feat(pipeline): add batch processing for scene graph construction

mini-nav/simulator/topdown.py

@@ -30,6 +30,7 @@ def render_topdown_scene_map(
     style: TopDownRenderStyle | None = None,
     maps_module: Any | None = None,
     plt_module: Any | None = None,
+    use_matplotlib: bool = True,
 ) -> Any:
     if not elements.room_nodes:
         raise ValueError("room_nodes must not be empty")
@@ -49,9 +50,6 @@ def render_topdown_scene_map(
     if maps_module is None:
         maps_module = import_module("habitat.utils.visualizations.maps")
 
-    if plt_module is None:
-        plt_module = import_module("matplotlib.pyplot")
-
     map_height = float(elements.room_nodes[0].center[1])
     top_down_map = maps_module.get_topdown_map(
         pathfinder,
@@ -59,6 +57,15 @@ def render_topdown_scene_map(
         meters_per_pixel=meters_per_pixel,
     )
 
+    if not use_matplotlib:
+        return top_down_map
+
+    if plt_module is None:
+        try:
+            plt_module = import_module("matplotlib.pyplot")
+        except ImportError:
+            return top_down_map
+
     plt_module.figure(figsize=style.figure_size)
     plt_module.imshow(top_down_map, cmap=style.map_cmap)