplodeDistance(qreal distance)
+{
+    if (m_explodeDistance != distance) {
+        m_explodeDistance = distance;
+        emit changed();
+    }
+}
+
 void QPieSlice::setPen(QPen pen)
 {
     if (m_pen != pen) {
diff --git a/src/piechart/qpieslice.h b/src/piechart/qpieslice.h
index 1d42328..c84225b 100644
--- a/src/piechart/qpieslice.h
+++ b/src/piechart/qpieslice.h
@@ -25,18 +25,19 @@ public:
     QString label() const;
     bool isLabelVisible() const;
     bool isExploded() const;
+    qreal explodeDistance() const;
 
     // generated data
     qreal percentage() const;
     qreal angle() const;
-    qreal span() const;
+    qreal angleSpan() const;
 
     // customization
     QPen pen() const;
     QBrush brush() const;
     QPen labelPen() const;
     QFont labelFont() const;
-    qreal labelArmLenght() const;
+    qreal labelArmLength() const;
 
 Q_SIGNALS:
     void clicked();
@@ -51,6 +52,7 @@ public Q_SLOTS:
     void setLabelVisible(bool visible);
     void setValue(qreal value);
     void setExploded(bool exploded);
+    void setExplodeDistance(qreal distance);
 
     // customization
     void setPen(QPen pen);
@@ -59,21 +61,27 @@ public Q_SLOTS:
     void setLabelPen(QPen pen);
     void setLabelArmLength(qreal len);
 
+    // TODO: label position in general
+    // setLabelFlags(inside|outside|labelArmOn|labelArmOff|???)
+    // setLabelOrientation(horizontal|vertical|same as slice center angle|???)
+
 private:
 
     // TODO: use private class
     friend class QPieSeries;
+    friend class PiePresenter;
 
     // data
     qreal m_value;
     QString m_label;
     bool m_isLabelVisible;
     bool m_isExploded;
+    qreal m_explodeDistance;
 
     // generated data
     qreal m_percentage;
     qreal m_angle;
-    qreal m_span;
+    qreal m_angleSpan;
 
     // customization
     QPen m_pen;