Fix for #34911, Compositor with multiple views autozooms to node when creating a link. In order to allow node trees have different offsets in different editor instances, the view_center is now stored primarily in the bNodeTreePath struct for each tree in a node space. The view_center in bNodeTree is only used as an initial setting when opening a node group or switching node trees.

source/blender/editors/space_node/node_draw.c

@@ -1194,12 +1194,12 @@ static void draw_tree_path(SpaceNode *snode)
 	BLF_draw_default(30, 30, 0.0f, info, sizeof(info));
 }
 
-static void snode_setup_v2d(SpaceNode *snode, ARegion *ar, float centerx, float centery)
+static void snode_setup_v2d(SpaceNode *snode, ARegion *ar, float center[2])
 {
 	View2D *v2d = &ar->v2d;
 	
 	/* shift view to node tree center */
-	UI_view2d_setcenter(v2d, centerx, centery);
+	UI_view2d_setcenter(v2d, center[0], center[1]);
 	UI_view2d_view_ortho(v2d);
 	
 	/* aspect+font, set each time */
@@ -1274,43 +1274,47 @@ void drawnodespace(const bContext *C, ARegion *ar)
 		bNodeLinkDrag *nldrag;
 		LinkData *linkdata;
 		
+		path = snode->treepath.last;
+		
 		/* current View2D center, will be set temporarily for parent node trees */
 		UI_view2d_getcenter(v2d, &center[0], &center[1]);
 		
-		/* store new view center in current edittree */
+		/* store new view center in path and current edittree */
+		copy_v2_v2(path->view_center, center);
 		if (snode->edittree)
 			copy_v2_v2(snode->edittree->view_center, center);
 		
 		depth = 0;
-		path = snode->treepath.last;
 		while (path->prev && depth < max_depth) {
 			path = path->prev;
 			++depth;
 		}
+		
 		/* parent node trees in the background */
-		for (curdepth = depth; curdepth >= 0; path = path->next, --curdepth) {
+		for (curdepth = depth; curdepth > 0; path = path->next, --curdepth) {
 			ntree = path->nodetree;
-			
 			if (ntree) {
-				snode_setup_v2d(snode, ar, ntree->view_center[0], ntree->view_center[1]);
-				
-				if (curdepth == 0) {
-					/* grid, uses theme color based on node path depth */
-					UI_view2d_multi_grid_draw(v2d, (depth > 0 ? TH_NODE_GROUP : TH_BACK), U.widget_unit, 5, 2);
-					
-					/* backdrop */
-					draw_nodespace_back_pix(C, ar, snode);
-				}
+				snode_setup_v2d(snode, ar, path->view_center);
 				
 				draw_nodetree(C, ar, ntree, path->parent_key);
 				
-				if (curdepth > 0)
-					draw_group_overlay(C, ar);
+				draw_group_overlay(C, ar);
 			}
 		}
 		
-		/* reset View2D */
-		UI_view2d_setcenter(v2d, center[0], center[1]);
+		/* top-level edit tree */
+		ntree = path->nodetree;
+		if (ntree) {
+			snode_setup_v2d(snode, ar, center);
+			
+			/* grid, uses theme color based on node path depth */
+			UI_view2d_multi_grid_draw(v2d, (depth > 0 ? TH_NODE_GROUP : TH_BACK), U.widget_unit, 5, 2);
+			
+			/* backdrop */
+			draw_nodespace_back_pix(C, ar, snode);
+			
+			draw_nodetree(C, ar, ntree, path->parent_key);
+		}
 		
 		/* temporary links */
 		glEnable(GL_BLEND);

source/blender/editors/space_node/space_node.c

@@ -75,8 +75,13 @@ void ED_node_tree_start(SpaceNode *snode, bNodeTree *ntree, ID *id, ID *from)
 		path = MEM_callocN(sizeof(bNodeTreePath), "node tree path");
 		path->nodetree = ntree;
 		path->parent_key = NODE_INSTANCE_KEY_BASE;
+		
+		/* copy initial offset from bNodeTree */
+		copy_v2_v2(path->view_center, ntree->view_center);
+		
 		if (id)
 			BLI_strncpy(path->node_name, id->name + 2, sizeof(path->node_name));
+		
 		BLI_addtail(&snode->treepath, path);
 	}
 	
@@ -85,7 +90,6 @@ void ED_node_tree_start(SpaceNode *snode, bNodeTree *ntree, ID *id, ID *from)
 	snode->id = id;
 	snode->from = from;
 	
-	/* listener updates the View2D center from edittree */
 	WM_main_add_notifier(NC_SCENE | ND_NODES, NULL);
 }
 
@@ -105,12 +109,14 @@ void ED_node_tree_push(SpaceNode *snode, bNodeTree *ntree, bNode *gnode)
 	else
 		path->parent_key = NODE_INSTANCE_KEY_BASE;
 	
+	/* copy initial offset from bNodeTree */
+	copy_v2_v2(path->view_center, ntree->view_center);
+	
 	BLI_addtail(&snode->treepath, path);
 	
 	/* update current tree */
 	snode->edittree = ntree;
 	
-	/* listener updates the View2D center from edittree */
 	WM_main_add_notifier(NC_SCENE | ND_NODES, NULL);
 }
 
@@ -205,20 +211,15 @@ void ED_node_tree_path_get_fixedbuf(SpaceNode *snode, char *value, int max_lengt
 void snode_group_offset(SpaceNode *snode, float *x, float *y)
 {
 	bNodeTreePath *path = snode->treepath.last;
-	float cx, cy;
 	
-	if (path) {
-		cx = path->nodetree->view_center[0];
-		cy = path->nodetree->view_center[1];
-		
-		if (path->prev) {
-			*x = cx - path->prev->nodetree->view_center[0];
-			*y = cy - path->prev->nodetree->view_center[1];
-			return;
-		}
+	if (path && path->prev) {
+		float dcenter[2];
+		sub_v2_v2v2(dcenter, path->view_center, path->prev->view_center);
+		*x = dcenter[0];
+		*y = dcenter[1];
 	}
-	
-	*x = *y = 0.0f;
+	else
+		*x = *y = 0.0f;
 }
 
 /* ******************** manage regions ********************* */
@@ -374,9 +375,10 @@ static void node_area_listener(ScrArea *sa, wmNotifier *wmn)
 			switch (wmn->data) {
 				case ND_NODES: {
 					ARegion *ar = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
+					bNodeTreePath *path = snode->treepath.last;
 					/* shift view to node tree center */
-					if (ar && snode->edittree)
-						UI_view2d_setcenter(&ar->v2d, snode->edittree->view_center[0], snode->edittree->view_center[1]);
+					if (ar && path)
+						UI_view2d_setcenter(&ar->v2d, path->view_center[0], path->view_center[1]);
 					
 					ED_area_tag_refresh(sa);
 					break;

source/blender/makesdna/DNA_space_types.h

@@ -891,6 +891,7 @@ typedef struct bNodeTreePath {
 	struct bNodeTree *nodetree;
 	bNodeInstanceKey parent_key;	/* base key for nodes in this tree instance */
 	int pad;
+	float view_center[2];			/* v2d center point, so node trees can have different offsets in editors */
 	/* XXX this is not automatically updated when node names are changed! */
 	char node_name[64];		/* MAX_NAME */
 } bNodeTreePath;