From 1aed597f9c95aa930dedc0b5d3274f23654ead43 Mon Sep 17 00:00:00 2001
From: Julian Stirling <julian@julianstirling.co.uk>
Date: Thu, 2 Jul 2026 09:49:22 +0100
Subject: [PATCH] Smart scan return cancelled if cancelled before stitching
 starts.

---
 .../things/smart_scan.py                          | 15 ++++++++++++---
 .../components/tabContentComponents/actionTab.vue |  1 +
 .../tabContentComponents/slideScanContent.vue     |  2 +-
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/openflexure_microscope_server/things/smart_scan.py b/src/openflexure_microscope_server/things/smart_scan.py
index d8ce6cf8..d4ee2d59 100644
--- a/src/openflexure_microscope_server/things/smart_scan.py
+++ b/src/openflexure_microscope_server/things/smart_scan.py
@@ -43,6 +43,7 @@ from .stage import BacklashCompensation, BaseStage
 T = TypeVar("T")
 P = ParamSpec("P")
 
+MIN_IMAGES_TO_STITCH = 2
 
 # This allows ActiveScanData to hold arbitrary workflow settings models during a scan.
 AnyModel = Annotated[
@@ -409,7 +410,10 @@ class SmartScanThing(OFMThing):
             # This scan can't stitch.
             return
         # Begin stitching once two images are captured
-        if self.scan_data.image_count >= 2 and not self._preview_stitcher.running:
+        if (
+            self.scan_data.image_count >= MIN_IMAGES_TO_STITCH
+            and not self._preview_stitcher.running
+        ):
             self._preview_stitcher.start()
 
     @_scan_running
@@ -449,9 +453,14 @@ class SmartScanThing(OFMThing):
             self._main_scan_loop(workflow)
             self._save_final_scan_data(scan_result="success")
 
-        except lt.exceptions.InvocationCancelledError:
+        except lt.exceptions.InvocationCancelledError as e:
             self.logger.info("Stopping scan because it was cancelled.")
             self._save_final_scan_data(scan_result="cancelled by user")
+            if self.scan_data.image_count < MIN_IMAGES_TO_STITCH:
+                # If too few images to stitch then, return to the centre and report
+                # cancelled
+                self._return_to_starting_position()
+                raise e
         except Exception as e:
             err_name = type(e).__name__
             if self._scan_data is not None:
@@ -760,6 +769,6 @@ class SmartScanThing(OFMThing):
         # Use the scan list (the data read by the gallery) to find any scans that
         # need stitching.
         for scan in self.get_data_for_gallery():
-            if scan.dzi is None and scan.number_of_images >= 2:
+            if scan.dzi is None and scan.number_of_images >= MIN_IMAGES_TO_STITCH:
                 self.logger.info(f"Stitching {scan.name}")
                 self.stitch_scan(scan_name=scan.name)
diff --git a/webapp/src/components/tabContentComponents/actionTab.vue b/webapp/src/components/tabContentComponents/actionTab.vue
index 36570daf..dba0fd56 100644
--- a/webapp/src/components/tabContentComponents/actionTab.vue
+++ b/webapp/src/components/tabContentComponents/actionTab.vue
@@ -66,6 +66,7 @@ mode.
               submit-label=""
               :can-terminate="true"
               @completed="$emit('completed')"
+              @finished="$emit('finished')"
               @update:task-status="taskStatus = $event"
               @update:progress="progress = $event"
               @update:log="log = $event"
diff --git a/webapp/src/components/tabContentComponents/slideScanContent.vue b/webapp/src/components/tabContentComponents/slideScanContent.vue
index 6ab945f9..5ea250b8 100644
--- a/webapp/src/components/tabContentComponents/slideScanContent.vue
+++ b/webapp/src/components/tabContentComponents/slideScanContent.vue
@@ -6,7 +6,7 @@
     :task-url="taskUrl"
     :task-info-title="infoPaneTitle"
     :task-info-stream="displayImageOnRight"
-    @completed="onScanCompleted"
+    @finished="onScanCompleted"
     @close-task="closeTask"
     @action-started-externally="startScanning"
   >