ohif-viewer/platform/docs/versioned_docs/version-3.11/migration-guide/3p10-to-3p11/hydration.md

title	sidebar_position	sidebar_label	summary
Hydration	3	Hydration	Migration guide for OHIF 3.11's hydration system changes, including the transition to a centralized hydration dialog and command-based hydration for secondary display sets.

Update Hydration Logic:

*   The `promptHydrateSEG` and `promptHydrateRT` functions have been updated to use the generic `utils.promptHydrationDialog` from `@ohif/extension-cornerstone`.
*   The actual hydration is now often triggered by the `hydrateSecondaryDisplaySet` command.

*Example: `promptHydrateRT` change*

```diff
// extensions/cornerstone-dicom-rt/src/utils/promptHydrateRT.ts
- const RESPONSE = {
-   NO_NEVER: -1,
-   CANCEL: 0,
-   HYDRATE_SEG: 5,
- };
+ import { utils, Types } from '@ohif/extension-cornerstone';

function promptHydrateRT({
  servicesManager,
  rtDisplaySet,
  viewportId,
  preHydrateCallbacks,
  hydrateRTDisplaySet,
-}: withAppTypes) {
-  const { uiViewportDialogService, customizationService } = servicesManager.services;
-  // ... lots of old promise and dialog logic
-  return new Promise(async function (resolve, reject) {
-    // ...
-  });
-}
-
-function _askHydrate(
-  // ...
-) {
-  // ...
-}
+}: {
+  servicesManager: AppTypes.ServicesManager;
+  rtDisplaySet: AppTypes.DisplaySet;
+  viewportId: string;
+  preHydrateCallbacks?: Types.HydrationCallback[];
+  hydrateRTDisplaySet: Types.HydrationCallback;
+}) {
+  return utils.promptHydrationDialog({
+    servicesManager,
+    viewportId,
+    displaySet: rtDisplaySet,
+    preHydrateCallbacks,
+    hydrateCallback: hydrateRTDisplaySet,
+    type: 'RTSTRUCT',
+  });
}
```
The `hydrateRTDisplaySet` callback passed to this function would now typically involve the `hydrateSecondaryDisplaySet` command.
```diff
// extensions/cornerstone-dicom-rt/src/viewports/OHIFCornerstoneRTViewport.tsx
useEffect(() => {
  if (rtIsLoading) {
    return;
  }
  promptHydrateRT({
    servicesManager,
    viewportId,
    rtDisplaySet,
-      preHydrateCallbacks: [storePresentationState],
-      hydrateRTDisplaySet,
-    }).then(isHydrated => {
-      if (isHydrated) {
-        setIsHydrated(true);
-      }
+      hydrateRTDisplaySet: async () => {
+        return commandsManager.runCommand('hydrateSecondaryDisplaySet', {
+          displaySet: rtDisplaySet,
+          viewportId,
+        });
+      },
  });
-  }, [servicesManager, viewportId, rtDisplaySet, rtIsLoading]);
+  }, [servicesManager, viewportId, rtDisplaySet, rtIsLoading, commandsManager]);
```