From fd819ae770873582b3c551ba5f629bd9df952e32 Mon Sep 17 00:00:00 2001
From: md-prog <26860200+md-prog@users.noreply.github.com>
Date: Fri, 7 Oct 2022 09:26:07 -0400
Subject: [PATCH] GPU rendering : reuse previously applied "voiRange" for the
 images that are rendered on the reused viewport but new actor

---
 packages/core/src/RenderingEngine/StackViewport.ts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/packages/core/src/RenderingEngine/StackViewport.ts b/packages/core/src/RenderingEngine/StackViewport.ts
index 83cb569b3..dac1b43f0 100644
--- a/packages/core/src/RenderingEngine/StackViewport.ts
+++ b/packages/core/src/RenderingEngine/StackViewport.ts
@@ -1765,6 +1765,15 @@ class StackViewport extends Viewport implements IStackViewport {
     }
 
     this.initialVOIRange = voiRange;
+
+    if (this.voiApplied && typeof voiRange === 'undefined') {
+      // There are some cases when different frames within the same multi-frame
+      // file are not hitting the actor cache because above
+      // this.__checkVTKImageDataMatchesCornerstoneImage() call results in
+      // "false".
+      // In that case we want to keep the applied VOI range.
+      voiRange = this.voiRange;
+    }
     this.setProperties({ voiRange });
 
     // At the moment it appears that vtkImageSlice actors do not automatically