add re layout button

app.py

@@ -31,7 +31,7 @@ logger = logging.getLogger(__name__)
 app = Flask(__name__)
 
 # Neo4j HTTP API endpoint (not Bolt)
-NEO4J_HTTP_URL = os.environ.get("NEO4J_HTTP_URL", "http://localhost")
+NEO4J_HTTP_URL = os.environ.get("NEO4J_HTTP_URL", "")
 NEO4J_USER = os.environ.get("NEO4J_USER", "neo4j")
 NEO4J_PASSWORD = os.environ.get("NEO4J_PASSWORD", "")
 NEO4J_DATABASE = os.environ.get("NEO4J_DATABASE", "neo4j")
@@ -40,6 +40,9 @@ SAMPLE_QUERIES_FILE = os.environ.get(
     os.path.join(os.path.dirname(__file__), "config", "sample_queries.json"),
 )
 
+# Cache for the last query result (avoids re-querying Neo4j for re-layout)
+_last_query_cache: dict = {}
+
 
 # ---------------------------------------------------------------------------
 # Neo4j HTTP Transactional API helpers
@@ -308,6 +311,13 @@ def api_query():
         nodes_dict, edges, records, keys = execute_cypher(cypher)
         t_query = time.time() - t0
 
+        # Cache raw results for re-layout
+        _last_query_cache.clear()
+        _last_query_cache["nodes_dict"] = {k: dict(v) for k, v in nodes_dict.items()}
+        _last_query_cache["edges"] = [dict(e) for e in edges]
+        _last_query_cache["records"] = records
+        _last_query_cache["keys"] = keys
+
         # Assign colours
         label_colors: dict[str, str] = {}
         for nd in nodes_dict.values():
@@ -374,6 +384,84 @@ def api_query():
         return jsonify({"error": str(exc)}), 400
 
 
+@app.route("/api/relayout", methods=["POST"])
+def api_relayout():
+    """Re-run layout on the cached query result without hitting Neo4j."""
+    if not _last_query_cache:
+        return jsonify({"error": "No cached query result. Run a query first."}), 400
+
+    data = request.get_json(force=True)
+    layout_algo = data.get("layout", "auto")
+    spacing = float(data.get("spacing", 1.0))
+    iterations = int(data.get("iterations", 300))
+
+    try:
+        # Deep-copy cached data so layout doesn't mutate the cache
+        nodes_dict = {k: dict(v) for k, v in _last_query_cache["nodes_dict"].items()}
+        edges = [dict(e) for e in _last_query_cache["edges"]]
+        records = _last_query_cache["records"]
+        keys = _last_query_cache["keys"]
+
+        # Assign colours
+        label_colors: dict[str, str] = {}
+        for nd in nodes_dict.values():
+            for lb in nd.get("labels", []):
+                if lb not in label_colors:
+                    label_colors[lb] = color_for_label(lb)
+
+        # Compute layout
+        t1 = time.time()
+        positions = compute_layout(
+            nodes_dict, edges,
+            algorithm=layout_algo, spacing=spacing, iterations=iterations,
+        )
+        t_layout = time.time() - t1
+
+        # Degree for sizing
+        degree: dict[str, int] = defaultdict(int)
+        for e in edges:
+            degree[e["source"]] += 1
+            degree[e["target"]] += 1
+        max_deg = max(degree.values()) if degree else 1
+
+        nodes_list = []
+        for nid, nd in nodes_dict.items():
+            pos = positions.get(nid, {"x": 0, "y": 0})
+            primary = nd["labels"][0] if nd.get("labels") else "Unknown"
+            nd["x"] = pos["x"]
+            nd["y"] = pos["y"]
+            nd["color"] = label_colors.get(primary, "#888888")
+            d = degree.get(nid, 0)
+            nd["size"] = 3 + (d / max(max_deg, 1)) * 22
+            nodes_list.append(nd)
+
+        seen = set()
+        unique_edges = []
+        for e in edges:
+            key = (e["source"], e["target"], e["type"])
+            if key not in seen:
+                seen.add(key)
+                unique_edges.append(e)
+
+        return jsonify({
+            "nodes": nodes_list,
+            "edges": unique_edges,
+            "label_colors": label_colors,
+            "records": records[:500],
+            "keys": keys,
+            "stats": {
+                "node_count": len(nodes_list),
+                "edge_count": len(unique_edges),
+                "labels": list(label_colors.keys()),
+                "query_time_ms": 0,
+                "layout_time_ms": round(t_layout * 1000),
+            },
+        })
+    except Exception as exc:
+        logger.exception("Re-layout failed")
+        return jsonify({"error": str(exc)}), 400
+
+
 @app.route("/api/schema")
 def api_schema():
     try:

config/sample_queries.json

@@ -1,43 +1,35 @@
 [
     {
-        "name": "Focused Entity Relation Graph",
+        "name": "Sample Graph (100)",
-        "query": "MATCH (a:Entity)-[r:RELATION]-(b:Entity) WHERE toLower(coalesce(a.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] AND toLower(coalesce(b.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] RETURN a, r, b LIMIT 1500"
+        "query": "MATCH (n)-[r]->(m) RETURN n, r, m LIMIT 100"
     },
     {
-        "name": "Persons <-> Events",
+        "name": "Sample Graph (500)",
-        "query": "MATCH (p:Entity)-[r:RELATION]-(e:Entity) WHERE toLower(coalesce(p.type, '')) IN ['person','people'] AND toLower(coalesce(e.type, '')) IN ['event','incident','meeting','occurrence'] RETURN p, r, e LIMIT 1500"
+        "query": "MATCH (n)-[r]->(m) RETURN n, r, m LIMIT 500"
     },
     {
-        "name": "Events <-> Dates",
+        "name": "Sample Graph (2000)",
-        "query": "MATCH (ev:Entity)-[r:RELATION]-(d:Entity) WHERE toLower(coalesce(ev.type, '')) IN ['event','incident','meeting','occurrence'] AND toLower(coalesce(d.type, '')) IN ['date','time','datetime'] RETURN ev, r, d LIMIT 1500"
+        "query": "MATCH (n)-[r]->(m) RETURN n, r, m LIMIT 2000"
     },
     {
-        "name": "Events <-> Locations",
+        "name": "Node Label Counts",
-        "query": "MATCH (ev:Entity)-[r:RELATION]-(loc:Entity) WHERE toLower(coalesce(ev.type, '')) IN ['event','incident','meeting','occurrence'] AND toLower(coalesce(loc.type, '')) IN ['location','place','city','country','gpe'] RETURN ev, r, loc LIMIT 1500"
+        "query": "MATCH (n) RETURN labels(n)[0] AS label, count(*) AS count ORDER BY count DESC LIMIT 25"
     },
     {
-        "name": "Persons <-> Locations",
+        "name": "Relationship Type Counts",
-        "query": "MATCH (p:Entity)-[r:RELATION]-(loc:Entity) WHERE toLower(coalesce(p.type, '')) IN ['person','people'] AND toLower(coalesce(loc.type, '')) IN ['location','place','city','country','gpe'] RETURN p, r, loc LIMIT 1500"
+        "query": "MATCH ()-[r]->() RETURN type(r) AS type, count(*) AS count ORDER BY count DESC LIMIT 25"
     },
     {
-        "name": "People Around Top Events (2 Hops)",
+        "name": "High-Connectivity Nodes",
-        "query": "MATCH (ev:Entity) WHERE toLower(coalesce(ev.type, '')) IN ['event','incident','meeting','occurrence'] MATCH (ev)-[r0:RELATION]-() WITH ev, count(r0) AS degree ORDER BY degree DESC LIMIT 20 MATCH path = (ev)-[:RELATION*1..2]-(n:Entity) WHERE toLower(coalesce(n.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] RETURN path LIMIT 2000"
+        "query": "MATCH (n)-[r]-() WITH n, count(r) AS degree ORDER BY degree DESC LIMIT 20 MATCH (n)-[r2]->(m) RETURN n, r2, m LIMIT 300"
     },
     {
-        "name": "Most Connected Focus Entities",
+        "name": "Shortest Path (sample)",
-        "query": "MATCH (e:Entity)-[r:RELATION]-(:Entity) WHERE toLower(coalesce(e.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] WITH e, count(r) AS degree ORDER BY degree DESC LIMIT 40 MATCH (e)-[r2:RELATION]-(n:Entity) WHERE toLower(coalesce(n.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] RETURN e, r2, n LIMIT 1800"
+        "query": "MATCH (a), (b) WHERE a <> b WITH a, b LIMIT 1 MATCH path = shortestPath((a)-[*..5]-(b)) RETURN path"
     },
     {
-        "name": "Relation Predicate Distribution (Focused Types)",
+        "name": "Connected Component (depth 3)",
-        "query": "MATCH (a:Entity)-[r:RELATION]->(b:Entity) WHERE toLower(coalesce(a.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] AND toLower(coalesce(b.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] RETURN coalesce(r.predicate_display, r.predicate, '<missing>') AS predicate, count(*) AS count ORDER BY count DESC LIMIT 50"
+        "query": "MATCH (start) WITH start LIMIT 1 MATCH path = (start)-[*1..3]-(connected) RETURN path LIMIT 300"
-    },
-    {
-        "name": "Entity Type Counts (Focused)",
-        "query": "MATCH (e:Entity) WHERE toLower(coalesce(e.type, '')) IN ['person','people','event','incident','meeting','occurrence','date','time','datetime','location','place','city','country','gpe'] RETURN toLower(coalesce(e.type, '<missing>')) AS entity_type, count(*) AS count ORDER BY count DESC"
-    },
-    {
-        "name": "Asymmetric Focused Relations",
-        "query": "MATCH (a:Entity)-[r:RELATION]->(b:Entity) WHERE toLower(coalesce(a.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] AND toLower(coalesce(b.type, '')) IN ['person','people','event','date','time','location','place','city','country','gpe'] AND NOT (b)-[:RELATION]->(a) RETURN a, r, b LIMIT 1500"
     },
     {
         "name": "Schema Visualization",

requirements.txt

@@ -3,6 +3,7 @@ neo4j>=5.0
 networkx>=3.0
 numpy>=1.24
 scipy>=1.10
+matplotlib>=3.10
 python-igraph>=0.11
 gunicorn>=21.0
 requests>=2.0

templates/index.html

@@ -12,7 +12,7 @@
   <script src="https://d3js.org/d3.v7.min.js"></script>
   <style>
     /* =========================================================
-   CSS — Cortex Graph Explorer
+   CSS — Graph Explorer
    Dark theme with glass-morphism, glow accents
    ========================================================= */
     *,
@@ -880,13 +880,13 @@
             placeholder="MATCH (n)-[r]->(m)&#10;RETURN n, r, m&#10;LIMIT 100"></textarea>
           <div class="controls-row">
             <button class="btn btn-primary" id="run-btn" onclick="runQuery()">▶ Run</button>
-            <button class="btn btn-secondary" onclick="runDemo()" title="Generate demo graph without Neo4j">✦
+            <button class="btn btn-secondary" onclick="reLayout()" title="Re-run layout on cached data (no DB query)">⟳ Re-Layout</button>
-              Demo</button>
             <select class="styled-select" id="layout-select" title="Layout algorithm">
               <option value="auto">Auto Layout</option>
             </select>
           </div>
           <div class="controls-row" style="margin-top:4px">
+            <button class="btn btn-secondary" onclick="runDemo()" title="Generate demo graph without Neo4j">✦ Demo</button>
             <select class="styled-select" id="demo-size" title="Demo graph size">
               <option value="100">Demo: 100 nodes</option>
               <option value="300" selected>Demo: 300 nodes</option>
@@ -1083,6 +1083,7 @@
       <button onclick="zoomOut()" title="Zoom out">−</button>
       <button onclick="fitGraph()" title="Fit to screen">⊡</button>
       <button onclick="resetView()" title="Reset">↺</button>
+      <button onclick="exportPNG()" title="Export as PNG">📷</button>
     </div>
 
     <div id="tooltip">
@@ -1155,7 +1156,7 @@
       const mmCanvas = document.getElementById('minimap-canvas');
       const mmCtx = mmCanvas.getContext('2d');
 
-      let dpr = window.devicePixelRatio || 1;
+      let dpr = Math.max(window.devicePixelRatio || 1, 2);
       let width, height;
       let transform = d3.zoomIdentity;
       let zoomBehavior;
@@ -1241,6 +1242,18 @@
           .call(zoomBehavior.transform, d3.zoomIdentity);
       };
 
+      window.exportPNG = function () {
+        // Export the current canvas at its full backing-store resolution (2x+)
+        canvas.toBlob(function(blob) {
+          const url = URL.createObjectURL(blob);
+          const a = document.createElement('a');
+          a.href = url;
+          a.download = 'graph-export.png';
+          a.click();
+          URL.revokeObjectURL(url);
+        }, 'image/png');
+      };
+
       /* =================================================================
          HOVER / CLICK
          ================================================================= */
@@ -1920,6 +1933,28 @@
         }
       };
 
+      window.reLayout = async function () {
+        const layout = document.getElementById('layout-select').value;
+        const spacing = state.vis.spacing;
+        const iterations = state.vis.iterations;
+
+        showLoading('Re-computing layout…');
+        try {
+          const resp = await fetch('/api/relayout', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ layout, spacing, iterations }),
+          });
+          const data = await resp.json();
+          if (data.error) throw new Error(data.error);
+          loadGraphData(data);
+          hideLoading();
+        } catch (err) {
+          hideLoading();
+          showError(err.message);
+        }
+      };
+
       window.runDemo = async function () {
         const size = parseInt(document.getElementById('demo-size').value);
         const layout = document.getElementById('layout-select').value;