made painter actually how I wanted it (draw now takes in an owned painter)

src/layout/ui.rs

@@ -93,16 +93,17 @@ impl<Ctx> Ui<Ctx> {
         Ctx: 'static,
     {
         self.active_sensors.clear();
+        self.primitives.clear();
         let mut painter = Painter::new(
             &self.widgets,
+            &mut self.primitives,
             ctx,
-            &mut self.sensor_map,
+            &self.sensor_map,
             &mut self.active_sensors,
         );
         if let Some(base) = &self.base {
-            painter.draw_inner(base);
+            painter.draw(base);
         }
-        self.primitives = painter.finish();
     }
 
     pub fn update(&mut self, ctx: &mut Ctx)