fix

rfg_adc_plotter/gui/pyqtgraph_backend.py

@@ -7,7 +7,7 @@ import sys
 import threading
 import time
 from queue import Empty, Queue
-from typing import Dict, List, Optional, Tuple
+from typing import Dict, List, Optional, Sequence, Tuple
 
 import numpy as np
 
@@ -40,6 +40,7 @@ from rfg_adc_plotter.types import SweepAuxCurves, SweepInfo, SweepPacket
 
 RAW_PLOT_MAX_POINTS = 4096
 RAW_WATERFALL_MAX_POINTS = 2048
+UI_MAX_PACKETS_PER_TICK = 8
 DEBUG_FRAME_LOG_EVERY = 10
 
 
@@ -242,6 +243,20 @@ def decimate_curve_for_display(
     return x_arr[display_idx], y_arr[display_idx]
 
 
+def coalesce_packets_for_ui(
+    packets: Sequence[SweepPacket],
+    *,
+    max_packets: int = UI_MAX_PACKETS_PER_TICK,
+) -> Tuple[List[SweepPacket], int]:
+    """Keep only the newest packets so a burst cannot starve the Qt event loop."""
+    packet_list = list(packets)
+    limit = max(1, int(max_packets))
+    if len(packet_list) <= limit:
+        return packet_list, 0
+    skipped = len(packet_list) - limit
+    return packet_list[-limit:], skipped
+
+
 def resolve_visible_fft_curves(
     fft_complex: Optional[np.ndarray],
     fft_mag: Optional[np.ndarray],
@@ -1244,6 +1259,7 @@ def run_pyqtgraph(args) -> None:
         pass
 
     processed_frames = 0
+    ui_frames_skipped = 0
     ui_started_at = time.perf_counter()
 
     def refresh_current_fft_cache(sweep_for_fft: np.ndarray, bins: int) -> None:
@@ -1257,14 +1273,20 @@ def run_pyqtgraph(args) -> None:
         runtime.current_fft_db = fft_mag_to_db(runtime.current_fft_mag)
 
     def drain_queue() -> int:
-        nonlocal processed_frames
-        drained = 0
+        nonlocal processed_frames, ui_frames_skipped
+        pending_packets: List[SweepPacket] = []
         while True:
             try:
-                sweep, info, aux_curves = queue.get_nowait()
+                pending_packets.append(queue.get_nowait())
             except Empty:
                 break
-            drained += 1
+        drained = len(pending_packets)
+        if drained <= 0:
+            return 0
+
+        pending_packets, skipped_packets = coalesce_packets_for_ui(pending_packets)
+        ui_frames_skipped += skipped_packets
+        for sweep, info, aux_curves in pending_packets:
             base_freqs = np.linspace(SWEEP_FREQ_MIN_GHZ, SWEEP_FREQ_MAX_GHZ, sweep.size, dtype=np.float64)
             runtime.full_current_aux_curves = None
             runtime.full_current_fft_source = None
@@ -1317,7 +1339,7 @@ def run_pyqtgraph(args) -> None:
                 elapsed_s = max(time.perf_counter() - ui_started_at, 1e-9)
                 frames_per_sec = float(processed_frames) / elapsed_s
                 sys.stderr.write(
-                    "[debug] ui frames:%d rate:%.2f/s last_sweep:%s ch:%s width:%d queue:%d\n"
+                    "[debug] ui frames:%d rate:%.2f/s last_sweep:%s ch:%s width:%d queue:%d dropped:%d\n"
                     % (
                         processed_frames,
                         frames_per_sec,
@@ -1325,10 +1347,10 @@ def run_pyqtgraph(args) -> None:
                         str(info.get("ch") if isinstance(info, dict) else None),
                         int(getattr(sweep, "size", 0)),
                         int(queue_size),
+                        int(ui_frames_skipped),
                     )
                 )
-        if drained > 0:
-            update_physical_axes()
+        update_physical_axes()
         return drained
 
     try: