update dd06 display

examples/gui/viewer2d/backend.py

@@ -8,10 +8,11 @@ Does not import camera, ROI, or `orisys.Sensor`.
 from __future__ import annotations
 
 from dataclasses import dataclass
-from typing import Optional, Sequence, Tuple
+from typing import Literal, Optional, Sequence, Tuple
 
 import cv2
 import numpy as np
+import orisys
 from scipy.signal import butter, filtfilt
 
 FORCE_SAMPLE_RATE_HZ = 30.0
@@ -19,6 +20,17 @@ PLOT_BUFFER_POINTS = 120
 PLOT_WINDOW_SEC = PLOT_BUFFER_POINTS / FORCE_SAMPLE_RATE_HZ
 Y_AXIS_MIN_SPAN = 20000.0
 
+ArrowBackground = Literal["pure_color", "captured"]
+# #0B1016 as BGR (matches demo_wuxi / promote_video theme)
+PURE_COLOR_BG_BGR = (22, 16, 11)
+
+_ARROW_DRAW_KW = dict(
+    threshold=2,
+    grid_spacing=20,
+    arrow_scale=0.5,
+    below_threshold_color=(160, 160, 160),
+)
+
 
 @dataclass
 class ViewerFrame:
@@ -92,6 +104,14 @@ def image_shape_meta(img: np.ndarray) -> Tuple[int, int, float]:
     return h, w, aspect
 
 
+def _base_bgr(snapshot) -> Optional[np.ndarray]:
+    for attr in ("image", "processed_image", "raw_image"):
+        out = ensure_bgr(getattr(snapshot, attr, None))
+        if out is not None:
+            return out
+    return None
+
+
 def select_display_image(snapshot) -> np.ndarray:
     """Pick flow overlay / processed / raw image for the left panel."""
     arrows = getattr(snapshot, "flow_overlay", None)
@@ -109,6 +129,29 @@ def select_display_image(snapshot) -> np.ndarray:
     return np.zeros((400, 400, 3), dtype=np.uint8)
 
 
+def build_display_image(
+    snapshot,
+    background: ArrowBackground = "pure_color",
+) -> np.ndarray:
+    """Build left-panel image: arrows on pure color or on the captured frame."""
+    flow = getattr(snapshot, "flow", None)
+    base = _base_bgr(snapshot)
+
+    if flow is not None and base is not None:
+        if background == "pure_color":
+            h, w = base.shape[:2]
+            canvas = np.empty((h, w, 3), dtype=np.uint8)
+            canvas[:, :] = PURE_COLOR_BG_BGR
+            return orisys.util.draw_arrows(canvas, flow, **_ARROW_DRAW_KW)
+
+        overlay = ensure_bgr(getattr(snapshot, "flow_overlay", None))
+        if overlay is not None:
+            return overlay
+        return orisys.util.draw_arrows(base, flow, **_ARROW_DRAW_KW)
+
+    return select_display_image(snapshot)
+
+
 def bgr_to_rgb_bytes(img_bgr: np.ndarray) -> Tuple[np.ndarray, int, int]:
     """Convert BGR uint8 image to contiguous RGB for QImage."""
     rgb = cv2.cvtColor(img_bgr, cv2.COLOR_BGR2RGB)
@@ -255,6 +298,7 @@ class QtViewerBackend:
         npoints: int = PLOT_BUFFER_POINTS,
         lowpass_cutoff_hz: float = 10.0,
         y_axis_min_span: float = Y_AXIS_MIN_SPAN,
+        arrow_background: ArrowBackground = "pure_color",
     ):
         self.force_history = ForceHistory(
             npoints=npoints,
@@ -263,6 +307,50 @@ class QtViewerBackend:
         )
         self._start_time: Optional[float] = None
         self.last_viewer_frame: Optional[ViewerFrame] = None
+        self.arrow_background: ArrowBackground = arrow_background
+
+    def set_arrow_background(self, background: ArrowBackground) -> None:
+        self.arrow_background = background
+
+    def rebuild_display(self, snapshot) -> ViewerFrame:
+        """Re-render display image without advancing force history."""
+        display = build_display_image(snapshot, self.arrow_background)
+        h, w, aspect = image_shape_meta(display)
+        prev = self.last_viewer_frame
+        if prev is not None:
+            frame = ViewerFrame(
+                display_image=display,
+                image_height=h,
+                image_width=w,
+                aspect_ratio=aspect,
+                depth=prev.depth,
+                normal_force=prev.normal_force,
+                shear_x=prev.shear_x,
+                shear_y=prev.shear_y,
+                normal_force_calibrated=prev.normal_force_calibrated,
+                fps=prev.fps,
+                timestamp=prev.timestamp,
+                record_frame=prev.record_frame,
+            )
+        else:
+            frame = ViewerFrame(
+                display_image=display,
+                image_height=h,
+                image_width=w,
+                aspect_ratio=aspect,
+                depth=getattr(snapshot, "depth", None),
+                normal_force=float(getattr(snapshot, "normal_force", 0.0)),
+                shear_x=float(getattr(snapshot, "shear_x", 0.0)),
+                shear_y=float(getattr(snapshot, "shear_y", 0.0)),
+                normal_force_calibrated=float(
+                    getattr(snapshot, "normal_force_calibrated", 0.0)
+                ),
+                fps=float(getattr(snapshot, "fps", 0.0)),
+                timestamp=float(getattr(snapshot, "timestamp", 0.0) or 0.0),
+                record_frame=ensure_bgr(getattr(snapshot, "record_frame", None)),
+            )
+        self.last_viewer_frame = frame
+        return frame
 
     def reset(self) -> None:
         self.force_history.reset()
@@ -271,7 +359,7 @@ class QtViewerBackend:
 
     def ingest(self, snapshot, *, now: Optional[float] = None) -> ViewerFrame:
         """Convert a FrameSnapshot into ViewerFrame and update force history."""
-        display = select_display_image(snapshot)
+        display = build_display_image(snapshot, self.arrow_background)
         h, w, aspect = image_shape_meta(display)
 
         fn = float(getattr(snapshot, "normal_force", 0.0))