empty viewport, prevent duplicate series meta from add, protect broadcast events when no data has changed

platform/ui/index.js

@@ -14,6 +14,9 @@ export {
   ImageViewerContext,
   ImageViewerProvider,
   useImageViewer,
+  ViewportGridContext,
+  ViewportGridProvider,
+  useViewportGrid,
 } from './src/contextProviders';
 
 /** COMPONENTS */

platform/ui/src/contextProviders/ViewportGridProvider.jsx

@@ -0,0 +1,20 @@
+import React, { createContext, useContext, useReducer } from 'react';
+
+// export const VIEWPORT_GRID_DEFAULT_VALUE = {
+//   numCols: 1,
+//   numRows: 1,
+//   activeViewportIndex: 0,
+//   viewports: [],
+// };
+
+export const ViewportGridContext = createContext();
+
+export function ViewportGridProvider({ reducer, initialState, children }) {
+  return (
+    <ViewportGridContext.Provider value={useReducer(reducer, initialState)}>
+      {children}
+    </ViewportGridContext.Provider>
+  );
+}
+
+export const useViewportGrid = () => useContext(ViewportGridContext);

platform/ui/src/contextProviders/index.js

@@ -16,4 +16,10 @@ export {
   useImageViewer,
 } from './ImageViewerProvider';
 
+export {
+  ViewportGridContext,
+  ViewportGridProvider,
+  useViewportGrid,
+} from './ViewportGridProvider';
+
 export { default as DragAndDropProvider } from './DragAndDropProvider';