fix: LSDV-4752: Support relations in MIG scenario (#1240)

* Support relations in MIG scenario

* Remove excess import

* Fix relations checks

* Render relation if above checks were skipped

* Fix formatting

* Remove excess checks

* Fix check

Author: nick-skriabin

package.json

@@ -162,7 +162,6 @@
     "mobx-state-tree": "^3.16.0",
     "nanoid": "^3.3.0",
     "node-fetch": "^2.6.1",
-    "node-sass": "^6.0.1",
     "pleasejs": "^0.4.2",
     "postcss": "^8.4.6",
     "postcss-loader": "^6.2.1",

src/components/RelationsOverlay/RelationsOverlay.js

@@ -164,7 +164,7 @@ const RelationItemObserver = observer(({ relation, startNode, endNode, visible,
 
   const visibility = visible && relation.visible;
 
-  return render ? (
+  return (render && relation.shouldRender) ? (
     <RelationItem
       id={relation.id}
       startNode={startNode}

src/stores/RelationStore.js

@@ -4,6 +4,7 @@ import { cloneNode, guidGenerator } from '../core/Helpers';
 import { RelationsModel } from '../tags/control/Relations';
 import { TRAVERSE_SKIP } from '../core/Tree';
 import Area from '../regions/Area';
+import { isDefined } from '../utils/utilities';
 
 /**
  * Relation between two different nodes
@@ -34,6 +35,24 @@ const Relation = types
 
       return r && r.children && r.children.length > 0;
     },
+
+    get shouldRender() {
+      const { node1: start, node2: end } = self;
+      const [sIdx, eIdx] = [start.item_index, end.item_index];
+
+      // as we don't currently have a unified solution for multi-object segmentation
+      // and the Image tag is the only one to support it, we rely on its API
+      // TODO: make multi-object solution more generic
+      if (isDefined(sIdx) &&
+          start.object.multiImage && 
+          sIdx !== start.object.currentImage) return false;
+
+      if (isDefined(eIdx) &&
+          end.object.multiImage && 
+          eIdx !== end.object.currentImage) return false;
+
+      return true;
+    },
   }))
   .actions(self => ({
     afterAttach() {