fix(viewer): preserve follow camera across layer toggles

src/k1link/viewer/recorded.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 from collections import OrderedDict
+from collections.abc import Callable
 from contextlib import suppress
 from threading import Lock
 from typing import Any, Literal
@@ -62,6 +63,7 @@ class _RecordedBlueprintStream:
         self.view_reset_generation = view_reset_generation
         self._lock = Lock()
         self._sequence = 0
+        self._follow_trajectory: bool | None = None
         self._closed = False
         native = bindings.new_blueprint(
             application_id=application_id,
@@ -78,10 +80,20 @@ class _RecordedBlueprintStream:
         )
         self._transport = rr.binary_stream(self._transport_recording)
 
-    def render(self, blueprint: rrb.Blueprint) -> bytes:
+    def render(
+        self,
+        blueprint_factory: Callable[[bool], rrb.Blueprint],
+        *,
+        follow_trajectory: bool,
+    ) -> bytes:
         with self._lock:
             if self._closed:
                 raise RecordedBlueprintError("stable blueprint stream is closed")
+            update_eye_controls = (
+                self._follow_trajectory is None
+                or self._follow_trajectory != follow_trajectory
+            )
+            blueprint = blueprint_factory(update_eye_controls)
             self._blueprint_recording.set_time(
                 "blueprint",
                 sequence=self._sequence,
@@ -98,6 +110,7 @@ class _RecordedBlueprintStream:
             payload = self._transport.read(flush=True, flush_timeout_sec=5.0)
             if not payload:
                 raise RecordedBlueprintError("stable blueprint stream produced no data")
+            self._follow_trajectory = follow_trajectory
             return payload
 
     def close(self) -> None:
@@ -156,6 +169,7 @@ def recorded_blueprint(
     show_segmentation: bool = False,
     show_cuboids_3d: bool = False,
     follow_trajectory: bool = False,
+    update_eye_controls: bool = True,
 ) -> rrb.Blueprint:
     accumulation = max(0.0, settings.accumulation_seconds)
     time_ranges: list[rr.VisibleTimeRange] | None = None
@@ -218,9 +232,13 @@ def recorded_blueprint(
         # Keeping the view id stable preserves the current orbit offset when
         # tracking is toggled. An explicit empty path clears tracking without
         # overwriting the position/look-target saved by user interaction.
-        eye_controls=rrb.EyeControls3D.from_fields(
-            kind=rrb.Eye3DKind.Orbital if follow_trajectory else None,
-            tracking_entity="/world/sensor_pose" if follow_trajectory else "",
+        eye_controls=(
+            rrb.EyeControls3D.from_fields(
+                kind=rrb.Eye3DKind.Orbital if follow_trajectory else None,
+                tracking_entity="/world/sensor_pose" if follow_trajectory else "",
+            )
+            if update_eye_controls
+            else None
         ),
     )
     spatial_view.id = (
@@ -274,9 +292,13 @@ def recorded_blueprint(
             # native cloud from /world/points.
             "/world/perception/lidar": rrb.EntityBehavior(visible=False),
         },
-        eye_controls=rrb.EyeControls3D.from_fields(
-            kind=rrb.Eye3DKind.Orbital if follow_trajectory else None,
-            tracking_entity="/world/sensor_pose" if follow_trajectory else "",
+        eye_controls=(
+            rrb.EyeControls3D.from_fields(
+                kind=rrb.Eye3DKind.Orbital if follow_trajectory else None,
+                tracking_entity="/world/sensor_pose" if follow_trajectory else "",
+            )
+            if update_eye_controls
+            else None
         ),
     )
     perception_3d_view.id = (
@@ -385,17 +407,20 @@ def recorded_blueprint_rrd(
 ) -> bytes:
     """Serialize a bounded active blueprint update without recorded data."""
 
-    blueprint = recorded_blueprint(
-        settings,
-        include_initial_playback_state=False,
-        active_view=active_view,
-        view_reset_generation=view_reset_generation,
-        unified_perception=unified_perception,
-        show_detections_2d=show_detections_2d,
-        show_segmentation=show_segmentation,
-        show_cuboids_3d=show_cuboids_3d,
-        follow_trajectory=follow_trajectory,
-    )
+    def build_blueprint(update_eye_controls: bool) -> rrb.Blueprint:
+        return recorded_blueprint(
+            settings,
+            include_initial_playback_state=False,
+            active_view=active_view,
+            view_reset_generation=view_reset_generation,
+            unified_perception=unified_perception,
+            show_detections_2d=show_detections_2d,
+            show_segmentation=show_segmentation,
+            show_cuboids_3d=show_cuboids_3d,
+            follow_trajectory=follow_trajectory,
+            update_eye_controls=update_eye_controls,
+        )
+
     payload: bytes | None
     if blueprint_session_id is not None:
         try:
@@ -404,12 +429,16 @@ def recorded_blueprint_rrd(
                 recording_id=recording_id,
                 blueprint_session_id=blueprint_session_id,
                 view_reset_generation=view_reset_generation,
-            ).render(blueprint)
+            ).render(
+                build_blueprint,
+                follow_trajectory=follow_trajectory,
+            )
         except RecordedBlueprintError:
             raise
         except Exception as exc:
             raise RecordedBlueprintError("failed to serialize stable recorded blueprint") from exc
     else:
+        blueprint = build_blueprint(True)
         recording = rr.RecordingStream(
             application_id,
             recording_id=recording_id,