refactor(sync): improve topdown rendering and make justfile adapt to windows

mini-nav/simulator/topdown.py

@@ -1,9 +1,13 @@
 from __future__ import annotations
 
 from dataclasses import dataclass, field
-from importlib import import_module
 from typing import Any, Sequence
 
+import numpy as np
+from matplotlib.backends.backend_agg import FigureCanvasAgg
+from matplotlib.figure import Figure
+from PIL import Image
+
 
 @dataclass(frozen=True)
 class TopDownSceneElements:
@@ -28,10 +32,26 @@ def render_topdown_scene_map(
     elements: TopDownSceneElements,
     meters_per_pixel: float,
     style: TopDownRenderStyle | None = None,
-    maps_module: Any | None = None,
-    plt_module: Any | None = None,
-    use_matplotlib: bool = True,
-) -> Any:
+) -> Image.Image:
+    """Render a top-down scene map as a PIL Image.
+
+    Uses matplotlib Agg backend (non-interactive) to draw room markers and
+    labels on the habitat top-down occupancy map, then returns the result
+    as a PIL Image.
+
+    Args:
+        pathfinder: Habitat pathfinder instance.
+        elements: Scene elements containing room nodes to annotate.
+        meters_per_pixel: Resolution for the top-down map.
+        style: Visual style configuration.
+
+    Returns:
+        PIL.Image.Image: Rendered top-down map with annotations.
+
+    Raises:
+        ValueError: If room_nodes is empty or meters_per_pixel <= 0.
+        NotImplementedError: If object_nodes or edges are provided.
+    """
     if not elements.room_nodes:
         raise ValueError("room_nodes must not be empty")
 
@@ -47,37 +67,33 @@ def render_topdown_scene_map(
     if style is None:
         style = TopDownRenderStyle()
 
-    if maps_module is None:
-        maps_module = import_module("habitat.utils.visualizations.maps")
+    # Import habitat maps internally — treated as required dependency.
+    from habitat.utils.visualizations import maps
 
+    # Generate raw top-down occupancy map.
     map_height = float(elements.room_nodes[0].center[1])
-    top_down_map = maps_module.get_topdown_map(
+    top_down_map = maps.get_topdown_map(
         pathfinder,
         height=map_height,
         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)
+    # Render with matplotlib Agg backend (no GUI required).
+    fig = Figure(figsize=style.figure_size)
+    _ = FigureCanvasAgg(fig)
+    ax = fig.add_subplot(111)
+    ax.imshow(top_down_map, cmap=style.map_cmap)
 
+    # Annotate room positions and labels.
     for room_node in elements.room_nodes:
-        grid_y, grid_x = maps_module.to_grid(
+        grid_y, grid_x = maps.to_grid(
             float(room_node.center[2]),
             float(room_node.center[0]),
             top_down_map.shape,
             pathfinder=pathfinder,
         )
-        plt_module.scatter(grid_x, grid_y, c=style.room_color, s=style.room_marker_size)
-        plt_module.text(
+        ax.scatter(grid_x, grid_y, c=style.room_color, s=style.room_marker_size)
+        ax.text(
             grid_x + style.room_label_offset,
             grid_y + style.room_label_offset,
             room_node.room_id,
@@ -85,7 +101,12 @@ def render_topdown_scene_map(
             fontsize=8,
         )
 
-    plt_module.title(style.title)
-    plt_module.axis("off")
-    plt_module.show()
-    return top_down_map
+    ax.set_title(style.title)
+    ax.axis("off")
+    fig.canvas.draw()
+
+    # Extract RGB pixels from the Agg canvas buffer.
+    rgba = np.asarray(fig.canvas.buffer_rgba(), dtype=np.uint8)
+    rgb = rgba[..., :3].copy()
+
+    return Image.fromarray(rgb)