From dc7f748d8f03aba605631965e21fb3ebfa675efa Mon Sep 17 00:00:00 2001
From: Johannes Bunk <johannes.bunk@mevis.fraunhofer.de>
Date: Mon, 15 Apr 2024 18:28:03 +0200
Subject: [PATCH] fix scroll bug

---
 packages/core/src/RenderingEngine/StackViewport.ts | 11 ++++++++---
 packages/core/src/types/IStackViewport.ts          |  5 ++++-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/packages/core/src/RenderingEngine/StackViewport.ts b/packages/core/src/RenderingEngine/StackViewport.ts
index 2b0312d83c..71f13c559b 100644
--- a/packages/core/src/RenderingEngine/StackViewport.ts
+++ b/packages/core/src/RenderingEngine/StackViewport.ts
@@ -2445,8 +2445,9 @@ class StackViewport extends Viewport implements IStackViewport, IImagesLoader {
   /**
    * Loads the image based on the provided imageIdIndex
    * @param imageIdIndex - number represents imageId index
+   * @param overwriteScrollIndex - can be used to also set the start position of scroll() to this index
    */
-  private async _setImageIdIndex(imageIdIndex: number): Promise<string> {
+  private async _setImageIdIndex(imageIdIndex: number, overwriteScrollIndex: boolean = false): Promise<string> {
     if (imageIdIndex >= this.imageIds.length) {
       throw new Error(
         `ImageIdIndex provided ${imageIdIndex} is invalid, the stack only has ${this.imageIds.length} elements`
@@ -2455,6 +2456,9 @@ class StackViewport extends Viewport implements IStackViewport, IImagesLoader {
 
     // Update the state of the viewport to the new imageIdIndex;
     this.currentImageIdIndex = imageIdIndex;
+    if (overwriteScrollIndex) {
+      this.targetImageIdIndex = this.currentImageIdIndex;
+    }
     this.hasPixelSpacing = true;
     this.viewportStatus = ViewportStatus.PRE_RENDER;
 
@@ -2583,8 +2587,9 @@ class StackViewport extends Viewport implements IStackViewport, IImagesLoader {
    *
    * @param imageIdIndex - number represents imageId index in the list of
    * provided imageIds in setStack
+   * @param overwriteScrollIndex - can be used to also set the start position of scroll() to this index
    */
-  public setImageIdIndex(imageIdIndex: number): Promise<string> {
+  public setImageIdIndex(imageIdIndex: number, overwriteScrollIndex: boolean = false): Promise<string> {
     this._throwIfDestroyed();
 
     // If we are already on this imageId index, stop here
@@ -2593,7 +2598,7 @@ class StackViewport extends Viewport implements IStackViewport, IImagesLoader {
     }
 
     // Otherwise, get the imageId and attempt to display it
-    const imageIdPromise = this._setImageIdIndex(imageIdIndex);
+    const imageIdPromise = this._setImageIdIndex(imageIdIndex, overwriteScrollIndex);
 
     return imageIdPromise;
   }
diff --git a/packages/core/src/types/IStackViewport.ts b/packages/core/src/types/IStackViewport.ts
index 5d7dfce45a..754eaa4c9f 100644
--- a/packages/core/src/types/IStackViewport.ts
+++ b/packages/core/src/types/IStackViewport.ts
@@ -158,7 +158,10 @@ export default interface IStackViewport extends IViewport {
    * Loads the image based on the provided imageIdIndex. It is an Async function which
    * returns a promise that resolves to the imageId.
    */
-  setImageIdIndex(imageIdIndex: number): Promise<string>;
+  setImageIdIndex(
+    imageIdIndex: number,
+    overwriteScrollIndex: boolean
+  ): Promise<string>;
   /**
    * Calibrates the image with new metadata that has been added for imageId. To calibrate
    * a viewport, you should add your calibration data manually to