fix: disable seg download/export buttons until a user has drawn something (#4953)

extensions/cornerstone/src/customizations/CustomDropdownMenuContent.tsx

@@ -108,6 +108,7 @@ export const CustomDropdownMenuContent = () => {
                 e.preventDefault();
                 actions.downloadCSVSegmentationReport(segmentationId);
               }}
+              disabled={!allowExport}
             >
               {t('CSV Report')}
             </DropdownMenuItem>

extensions/cornerstone/src/panels/PanelSegmentation.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import { SegmentationTable } from '@ohif/ui-next';
 import { useActiveViewportSegmentationRepresentations } from '../hooks/useActiveViewportSegmentationRepresentations';
-import { metaData } from '@cornerstonejs/core';
+import { metaData, cache } from '@cornerstonejs/core';
 import { useSystem } from '@ohif/core/src';
 
 export default function PanelSegmentation({ children }: withAppTypes) {
@@ -104,6 +104,26 @@ export default function PanelSegmentation({ children }: withAppTypes) {
       return { segmentationId, isExportable: true };
     }
 
+    // Check if any segments have anything drawn in any of the viewports
+    const hasAnySegmentData = (() => {
+      const imageIds = Labelmap.imageIds;
+      if (!imageIds?.length) return false;
+
+      for (const imageId of imageIds) {
+        const pixelData = cache.getImage(imageId)?.getPixelData();
+        if (!pixelData) continue;
+
+        for (let i = 0; i < pixelData.length; i++) {
+          if (pixelData[i] !== 0) return true;
+        }
+      }
+      return false;
+    })();
+
+    if (!hasAnySegmentData) {
+      return { segmentationId, isExportable: false };
+    }
+
     const referencedImageIds = Labelmap.referencedImageIds;
     const firstImageId = referencedImageIds[0];
     const instance = metaData.get('instance', firstImageId);