adapted to new interface

rects/RectSaver.cpp

@@ -14,20 +14,14 @@ class RectSaver : public ScreensaverPlugin {
         RectSaver() = default;
         ~RectSaver() = default;
 
-        void setup(cairo_t* context, const cairo_rectangle_t& rect) override;
-        void draw_frame() override;
         int fps() const override;
+        void draw_frame() override;
 };
 
 ScreensaverPlugin* create_instance() {
     return new RectSaver;
 }
 
-void RectSaver::setup(cairo_t* context, const cairo_rectangle_t& rect) {
-    ScreensaverPlugin::setup(context, rect);
-    make_black();
-}
-
 int RectSaver::fps() const {
     return 2;
 }