[libcalamares] Introduce slideshowAPI setting

src/branding/default/branding.desc

@@ -93,6 +93,17 @@ images:
 # The slideshow is displayed during execution steps (e.g. when the
 # installer is actually writing to disk and doing other slow things).
 slideshow:               "show.qml"
+# There are two available APIs for the slideshow:
+#  - 1 (the default) loads the entire slideshow when the installation-
+#      slideshow page is shown and starts the QML then. The QML
+#      is never stopped (after installation is done, times etc.
+#      continue to fire).
+#  - 2 loads the slideshow on startup and calls onActivate() and
+#      onLeave() in the root object. After the installation is done,
+#      the show is stopped (first by calling onLeave(), then destroying
+#      the QML components).
+slideshowAPI: 2
+
 
 # Colors for text and background components.
 #

src/libcalamaresui/Branding.cpp

@@ -127,6 +127,7 @@ Branding::Branding( const QString& brandingFilePath,
     , m_descriptorPath( brandingFilePath )
     , m_welcomeStyleCalamares( false )
     , m_welcomeExpandingLogo( true )
+    , m_slideshowAPI( 1 )
 {
     cDebug() << "Using Calamares branding file at" << brandingFilePath;
 
@@ -234,6 +235,14 @@ Branding::Branding( const QString& brandingFilePath,
             }
             else
                 bail( "Syntax error in slideshow sequence." );
+
+            int api = doc[ "slideshowAPI" ].IsScalar() ? doc[ "slideshowAPI" ].as<int>() : -1;
+            if ( ( api < 1 ) || ( api > 2 ) )
+            {
+                cWarning() << "Invalid or missing *slideshowAPI* in branding file.";
+                api = 1;
+            }
+            m_slideshowAPI = api;
         }
         catch ( YAML::Exception& e )
         {

src/libcalamaresui/Branding.h

@@ -118,6 +118,7 @@ public:
 
     /** @brief Path to the slideshow QML file, if any. */
     QString slideshowPath() const { return m_slideshowPath; }
+    int slideshowAPI() const { return m_slideshowAPI; }
 
     QString string( Branding::StringEntry stringEntry ) const;
     QString styleString( Branding::StyleEntry styleEntry ) const;
@@ -172,6 +173,7 @@ private:
     QMap< QString, QString > m_images;
     QMap< QString, QString > m_style;
     QString m_slideshowPath;
+    int m_slideshowAPI;
     QString m_translationsPathPrefix;
 
     /** @brief Initialize the simple settings below */