release broadcasted backgrounds when not needed

--an example could be when the user decides to change
wallpaper plugin for its desktop from a slideshow
to other wallpaper plugins

liblatte2/plasma/extended/backgroundcache.cpp

@@ -88,8 +88,7 @@ void BackgroundCache::settingsFileChanged(const QString &file) {
     }
 }
 
-QString BackgroundCache::backgroundFromConfig(const KConfigGroup &config) const {
-    auto wallpaperPlugin = config.readEntry("wallpaperplugin");
+QString BackgroundCache::backgroundFromConfig(const KConfigGroup &config, QString wallpaperPlugin) const {
     auto wallpaperConfig = config.group("Wallpaper").group(wallpaperPlugin).group("General");
 
     if (wallpaperConfig.hasKey("Image")) {
@@ -131,6 +130,7 @@ void BackgroundCache::reload()
 
     for (const auto &containmentId : plasmaConfigContainments.groupList()) {
         const auto containment = plasmaConfigContainments.group(containmentId);
+        const auto wallpaperPlugin = containment.readEntry("wallpaperplugin", QString());
         const auto lastScreen  = containment.readEntry("lastScreen", 0);
         const auto activity    = containment.readEntry("activityId", QString());
 
@@ -138,7 +138,7 @@ void BackgroundCache::reload()
         //! the containment is not a plasma desktop
         if (activity.isEmpty() || !isDesktopContainment(containment)) continue;
 
-        const auto returnedBackground = backgroundFromConfig(containment);
+        const auto returnedBackground = backgroundFromConfig(containment, wallpaperPlugin);
 
         QString background = returnedBackground;
 
@@ -152,6 +152,16 @@ void BackgroundCache::reload()
 
         QString screenName = m_pool->connector(lastScreen);
 
+        //! Take case of broadcasted backgrounds, when their plugin is changed they should be disabled
+        if (pluginExistsFor(activity,screenName)
+                && m_plugins[activity][screenName] != wallpaperPlugin
+                && backgroundIsBroadcasted(activity, screenName)){
+            //! in such case the Desktop changed wallpaper plugin and the broadcasted wallpapers should be removed
+            setBroadcastedBackgroundsEnabled(activity, screenName, false);
+        }
+
+        m_plugins[activity][screenName] = wallpaperPlugin;
+
         if (backgroundIsBroadcasted(activity, screenName)) {
             continue;
         }
@@ -428,5 +438,10 @@ bool BackgroundCache::backgroundIsBroadcasted(QString activity, QString screenNa
     return m_broadcasted.contains(activity) && m_broadcasted[activity].contains(screenName);
 }
 
+bool BackgroundCache::pluginExistsFor(QString activity, QString screenName)
+{
+    return m_plugins.contains(activity) && m_plugins[activity].contains(screenName);
+}
+
 }
 }

liblatte2/plasma/extended/backgroundcache.h

@@ -71,13 +71,14 @@ private:
     BackgroundCache(QObject *parent = nullptr);
 
     bool backgroundIsBroadcasted(QString activity, QString screenName);
+    bool pluginExistsFor(QString activity, QString screenName);
     bool areaIsBusy(float bright1, float bright2);
     bool busyForFile(QString imageFile, Plasma::Types::Location location);
     bool isDesktopContainment(const KConfigGroup &containment) const;
 
     float brightnessForFile(QString imageFile, Plasma::Types::Location location);
     float brightnessFromArea(QImage &image, int firstRow, int firstColumn, int endRow, int endColumn);
-    QString backgroundFromConfig(const KConfigGroup &config) const;
+    QString backgroundFromConfig(const KConfigGroup &config, QString wallpaperPlugin) const;
 
     void updateImageCalculations(QString imageFile, Plasma::Types::Location location);
 
@@ -88,9 +89,14 @@ private:
 
     //! screen aware backgrounds: activity id, screen name, backgroundfile
     QHash<QString, QHash<QString, QString>> m_backgrounds;
-    //! backgrounds that are broadcasted (not found through plasma files)
-    //! for specific: activity id, screen names tracked
+
+    //! plugin names tracked: activity id, screen name, pluginName
+    QHash<QString, QHash<QString, QString>> m_plugins;
+
+    //! backgrounds that are broadcasted (not found through plasma files):
+    //! and have higher priority: activity id, screen names
     QHash<QString, QList<QString>> m_broadcasted;
+
     //! image file and brightness per edge
     QHash<QString, EdgesHash> m_hintsCache;