QGtkStyle: Fix styling and palette issues related to combo box

Well actually this change is a bit bigger than just that.

*We no longer override the palette you provide in polish so it should
be a bit more frienly toward custom application changes.

* Another issue  was that we  would generate the palette information
when we got the style callback from gtkButton but then the line edits might not yet have been
polished. Hence we now return from the callback and instead post the
update for later.

* We had to modify the PE_Frame entry to draw a raised menu when the
custom combo box delegate was used.

* We now simply ignore custom
qtconfig palette entries when using GtkStyle since they only cause
trouble with it.

Task-number: 250142
Reviewed-by: nrc

3 files changed, 83 insertions, 36 deletions

diff --git a/src/gui/styles/gtksymbols.cpp b/src/gui/styles/gtksymbols.cpp
index f60c980..8123d32 100644
--- a/src/gui/styles/gtksymbols.cpp
+++ b/src/gui/styles/gtksymbols.cpp
@@ -75,6 +75,7 @@
 QT_BEGIN_NAMESPACE
 
 static bool displayDepth  =  -1;
+Q_GLOBAL_STATIC(QGtkStyleUpdateScheduler, styleScheduler)
 
 typedef QHash<QString, GtkWidget*> WidgetMap;
 Q_GLOBAL_STATIC(WidgetMap, gtkWidgetMap)
@@ -486,11 +487,11 @@ static void init_gtk_menu()
 }
 
 // Updates window/windowtext palette based on the indicated gtk widget
-static void ensureWidgetPalette(QWidget* widget, const QString &gtkWidgetName)
+static QPalette gtkWidgetPalette(const QString &gtkWidgetName)
 {
     GtkWidget *gtkWidget = QGtk::gtkWidget(gtkWidgetName);
     Q_ASSERT(gtkWidget);
-    QPalette pal = widget->palette();
+    QPalette pal = QApplication::palette();
     GdkColor gdkBg = gtkWidget->style->bg[GTK_STATE_NORMAL];
     GdkColor gdkText = gtkWidget->style->fg[GTK_STATE_NORMAL];
     GdkColor gdkDisabledText = gtkWidget->style->fg[GTK_STATE_INSENSITIVE];
@@ -503,8 +504,14 @@ static void ensureWidgetPalette(QWidget* widget, const QString &gtkWidgetName)
     pal.setBrush(QPalette::Disabled, QPalette::WindowText, disabledTextColor);
     pal.setBrush(QPalette::All, QPalette::ButtonText, textColor);
     pal.setBrush(QPalette::Disabled, QPalette::ButtonText, disabledTextColor);
-    widget->setPalette(pal);
-    widget->setAttribute(Qt::WA_SetPalette, false);
+    if (gtkWidgetName == QLS("GtkMenu")) {
+        // This really applies to the combo box rendering since
+        // QComboBox copies the palette from a QMenu
+        GdkColor gdkBg = gtkWidget->style->bg[GTK_STATE_NORMAL];
+        QColor bgColor(gdkBg.red>>8, gdkBg.green>>8, gdkBg.blue>>8);
+        pal.setBrush(QPalette::Base, bgColor);
+    }
+    return pal;
 }
 
 bool QGtk::isKDE4Session()
@@ -515,44 +522,45 @@ bool QGtk::isKDE4Session()
     return (version == 4);
 }
 
-// Maps a Gtk widget palettes to a Qt widget
-void QGtk::applyGtkSystemPalette(QWidget *widget)
+void QGtk::applyCustomPaletteHash()
 {
-    // Do not apply if the widget has a custom palette;
-    if (widget->testAttribute(Qt::WA_SetPalette))
-        return;
+    QPalette menuPal = gtkWidgetPalette(QLS("GtkMenu"));
+    GdkColor gdkBg = QGtk::gtkWidget(QLS("GtkMenu"))->style->bg[GTK_STATE_NORMAL];
+    QColor bgColor(gdkBg.red>>8, gdkBg.green>>8, gdkBg.blue>>8);
+    menuPal.setBrush(QPalette::Base, bgColor);
+    qApp->setPalette(menuPal, "QMenu");
 
-    QPalette pal;
-    if (QStatusBar *statusbar = qobject_cast<QStatusBar*> (widget))
-        ensureWidgetPalette(statusbar, QLS("GtkStatusbar"));
-    else if (QMenuBar *menubar = qobject_cast<QMenuBar*> (widget))
-        ensureWidgetPalette(menubar, QLS("GtkMenuBar"));
-    else if (QToolBar *toolbar = qobject_cast<QToolBar*> (widget))
-        ensureWidgetPalette(toolbar, QLS("GtkToolbar"));
-    else if (QMenu *menu = qobject_cast<QMenu*> (widget)) {
-        // This really applies to the combo box rendering since
-        // QComboBox copies the palette from a QMenu
-        QPalette pal = widget->palette();
-        GdkColor gdkBg = QGtk::gtkWidget(QLS("GtkMenu"))->style->bg[GTK_STATE_NORMAL];
-        QColor bgColor(gdkBg.red>>8, gdkBg.green>>8, gdkBg.blue>>8);
-        pal.setBrush(QPalette::Base, bgColor);
-        menu->setPalette(pal);
-    }
-    widget->setAttribute(Qt::WA_SetPalette, false);
+    QPalette toolbarPal = gtkWidgetPalette(QLS("GtkToolbar"));
+    qApp->setPalette(toolbarPal, "QToolBar");
+
+    QPalette menuBarPal = gtkWidgetPalette(QLS("GtkMenuBar"));
+    qApp->setPalette(menuBarPal, "QMenuBar");
 }
 
 static void gtkStyleSetCallback(GtkWidget*, GtkStyle*, void*)
 {
+    // We have to let this function return and complete the event
+    // loop to ensure that all gtk widgets have been styled before
+    // updating
+    QMetaObject::invokeMethod(styleScheduler(), "updateTheme", Qt::QueuedConnection);
+}
+
+void QGtkStyleUpdateScheduler::updateTheme()
+{
     static QString oldTheme(QLS("qt_not_set"));
     QPixmapCache::clear();
-    qApp->setFont(QGtk::getThemeFont());
-    QGtk::initGtkWidgets();
     if (oldTheme != getThemeName()) {
         oldTheme = getThemeName();
-        QApplicationPrivate::setSystemPalette(qApp->style()->standardPalette());
+        qApp->setFont(QGtk::getThemeFont());
+        QPalette newPalette = qApp->style()->standardPalette();
+        QApplicationPrivate::setSystemPalette(newPalette);
+        QApplication::setPalette(newPalette);
+        QGtk::applyCustomPaletteHash();
         QList<QWidget*> widgets = QApplication::allWidgets();
+        // Notify all widgets that size metrics might have changed
         foreach (QWidget *widget, widgets) {
-            QGtk::applyGtkSystemPalette(widget);
+            QEvent e(QEvent::StyleChange);
+            QApplication::sendEvent(widget, &e);
         }
     }
 }
diff --git a/src/gui/styles/gtksymbols_p.h b/src/gui/styles/gtksymbols_p.h
index 0cea542..74c5dc3 100644
--- a/src/gui/styles/gtksymbols_p.h
+++ b/src/gui/styles/gtksymbols_p.h
@@ -204,7 +204,7 @@ public:
     static void cleanup_gtk_widgets();
     static void initGtkWidgets();
     static bool isKDE4Session();
-    static void applyGtkSystemPalette(QWidget* widget);
+    static void applyCustomPaletteHash();
     static QFont getThemeFont();
     static bool isThemeAvailable() { return gtkStyle() != 0; }
 
@@ -329,6 +329,15 @@ public:
     static Ptr_gconf_client_get_string gconf_client_get_string;
 };
 
+// Helper to ensure that we have polished all our gtk widgets
+// before updating our own palettes
+class QGtkStyleUpdateScheduler : public QObject
+{
+    Q_OBJECT
+public slots:
+    void updateTheme();
+};
+
 QT_END_NAMESPACE
 
 #endif // !QT_NO_STYLE_GTK
diff --git a/src/gui/styles/qgtkstyle.cpp b/src/gui/styles/qgtkstyle.cpp
index 81d7cb8..6354ce7 100644
--- a/src/gui/styles/qgtkstyle.cpp
+++ b/src/gui/styles/qgtkstyle.cpp
@@ -38,7 +38,6 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
-
 #include "qgtkstyle.h"
 
 #if !defined(QT_NO_STYLE_GTK)
@@ -138,6 +137,30 @@ static const char * const dock_widget_restore_xpm[] =
     };
 
 
+class QGtkStyleFilter : public QObject
+{
+public:
+    QGtkStyleFilter() {
+        qApp->installEventFilter(this);
+    }
+
+private:
+    bool eventFilter(QObject *obj, QEvent *e);
+};
+
+bool QGtkStyleFilter::eventFilter(QObject *obj, QEvent *e)
+{
+    if (e->type() == QEvent::ApplicationPaletteChange) {
+        // Only do this the first time since this will also
+        // generate applicationPaletteChange events
+        extern QHash<QByteArray, QPalette> *qt_app_palettes_hash(); //qapplication.cpp
+        if (!qt_app_palettes_hash() ||  qt_app_palettes_hash()->isEmpty()) {
+            QGtk::applyCustomPaletteHash();
+        }
+    }
+    return QObject::eventFilter(obj, e);
+}
+
 class QGtkStylePrivate : public QCleanlooksStylePrivate
 {
     Q_DECLARE_PUBLIC(QGtkStyle)
@@ -145,6 +168,7 @@ public:
     QGtkStylePrivate()
             : QCleanlooksStylePrivate()
     {}
+    QGtkStyleFilter filter;
 };
 
 static const int groupBoxBottomMargin    =  2;  // space below the groupbox
@@ -217,6 +241,7 @@ static QString uniqueName(const QString &key, const QStyleOption *option, const
     Constructs a QGtkStyle object.
 */
 QGtkStyle::QGtkStyle()
+    : QCleanlooksStyle(*new QGtkStylePrivate)
 {
     QGtk::initGtkWidgets();
 }
@@ -313,7 +338,7 @@ void QGtkStyle::polish(QPalette &palette)
     if (!QGtk::isThemeAvailable())
         QCleanlooksStyle::polish(palette);
     else
-        palette = standardPalette();
+        palette = palette.resolve(standardPalette());
 }
 
 /*!
@@ -328,6 +353,7 @@ void QGtkStyle::polish(QApplication *app)
     if (app->desktopSettingsAware() && QGtk::isThemeAvailable()) {
         QApplicationPrivate::setSystemPalette(standardPalette());
         QApplicationPrivate::setSystemFont(QGtk::getThemeFont());
+        QGtk::applyCustomPaletteHash();
         if (!QGtk::isKDE4Session()) {
             qt_filedialog_open_filename_hook = &QGtk::openFilename;
             qt_filedialog_save_filename_hook = &QGtk::saveFilename;
@@ -357,12 +383,12 @@ void QGtkStyle::unpolish(QApplication *app)
 /*!
     \reimp
 */
+
 void QGtkStyle::polish(QWidget *widget)
 {
     QCleanlooksStyle::polish(widget);
     if (!QGtk::isThemeAvailable())
         return;
-
     if (qobject_cast<QAbstractButton*>(widget)
             || qobject_cast<QToolButton*>(widget)
             || qobject_cast<QComboBox*>(widget)
@@ -375,8 +401,6 @@ void QGtkStyle::polish(QWidget *widget)
         widget->setAttribute(Qt::WA_Hover);
     else if (QTreeView *tree = qobject_cast<QTreeView *> (widget))
         tree->viewport()->setAttribute(Qt::WA_Hover);
-
-    QGtk::applyGtkSystemPalette(widget);
 }
 
 /*!
@@ -647,6 +671,12 @@ void QGtkStyle::drawPrimitive(PrimitiveElement element,
 
     switch (element) {
       case PE_Frame: {
+        if (widget && widget->inherits("QComboBoxPrivateContainer")){
+            QStyleOption copy = *option;
+            copy.state |= State_Raised;
+            drawPrimitive(PE_PanelMenu, &copy, painter, widget);
+            break;
+        }
         // Drawing the entire itemview frame is very expensive, especially on the native X11 engine
         // Instead we cheat a bit and draw a border image without the center part, hence only scaling
         // thin rectangular images