fix (static-blur): Invalidate cached wallpaper when changed

src/CMakeLists.txt

@@ -29,6 +29,7 @@ if(BETTERBLUR_WAYLAND)
         KDecoration3::KDecoration
         KF6::ConfigGui
         KWin::kwin
+        Qt6::DBus
     )
     install(TARGETS forceblur DESTINATION ${KDE_INSTALL_PLUGINDIR}/kwin/effects/plugins)
 endif()
@@ -38,6 +39,7 @@ if(BETTERBLUR_X11)
         KDecoration3::KDecoration
         KF6::ConfigGui
         KWinX11::kwin
+        Qt6::DBus
     )
     target_compile_definitions(forceblur_x11 PRIVATE BETTERBLUR_X11)
     install(TARGETS forceblur_x11 DESTINATION ${KDE_INSTALL_PLUGINDIR}/kwin-x11/effects/plugins)

src/blur.cpp

@@ -25,10 +25,12 @@
 #include "wayland/display.h"
 #include "wayland/surface.h"
 
+#include <QDBusConnection>
 #include <QGuiApplication>
 #include <QImage>
 #include <QMatrix4x4>
 #include <QScreen>
+#include <QStringLiteral>
 #include <QTime>
 #include <QTimer>
 #include <QWindow>
@@ -160,6 +162,8 @@ BlurEffect::BlurEffect()
         slotScreenAdded(screen);
     }
 
+    updateWallpaperChangedConnection();
+
     m_valid = true;
 }
 
@@ -169,6 +173,17 @@ BlurEffect::~BlurEffect()
     if (s_blurManager) {
         s_blurManagerRemoveTimer->start(1000);
     }
+
+    // Disconnect from DBus if connected
+    if (m_wallpaperChangedConnectionActive)
+    {
+        QDBusConnection::sessionBus().disconnect(QStringLiteral("org.kde.plasmashell"),
+                                                QStringLiteral("/PlasmaShell"),
+                                                QStringLiteral("org.kde.PlasmaShell"),
+                                                QStringLiteral("wallpaperChanged"),
+                                                this,
+                                                SLOT(slotWallpaperChanged(uint)));
+    }
 }
 
 void BlurEffect::initBlurStrengthValues()
@@ -232,6 +247,7 @@ void BlurEffect::initBlurStrengthValues()
 void BlurEffect::reconfigure(ReconfigureFlags flags)
 {
     m_settings.read();
+    updateWallpaperChangedConnection();
 
     m_iterationCount = blurStrengthValues[m_settings.general.blurStrength].iteration;
     m_offset = blurStrengthValues[m_settings.general.blurStrength].offset;
@@ -329,6 +345,32 @@ bool BlurEffect::hasStaticBlur(EffectWindow *w)
     return true;
 }
 
+void BlurEffect::updateWallpaperChangedConnection()
+{
+    const bool shouldBeConnected = m_settings.staticBlur.enable
+                                && m_settings.staticBlur.imageSource == StaticBlurImageSource::DesktopWallpaper;
+
+    if (shouldBeConnected && !m_wallpaperChangedConnectionActive) {
+        m_wallpaperChangedConnectionActive = QDBusConnection::sessionBus().connect(QStringLiteral("org.kde.plasmashell"),
+                                                                                   QStringLiteral("/PlasmaShell"),
+                                                                                   QStringLiteral("org.kde.PlasmaShell"),
+                                                                                   QStringLiteral("wallpaperChanged"),
+                                                                                   this,
+                                                                                   SLOT(slotWallpaperChanged(uint)));
+        if (!m_wallpaperChangedConnectionActive) {
+            qCWarning(KWIN_BLUR) <<"Failed to connect to wallpaperChanged DBus signal.";
+        }
+    } else if (!shouldBeConnected && m_wallpaperChangedConnectionActive) {
+        QDBusConnection::sessionBus().disconnect(QStringLiteral("org.kde.plasmashell"),
+                                                 QStringLiteral("/PlasmaShell"),
+                                                 QStringLiteral("org.kde.PlasmaShell"),
+                                                 QStringLiteral("wallpaperChanged"),
+                                                 this,
+                                                 SLOT(slotWallpaperChanged(uint)));
+        m_wallpaperChangedConnectionActive = false;
+    }
+}
+
 void BlurEffect::slotWindowAdded(EffectWindow *w)
 {
     SurfaceInterface *surf = w->surface();
@@ -434,6 +476,18 @@ void BlurEffect::setupDecorationConnections(EffectWindow *w)
     });
 }
 
+void BlurEffect::slotWallpaperChanged(uint screenNum) {
+    const auto screens = effects->screens();
+
+    if (screenNum >= screens.size()) {
+        return;
+    }
+
+    Output *screen = screens.at(screenNum);
+
+    m_staticBlurTextures.erase(screen);
+}
+
 bool BlurEffect::eventFilter(QObject *watched, QEvent *event)
 {
     auto internal = qobject_cast<QWindow *>(watched);

src/blur.h

@@ -84,6 +84,9 @@ public Q_SLOTS:
     void slotPropertyNotify(KWin::EffectWindow *w, long atom);
     void setupDecorationConnections(EffectWindow *w);
 
+private Q_SLOTS:
+  void slotWallpaperChanged(uint screenNum);
+
 private:
     void initBlurStrengthValues();
     QRegion blurRegion(EffectWindow *w) const;
@@ -93,6 +96,7 @@ public Q_SLOTS:
     bool shouldForceBlur(const EffectWindow *w) const;
     void updateBlurRegion(EffectWindow *w, bool geometryChanged = false);
     bool hasStaticBlur(EffectWindow *w);
+    void updateWallpaperChangedConnection();
     QMatrix4x4 colorMatrix(const float &brightness, const float &saturation, const float &contrast) const;
 
     /*
@@ -213,6 +217,7 @@ public Q_SLOTS:
     QList<BlurValuesStruct> blurStrengthValues;
 
     std::unordered_map<const Output*, std::unique_ptr<GLTexture>> m_staticBlurTextures;
+    bool m_wallpaperChangedConnectionActive = false;
 
     // Windows to blur even when transformed.
     QList<const EffectWindow*> m_blurWhenTransformed;