From 40c576280e9dbbad7670d9eae2dd65abbe007310 Mon Sep 17 00:00:00 2001
From: Oshgnacknak <osh@oshgnacknak.de>
Date: Sun, 5 Sep 2021 22:47:54 +0200
Subject: [PATCH] Use and display MinimumSpanningForestAlgorithm results

---
 README.md                                     |  3 ++
 .../de/oshgnacknak/gruphi/GruphiFrame.java    | 36 +++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/README.md b/README.md
index a5d2291..332e577 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,9 @@ Gewichtung für die nächste Kante verkleinern/vergrößern
 - `O`:
 Gewichtung für die nächste Kante auf 1 zurücksetzten
 
+- `F`:
+Berechne oder verstecke den minimalen Spannbaum (blau) 
+
 ## Wenn Knoten ausgewählt (rot)
 
 - WASD:
diff --git a/src/main/java/de/oshgnacknak/gruphi/GruphiFrame.java b/src/main/java/de/oshgnacknak/gruphi/GruphiFrame.java
index c3d57b7..32c47a5 100644
--- a/src/main/java/de/oshgnacknak/gruphi/GruphiFrame.java
+++ b/src/main/java/de/oshgnacknak/gruphi/GruphiFrame.java
@@ -31,6 +31,8 @@ class GruphiFrame extends JFrame {
 
     private final DirectedGraph<Node, Double> graph;
 
+    private DirectedGraph<Node, Double> forest;
+
     private final MazeGenerator<Node> mazeGenerator;
     private final Gruphi gruphi;
 
@@ -112,6 +114,7 @@ class GruphiFrame extends JFrame {
                             }
                             graph.removeNode(selected);
                             selected = null;
+                            forest = null;
                         }
                     } break;
 
@@ -154,6 +157,10 @@ class GruphiFrame extends JFrame {
                         weight = 1.0;
                     } break;
 
+                    case KeyEvent.VK_F: {
+                        generateForest();
+                    } break;
+
                     default: break;
                 }
             }
@@ -199,6 +206,19 @@ class GruphiFrame extends JFrame {
         });
     }
 
+    private void generateForest() {
+        if (forest != null) {
+            forest = null;
+            return;
+        }
+
+        var algo = Objects.requireNonNull(
+            gruphi.getMinimumSpanningForestAlgorithm(),
+            "Did you supply a spanning forest implementation");
+
+        forest = algo.minimumSpanningForest(graph, Comparable::compareTo, gruphi.getDirectedGraphFactory());
+    }
+
     private void generatePaths() {
         clearPaths();
 
@@ -278,6 +298,7 @@ class GruphiFrame extends JFrame {
 
     private void clearGraph() {
         selected = null;
+        forest = null;
         clearPaths();
         for (var node : graph.getAllNodes()) {
             graph.removeNode(node);
@@ -317,6 +338,21 @@ class GruphiFrame extends JFrame {
         drawCells(d);
 
         drawPath(d);
+        drawForest(d);
+    }
+
+    private void drawForest(Drawable d) {
+        if (forest == null) {
+            return;
+        }
+
+        d.strokeWeight(2);
+        d.fill(Color.BLUE);
+        for (var node : forest.getAllNodes()) {
+            for (var child : forest.getChildrenForNode(node)) {
+                d.line(node.pos.x, node.pos.y, child.pos.x, child.pos.y);
+            }
+        }
     }
 
     private void drawCells(Drawable d) {