From 1674254a3c64fdb34e50f75cf1042ed0edd30d06 Mon Sep 17 00:00:00 2001
From: Ross <xkjq@ymail.com>
Date: Mon, 11 May 2026 11:34:36 +0100
Subject: [PATCH] Add clearViewer function to reset viewer state and
 annotations

---
 dicom-viewer/src/App.tsx | 52 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/dicom-viewer/src/App.tsx b/dicom-viewer/src/App.tsx
index f537572..e4bbd52 100644
--- a/dicom-viewer/src/App.tsx
+++ b/dicom-viewer/src/App.tsx
@@ -2254,6 +2254,56 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
     }
   }
 
+  function clearViewer() {
+    const renderingEngine = renderingEngineRef.current;
+
+    // Disable viewports so stale frames are removed from the DOM/canvas.
+    if (renderingEngine) {
+      for (let i = 0; i < MAX_VIEWPORTS; i++) {
+        const viewportId = `CT_${i}`;
+        try {
+          const viewport = renderingEngine.getViewport(viewportId);
+          if (viewport) {
+            renderingEngine.disableElement(viewportId);
+          }
+        } catch (e) {
+          // Ignore missing/disabled viewport errors.
+        }
+      }
+    }
+
+    // Clear per-viewport DOM state so they can be re-enabled cleanly later.
+    for (let i = 0; i < MAX_VIEWPORTS; i++) {
+      const element = viewportRefs.current[i];
+      if (!element) continue;
+      if (element._resizeObserver) {
+        try {
+          element._resizeObserver.disconnect();
+        } catch (e) {
+          // Ignore observer teardown issues.
+        }
+        element._resizeObserver = undefined;
+      }
+      element._cornerstoneEnabled = false;
+      element._lastViewportType = undefined;
+      element._overlayListener = undefined;
+      element.innerHTML = '';
+    }
+
+    if (cornerstoneTools?.annotation?.state?.removeAllAnnotations) {
+      cornerstoneTools.annotation.state.removeAllAnnotations();
+    }
+
+    setAvailableStacks([]);
+    setViewportImageIds(Array(MAX_VIEWPORTS).fill([]));
+    setSelectedStackIdx(Array(MAX_VIEWPORTS).fill(0));
+    setViewportModes(Array(MAX_VIEWPORTS).fill('stack'));
+    setStackThumbnails({});
+    thumbRequestedRef.current = {};
+    setStackOrderModified(false);
+    setActiveViewport(0);
+  }
+
   function truncateStack(lower: number, upper: number) {
     // Only allow when 1 viewport and 1 stack is loaded
     console.log("Truncating stack from", lower, "to", upper);
@@ -2345,6 +2395,7 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
 
     window[`jumpToSliceByImageId_${apiKey}`] = jumpToSliceByImageId;
     window[`resetViewer_${apiKey}`] = resetViewer;
+    window[`clearViewer_${apiKey}`] = clearViewer;
     window[`truncateStack_${apiKey}`] = truncateStack;
     window[`getCurrentStackPosition_${apiKey}`] = getCurrentStackPosition;
 
@@ -2864,6 +2915,7 @@ function App({ container_id, imageStacks, autoCacheStack, annotationJson, viewer
       window[`importLegacyViewport_${apiKey}`] = undefined;
       window[`jumpToSliceByImageId_${apiKey}`] = undefined;
       window[`resetViewer_${apiKey}`] = undefined;
+      window[`clearViewer_${apiKey}`] = undefined;
       window[`truncateStack_${apiKey}`] = undefined;
       window[`getCurrentStackPosition_${apiKey}`] = undefined;
       window[`loadAdditionalStack_${apiKey}`] = undefined;