xcb: Propagate a few theme hint changes to QGuiApplication

When the xsettings value of relevant style hints is changed
we propagate it to QGuiApplication via handleThemeChange.

Change-Id: I316c90e776f52e92c1249aa4e1fcb3ced331f8f5
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 23 insertions, 5 deletions

diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index 8b49fb73ca..e32891e814 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/src/plugins/platforms/xcb/qxcbintegration.cpp
@@ -325,6 +325,13 @@ QAbstractEventDispatcher *QXcbIntegration::createEventDispatcher() const
     return QXcbEventDispatcher::createEventDispatcher(connection());
 }
 
+using namespace Qt::Literals::StringLiterals;
+static const auto xsNetCursorBlink = "Net/CursorBlink"_ba;
+static const auto xsNetCursorBlinkTime = "Net/CursorBlinkTime"_ba;
+static const auto xsNetDoubleClickTime = "Net/DoubleClickTime"_ba;
+static const auto xsNetDoubleClickDistance = "Net/DoubleClickDistance"_ba;
+static const auto xsNetDndDragThreshold = "Net/DndDragThreshold"_ba;
+
 void QXcbIntegration::initialize()
 {
     const auto defaultInputContext = "compose"_L1;
@@ -338,6 +345,17 @@ void QXcbIntegration::initialize()
         m_inputContext.reset(QPlatformInputContextFactory::create(defaultInputContext));
 
     connection()->keyboard()->initialize();
+
+    auto notifyThemeChanged = [](QXcbVirtualDesktop *, const QByteArray &, const QVariant &, void *) {
+        QWindowSystemInterface::handleThemeChange();
+    };
+
+    auto *xsettings = connection()->primaryScreen()->xSettings();
+    xsettings->registerCallbackForProperty(xsNetCursorBlink, notifyThemeChanged, this);
+    xsettings->registerCallbackForProperty(xsNetCursorBlinkTime, notifyThemeChanged, this);
+    xsettings->registerCallbackForProperty(xsNetDoubleClickTime, notifyThemeChanged, this);
+    xsettings->registerCallbackForProperty(xsNetDoubleClickDistance, notifyThemeChanged, this);
+    xsettings->registerCallbackForProperty(xsNetDndDragThreshold, notifyThemeChanged, this);
 }
 
 void QXcbIntegration::moveToScreen(QWindow *window, int screen)
@@ -435,17 +453,17 @@ QVariant QXcbIntegration::styleHint(QPlatformIntegration::StyleHint hint) const
     case QPlatformIntegration::CursorFlashTime: {
         bool ok = false;
         // If cursor blinking is off, returns 0 to keep the cursor awlays display.
-        if (connection()->primaryScreen()->xSettings()->setting(QByteArrayLiteral("Net/CursorBlink")).toInt(&ok) == 0 && ok)
+        if (connection()->primaryScreen()->xSettings()->setting(xsNetCursorBlink).toInt(&ok) == 0 && ok)
             return 0;
 
-        RETURN_VALID_XSETTINGS(QByteArrayLiteral("Net/CursorBlinkTime"));
+        RETURN_VALID_XSETTINGS(xsNetCursorBlinkTime);
         break;
     }
     case QPlatformIntegration::MouseDoubleClickInterval:
-        RETURN_VALID_XSETTINGS(QByteArrayLiteral("Net/DoubleClickTime"));
+        RETURN_VALID_XSETTINGS(xsNetDoubleClickTime);
         break;
     case QPlatformIntegration::MouseDoubleClickDistance:
-        RETURN_VALID_XSETTINGS(QByteArrayLiteral("Net/DoubleClickDistance"));
+        RETURN_VALID_XSETTINGS(xsNetDoubleClickDistance);
         break;
     case QPlatformIntegration::KeyboardInputInterval:
     case QPlatformIntegration::StartDragTime:
@@ -457,7 +475,7 @@ QVariant QXcbIntegration::styleHint(QPlatformIntegration::StyleHint hint) const
         // TODO using various xcb, gnome or KDE settings
         break; // Not implemented, use defaults
     case QPlatformIntegration::StartDragDistance: {
-        RETURN_VALID_XSETTINGS(QByteArrayLiteral("Net/DndDragThreshold"));
+        RETURN_VALID_XSETTINGS(xsNetDndDragThreshold);
 
         // The default (in QPlatformTheme::defaultThemeHint) is 10 pixels, but
         // on a high-resolution screen it makes sense to increase it.