the monitor preview becomes optional, with Wallpaper::setPreviewDuringConfiguration() (default off)

image uses it just for slideshows

together with the previous related commits,
FEATURE: new appearance to the background config dialog

svn path=/trunk/KDE/kdelibs/; revision=1162831

private/wallpaper_p.h

@@ -77,6 +77,7 @@ public:
     bool needsConfig : 1;
     bool scriptInitialized : 1;
     bool previewing : 1;
+    bool needsPreviewDuringConfiguration : 1;
 };
 
 class LoadImageThread : public QObject, public QRunnable

wallpaper.cpp

@@ -471,7 +471,8 @@ WallpaperPrivate::WallpaperPrivate(KService::Ptr service, Wallpaper *wallpaper)
     initialized(false),
     needsConfig(false),
     scriptInitialized(false),
-    previewing(false)
+    previewing(false),
+    needsPreviewDuringConfiguration(false)
 {
     if (wallpaperDescription.isValid()) {
         QString api = wallpaperDescription.property("X-Plasma-API").toString();
@@ -665,6 +666,16 @@ void Wallpaper::setPreviewing(bool previewing)
     d->previewing = previewing;
 }
 
+bool Wallpaper::needsPreviewDuringConfiguration() const
+{
+    return d->needsPreviewDuringConfiguration;
+}
+
+void Wallpaper::setPreviewDuringConfiguration(const bool preview)
+{
+    d->needsPreviewDuringConfiguration = preview;
+}
+
 const Package *Wallpaper::package() const
 {
     return d->package;

wallpaper.h

@@ -343,6 +343,13 @@ class PLASMA_EXPORT Wallpaper : public QObject
          */
         void setPreviewing(bool previewing);
 
+        /**
+         * @return true if the wallpaper needs a live preview in the configuration UI
+         * @since 4.6
+         */
+        bool needsPreviewDuringConfiguration() const;
+
+
     Q_SIGNALS:
         /**
          * This signal indicates that wallpaper needs to be repainted.
@@ -490,6 +497,16 @@ class PLASMA_EXPORT Wallpaper : public QObject
         //FIXME: KDE5, this must be moved to the dptr
         QList<QAction*> contextActions;
 
+        /**
+         * Sets whether the configuration user interface of the wallpaper should have
+         * a live preview rendered by a Wallpaper instance. note: this is just an
+         * hint, the configuration user interface can choose to ignore it
+         *
+         * @param preview true if a preview should be shown
+         * @since 4.6
+         */
+        void setPreviewDuringConfiguration(const bool preview);
+
     private:
         Q_PRIVATE_SLOT(d, void renderCompleted(WallpaperRenderThread *renderer, int token, const QImage &image,
                                                const QString &sourceImagePath, const QSize &size,