fix: seg sync for data without FOR (#5565)

* fix: seg sync for data without FOR

* test commit to trigger deploy re-run

* test commit to trigger deploy re-run

* Revert "test commit to trigger deploy re-run"

This reverts commit 42c532c6f404798e39e3d137fff7c1e7569956ad.

* chore: comments updated

* review commnets

---------

Co-authored-by: Bill Wallace <wayfarer3130@gmail.com>

extensions/cornerstone/src/services/SyncGroupService/createHydrateSegmentationSynchronizer.ts

@@ -6,6 +6,8 @@ import {
   Types as ToolsTypes,
 } from '@cornerstonejs/tools';
 
+import { isAnyDisplaySetCommon } from '../../utils/isAnyDisplaySetCommon';
+
 const { createSynchronizer } = SynchronizerManager;
 const { SEGMENTATION_REPRESENTATION_MODIFIED } = Enums.Events;
 const { BlendModes } = CoreEnums;
@@ -34,6 +36,12 @@ export default function createHydrateSegmentationSynchronizer(
   return stackImageSynchronizer;
 }
 
+/**
+ * This method will add the segmentation representation to any target viewports having:
+ *
+ * 1. the same FrameOfReferenceUID (FOR) as the segmentation representation, or
+ * 2. a shared DisplaySet with the source viewport when no FOR is present.
+ */
 const segmentationRepresentationModifiedCallback = async (
   synchronizerInstance: Synchronizer,
   sourceViewport: Types.IViewportId,
@@ -44,15 +52,21 @@ const segmentationRepresentationModifiedCallback = async (
   const event = sourceEvent as ToolsTypes.EventTypes.SegmentationRepresentationModifiedEventType;
 
   const { segmentationId, type: segmentationRepresentationType } = event.detail;
-  const { segmentationService } = servicesManager.services;
+  const { segmentationService, cornerstoneViewportService } = servicesManager.services;
 
   const targetViewportId = targetViewport.viewportId;
+  const sourceViewportId = sourceViewport.viewportId;
 
   const { viewport } = getEnabledElementByViewportId(targetViewportId);
+  const sourceViewportInfo = cornerstoneViewportService.getViewportInfo(sourceViewportId);
+  const targetViewportInfo = cornerstoneViewportService.getViewportInfo(targetViewportId);
 
-  const targetFrameOfReferenceUID = viewport.getFrameOfReferenceUID();
+  const sourceDisplaySetUIDs = extractDisplaySetUIDs(sourceViewportInfo);
+  const targetDisplaySetUIDs = extractDisplaySetUIDs(targetViewportInfo);
 
-  if (!targetFrameOfReferenceUID) {
+  const sharedDisplaySetExists = isAnyDisplaySetCommon(sourceDisplaySetUIDs, targetDisplaySetUIDs);
+
+  if (!sharedDisplaySetExists && !viewport.getFrameOfReferenceUID()) {
     return;
   }
 
@@ -81,3 +95,10 @@ const segmentationRepresentationModifiedCallback = async (
     },
   });
 };
+
+/**
+ * Extracts the displaySetInstanceUIDs from a viewportInfo.
+ */
+function extractDisplaySetUIDs(viewportInfo) {
+  return viewportInfo.getViewportData().data.map(ds => ds.displaySetInstanceUID);
+}

extensions/cornerstone/src/utils/isAnyDisplaySetCommon.ts

@@ -0,0 +1,18 @@
+/**
+ * Checks whether two viewports share at least one common display set.
+ *
+ * This method checks to see if the source and target share a display set.
+ * It performs an O(n * m) comparison between the display sets of each viewport.
+ * Since each viewport typically contains only a small number of display sets (≤ 5),
+ * the computational cost is negligible.
+ *
+ * @param sourceDisplaySetUIDs - Array of displaySetInstanceUID from the source viewport.
+ * @param targetDisplaySetUIDs - Array of displaySetInstanceUID from the target viewport.
+ * @returns true if at least one display set is common; false otherwise.
+ */
+export function isAnyDisplaySetCommon(
+  sourceDisplaySetUIDs: string[],
+  targetDisplaySetUIDs: string[]
+): boolean {
+  return sourceDisplaySetUIDs.some(uid => targetDisplaySetUIDs.includes(uid));
+}