Refactoring and bug fixes to moving_camera, multi_camera, zoomed_scene mix

camera/moving_camera.py

@@ -49,3 +49,10 @@ class MovingCamera(Camera):
         else:
             self.frame_shape = (self.frame.get_height(), width)
         self.resize_frame_shape(fixed_dimension=self.fixed_dimension)
+
+    def get_mobjects_indicating_movement(self):
+        """
+        Returns all mobjets whose movement implies that the camera
+        should think of all other mobjects on the screen as moving
+        """
+        return [self.frame]

camera/multi_camera.py

@@ -53,3 +53,8 @@ class MultiCamera(MovingCamera):
             imfc.camera.capture_mobjects(to_add, **kwargs)
         MovingCamera.capture_mobjects(self, mobjects, **kwargs)
 
+    def get_mobjects_indicating_movement(self):
+        return [self.frame] + [
+            imfc.camera.frame
+            for imfc in self.image_mobjects_from_cameras
+        ]

scene/moving_camera_scene.py

@@ -2,6 +2,7 @@ from __future__ import absolute_import
 
 from scene.scene import Scene
 from camera.moving_camera import MovingCamera
+from utils.iterables import list_update
 
 
 class MovingCameraScene(Scene):
@@ -18,10 +19,14 @@ class MovingCameraScene(Scene):
         return self
 
     def get_moving_mobjects(self, *animations):
-        # TODO: Code repetition from ZoomedScene
         moving_mobjects = Scene.get_moving_mobjects(self, *animations)
-        if self.camera_frame in moving_mobjects:
-            # When the camera is moving, so is everything,
-            return self.mobjects
-        else:
+        all_moving_mobjects = self.camera.extract_mobject_family_members(
+            moving_mobjects
+        )
+        movement_indicators = self.camera.get_mobjects_indicating_movement()
+        for movement_indicator in movement_indicators:
+            if movement_indicator in all_moving_mobjects:
+                # When one of these is moving, the camera should
+                # consider all mobjects to be moving
+                return list_update(self.mobjects, moving_mobjects)
         return moving_mobjects

scene/zoomed_scene.py

@@ -81,16 +81,6 @@ class ZoomedScene(MovingCameraScene):
         else:
             self.add_foreground_mobjects(*to_add)
 
-    def get_moving_mobjects(self, *animations):
-        moving_mobjects = MovingCameraScene.get_moving_mobjects(self, *animations)
-        zoomed_mobjects = [self.zoomed_camera.frame, self.zoomed_display]
-        moving_zoomed_mobjects = set(moving_mobjects).intersection(zoomed_mobjects)
-        if self.zoom_activated and moving_zoomed_mobjects:
-            # If either of the zoomed_mobjects are moving, then so is
-            # everything
-            return self.mobjects
-        return moving_mobjects
-
     def get_zoom_factor(self):
         return fdiv(
             self.zoomed_camera.frame.get_width(),