Added automatic graphicssystem switching on meego when app is minimized.

When all top-level widgets are minimized we switch to raster to reduce
GPU memory consumption. We switch back to graphicssystem meego when at
least one top-level widget is shown normally again. The switching only
applies when the runtime graphicssystem is being used. The switching
only applies when the runtime graphicssystem is being used.

Task-number: QTBUG-18013
Reviewed-by: Armin Berres

3 files changed, 178 insertions, 15 deletions

diff --git a/src/gui/painting/qgraphicssystem_runtime.cpp b/src/gui/painting/qgraphicssystem_runtime.cpp
index 5841d40..33652ee 100644
--- a/src/gui/painting/qgraphicssystem_runtime.cpp
+++ b/src/gui/painting/qgraphicssystem_runtime.cpp
@@ -394,7 +394,10 @@ void QRuntimeGraphicsSystem::setGraphicsSystem(const QString &name)
         if(m_windowSurfaceDestroyPolicy == DestroyAfterFirstFlush)
             proxy->m_pendingWindowSurface.reset(proxy->m_windowSurface.take());
 
-        proxy->m_windowSurface.reset(m_graphicsSystem->createWindowSurface(widget));
+        QWindowSurface *newWindowSurface = m_graphicsSystem->createWindowSurface(widget);
+        newWindowSurface->setGeometry(proxy->geometry());
+
+        proxy->m_windowSurface.reset(newWindowSurface);
         qt_widget_private(widget)->invalidateBuffer(widget->rect());
     }
 
diff --git a/src/plugins/graphicssystems/meego/qmeegographicssystem.cpp b/src/plugins/graphicssystems/meego/qmeegographicssystem.cpp
index 13eab7f..18a0944 100644
--- a/src/plugins/graphicssystems/meego/qmeegographicssystem.cpp
+++ b/src/plugins/graphicssystems/meego/qmeegographicssystem.cpp
@@ -63,6 +63,8 @@ bool QMeeGoGraphicsSystem::surfaceWasCreated = false;
 
 QHash <Qt::HANDLE, QPixmap*> QMeeGoGraphicsSystem::liveTexturePixmaps;
 
+QList<QMeeGoSwitchCallback> QMeeGoGraphicsSystem::switchCallbacks;
+
 QMeeGoGraphicsSystem::QMeeGoGraphicsSystem()
 {
     qDebug("Using the meego graphics system");
@@ -74,6 +76,78 @@ QMeeGoGraphicsSystem::~QMeeGoGraphicsSystem()
     qt_destroy_gl_share_widget();
 }
 
+class QMeeGoGraphicsSystemSwitchHandler : public QObject
+{
+    Q_OBJECT
+public:
+    QMeeGoGraphicsSystemSwitchHandler();
+
+    void addWidget(QWidget *widget);
+    bool eventFilter(QObject *, QEvent *);
+
+private slots:
+    void removeWidget(QObject *object);
+
+private:
+    int visibleWidgets() const;
+
+private:
+    QList<QWidget *> m_widgets;
+};
+
+QMeeGoGraphicsSystemSwitchHandler::QMeeGoGraphicsSystemSwitchHandler()
+{
+}
+
+void QMeeGoGraphicsSystemSwitchHandler::addWidget(QWidget *widget)
+{
+    if (!m_widgets.contains(widget)) {
+        widget->installEventFilter(this);
+        connect(widget, SIGNAL(destroyed(QObject *)), this, SLOT(removeWidget(QObject *)));
+        m_widgets << widget;
+    }
+}
+
+void QMeeGoGraphicsSystemSwitchHandler::removeWidget(QObject *object)
+{
+    m_widgets.removeOne(static_cast<QWidget *>(object));
+}
+
+int QMeeGoGraphicsSystemSwitchHandler::visibleWidgets() const
+{
+    int count = 0;
+    for (int i = 0; i < m_widgets.size(); ++i)
+        count += m_widgets.at(i)->isVisible() && !(m_widgets.at(i)->windowState() & Qt::WindowMinimized);
+    return count;
+}
+
+bool QMeeGoGraphicsSystemSwitchHandler::eventFilter(QObject *object, QEvent *event)
+{
+    if (event->type() == QEvent::WindowStateChange) {
+        QWindowStateChangeEvent *change = static_cast<QWindowStateChangeEvent *>(event);
+        QWidget *widget = static_cast<QWidget *>(object);
+
+        Qt::WindowStates current = widget->windowState();
+        Qt::WindowStates old = change->oldState();
+
+        // did minimized flag change?
+        if ((current ^ old) & Qt::WindowMinimized) {
+            if (current & Qt::WindowMinimized) {
+                if (visibleWidgets() == 0)
+                    QMeeGoGraphicsSystem::switchToRaster();
+            } else {
+                if (visibleWidgets() == 1)
+                    QMeeGoGraphicsSystem::switchToMeeGo();
+            }
+        }
+    }
+
+    // resume processing of event
+    return false;
+}
+
+Q_GLOBAL_STATIC(QMeeGoGraphicsSystemSwitchHandler, switch_handler)
+
 QWindowSurface* QMeeGoGraphicsSystem::createWindowSurface(QWidget *widget) const
 {
     QGLWidget *shareWidget = qt_gl_share_widget();
@@ -83,6 +157,9 @@ QWindowSurface* QMeeGoGraphicsSystem::createWindowSurface(QWidget *widget) const
 
     QGLShareContextScope ctx(shareWidget->context());
 
+    if (QApplicationPrivate::instance()->graphics_system_name == QLatin1String("runtime"))
+        switch_handler()->addWidget(widget);
+
     QMeeGoGraphicsSystem::surfaceWasCreated = true;
     QWindowSurface *surface = new QGLWindowSurface(widget);
     return surface;
@@ -203,18 +280,7 @@ QPixmapData *QMeeGoGraphicsSystem::pixmapDataWithGLTexture(int w, int h)
 
 bool QMeeGoGraphicsSystem::meeGoRunning()
 {
-    if (! QApplicationPrivate::instance()) {
-        qWarning("Application not running just yet... hard to know what system running!");
-        return false;
-    }
-
-    QString name = QApplicationPrivate::instance()->graphics_system_name;
-    if (name == "runtime") {
-        QRuntimeGraphicsSystem *rsystem = (QRuntimeGraphicsSystem *) QApplicationPrivate::instance()->graphics_system;
-        name = rsystem->graphicsSystemName();
-    }
-
-    return (name == "meego");
+    return runningGraphicsSystemName() == "meego";
 }
 
 QPixmapData* QMeeGoGraphicsSystem::pixmapDataWithNewLiveTexture(int w, int h, QImage::Format format)
@@ -259,6 +325,69 @@ void QMeeGoGraphicsSystem::destroyFenceSync(void *fenceSync)
     QMeeGoExtensions::eglDestroySyncKHR(QEgl::display(), fenceSync);
 }
 
+QString QMeeGoGraphicsSystem::runningGraphicsSystemName()
+{
+    if (!QApplicationPrivate::instance()) {
+        qWarning("Querying graphics system but application not running yet!");
+        return QString();
+    }
+
+    QString name = QApplicationPrivate::instance()->graphics_system_name;
+    if (name == QLatin1String("runtime")) {
+        QRuntimeGraphicsSystem *rsystem = (QRuntimeGraphicsSystem *) QApplicationPrivate::instance()->graphics_system;
+        name = rsystem->graphicsSystemName();
+    }
+
+    return name;
+}
+
+void QMeeGoGraphicsSystem::switchToMeeGo()
+{
+    if (meeGoRunning())
+        return;
+
+    if (QApplicationPrivate::instance()->graphics_system_name != QLatin1String("runtime"))
+        qWarning("Can't switch to meego - switching only supported with 'runtime' graphics system.");
+    else {
+        triggerSwitchCallbacks(0, "meego");
+
+        QApplication *app = static_cast<QApplication *>(QCoreApplication::instance());
+        app->setGraphicsSystem(QLatin1String("meego"));
+
+        triggerSwitchCallbacks(1, "meego");
+    }
+}
+
+void QMeeGoGraphicsSystem::switchToRaster()
+{
+    if (runningGraphicsSystemName() == QLatin1String("raster"))
+        return;
+
+    if (QApplicationPrivate::instance()->graphics_system_name != QLatin1String("runtime"))
+        qWarning("Can't switch to raster - switching only supported with 'runtime' graphics system.");
+    else {
+        triggerSwitchCallbacks(0, "raster");
+
+        QApplication *app = static_cast<QApplication *>(QCoreApplication::instance());
+        app->setGraphicsSystem(QLatin1String("raster"));
+
+        QMeeGoLivePixmapData::invalidateSurfaces();
+
+        triggerSwitchCallbacks(1, "raster");
+    }
+}
+
+void QMeeGoGraphicsSystem::registerSwitchCallback(QMeeGoSwitchCallback callback)
+{
+    switchCallbacks << callback;
+}
+
+void QMeeGoGraphicsSystem::triggerSwitchCallbacks(int type, const char *name)
+{
+    for (int i = 0; i < switchCallbacks.size(); ++i)
+        switchCallbacks.at(i)(type, name);
+}
+
 /* C API */
 
 int qt_meego_image_to_egl_shared_image(const QImage &image)
@@ -340,3 +469,20 @@ void qt_meego_invalidate_live_surfaces(void)
 {
     return QMeeGoLivePixmapData::invalidateSurfaces();
 }
+
+void qt_meego_switch_to_raster(void)
+{
+    QMeeGoGraphicsSystem::switchToRaster();
+}
+
+void qt_meego_switch_to_meego(void)
+{
+    QMeeGoGraphicsSystem::switchToMeeGo();
+}
+
+void qt_meego_register_switch_callback(QMeeGoSwitchCallback callback)
+{
+    QMeeGoGraphicsSystem::registerSwitchCallback(callback);
+}
+
+#include "qmeegographicssystem.moc"
diff --git a/src/plugins/graphicssystems/meego/qmeegographicssystem.h b/src/plugins/graphicssystems/meego/qmeegographicssystem.h
index 27a4e7a..ecc85b2 100644
--- a/src/plugins/graphicssystems/meego/qmeegographicssystem.h
+++ b/src/plugins/graphicssystems/meego/qmeegographicssystem.h
@@ -47,6 +47,8 @@
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 
+extern "C" typedef void (*QMeeGoSwitchCallback)(int type, const char *name);
+
 class QMeeGoGraphicsSystem : public QGraphicsSystem
 {
 public:
@@ -76,13 +78,22 @@ public:
     static void* createFenceSync();
     static void destroyFenceSync(void* fenceSync);
 
+    static void switchToRaster();
+    static void switchToMeeGo();
+    static QString runningGraphicsSystemName();
+
+    static void registerSwitchCallback(QMeeGoSwitchCallback callback);
+
 private:
     static bool meeGoRunning();
     static EGLSurface getSurfaceForLiveTexturePixmap(QPixmap *pixmap);
     static void destroySurfaceForLiveTexturePixmap(QPixmapData* pmd);
+    static void triggerSwitchCallbacks(int type, const char *name);
 
     static bool surfaceWasCreated;
-    static QHash <Qt::HANDLE, QPixmap*> liveTexturePixmaps;
+    static QHash<Qt::HANDLE, QPixmap*> liveTexturePixmaps;
+    static QList<QMeeGoSwitchCallback> switchCallbacks;
+
 };
 
 /* C api */
@@ -95,7 +106,7 @@ extern "C" {
     Q_DECL_EXPORT bool qt_meego_destroy_egl_shared_image(Qt::HANDLE handle);
     Q_DECL_EXPORT void qt_meego_set_surface_fixed_size(int width, int height);
     Q_DECL_EXPORT void qt_meego_set_surface_scaling(int x, int y, int width, int height);
-    Q_DECL_EXPORT void qt_meego_set_translucent(bool translucent);    
+    Q_DECL_EXPORT void qt_meego_set_translucent(bool translucent);
     Q_DECL_EXPORT QPixmapData* qt_meego_pixmapdata_with_new_live_texture(int w, int h, QImage::Format format);
     Q_DECL_EXPORT QPixmapData* qt_meego_pixmapdata_from_live_texture_handle(Qt::HANDLE handle);
     Q_DECL_EXPORT QImage* qt_meego_live_texture_lock(QPixmap *pixmap, void *fenceSync);
@@ -104,6 +115,9 @@ extern "C" {
     Q_DECL_EXPORT void* qt_meego_create_fence_sync(void);
     Q_DECL_EXPORT void qt_meego_destroy_fence_sync(void* fs);
     Q_DECL_EXPORT void qt_meego_invalidate_live_surfaces(void);
+    Q_DECL_EXPORT void qt_meego_switch_to_raster(void);
+    Q_DECL_EXPORT void qt_meego_switch_to_meego(void);
+    Q_DECL_EXPORT void qt_meego_register_switch_callback(QMeeGoSwitchCallback callback);
 }
 
 #endif