Fix theme ownership

Theme ownership now uses similar model as axis and inputhandler
ownership: Graph can own multiple themes, but only one is active
at the time.

Task-number: QTRD-2623

Change-Id: I7134384df6f8cc465cc28fbebb454b7d2e254f83
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@digia.com>

18 files changed, 256 insertions, 176 deletions

diff --git a/src/datavisualization/doc/snippets/doc_src_q3dtheme.cpp b/src/datavisualization/doc/snippets/doc_src_q3dtheme.cpp
index 5a539e62..aa0ee859 100644
--- a/src/datavisualization/doc/snippets/doc_src_q3dtheme.cpp
+++ b/src/datavisualization/doc/snippets/doc_src_q3dtheme.cpp
@@ -57,9 +57,9 @@ int main(int argc, char **argv)
 
     //! [3]
     Q3DBars *graph = new Q3DBars();
-    graph->setTheme(new Q3DTheme(Q3DTheme::ThemePrimaryColors));
-    graph->theme()->setBaseColor(Qt::red);
-    graph->theme()->setSingleHighlightColor(Qt::yellow);
+    graph->setActiveTheme(new Q3DTheme(Q3DTheme::ThemePrimaryColors));
+    graph->activeTheme()->setBaseColor(Qt::red);
+    graph->activeTheme()->setSingleHighlightColor(Qt::yellow);
     //! [3]
 }
 
diff --git a/src/datavisualization/doc/src/qtdatavisualization-qml-abstractdeclarative.qdoc b/src/datavisualization/doc/src/qtdatavisualization-qml-abstractdeclarative.qdoc
index 7493709f..21dabf66 100644
--- a/src/datavisualization/doc/src/qtdatavisualization-qml-abstractdeclarative.qdoc
+++ b/src/datavisualization/doc/src/qtdatavisualization-qml-abstractdeclarative.qdoc
@@ -48,5 +48,5 @@
 
 /*!
   \qmlproperty Theme3D AbstractGraph3D::theme
-  Theme of the graph.
+  The active theme of the graph.
  */
diff --git a/src/datavisualization/engine/abstract3dcontroller.cpp b/src/datavisualization/engine/abstract3dcontroller.cpp
index 9835dbe4..500ce9dc 100644
--- a/src/datavisualization/engine/abstract3dcontroller.cpp
+++ b/src/datavisualization/engine/abstract3dcontroller.cpp
@@ -52,7 +52,7 @@ Abstract3DController::Abstract3DController(QRect initialViewport, QObject *paren
     m_renderPending(false)
 {
     // Set initial theme
-    setTheme(new Q3DTheme(Q3DTheme::ThemeQt));
+    setActiveTheme(new Q3DTheme(Q3DTheme::ThemeQt));
 
     m_scene->d_ptr->setViewport(initialViewport);
 
@@ -102,7 +102,7 @@ void Abstract3DController::addSeries(QAbstract3DSeries *series)
                          this, &Abstract3DController::handleSeriesVisibilityChanged);
         if (series->isVisible())
             handleSeriesVisibilityChangedBySender(series);
-        series->d_ptr->resetToTheme(*m_themeManager->theme(), oldSize, false);
+        series->d_ptr->resetToTheme(*m_themeManager->activeTheme(), oldSize, false);
     }
 }
 
@@ -135,7 +135,7 @@ void Abstract3DController::synchDataToRenderer()
 
     m_renderer->updateScene(m_scene);
 
-    m_renderer->updateTheme(m_themeManager->theme());
+    m_renderer->updateTheme(m_themeManager->activeTheme());
 
     if (m_changeTracker.shadowQualityChanged) {
         m_renderer->updateShadowQuality(m_shadowQuality);
@@ -595,22 +595,43 @@ void Abstract3DController::setZoomLevel(int zoomLevel)
     emitNeedRender();
 }
 
-void Abstract3DController::setTheme(Q3DTheme *theme)
+void Abstract3DController::addTheme(Q3DTheme *theme)
 {
-    if (theme != m_themeManager->theme()) {
-        m_themeManager->setTheme(theme);
+    m_themeManager->addTheme(theme);
+}
+
+void Abstract3DController::releaseTheme(Q3DTheme *theme)
+{
+    Q3DTheme *oldTheme = m_themeManager->activeTheme();
+
+    m_themeManager->releaseTheme(theme);
+
+    if (oldTheme != m_themeManager->activeTheme())
+        emit activeThemeChanged(m_themeManager->activeTheme());
+}
+QList<Q3DTheme *> Abstract3DController::themes() const
+{
+    return m_themeManager->themes();
+}
+
+void Abstract3DController::setActiveTheme(Q3DTheme *theme)
+{
+    if (theme != m_themeManager->activeTheme()) {
+        m_themeManager->setActiveTheme(theme);
         m_changeTracker.themeChanged = true;
+        // Default theme can be created by theme manager, so ensure we have correct theme
+        Q3DTheme *newActiveTheme = m_themeManager->activeTheme();
         // Reset all attached series to the new theme
         for (int i = 0; i < m_seriesList.size(); i++)
-            m_seriesList.at(i)->d_ptr->resetToTheme(*theme, i, true);
+            m_seriesList.at(i)->d_ptr->resetToTheme(*newActiveTheme, i, true);
         markSeriesVisualsDirty();
-        emit themeChanged(theme);
+        emit activeThemeChanged(newActiveTheme);
     }
 }
 
-Q3DTheme *Abstract3DController::theme() const
+Q3DTheme *Abstract3DController::activeTheme() const
 {
-    return m_themeManager->theme();
+    return m_themeManager->activeTheme();
 }
 
 void Abstract3DController::setSelectionMode(QDataVis::SelectionFlags mode)
diff --git a/src/datavisualization/engine/abstract3dcontroller_p.h b/src/datavisualization/engine/abstract3dcontroller_p.h
index c56b8a72..a862a961 100644
--- a/src/datavisualization/engine/abstract3dcontroller_p.h
+++ b/src/datavisualization/engine/abstract3dcontroller_p.h
@@ -191,8 +191,11 @@ public:
     virtual int zoomLevel();
     virtual void setZoomLevel(int zoomLevel);
 
-    virtual void setTheme(Q3DTheme *theme);
-    virtual Q3DTheme *theme() const;
+    virtual void addTheme(Q3DTheme *theme);
+    virtual void releaseTheme(Q3DTheme *theme);
+    virtual void setActiveTheme(Q3DTheme *theme);
+    virtual Q3DTheme *activeTheme() const;
+    virtual QList<Q3DTheme *> themes() const;
 
     virtual void setSelectionMode(QDataVis::SelectionFlags mode);
     virtual QDataVis::SelectionFlags selectionMode() const;
@@ -253,7 +256,7 @@ public slots:
 signals:
     void shadowQualityChanged(QDataVis::ShadowQuality quality);
     void activeInputHandlerChanged(QAbstract3DInputHandler *inputHandler);
-    void themeChanged(Q3DTheme *theme);
+    void activeThemeChanged(Q3DTheme *activeTheme);
     void selectionModeChanged(QDataVis::SelectionFlags mode);
     void needRender();
 
diff --git a/src/datavisualization/engine/bars3dcontroller.cpp b/src/datavisualization/engine/bars3dcontroller.cpp
index 5232a566..007fdffc 100644
--- a/src/datavisualization/engine/bars3dcontroller.cpp
+++ b/src/datavisualization/engine/bars3dcontroller.cpp
@@ -72,7 +72,7 @@ void Bars3DController::initializeOpenGL()
 void Bars3DController::synchDataToRenderer()
 {
     // Background change requires reloading the meshes in bar graphs, so dirty the series visuals
-    if (m_themeManager->theme()->d_ptr->m_dirtyBits.backgroundEnabledDirty) {
+    if (m_themeManager->activeTheme()->d_ptr->m_dirtyBits.backgroundEnabledDirty) {
         m_isSeriesVisualsDirty = true;
         foreach (QAbstract3DSeries *series, m_seriesList)
             series->d_ptr->m_changeTracker.meshChanged = true;
diff --git a/src/datavisualization/engine/q3dbars.cpp b/src/datavisualization/engine/q3dbars.cpp
index d4e97519..530235f2 100644
--- a/src/datavisualization/engine/q3dbars.cpp
+++ b/src/datavisualization/engine/q3dbars.cpp
@@ -108,8 +108,6 @@ Q3DBars::Q3DBars(QWindow *parent)
                      &Q3DBars::selectionModeChanged);
     QObject::connect(dptr()->m_shared, &Abstract3DController::shadowQualityChanged, this,
                      &Q3DBars::shadowQualityChanged);
-    QObject::connect(dptr()->m_shared, &Abstract3DController::themeChanged, this,
-                     &Q3DBars::themeChanged);
     QObject::connect(dptr()->m_shared, &Abstract3DController::needRender, d_ptr.data(),
                      &Q3DWindowPrivate::renderLater);
     QObject::connect(dptr()->m_shared, &Abstract3DController::shadowQualityChanged, dptr(),
@@ -272,23 +270,6 @@ bool Q3DBars::isBarSpacingRelative()
 }
 
 /*!
- * \property Q3DBars::theme
- *
- * A \a theme to be used for the graph. Ownership of the \a theme is transferred. Previous theme
- * is deleted when a new one is set. Properties of the \a theme can be modified even after setting
- * it, and the modifications take effect immediately.
- */
-void Q3DBars::setTheme(Q3DTheme *theme)
-{
-    dptr()->m_shared->setTheme(theme);
-}
-
-Q3DTheme *Q3DBars::theme() const
-{
-    return dptrc()->m_shared->theme();
-}
-
-/*!
  * \property Q3DBars::selectionMode
  *
  * Sets bar selection \a mode to a combination of \c QDataVis::SelectionFlags. It is preset to
diff --git a/src/datavisualization/engine/q3dbars.h b/src/datavisualization/engine/q3dbars.h
index add3b11b..fac9558f 100644
--- a/src/datavisualization/engine/q3dbars.h
+++ b/src/datavisualization/engine/q3dbars.h
@@ -21,7 +21,6 @@
 
 #include <QtDataVisualization/qdatavisualizationenums.h>
 #include <QtDataVisualization/q3dwindow.h>
-#include <QtDataVisualization/q3dtheme.h>
 #include <QFont>
 #include <QLinearGradient>
 
@@ -42,7 +41,6 @@ class QT_DATAVISUALIZATION_EXPORT Q3DBars : public Q3DWindow
     Q_PROPERTY(float barThickness READ barThickness WRITE setBarThickness NOTIFY barThicknessChanged)
     Q_PROPERTY(QSizeF barSpacing READ barSpacing WRITE setBarSpacing NOTIFY barSpacingChanged)
     Q_PROPERTY(bool barSpacingRelative READ isBarSpacingRelative WRITE setBarSpacingRelative NOTIFY barSpacingRelativeChanged)
-    Q_PROPERTY(Q3DTheme* theme READ theme WRITE setTheme NOTIFY themeChanged)
     Q_PROPERTY(Q3DScene* scene READ scene)
 
 public:
@@ -53,9 +51,6 @@ public:
     void removeSeries(QBar3DSeries *series);
     QList<QBar3DSeries *> seriesList();
 
-    void setTheme(Q3DTheme *theme);
-    Q3DTheme *theme() const;
-
     void setBarThickness(float thicknessRatio);
     float barThickness();
 
@@ -89,7 +84,6 @@ signals:
     void barThicknessChanged(float thicknessRatio);
     void barSpacingChanged(QSizeF spacing);
     void barSpacingRelativeChanged(bool relative);
-    void themeChanged(Q3DTheme *theme);
 
 protected:
 
diff --git a/src/datavisualization/engine/q3dscatter.cpp b/src/datavisualization/engine/q3dscatter.cpp
index 3c28b4a5..13b22df4 100644
--- a/src/datavisualization/engine/q3dscatter.cpp
+++ b/src/datavisualization/engine/q3dscatter.cpp
@@ -92,8 +92,6 @@ Q3DScatter::Q3DScatter(QWindow *parent)
                      &Q3DScatter::selectionModeChanged);
     QObject::connect(dptr()->m_shared, &Abstract3DController::shadowQualityChanged, this,
                      &Q3DScatter::shadowQualityChanged);
-    QObject::connect(dptr()->m_shared, &Abstract3DController::themeChanged, this,
-                     &Q3DScatter::themeChanged);
     QObject::connect(dptr()->m_shared, &Abstract3DController::needRender, d_ptr.data(),
                      &Q3DWindowPrivate::renderLater);
     QObject::connect(dptr()->m_shared, &Abstract3DController::shadowQualityChanged, dptr(),
@@ -192,23 +190,6 @@ const Q3DScatterPrivate *Q3DScatter::dptrc() const
 }
 
 /*!
- * \property Q3DScatter::theme
- *
- * A \a theme to be used for the graph. Ownership of the \a theme is transferred. Previous theme
- * is deleted when a new one is set. Properties of the \a theme can be modified even after setting
- * it, and the modifications take effect immediately.
- */
-void Q3DScatter::setTheme(Q3DTheme *theme)
-{
-    dptr()->m_shared->setTheme(theme);
-}
-
-Q3DTheme *Q3DScatter::theme() const
-{
-    return dptrc()->m_shared->theme();
-}
-
-/*!
  * \property Q3DScatter::selectionMode
  *
  * Sets item selection \a mode to a combination of \c QDataVis::SelectionFlags. It is preset to
diff --git a/src/datavisualization/engine/q3dscatter.h b/src/datavisualization/engine/q3dscatter.h
index e58146a1..f71b469e 100644
--- a/src/datavisualization/engine/q3dscatter.h
+++ b/src/datavisualization/engine/q3dscatter.h
@@ -22,7 +22,6 @@
 #include <QtDataVisualization/qdatavisualizationenums.h>
 #include <QtDataVisualization/q3dwindow.h>
 #include <QtDataVisualization/q3dscene.h>
-#include <QtDataVisualization/q3dtheme.h>
 #include <QFont>
 #include <QLinearGradient>
 
@@ -33,14 +32,12 @@ class LabelItem;
 class Q3DValueAxis;
 class Q3DCategoryAxis;
 class QScatter3DSeries;
-class Q3DTheme;
 
 class QT_DATAVISUALIZATION_EXPORT Q3DScatter : public Q3DWindow
 {
     Q_OBJECT
     Q_PROPERTY(QtDataVisualization::QDataVis::SelectionFlags selectionMode READ selectionMode WRITE setSelectionMode NOTIFY selectionModeChanged)
     Q_PROPERTY(QtDataVisualization::QDataVis::ShadowQuality shadowQuality READ shadowQuality WRITE setShadowQuality NOTIFY shadowQualityChanged)
-    Q_PROPERTY(Q3DTheme* theme READ theme WRITE setTheme NOTIFY themeChanged)
     Q_PROPERTY(Q3DScene* scene READ scene)
 
 public:
@@ -51,9 +48,6 @@ public:
     void removeSeries(QScatter3DSeries *series);
     QList<QScatter3DSeries *> seriesList();
 
-    void setTheme(Q3DTheme *theme);
-    Q3DTheme *theme() const;
-
     void setSelectionMode(QDataVis::SelectionFlags mode);
     QDataVis::SelectionFlags selectionMode() const;
 
@@ -75,7 +69,6 @@ public:
 signals:
     void selectionModeChanged(QDataVis::SelectionFlags mode);
     void shadowQualityChanged(QDataVis::ShadowQuality quality);
-    void themeChanged(Q3DTheme* theme);
 
 protected:
     void mouseDoubleClickEvent(QMouseEvent *event);
diff --git a/src/datavisualization/engine/q3dsurface.cpp b/src/datavisualization/engine/q3dsurface.cpp
index ce738685..feb2ef22 100644
--- a/src/datavisualization/engine/q3dsurface.cpp
+++ b/src/datavisualization/engine/q3dsurface.cpp
@@ -103,8 +103,6 @@ Q3DSurface::Q3DSurface(QWindow *parent)
     dptr()->m_shared->initializeOpenGL();
     QObject::connect(dptr()->m_shared, &Abstract3DController::selectionModeChanged, this,
                      &Q3DSurface::selectionModeChanged);
-    QObject::connect(dptr()->m_shared, &Abstract3DController::themeChanged, this,
-                     &Q3DSurface::themeChanged);
     QObject::connect(dptr()->m_shared, &Abstract3DController::shadowQualityChanged, this,
                      &Q3DSurface::shadowQualityChanged);
     QObject::connect(dptr()->m_shared, &Abstract3DController::needRender, d_ptr.data(),
@@ -205,23 +203,6 @@ const Q3DSurfacePrivate *Q3DSurface::dptrc() const
 }
 
 /*!
- * \property Q3DSurface::theme
- *
- * A \a theme to be used for the graph. Ownership of the \a theme is transferred. Previous theme
- * is deleted when a new one is set. Properties of the \a theme can be modified even after setting
- * it, and the modifications take effect immediately.
- */
-void Q3DSurface::setTheme(Q3DTheme *theme)
-{
-    dptr()->m_shared->setTheme(theme);
-}
-
-Q3DTheme *Q3DSurface::theme() const
-{
-    return dptrc()->m_shared->theme();
-}
-
-/*!
  * \property Q3DSurface::shadowQuality
  *
  * Sets shadow \a quality to one of \c QDataVis::ShadowQuality. It is preset to
diff --git a/src/datavisualization/engine/q3dsurface.h b/src/datavisualization/engine/q3dsurface.h
index bdbe65f5..b91854d5 100644
--- a/src/datavisualization/engine/q3dsurface.h
+++ b/src/datavisualization/engine/q3dsurface.h
@@ -29,13 +29,11 @@ QT_DATAVISUALIZATION_BEGIN_NAMESPACE
 class Q3DSurfacePrivate;
 class Q3DValueAxis;
 class QSurface3DSeries;
-class Q3DTheme;
 
 class QT_DATAVISUALIZATION_EXPORT Q3DSurface : public Q3DWindow
 {
     Q_OBJECT
     Q_PROPERTY(QtDataVisualization::QDataVis::SelectionFlags selectionMode READ selectionMode WRITE setSelectionMode NOTIFY selectionModeChanged)
-    Q_PROPERTY(Q3DTheme* theme READ theme WRITE setTheme NOTIFY themeChanged)
     Q_PROPERTY(QtDataVisualization::QDataVis::ShadowQuality shadowQuality READ shadowQuality WRITE setShadowQuality NOTIFY shadowQualityChanged)
     Q_PROPERTY(Q3DScene* scene READ scene)
 
@@ -47,9 +45,6 @@ public:
     void removeSeries(QSurface3DSeries *series);
     QList<QSurface3DSeries *> seriesList();
 
-    void setTheme(Q3DTheme *theme);
-    Q3DTheme *theme() const;
-
     void setShadowQuality(QDataVis::ShadowQuality quality);
     QDataVis::ShadowQuality shadowQuality() const;
 
@@ -71,7 +66,6 @@ public:
 
 signals:
     void selectionModeChanged(QDataVis::SelectionFlags mode);
-    void themeChanged(Q3DTheme *theme);
     void shadowQualityChanged(QDataVis::ShadowQuality quality);
 
 protected:
diff --git a/src/datavisualization/engine/q3dwindow.cpp b/src/datavisualization/engine/q3dwindow.cpp
index 5285b585..6bf7da5e 100644
--- a/src/datavisualization/engine/q3dwindow.cpp
+++ b/src/datavisualization/engine/q3dwindow.cpp
@@ -92,6 +92,10 @@ Q3DWindow::Q3DWindow(Q3DWindowPrivate *d, QWindow *parent)
     if (splitversionstr[0].toFloat() < 1.2)
         qFatal("GLSL version must be 1.20 or higher. Try installing latest display drivers.");
 #endif
+
+    QObject::connect(d_ptr->m_visualController, &Abstract3DController::activeThemeChanged, this,
+                     &Q3DWindow::activeThemeChanged);
+
     d_ptr->renderLater();
 }
 
@@ -149,6 +153,62 @@ QAbstract3DInputHandler *Q3DWindow::activeInputHandler()
 }
 
 /*!
+ * Adds the given \a theme to the graph. The themes added via addTheme are not taken in to use
+ * directly. Only the ownership of the a\ theme is given to the graph.
+ * The \a theme must not be null or already added to another graph.
+ *
+ * \sa releaseTheme(), setActiveTheme()
+ */
+void Q3DWindow::addTheme(Q3DTheme *theme)
+{
+    d_ptr->m_visualController->addTheme(theme);
+}
+
+/*!
+ * Releases the ownership of the \a theme back to the caller, if it was added to this graph.
+ * If the released \a theme is in use, a new default theme will be created and set active.
+ *
+ * If the default theme is released and added back later, it behaves as any other theme would.
+ *
+ * \sa addTheme(), setActiveTheme()
+ */
+void Q3DWindow::releaseTheme(Q3DTheme *theme)
+{
+    d_ptr->m_visualController->releaseTheme(theme);
+}
+
+/*!
+ * \property Q3DWindow::activeTheme
+ *
+ * The active \a theme to be used for the graph. Implicitly calls addTheme() to transfer ownership
+ * of the \a theme to this graph.
+ * If the \a theme is null, a temporary default theme is created. This temporary theme is destroyed
+ * if any theme is explicitly set later.
+ * Properties of the \a theme can be modified even after setting it, and the modifications take
+ * effect immediately.
+ */
+void Q3DWindow::setActiveTheme(Q3DTheme *theme)
+{
+    d_ptr->m_visualController->setActiveTheme(theme);
+}
+
+
+Q3DTheme *Q3DWindow::activeTheme() const
+{
+    return d_ptr->m_visualController->activeTheme();
+}
+
+/*!
+ * \return list of all added themes.
+ *
+ * \sa addTheme()
+ */
+QList<Q3DTheme *> Q3DWindow::themes() const
+{
+    return d_ptr->m_visualController->themes();
+}
+
+/*!
  * \internal
  */
 bool Q3DWindow::event(QEvent *event)
diff --git a/src/datavisualization/engine/q3dwindow.h b/src/datavisualization/engine/q3dwindow.h
index cdffc6b9..18542868 100644
--- a/src/datavisualization/engine/q3dwindow.h
+++ b/src/datavisualization/engine/q3dwindow.h
@@ -32,10 +32,12 @@ QT_DATAVISUALIZATION_BEGIN_NAMESPACE
 class Q3DWindowPrivate;
 class Abstract3DController;
 class QAbstract3DInputHandler;
+class Q3DTheme;
 
 class QT_DATAVISUALIZATION_EXPORT Q3DWindow : public QWindow, protected QOpenGLFunctions
 {
     Q_OBJECT
+    Q_PROPERTY(Q3DTheme* activeTheme READ activeTheme WRITE setActiveTheme NOTIFY activeThemeChanged)
 
 protected:
     explicit Q3DWindow(Q3DWindowPrivate *d, QWindow *parent = 0);
@@ -47,11 +49,20 @@ public:
     void setActiveInputHandler(QAbstract3DInputHandler *inputHandler);
     QAbstract3DInputHandler *activeInputHandler();
 
+    void addTheme(Q3DTheme *theme);
+    void releaseTheme(Q3DTheme *theme);
+    void setActiveTheme(Q3DTheme *theme);
+    Q3DTheme *activeTheme() const;
+    QList<Q3DTheme *> themes() const;
+
 protected:
     bool event(QEvent *event);
     void resizeEvent(QResizeEvent *event);
     void exposeEvent(QExposeEvent *event);
 
+signals:
+    void activeThemeChanged(Q3DTheme *theme);
+
 private:
     QScopedPointer<Q3DWindowPrivate> d_ptr;
 
diff --git a/src/datavisualization/theme/q3dtheme.cpp b/src/datavisualization/theme/q3dtheme.cpp
index 3d85b9fa..11773940 100644
--- a/src/datavisualization/theme/q3dtheme.cpp
+++ b/src/datavisualization/theme/q3dtheme.cpp
@@ -377,6 +377,10 @@ QT_DATAVISUALIZATION_BEGIN_NAMESPACE
  * \qmlproperty Theme3D.Theme Theme3D::type
  *
  * The type of the theme. If no type is set, the type is \c Theme3D.ThemeUserDefined.
+ * \note Changing the type to one of the predefined types doesn't reset the properties
+ * that have been explicitly set since the last render cycle. This is done to allow
+ * customization of predefined types also from QML. It is not recommended
+ * changing the type of an existing Theme3D item via this property.
  */
 
 /*!
@@ -862,8 +866,11 @@ Q3DTheme::ColorStyle Q3DTheme::colorStyle() const
 /*!
  * \property Q3DTheme::type
  *
- * The type of the theme. Type is automatically set when constructing a theme. User should not
- * need to use this when using C++ API.
+ * The type of the theme. Type is automatically set when constructing a theme.
+ * \note Changing the type to one of the predefined types doesn't reset the properties
+ * that have been explicitly set since the last render cycle. This is done to allow
+ * customization of predefined types also from QML. It is not recommended
+ * changing the type of an existing Q3DTheme object via this property.
  */
 void Q3DTheme::setType(Theme themeType)
 {
@@ -907,6 +914,7 @@ Q3DThemePrivate::Q3DThemePrivate(Q3DTheme *q, Q3DTheme::Theme theme_id)
       m_backgoundEnabled(true),
       m_gridEnabled(true),
       m_labelBackground(true),
+      m_isDefaultTheme(false),
       q_ptr(q)
 {
     m_baseColors.append(QColor(Qt::black));
diff --git a/src/datavisualization/theme/q3dtheme_p.h b/src/datavisualization/theme/q3dtheme_p.h
index c9f59d99..24994854 100644
--- a/src/datavisualization/theme/q3dtheme_p.h
+++ b/src/datavisualization/theme/q3dtheme_p.h
@@ -97,6 +97,9 @@ public:
 
     bool sync(Q3DThemePrivate &other);
 
+    inline bool isDefaultTheme() { return m_isDefaultTheme; }
+    inline void setDefaultTheme(bool isDefault) { m_isDefaultTheme = isDefault; }
+
 signals:
     void needRender();
 
@@ -126,6 +129,7 @@ public:
     bool m_backgoundEnabled;
     bool m_gridEnabled;
     bool m_labelBackground;
+    bool m_isDefaultTheme;
 
 protected:
     Q3DTheme *q_ptr;
diff --git a/src/datavisualization/theme/thememanager.cpp b/src/datavisualization/theme/thememanager.cpp
index cc5362ef..82e7bb53 100644
--- a/src/datavisualization/theme/thememanager.cpp
+++ b/src/datavisualization/theme/thememanager.cpp
@@ -25,7 +25,7 @@ const float defaultBuiltInColorLevel = 0.7f; // for built-in gradient themes
 const float defaultColorLevel = 0.5f; // for built-in uniform themes
 
 ThemeManager::ThemeManager(Abstract3DController *controller)
-    : m_theme(0),
+    : m_activeTheme(0),
       m_controller(controller)
 {
 }
@@ -34,60 +34,105 @@ ThemeManager::~ThemeManager()
 {
 }
 
-void ThemeManager::setTheme(Q3DTheme *theme)
+void ThemeManager::addTheme(Q3DTheme *theme)
 {
-    if (!theme)
-        return;
-
-    if (m_theme.data() != theme) {
-        // Disconnect old theme signal connections
-        if (m_theme) {
-            disconnect(m_theme->d_ptr.data(), 0, m_controller, 0);
-            disconnect(m_theme.data(), 0, m_controller, 0);
-            disconnect(m_theme.data(), 0, this, 0);
-        }
+    Q_ASSERT(theme);
+    ThemeManager *owner = qobject_cast<ThemeManager *>(theme->parent());
+    if (owner != this) {
+        Q_ASSERT_X(!owner, "addTheme", "Theme already attached to a graph.");
+        theme->setParent(this);
+    }
+    if (!m_themes.contains(theme))
+        m_themes.append(theme);
+}
 
-        m_theme.reset(theme);
+void ThemeManager::releaseTheme(Q3DTheme *theme)
+{
+    if (theme && m_themes.contains(theme)) {
+        // Clear the default status from released default theme
+        if (theme->d_ptr->isDefaultTheme())
+            theme->d_ptr->setDefaultTheme(false);
 
-        Q3DTheme::Theme type = m_theme->type();
+        // If the axis is in use, replace it with a temporary one
+        if (theme == m_activeTheme)
+            setActiveTheme(0);
 
-        if (type != Q3DTheme::ThemeUserDefined) {
-            useTheme(type);
-            // Reset all bits to dirty for sync
-            m_theme->d_ptr->resetDirtyBits();
-        }
+        m_themes.removeAll(theme);
+        theme->setParent(0);
+    }
+}
+
+void ThemeManager::setActiveTheme(Q3DTheme *theme)
+{
+    // Setting null theme indicates using default theme
+    if (!theme) {
+        theme = new Q3DTheme;
+        theme->d_ptr->setDefaultTheme(true);
+    }
 
-        // Connect signals from new one
-        connectThemeSignals();
+    // If the old theme is default theme, delete it
+    Q3DTheme *oldTheme = m_activeTheme;
+    if (oldTheme) {
+        if (oldTheme->d_ptr->isDefaultTheme()) {
+            m_themes.removeAll(oldTheme);
+            delete oldTheme;
+            oldTheme = 0;
+        } else {
+            // Disconnect the old theme from use
+            disconnect(m_activeTheme->d_ptr.data(), 0, m_controller, 0);
+            disconnect(m_activeTheme, 0, m_controller, 0);
+            disconnect(m_activeTheme, 0, this, 0);
+        }
     }
+
+    // Assume ownership
+    addTheme(theme);
+
+    m_activeTheme = theme;
+
+    Q3DTheme::Theme type = m_activeTheme->type();
+
+    if (type != Q3DTheme::ThemeUserDefined)
+        useTheme(type);
+
+    // Reset all bits to dirty for sync
+    m_activeTheme->d_ptr->resetDirtyBits();
+
+    // Connect signals from new one
+    connectThemeSignals();
+}
+
+Q3DTheme *ThemeManager::activeTheme() const
+{
+    return m_activeTheme;
 }
 
-Q3DTheme *ThemeManager::theme() const
+QList<Q3DTheme *> ThemeManager::themes() const
 {
-    return m_theme.data();
+    return m_themes;
 }
 
 void ThemeManager::connectThemeSignals()
 {
-    connect(m_theme.data(), &Q3DTheme::colorStyleChanged,
+    connect(m_activeTheme, &Q3DTheme::colorStyleChanged,
             m_controller, &Abstract3DController::handleThemeColorStyleChanged);
-    connect(m_theme.data(), &Q3DTheme::baseColorsChanged,
+    connect(m_activeTheme, &Q3DTheme::baseColorsChanged,
             m_controller, &Abstract3DController::handleThemeBaseColorsChanged);
-    connect(m_theme.data(), &Q3DTheme::singleHighlightColorChanged,
+    connect(m_activeTheme, &Q3DTheme::singleHighlightColorChanged,
             m_controller, &Abstract3DController::handleThemeSingleHighlightColorChanged);
-    connect(m_theme.data(), &Q3DTheme::multiHighlightColorChanged,
+    connect(m_activeTheme, &Q3DTheme::multiHighlightColorChanged,
             m_controller, &Abstract3DController::handleThemeMultiHighlightColorChanged);
-    connect(m_theme.data(), &Q3DTheme::baseGradientsChanged,
+    connect(m_activeTheme, &Q3DTheme::baseGradientsChanged,
             m_controller, &Abstract3DController::handleThemeBaseGradientsChanged);
-    connect(m_theme.data(), &Q3DTheme::singleHighlightGradientChanged,
+    connect(m_activeTheme, &Q3DTheme::singleHighlightGradientChanged,
             m_controller, &Abstract3DController::handleThemeSingleHighlightGradientChanged);
-    connect(m_theme.data(), &Q3DTheme::multiHighlightGradientChanged,
+    connect(m_activeTheme, &Q3DTheme::multiHighlightGradientChanged,
             m_controller, &Abstract3DController::handleThemeMultiHighlightGradientChanged);
 
-    connect(m_theme->d_ptr.data(), &Q3DThemePrivate::needRender,
+    connect(m_activeTheme->d_ptr.data(), &Q3DThemePrivate::needRender,
             m_controller, &Abstract3DController::needRender);
 
-    connect(m_theme.data(), &Q3DTheme::typeChanged, this, &ThemeManager::useTheme);
+    connect(m_activeTheme, &Q3DTheme::typeChanged, this, &ThemeManager::useTheme);
 }
 
 void ThemeManager::useTheme(Q3DTheme::Theme type)
@@ -425,128 +470,128 @@ QLinearGradient ThemeManager::createGradient(const QColor &color, float colorLev
 
 void ThemeManager::setBaseColors(const QList<QColor> &colors)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.baseColorDirty)
-        m_theme->setBaseColors(colors);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.baseColorDirty)
+        m_activeTheme->setBaseColors(colors);
 }
 
 void ThemeManager::setBackgroundColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.backgroundColorDirty)
-        m_theme->setBackgroundColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.backgroundColorDirty)
+        m_activeTheme->setBackgroundColor(color);
 }
 
 void ThemeManager::setWindowColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.windowColorDirty)
-        m_theme->setWindowColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.windowColorDirty)
+        m_activeTheme->setWindowColor(color);
 }
 
 void ThemeManager::setTextColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.labelTextColorDirty)
-        m_theme->setLabelTextColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.labelTextColorDirty)
+        m_activeTheme->setLabelTextColor(color);
 }
 
 void ThemeManager::setTextBackgroundColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.labelBackgroundColorDirty)
-        m_theme->setLabelBackgroundColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.labelBackgroundColorDirty)
+        m_activeTheme->setLabelBackgroundColor(color);
 }
 
 void ThemeManager::setGridLineColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.gridLineColorDirty)
-        m_theme->setGridLineColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.gridLineColorDirty)
+        m_activeTheme->setGridLineColor(color);
 }
 
 void ThemeManager::setSingleHighlightColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.singleHighlightColorDirty)
-        m_theme->setSingleHighlightColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.singleHighlightColorDirty)
+        m_activeTheme->setSingleHighlightColor(color);
 }
 
 void ThemeManager::setMultiHighlightColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.multiHighlightColorDirty)
-        m_theme->setMultiHighlightColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.multiHighlightColorDirty)
+        m_activeTheme->setMultiHighlightColor(color);
 }
 
 void ThemeManager::setLightColor(const QColor &color)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.lightColorDirty)
-        m_theme->setLightColor(color);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.lightColorDirty)
+        m_activeTheme->setLightColor(color);
 }
 
 void ThemeManager::setBaseGradients(const QList<QLinearGradient> &gradients)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.baseGradientDirty)
-        m_theme->setBaseGradients(gradients);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.baseGradientDirty)
+        m_activeTheme->setBaseGradients(gradients);
 }
 
 void ThemeManager::setSingleHighlightGradient(const QLinearGradient &gradient)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.singleHighlightGradientDirty)
-        m_theme->setSingleHighlightGradient(gradient);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.singleHighlightGradientDirty)
+        m_activeTheme->setSingleHighlightGradient(gradient);
 }
 
 void ThemeManager::setMultiHighlightGradient(const QLinearGradient &gradient)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.multiHighlightGradientDirty)
-        m_theme->setMultiHighlightGradient(gradient);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.multiHighlightGradientDirty)
+        m_activeTheme->setMultiHighlightGradient(gradient);
 }
 
 void ThemeManager::setLightStrength(float strength)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.lightStrengthDirty)
-        m_theme->setLightStrength(strength);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.lightStrengthDirty)
+        m_activeTheme->setLightStrength(strength);
 }
 
 void ThemeManager::setAmbientLightStrength(float strength)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.ambientLightStrengthDirty)
-        m_theme->setAmbientLightStrength(strength);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.ambientLightStrengthDirty)
+        m_activeTheme->setAmbientLightStrength(strength);
 }
 
 void ThemeManager::setHighlightLightStrength(float strength)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.highlightLightStrengthDirty)
-        m_theme->setHighlightLightStrength(strength);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.highlightLightStrengthDirty)
+        m_activeTheme->setHighlightLightStrength(strength);
 }
 
 void ThemeManager::setLabelBorderEnabled(bool enabled)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.labelBorderEnabledDirty)
-        m_theme->setLabelBorderEnabled(enabled);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.labelBorderEnabledDirty)
+        m_activeTheme->setLabelBorderEnabled(enabled);
 }
 
 void ThemeManager::setFont(const QFont &font)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.fontDirty)
-        m_theme->setFont(font);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.fontDirty)
+        m_activeTheme->setFont(font);
 }
 
 void ThemeManager::setBackgroundEnabled(bool enabled)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.backgroundEnabledDirty)
-        m_theme->setBackgroundEnabled(enabled);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.backgroundEnabledDirty)
+        m_activeTheme->setBackgroundEnabled(enabled);
 }
 
 void ThemeManager::setGridEnabled(bool enabled)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.gridEnabledDirty)
-        m_theme->setGridEnabled(enabled);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.gridEnabledDirty)
+        m_activeTheme->setGridEnabled(enabled);
 }
 
 void ThemeManager::setLabelBackgroundEnabled(bool enabled)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.labelBackgroundEnabledDirty)
-        m_theme->setLabelBackgroundEnabled(enabled);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.labelBackgroundEnabledDirty)
+        m_activeTheme->setLabelBackgroundEnabled(enabled);
 }
 
 void ThemeManager::setColorStyle(Q3DTheme::ColorStyle style)
 {
-    if (!m_theme->d_ptr->m_dirtyBits.colorStyleDirty)
-        m_theme->setColorStyle(style);
+    if (!m_activeTheme->d_ptr->m_dirtyBits.colorStyleDirty)
+        m_activeTheme->setColorStyle(style);
 }
 
 QT_DATAVISUALIZATION_END_NAMESPACE
diff --git a/src/datavisualization/theme/thememanager_p.h b/src/datavisualization/theme/thememanager_p.h
index c6e6a107..254bb7bf 100644
--- a/src/datavisualization/theme/thememanager_p.h
+++ b/src/datavisualization/theme/thememanager_p.h
@@ -42,8 +42,11 @@ public:
     ThemeManager(Abstract3DController *controller);
     ~ThemeManager();
 
-    void setTheme(Q3DTheme *theme);
-    Q3DTheme *theme() const;
+    void addTheme(Q3DTheme *theme);
+    void releaseTheme(Q3DTheme *theme);
+    void setActiveTheme(Q3DTheme *theme);
+    Q3DTheme *activeTheme() const;
+    QList<Q3DTheme *> themes() const;
 
 protected:
     void connectThemeSignals();
@@ -72,7 +75,8 @@ protected:
     void setColorStyle(Q3DTheme::ColorStyle style);
 
 private:
-    QScopedPointer<Q3DTheme> m_theme;
+    Q3DTheme *m_activeTheme;
+    QList<Q3DTheme *> m_themes; // List of all added themes
     Abstract3DController *m_controller;
 };
 
diff --git a/src/datavisualizationqml2/abstractdeclarative.cpp b/src/datavisualizationqml2/abstractdeclarative.cpp
index 587ea879..b9f26938 100644
--- a/src/datavisualizationqml2/abstractdeclarative.cpp
+++ b/src/datavisualizationqml2/abstractdeclarative.cpp
@@ -43,12 +43,12 @@ Q3DScene* AbstractDeclarative::scene() const
 
 void AbstractDeclarative::setTheme(Q3DTheme *theme)
 {
-    m_controller->setTheme(theme);
+    m_controller->setActiveTheme(theme);
 }
 
 Q3DTheme *AbstractDeclarative::theme() const
 {
-    return m_controller->theme();
+    return m_controller->activeTheme();
 }
 
 void AbstractDeclarative::setSelectionMode(QDataVis::SelectionFlags mode)
@@ -79,7 +79,7 @@ void AbstractDeclarative::setSharedController(Abstract3DController *controller)
                      &AbstractDeclarative::shadowQualityChanged);
     QObject::connect(m_controller, &Abstract3DController::activeInputHandlerChanged, this,
                      &AbstractDeclarative::inputHandlerChanged);
-    QObject::connect(m_controller, &Abstract3DController::themeChanged, this,
+    QObject::connect(m_controller, &Abstract3DController::activeThemeChanged, this,
                      &AbstractDeclarative::themeChanged);
     QObject::connect(m_controller, &Abstract3DController::selectionModeChanged, this,
                      &AbstractDeclarative::selectionModeChanged);