Small improvements to tracking

sleap/config/pipeline_form.yaml

@@ -424,10 +424,6 @@ inference:
       This tracker "shifts" instances from previous frames using optical flow
       before matching instances in each frame to the <i>shifted</i> instances from
       prior frames.'
-    # - name: tracking.max_tracking
-    #   label: Limit max number of tracks
-    #   type: bool
-      default: false
     - name: tracking.max_tracks
       label: Max number of tracks
       type: optional_int
@@ -459,10 +455,12 @@ inference:
       none_label: Use max (non-robust)
       range: 0,1
       default: 0.95
-    # - name: tracking.save_shifted_instances
-    #   label: Save shifted instances
-    #   type: bool
-    #   default: false
+    - name: tracking.save_shifted_instances
+      label: Save shifted instances
+      help: 'Save the flow-shifted instances between elapsed frames. It improves
+      instance matching at the cost of using a bit more of memory.'
+      type: bool
+      default: false
     - type: text
       text: '<b>Kalman filter-based tracking</b>:<br />
       Uses the above tracking options to track instances for an initial

sleap/gui/learning/dialog.py

@@ -733,7 +733,7 @@ def run(self):
         # count < 0 means there was an error and we didn't get any results.
         if new_counts is not None and new_counts >= 0:
             total_count = items_for_inference.total_frame_count
-            no_result_count = total_count - new_counts
+            no_result_count = max(0, total_count - new_counts)
 
             message = (
                 f"Inference ran on {total_count} frames."

sleap/gui/widgets/video.py

@@ -816,6 +816,8 @@ def __init__(self, state=None, player=None, *args, **kwargs):
         self.click_mode = ""
         self.in_zoom = False
 
+        self._down_pos = None
+
         self.zoomFactor = 1
         anchor_mode = QGraphicsView.AnchorUnderMouse
         self.setTransformationAnchor(anchor_mode)
@@ -1039,7 +1041,7 @@ def mouseReleaseEvent(self, event):
         scenePos = self.mapToScene(event.pos())
 
         # check if mouse moved during click
-        has_moved = event.pos() != self._down_pos
+        has_moved = self._down_pos is not None and event.pos() != self._down_pos
         if event.button() == Qt.LeftButton:
 
             if self.in_zoom: