support wallpaper slideshows

app/dbus/org.kde.LatteDock.xml

@@ -22,5 +22,15 @@
     <method name="contextMenuData">
         <arg name="data" type="as" direction="out"/>
     </method>
+    <method name="setBackgroundFromBroadcast">
+        <arg name="activity" type="s" direction="in"/>
+        <arg name="screenName" type="s" direction="in"/>
+        <arg name="filename" type="s" direction="in"/>
+    </method>
+    <method name="setBroadcastedBackgroundsEnabled">
+        <arg name="activity" type="s" direction="in"/>
+        <arg name="screenName" type="s" direction="in"/>
+        <arg name="enabled" type="b" direction="in"/>
+    </method>
   </interface>
 </node>

app/lattecorona.cpp

@@ -63,7 +63,7 @@
 #include <KPackage/PackageLoader>
 #include <KAboutData>
 #include <KActivities/Consumer>
-#include <KDeclarative/QmlObject>
+#include <KDeclarative/QmlObjectSharedEngine>
 #include <KWindowSystem>
 #include <KWayland/Client/connection_thread.h>
 #include <KWayland/Client/registry.h>
@@ -128,6 +128,12 @@ Corona::Corona(bool defaultLayoutOnStartup, QString layoutNameOnStartUp, int use
         m_viewsScreenSyncTimer.setInterval(m_universalSettings->screenTrackerInterval());
     });
 
+    //! initialize the background tracer for broadcasted backgrounds
+    m_backgroundTracer = new KDeclarative::QmlObjectSharedEngine(this);
+    m_backgroundTracer->setInitializationDelayed(true);
+    m_backgroundTracer->setSource(kPackage().filePath("backgroundTracer"));
+    m_backgroundTracer->completeInitialization();
+
     //! Dbus adaptor initialization
     new LatteDockAdaptor(this);
     QDBusConnection dbus = QDBusConnection::sessionBus();
@@ -170,6 +176,7 @@ Corona::~Corona()
     m_screenPool->deleteLater();
     m_universalSettings->deleteLater();
     m_plasmaScreenPool->deleteLater();
+    m_backgroundTracer->deleteLater();
     m_themeExtended->deleteLater();
 
     disconnect(m_activityConsumer, &KActivities::Consumer::serviceStatusChanged, this, &Corona::load);
@@ -783,13 +790,13 @@ void Corona::showAlternativesForApplet(Plasma::Applet *applet)
 
     Latte::View *latteView = (*views)[applet->containment()];
 
-    KDeclarative::QmlObject *qmlObj{nullptr};
+    KDeclarative::QmlObjectSharedEngine *qmlObj{nullptr};
 
     if (latteView) {
         latteView->setAlternativesIsShown(true);
-        qmlObj = new KDeclarative::QmlObject(latteView);
+        qmlObj = new KDeclarative::QmlObjectSharedEngine(latteView);
     } else {
-        qmlObj = new KDeclarative::QmlObject(this);
+        qmlObj = new KDeclarative::QmlObjectSharedEngine(this);
     }
 
     qmlObj->setInitializationDelayed(true);
@@ -814,10 +821,10 @@ void Corona::showAlternativesForApplet(Plasma::Applet *applet)
             return;
         }
 
-        QMutableListIterator<KDeclarative::QmlObject *> it(m_alternativesObjects);
+        QMutableListIterator<KDeclarative::QmlObjectSharedEngine *> it(m_alternativesObjects);
 
         while (it.hasNext()) {
-            KDeclarative::QmlObject *obj = it.next();
+            KDeclarative::QmlObjectSharedEngine *obj = it.next();
 
             if (obj == qmlObj) {
                 it.remove();
@@ -835,10 +842,10 @@ void Corona::alternativesVisibilityChanged(bool visible)
 
     QObject *root = sender();
 
-    QMutableListIterator<KDeclarative::QmlObject *> it(m_alternativesObjects);
+    QMutableListIterator<KDeclarative::QmlObjectSharedEngine *> it(m_alternativesObjects);
 
     while (it.hasNext()) {
-        KDeclarative::QmlObject *obj = it.next();
+        KDeclarative::QmlObjectSharedEngine *obj = it.next();
 
         if (obj->rootObject() == root) {
             it.remove();
@@ -1003,6 +1010,28 @@ QStringList Corona::contextMenuData()
     return data;
 }
 
+void Corona::setBackgroundFromBroadcast(QString activity, QString screenName, QString filename)
+{
+    if (filename.startsWith("file://")) {
+        filename = filename.remove(0,7);
+    }
+
+    QMetaObject::invokeMethod(m_backgroundTracer->rootObject(),
+                              "setBackgroundFromBroadcast",
+                              Q_ARG(QVariant, activity),
+                              Q_ARG(QVariant, screenName),
+                              Q_ARG(QVariant, filename));
+}
+
+void Corona::setBroadcastedBackgroundsEnabled(QString activity, QString screenName, bool enabled)
+{
+    QMetaObject::invokeMethod(m_backgroundTracer->rootObject(),
+                              "setBroadcastedBackgroundsEnabled",
+                              Q_ARG(QVariant, activity),
+                              Q_ARG(QVariant, screenName),
+                              Q_ARG(QVariant, enabled));
+}
+
 inline void Corona::qmlRegisterTypes() const
 {
     qmlRegisterType<QScreen>();

app/lattecorona.h

@@ -36,7 +36,7 @@
 #include <KAboutApplicationDialog>
 
 namespace KDeclarative {
-class QmlObject;
+class QmlObjectSharedEngine;
 }
 
 namespace Plasma {
@@ -125,10 +125,13 @@ public:
 public slots:
     void aboutApplication();
     void activateLauncherMenu();
-    //! they are separated with a "-" character
-    void windowColorScheme(QString windowIdAndScheme);
     void loadDefaultLayout() override;
+    void setBackgroundFromBroadcast(QString activity, QString screenName, QString filename);
+    void setBroadcastedBackgroundsEnabled(QString activity, QString screenName, bool enabled);
+    //! values are separated with a "-" character
+    void windowColorScheme(QString windowIdAndScheme);
     void updateDockItemBadge(QString identifier, QString value);
+
     void unload();
 
 signals:
@@ -171,7 +174,9 @@ private:
 
     QString m_layoutNameOnStartUp;
 
-    QList<KDeclarative::QmlObject *> m_alternativesObjects;
+    QList<KDeclarative::QmlObjectSharedEngine *> m_alternativesObjects;
+
+    KDeclarative::QmlObjectSharedEngine *m_backgroundTracer;
 
     QTimer m_viewsScreenSyncTimer;
 

app/package/lattepackage.cpp

@@ -66,6 +66,8 @@ void Package::initPackage(KPackage::Package *package)
 
     package->addFileDefinition("themesExtendedInfo", QStringLiteral("themes/themesExtendedInforc"), i18n("a file that contains extended information for plasma themes"));
 
+    package->addFileDefinition("backgroundTracer", QStringLiteral("scripting/BackgroundTracer.qml"), i18n("a qml file that is used to publish broadcasted backgrounds"));
+
     package->setFallbackPackage(fallback);
     qDebug() << "package is valid" << package->isValid();
 }

liblatte2/backgroundtracker.cpp

@@ -120,4 +120,14 @@ void BackgroundTracker::update()
     emit isBusyChanged();
 }
 
+void BackgroundTracker::setBackgroundFromBroadcast(QString activity, QString screen, QString filename)
+{
+    m_cache->setBackgroundFromBroadcast(activity, screen, filename);
+}
+
+void BackgroundTracker::setBroadcastedBackgroundsEnabled(QString activity, QString screen, bool enabled)
+{
+    m_cache->setBroadcastedBackgroundsEnabled(activity, screen, enabled);
+}
+
 }

liblatte2/backgroundtracker.h

@@ -59,6 +59,10 @@ public:
     QString screenName() const;
     void setScreenName(QString name);
 
+public slots:
+    Q_INVOKABLE void setBackgroundFromBroadcast(QString activity, QString screen, QString filename);
+    Q_INVOKABLE void setBroadcastedBackgroundsEnabled(QString activity, QString screen, bool enabled);
+
 signals:
     void activityChanged();
     void currentBrightnessChanged();

liblatte2/plasma/extended/backgroundcache.cpp

@@ -24,7 +24,9 @@
 
 // Qt
 #include <QDebug>
+#include <QFileInfo>
 #include <QImage>
+#include <QList>
 #include <QRgb>
 #include <QtMath>
 
@@ -144,10 +146,16 @@ void BackgroundCache::reload()
             background = returnedBackground.mid(7);
         }
 
-        if (background.isEmpty()) continue;
+        if (background.isEmpty()) {
+            continue;
+        }
 
         QString screenName = m_pool->connector(lastScreen);
 
+        if (backgroundIsBroadcasted(activity, screenName)) {
+            continue;
+        }
+
         if(!m_backgrounds.contains(activity)
                 || !m_backgrounds[activity].contains(screenName)
                 || m_backgrounds[activity][screenName] != background) {
@@ -387,5 +395,38 @@ bool BackgroundCache::busyForFile(QString imageFile, Plasma::Types::Location loc
     return false;
 }
 
+void BackgroundCache::setBackgroundFromBroadcast(QString activity, QString screen, QString filename)
+{
+    if (QFileInfo(filename).exists()) {
+        setBroadcastedBackgroundsEnabled(activity, screen, true);
+        m_backgrounds[activity][screen] = filename;
+        emit backgroundChanged(activity, screen);
+    }
+}
+
+void BackgroundCache::setBroadcastedBackgroundsEnabled(QString activity, QString screen, bool enabled)
+{
+    if (enabled && !backgroundIsBroadcasted(activity, screen)) {
+        if (!m_broadcasted.contains(activity)) {
+            m_broadcasted[activity] = QList<QString>();
+        }
+
+        m_broadcasted[activity].append(screen);
+    } else if (!enabled && backgroundIsBroadcasted(activity, screen)) {
+        m_broadcasted[activity].removeAll(screen);
+
+        if (m_broadcasted[activity].isEmpty()) {
+            m_broadcasted.remove(activity);
+        }
+
+        reload();
+    }
+}
+
+bool BackgroundCache::backgroundIsBroadcasted(QString activity, QString screenName)
+{
+    return m_broadcasted.contains(activity) && m_broadcasted[activity].contains(screenName);
+}
+
 }
 }

liblatte2/plasma/extended/backgroundcache.h

@@ -57,6 +57,9 @@ public:
 
     QString background(QString activity, QString screen);
 
+    void setBackgroundFromBroadcast(QString activity, QString screen, QString filename);
+    void setBroadcastedBackgroundsEnabled(QString activity, QString screen, bool enabled);
+
 signals:
     void backgroundChanged(const QString &activity, const QString &screenName);
 
@@ -67,6 +70,7 @@ private slots:
 private:
     BackgroundCache(QObject *parent = nullptr);
 
+    bool backgroundIsBroadcasted(QString activity, QString screenName);
     bool areaIsBusy(float bright1, float bright2);
     bool busyForFile(QString imageFile, Plasma::Types::Location location);
     bool isDesktopContainment(const KConfigGroup &containment) const;
@@ -84,6 +88,9 @@ 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
+    QHash<QString, QList<QString>> m_broadcasted;
     //! image file and brightness per edge
     QHash<QString, EdgesHash> m_hintsCache;
 

shell/package/contents/scripting/BackgroundTracer.qml

@@ -0,0 +1,39 @@
+/*
+*  Copyright 2019  Michail Vourlakos <mvourlakos@gmail.com>
+*
+*  This file is part of Latte-Dock
+*
+*  Latte-Dock is free software; you can redistribute it and/or
+*  modify it under the terms of the GNU General Public License as
+*  published by the Free Software Foundation; either version 2 of
+*  the License, or (at your option) any later version.
+*
+*  Latte-Dock is distributed in the hope that it will be useful,
+*  but WITHOUT ANY WARRANTY; without even the implied warranty of
+*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*  GNU General Public License for more details.
+*
+*  You should have received a copy of the GNU General Public License
+*  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import QtQuick 2.7
+import org.kde.latte 0.2 as Latte
+
+Item{
+    Latte.BackgroundTracker {
+        id: backgroundTracker
+    }
+
+    function setBackgroundFromBroadcast(activity, screen, filename) {
+        console.log(" Background Tracer set image ::: " + activity + " _ " + screen + " _ " + filename);
+        backgroundTracker.setBackgroundFromBroadcast(activity, screen, filename);
+    }
+
+    function setBroadcastedBackgroundsEnabled(activity, screen, enabled) {
+        console.log(" Background Tracer State ::: " + activity + " _ " + screen + " _ " + enabled);
+        backgroundTracker.setBroadcastedBackgroundsEnabled(activity, screen, enabled);
+    }
+
+
+}