On Monday 18 July 2011, Aaron J. Seigo wrote:
> On Saturday, July 16, 2011 15:36:19 Martin Gräßlin wrote:
> > The bug is much simpler - Plasma just simply fails to recognize that a
> > compositing manager is active. I can see this each time I restart kwin
> > (which is considerable often). In order to get translucent panels back, I
> > have to kquitapp plasma-desktop, plasma-desktop.
>
> Plasma::Theme uses a KSelectionWatcher which watches _NET_WM_CM_S# where # is
> the number of the default screen.
>
> i can imagine a few things going wrong with this:
>
> * the default screen # changes or even goes away completely; that could
> render
> the selection manager useless. why is the CM atom per screen again? *sigh*
Screen here is about traditional multi-head where you can have different
window managers / compositing managers managing each screen.
> * a race condition as Alex outlined. if kwin is indeed responding to each
> xrandr even with a change in the CM, that seems like a perfect candidate for
> event compression if at all possible: don't tell the world outside that
> things
> have changed until the events have stopped coming in. the timeout for this
> shouldn't need to be long at all, so the user shouldn't see a big change at
> all
>
> * KSelectionWatcher itself and/or kwin's setting of the atom could be broken.
> in times past we've had isses where the KSelectionWatcher object simply did
> not emit any signals at all when kwin changed compositing.
I thought this bug was fixed, because I haven't seen it in a long time.
But I realized that I still have a patch applied that I created a couple
of years ago.
It adds a compositingChanged() signal to KWindowSystem and makes
Plasma::Theme use it. It also uses Xfixes instead of KSelectionWatcher
to monitor the selection.
I never committed the patch because Lubos didn't like the idea. IIRC the
reason was that the signal would be emitted before the compositing
plugins are initialized in kwin.
I have attached the diff in case it fixes the problem for those who are
still seeing it.
Regards,
Fredrik
diff --git a/kdeui/windowmanagement/kwindowsystem.h b/kdeui/windowmanagement/kwindowsystem.h
index dba1da4..6b79cb0 100644
--- a/kdeui/windowmanagement/kwindowsystem.h
+++ b/kdeui/windowmanagement/kwindowsystem.h
@@ -621,6 +621,12 @@ Q_SIGNALS:
*/
void showingDesktopChanged( bool showing );
+ /**
+ * Compositing was enabled or disabled.
+ * @since 4.4
+ */
+ void compositingChanged( bool enabled );
+
protected:
virtual void connectNotify( const char* signal );
diff --git a/kdeui/windowmanagement/kwindowsystem_x11.cpp b/kdeui/windowmanagement/kwindowsystem_x11.cpp
index 51b8e56..741393c 100644
--- a/kdeui/windowmanagement/kwindowsystem_x11.cpp
+++ b/kdeui/windowmanagement/kwindowsystem_x11.cpp
@@ -36,6 +36,12 @@
#include <QtGui/QX11Info>
#include <X11/Xatom.h>
+#include <config.h>
+
+#ifdef HAVE_XFIXES
+#include <X11/extensions/Xfixes.h>
+#endif
+
class KWindowSystemStaticContainer {
public:
KWindowSystemStaticContainer() : d(0) {}
@@ -46,6 +52,8 @@ public:
K_GLOBAL_STATIC(KWindowSystemStaticContainer, g_kwmInstanceContainer)
+static Atom net_wm_cm;
+static void create_atoms( Display* dpy = QX11Info::display() );
static unsigned long windows_properties[ 2 ] = { NET::ClientList | NET::ClientListStacking |
NET::Supported |
@@ -92,7 +100,10 @@ public:
QList<StrutData> strutWindows;
QList<WId> possibleStrutWindows;
bool strutSignalConnected;
+ bool compositingEnabled;
+ bool haveXfixes;
int what;
+ int xfixesEventBase;
bool mapViewport();
void addClient(Window);
@@ -110,10 +121,23 @@ KWindowSystemPrivate::KWindowSystemPrivate(int _what)
_what >= KWindowSystem::INFO_WINDOWS ? windows_properties : desktop_properties,
2, -1, false ),
strutSignalConnected( false ),
+ haveXfixes( false ),
what( _what )
{
KSystemEventFilter::installEventFilter(this);
(void ) qApp->desktop(); //trigger desktop widget creation to select root window events
+
+#ifdef HAVE_XFIXES
+ int errorBase;
+ if ((haveXfixes = XFixesQueryExtension(QX11Info::display(), &xfixesEventBase, &errorBase))) {
+ create_atoms();
+ XFixesSelectSelectionInput(QX11Info::display(), winId(), net_wm_cm,
+ XFixesSetSelectionOwnerNotifyMask |
+ XFixesSelectionWindowDestroyNotifyMask |
+ XFixesSelectionClientCloseNotifyMask);
+ compositingEnabled = XGetSelectionOwner(QX11Info::display(), net_wm_cm) != None;
+ }
+#endif
}
// not virtual, but it's called directly only from init()
@@ -127,6 +151,18 @@ bool KWindowSystemPrivate::x11Event( XEvent * ev )
{
KWindowSystem* s_q = KWindowSystem::self();
+#ifdef HAVE_XFIXES
+ if ( ev->type == xfixesEventBase + XFixesSelectionNotify && ev->xany.window == winId() ) {
+ XFixesSelectionNotifyEvent *event = reinterpret_cast<XFixesSelectionNotifyEvent*>(ev);
+ bool haveOwner = event->owner != None;
+ if (compositingEnabled != haveOwner) {
+ compositingEnabled = haveOwner;
+ emit s_q->compositingChanged( compositingEnabled );
+ }
+ return true;
+ }
+#endif
+
if ( ev->xany.window == QX11Info::appRootWindow() ) {
int old_current_desktop = currentDesktop();
WId old_active_window = activeWindow();
@@ -273,9 +309,8 @@ static bool atoms_created = false;
static Atom kde_wm_change_state;
static Atom _wm_protocols;
static Atom kwm_utf8_string;
-static Atom net_wm_cm;
-static void create_atoms( Display* dpy = QX11Info::display()) {
+static void create_atoms( Display* dpy ) {
if (!atoms_created){
const int max = 20;
Atom* atoms[max];
@@ -759,8 +794,13 @@ void KWindowSystem::lowerWindow( WId win )
bool KWindowSystem::compositingActive()
{
if( QX11Info::display()) {
- create_atoms();
- return XGetSelectionOwner( QX11Info::display(), net_wm_cm ) != None;
+ init( INFO_BASIC );
+ if (s_d_func()->haveXfixes) {
+ return s_d_func()->compositingEnabled;
+ } else {
+ create_atoms();
+ return XGetSelectionOwner( QX11Info::display(), net_wm_cm );
+ }
} else { // work even without QApplication instance
Display* dpy = XOpenDisplay( NULL );
create_atoms( dpy );
diff --git a/plasma/theme.cpp b/plasma/theme.cpp
index c7cc7a3..e21e818 100644
--- a/plasma/theme.cpp
+++ b/plasma/theme.cpp
@@ -97,23 +97,13 @@ public:
ThemeConfig config;
cacheTheme = config.cacheTheme();
-#ifdef Q_WS_X11
- Display *dpy = QX11Info::display();
- int screen = DefaultScreen(dpy);
- locolor = DefaultDepth(dpy, screen) < 16;
-
- if (!locolor) {
- char net_wm_cm_name[100];
- sprintf(net_wm_cm_name, "_NET_WM_CM_S%d", screen);
- compositeWatch = new KSelectionWatcher(net_wm_cm_name, -1, q);
- QObject::connect(compositeWatch, SIGNAL(newOwner(Window)), q, SLOT(compositingChanged()));
- QObject::connect(compositeWatch, SIGNAL(lostOwner()), q, SLOT(compositingChanged()));
+ if (QPixmap::defaultDepth() > 8) {
+ QObject::connect(KWindowSystem::self(), SIGNAL(compositingChanged(bool)), q, SLOT(compositingChanged(bool)));
//watch for blur effect property changes as well
effectWatcher = 0;
effectWatcher = new EffectWatcher("_KDE_NET_WM_BLUR_BEHIND_REGION");
QObject::connect(effectWatcher, SIGNAL(blurBehindChanged(bool)), q, SLOT(blurBehindChanged(bool)));
}
-#endif
saveTimer = new QTimer(q);
saveTimer->setSingleShot(true);
@@ -149,7 +139,7 @@ public:
}
QString findInTheme(const QString &image, const QString &theme) const;
- void compositingChanged();
+ void compositingChanged(bool active);
void discardCache(CacheTypes caches);
void scheduledCacheUpdate();
void colorsChanged();
@@ -266,12 +256,11 @@ QString ThemePrivate::findInTheme(const QString &image, const QString &theme) co
return search;
}
-void ThemePrivate::compositingChanged()
+void ThemePrivate::compositingChanged(bool active)
{
#ifdef Q_WS_X11
- bool nowCompositingActive = compositeWatch->owner() != None;
- if (compositingActive != nowCompositingActive) {
- compositingActive = nowCompositingActive;
+ if (compositingActive != active) {
+ compositingActive = active;
discardCache(PixmapCache | SvgElementsCache);
emit q->themeChanged();
}
diff --git a/plasma/theme.h b/plasma/theme.h
index e4618e2..b511827 100644
--- a/plasma/theme.h
+++ b/plasma/theme.h
@@ -397,7 +397,7 @@ class PLASMA_EXPORT Theme : public QObject
friend class ThemePrivate;
ThemePrivate *const d;
- Q_PRIVATE_SLOT(d, void compositingChanged())
+ Q_PRIVATE_SLOT(d, void compositingChanged(bool))
Q_PRIVATE_SLOT(d, void colorsChanged())
Q_PRIVATE_SLOT(d, void blurBehindChanged(bool blur))
Q_PRIVATE_SLOT(d, void settingsFileChanged(const QString &))
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