Preview point size while dragging slider

Change slider behavior so moves provide a live visual preview while commits occur only on release. setTracking(False) is set on the size slider; sliderMoved is connected to _on_slider_moved_preview to update the label and emit point_size_changed for visual-only updates, while valueChanged is connected to _on_value_changed_commit to update the label and emit point_size_commit_requested for persisting the change. This improves UX by avoiding premature commits during dragging and clarifies signal semantics.

Author: C-Achard

src/napari_deeplabcut/ui/layer_stats.py

@@ -66,14 +66,20 @@ def __init__(self, parent: QWidget | None = None):
         wrapper = QVBoxLayout(self)
         wrapper.addLayout(form)
 
-        self._size_slider.valueChanged.connect(self._on_slider_changed)
-        self._size_slider.sliderReleased.connect(self._emit_commit)
+        self._size_slider.setTracking(False)
+
+        self._size_slider.sliderMoved.connect(self._on_slider_moved_preview)
+        self._size_slider.valueChanged.connect(self._on_value_changed_commit)
 
         self.set_point_size_enabled(False, reason="Select a DLC keypoints layer to edit point size.")
 
-    def _on_slider_changed(self, value: int) -> None:
+    def _on_slider_moved_preview(self, value: int) -> None:
+        self._size_value.setText(str(int(value)))
+        self.point_size_changed.emit(int(value))  # visual only
+
+    def _on_value_changed_commit(self, value: int) -> None:
         self._size_value.setText(str(int(value)))
-        self.point_size_changed.emit(int(value))
+        self.point_size_commit_requested.emit(int(value))  # save / persist
 
     def _emit_commit(self) -> None:
         self.point_size_commit_requested.emit(self.point_size())