Update comment

src/openflexure_microscope_server/things/scan_workflows.py

@@ -261,16 +261,16 @@ class RectGridWorkflow(
 
     def _get_stitching_settings_model(self) -> StitchingSettings:
         """Return a stitching settings model based on current settings."""
+        # Use the save resolution and target stitch resolution to choose a unit fraction,
+        # which makes correlating faster
         width, height = self.save_resolution
-
         # Target area in pixels
         target_area = TARGET_STITCHING_DIMENSION**2
-
         # Find N so that (width/N) * (height/N) ~ target_area
         # N^2 ~ (width * height) / target_area
         downsample_factor = max(1, round((width * height / target_area) ** 0.5))
-
         correlation_resize = 1 / downsample_factor
+
         return StitchingSettings(
             overlap=self.overlap,
             correlation_resize=correlation_resize,

tests/unit_tests/test_scan_workflows.py

@@ -434,14 +434,15 @@ def test_histo_workflow_settings_ui(histo_workflow, mocker):
 
 
 @pytest.mark.parametrize(
-    ("save_res,expected_resize",)[
-        ((1400, 1400), 1 / 2),  # width=1400 -> N=2
-        ((1640, 1232), 1 / 2),  # width=1640 -> round(1640/750)=2
-        ((760, 750), 1 / 1),  # width=760 -> N=1
-        ((1499, 1000), 1 / 2),  # width ~1500 -> N=2
-        ((2250, 1800), 1 / 3),  # width=2250 -> N=3
-        ((700, 700), 1 / 1),  # width < 750 -> N=1
-    ]
+    ("save_res", "expected_resize"),
+    [
+        ((1400, 1400), 1 / 2),
+        ((1640, 1232), 1 / 2),
+        ((760, 750), 1 / 1),
+        ((1499, 1000), 1 / 2),
+        ((2250, 1800), 1 / 3),
+        ((700, 700), 1 / 1),
+    ],
 )
 def test_correlation_resize(histo_workflow, save_res, expected_resize):
     """Test that scan_workflows chooses a suitable correlation_resize factor.