feat: tikz export with custom layouts

Author: pmbittner

src/main/java/org/variantsync/diffdetective/variation/diff/serialize/TikzExporter.java

@@ -1,20 +1,22 @@
 package org.variantsync.diffdetective.variation.diff.serialize;
 
+import org.variantsync.diffdetective.show.engine.geom.Vec2;
+import org.variantsync.diffdetective.util.LaTeX;
+import org.variantsync.diffdetective.variation.diff.DiffNode;
+import org.variantsync.diffdetective.variation.diff.DiffTree;
+
 import java.io.BufferedInputStream;
-import java.io.BufferedReader;
 import java.io.IOException;
-import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.PrintStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.util.HashMap;
 import java.util.Locale;
-import java.util.regex.Pattern;
+import java.util.Map;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 
-import org.variantsync.diffdetective.util.LaTeX;
-import org.variantsync.diffdetective.variation.diff.DiffTree;
-
 /**
  * Exporter for TikZ pictures which can be embedded into a LaTeX document.
  *
@@ -55,13 +57,34 @@ public void exportDiffTree(
             GraphvizExporter.LayoutAlgorithm algorithm,
             OutputStream destination
             ) throws IOException {
+        final Map<Integer, DiffNode> ids = new HashMap<>();
+        diffTree.forAll(node -> ids.put(node.getID(), node));
+
+        // Convert the layout information received by Graphviz to coordinates used by TikZ.
+        final Map<DiffNode, Vec2> positions = new HashMap<>();
+        GraphvizExporter.layoutNodesIn(diffTree, format, algorithm, (id, x, y) ->
+                positions.put(ids.get(id), new Vec2(x, y))
+        );
+
+        exportDiffTree(
+                diffTree,
+                positions::get,
+                destination);
+    }
+
+    public void exportDiffTree(
+            DiffTree diffTree,
+            Function<DiffNode, Vec2> nodeLayout,
+            OutputStream destination
+    ) {
         // Start tikz picture.
         var output = new PrintStream(destination);
         output.println("\\begin{tikzpicture}");
 
         // Convert the layout information received by Graphviz to coordinates used by TikZ.
-        GraphvizExporter.layoutNodesIn(diffTree, format, algorithm, (id, x, y) -> {
-            output.format("\t\\coordinate (%s) at (%s,%s);%n", id, x, y);
+        diffTree.forAll(node -> {
+            final Vec2 position = nodeLayout.apply(node);
+            output.format("\t\\coordinate (%s) at (%s,%s);%n", node.getID(), position.x(), position.y());
         });
 
         // Add all TikZ nodes positioned at the Graphviz coordinates.
@@ -72,7 +95,7 @@ public void exportDiffTree(
                 node.getID(),
                 node.getID());
         });
-        output.println("");
+        output.println();
 
         // Add all TikZ edges positioned.
         output.format("%n\t\\draw[vtdarrow]");