common code for force layout algorithms

Signed-off-by: Luma <[email protected]>

diagram-util/src/main/java/com/powsybl/diagram/util/forcelayout/AbstractForceLayout.java

@@ -48,15 +48,20 @@ public abstract class AbstractForceLayout<V, E> {
 
     private boolean hasBeenExecuted = false;
 
-    public abstract void execute();
-
     protected AbstractForceLayout(Graph<V, E> graph) {
         this.maxSteps = DEFAULT_MAX_STEPS;
         this.minEnergyThreshold = DEFAULT_MIN_ENERGY_THRESHOLD;
         this.deltaTime = DEFAULT_DELTA_TIME;
         this.graph = Objects.requireNonNull(graph);
     }
 
+    public final void computePositions() {
+        execute();
+        hasBeenExecuted = true;
+    }
+
+    protected abstract void execute();
+
     public AbstractForceLayout<V, E> setMaxSteps(int maxSteps) {
         this.maxSteps = maxSteps;
         return this;
@@ -96,52 +101,6 @@ public AbstractForceLayout<V, E> setFixedNodes(Set<V> fixedNodes) {
         return this;
     }
 
-    public void setHasBeenExecuted(boolean hasBeenExecuted) {
-        this.hasBeenExecuted = hasBeenExecuted;
-    }
-
-    void initializePoints() {
-        for (V vertex : graph.vertexSet()) {
-            Point p;
-            if (initialPoints.containsKey(vertex)) {
-                Point pInitial = initialPoints.get(vertex);
-                p = new Point(pInitial.getPosition().getX(), pInitial.getPosition().getY(), graph.degreeOf(vertex));
-            } else {
-                p = new Point(random.nextDouble(), random.nextDouble(), graph.degreeOf(vertex));
-            }
-            points.put(vertex, p);
-        }
-    }
-
-    void initializeSprings() {
-        for (E e : graph.edgeSet()) {
-            Point pointSource = points.get(graph.getEdgeSource(e));
-            Point pointTarget = points.get(graph.getEdgeTarget(e));
-            if (pointSource != pointTarget) { // no use in force layout to add loops
-                springs.add(new Spring(pointSource, pointTarget, graph.getEdgeWeight(e)));
-            }
-        }
-    }
-
-    void updatePosition() {
-        // Optimisation hint: do not compute forces or update velocities for fixed nodes
-        // We have computed forces and velocities for all nodes, even for the fixed ones
-        // We can optimize calculations by ignoring fixed nodes in those calculations
-        // Here we only update the position for the nodes that do not have fixed positions
-        for (Map.Entry<V, Point> vertexPoint : points.entrySet()) {
-            if (fixedNodes.contains(vertexPoint.getKey())) {
-                continue;
-            }
-            Point point = vertexPoint.getValue();
-            Vector position = point.getPosition().add(point.getVelocity().multiply(deltaTime));
-            point.setPosition(position);
-        }
-    }
-
-    boolean isStable() {
-        return points.values().stream().allMatch(p -> p.getEnergy() < minEnergyThreshold);
-    }
-
     public Vector getStablePosition(V vertex) {
         if (!hasBeenExecuted) {
             LOGGER.warn("Force layout has not been executed yet");
@@ -197,4 +156,46 @@ public void toSVG(Function<V, String> tooltip, Writer writer) {
 
         printWriter.close();
     }
+
+    protected void initializePoints() {
+        for (V vertex : graph.vertexSet()) {
+            Point p;
+            if (initialPoints.containsKey(vertex)) {
+                Point pInitial = initialPoints.get(vertex);
+                p = new Point(pInitial.getPosition().getX(), pInitial.getPosition().getY(), graph.degreeOf(vertex));
+            } else {
+                p = new Point(random.nextDouble(), random.nextDouble(), graph.degreeOf(vertex));
+            }
+            points.put(vertex, p);
+        }
+    }
+
+    protected void initializeSprings() {
+        for (E e : graph.edgeSet()) {
+            Point pointSource = points.get(graph.getEdgeSource(e));
+            Point pointTarget = points.get(graph.getEdgeTarget(e));
+            if (pointSource != pointTarget) { // no use in force layout to add loops
+                springs.add(new Spring(pointSource, pointTarget, graph.getEdgeWeight(e)));
+            }
+        }
+    }
+
+    protected void updatePosition() {
+        // Optimisation hint: do not compute forces or update velocities for fixed nodes
+        // We have computed forces and velocities for all nodes, even for the fixed ones
+        // We can optimize calculations by ignoring fixed nodes in those calculations
+        // Here we only update the position for the nodes that do not have fixed positions
+        for (Map.Entry<V, Point> vertexPoint : points.entrySet()) {
+            if (fixedNodes.contains(vertexPoint.getKey())) {
+                continue;
+            }
+            Point point = vertexPoint.getValue();
+            Vector position = point.getPosition().add(point.getVelocity().multiply(deltaTime));
+            point.setPosition(position);
+        }
+    }
+
+    protected boolean isStable() {
+        return points.values().stream().allMatch(p -> p.getEnergy() < minEnergyThreshold);
+    }
 }

diagram-util/src/main/java/com/powsybl/diagram/util/forcelayout/ForceAtlas2Layout.java

@@ -174,8 +174,6 @@ public void execute() {
             }
         }
 
-        setHasBeenExecuted(true);
-
         long elapsedTime = System.nanoTime() - start;
 
         LOGGER.info("Number of steps: {}", i);

diagram-util/src/main/java/com/powsybl/diagram/util/forcelayout/ForceLayoutSpringy.java

@@ -104,8 +104,6 @@ public void execute() {
             }
         }
 
-        setHasBeenExecuted(true);
-
         long elapsedTime = System.nanoTime() - start;
 
         LOGGER.info("Number of steps: {}", i);

network-area-diagram/src/main/java/com/powsybl/nad/NadParameters.java

@@ -9,7 +9,7 @@
 
 import com.powsybl.iidm.network.Network;
 import com.powsybl.nad.build.iidm.IntIdProvider;
-import com.powsybl.nad.layout.BasicForceLayoutFactory;
+import com.powsybl.nad.layout.BasicForceLayoutSpringyFactory;
 import com.powsybl.nad.layout.LayoutFactory;
 import com.powsybl.nad.layout.LayoutParameters;
 import com.powsybl.nad.svg.LabelProvider;
@@ -28,7 +28,7 @@ public class NadParameters {
     private LayoutParameters layoutParameters = new LayoutParameters();
     private StyleProviderFactory styleProviderFactory = TopologicalStyleProvider::new;
     private LabelProviderFactory labelProviderFactory = DefaultLabelProvider::new;
-    private LayoutFactory layoutFactory = new BasicForceLayoutFactory();
+    private LayoutFactory layoutFactory = new BasicForceLayoutSpringyFactory();
     private IdProviderFactory idProviderFactory = IntIdProvider::new;
 
     public SvgParameters getSvgParameters() {

network-area-diagram/src/main/java/com/powsybl/nad/layout/BasicForceLayout.java → network-area-diagram/src/main/java/com/powsybl/nad/layout/AbstractBasicForceLayout.java

@@ -6,7 +6,7 @@
  */
 package com.powsybl.nad.layout;
 
-import com.powsybl.diagram.util.forcelayout.ForceLayoutSpringy;
+import com.powsybl.diagram.util.forcelayout.AbstractForceLayout;
 import com.powsybl.diagram.util.forcelayout.Vector;
 import com.powsybl.nad.model.Edge;
 import com.powsybl.nad.model.Graph;
@@ -19,16 +19,18 @@
 
 /**
  * @author Florian Dupuy {@literal <florian.dupuy at rte-france.com>}
+ * @author Luma Zamarreño {@literal <zamarrenolm at aia.es>}
  */
-public class BasicForceLayout extends AbstractLayout {
+public abstract class AbstractBasicForceLayout extends AbstractLayout {
 
-    private static final int SCALE = 100;
+    protected abstract int getScale();
+
+    protected abstract AbstractForceLayout<Node, Edge> getForceLayoutAlgorithm(org.jgrapht.Graph<Node, Edge> jgraphtGraph, LayoutParameters layoutParameters);
 
     @Override
     protected void nodesLayout(Graph graph, LayoutParameters layoutParameters) {
         org.jgrapht.Graph<Node, Edge> jgraphtGraph = graph.getJgraphtGraph(layoutParameters.isTextNodesForceLayout());
-        ForceLayoutSpringy<Node, Edge> forceLayout = new ForceLayoutSpringy<>(jgraphtGraph);
-        forceLayout.setSpringRepulsionFactor(layoutParameters.getSpringRepulsionFactorForceLayout());
+        AbstractForceLayout<Node, Edge> forceLayout = getForceLayoutAlgorithm(jgraphtGraph, layoutParameters);
         forceLayout.setMaxSteps(layoutParameters.getMaxSteps());
 
         setInitialPositions(forceLayout, graph);
@@ -38,27 +40,29 @@ protected void nodesLayout(Graph graph, LayoutParameters layoutParameters) {
                 .collect(Collectors.toSet());
         forceLayout.setFixedNodes(fixedNodes);
 
-        forceLayout.execute();
+        forceLayout.computePositions();
 
+        int scale = getScale();
         jgraphtGraph.vertexSet().forEach(node -> {
             Vector p = forceLayout.getStablePosition(node);
-            node.setPosition(SCALE * p.getX(), SCALE * p.getY());
+            node.setPosition(scale * p.getX(), scale * p.getY());
         });
 
         if (!layoutParameters.isTextNodesForceLayout()) {
             graph.getTextEdgesMap().values().forEach(nodePair -> fixedTextNodeLayout(nodePair, layoutParameters));
         }
     }
 
-    private void setInitialPositions(ForceLayoutSpringy<Node, Edge> forceLayout, Graph graph) {
+    private void setInitialPositions(AbstractForceLayout<Node, Edge> forceLayout, Graph graph) {
+        int scale = getScale();
         Map<Node, com.powsybl.diagram.util.forcelayout.Point> initialPoints = getInitialNodePositions().entrySet().stream()
                 // Only accept positions for nodes in the graph
                 .filter(nodePosition -> graph.getNode(nodePosition.getKey()).isPresent())
                 .collect(Collectors.toMap(
                     nodePosition -> graph.getNode(nodePosition.getKey()).orElseThrow(),
                     nodePosition -> new com.powsybl.diagram.util.forcelayout.Point(
-                            nodePosition.getValue().getX() / SCALE,
-                            nodePosition.getValue().getY() / SCALE)
+                            nodePosition.getValue().getX() / scale,
+                            nodePosition.getValue().getY() / scale)
                 ));
         forceLayout.setInitialPoints(initialPoints);
     }

network-area-diagram/src/main/java/com/powsybl/nad/layout/BasicForceAtlas2Layout.java

@@ -7,60 +7,28 @@
  */
 package com.powsybl.nad.layout;
 
+import com.powsybl.diagram.util.forcelayout.AbstractForceLayout;
 import com.powsybl.diagram.util.forcelayout.ForceAtlas2Layout;
-import com.powsybl.diagram.util.forcelayout.Vector;
 import com.powsybl.nad.model.Edge;
-import com.powsybl.nad.model.Graph;
 import com.powsybl.nad.model.Node;
 
-import java.util.Map;
-import java.util.Optional;
-import java.util.Set;
-import java.util.stream.Collectors;
-
 /**
  * @author Luma Zamarreño {@literal <zamarrenolm at aia.es>}
  * @author José Antonio Marqués {@literal <marquesja at aia.es>}
  */
-public class BasicForceAtlas2Layout extends AbstractLayout {
+public class BasicForceAtlas2Layout extends AbstractBasicForceLayout {
 
     private static final int SCALE = 20;
 
     @Override
-    protected void nodesLayout(Graph graph, LayoutParameters layoutParameters) {
-        org.jgrapht.Graph<Node, Edge> jgraphtGraph = graph.getJgraphtGraph(layoutParameters.isTextNodesForceLayout());
-        ForceAtlas2Layout<Node, Edge> forceLayout = new ForceAtlas2Layout<>(jgraphtGraph);
-        forceLayout.setMaxSteps(layoutParameters.getMaxSteps());
-
-        setInitialPositions(forceLayout, graph);
-        Set<Node> fixedNodes = getNodesWithFixedPosition().stream()
-                .map(graph::getNode)
-                .flatMap(Optional::stream)
-                .collect(Collectors.toSet());
-        forceLayout.setFixedNodes(fixedNodes);
-
-        forceLayout.execute();
-
-        jgraphtGraph.vertexSet().forEach(node -> {
-            Vector p = forceLayout.getStablePosition(node);
-            node.setPosition(SCALE * p.getX(), SCALE * p.getY());
-        });
-
-        if (!layoutParameters.isTextNodesForceLayout()) {
-            graph.getTextEdgesMap().values().forEach(nodePair -> fixedTextNodeLayout(nodePair, layoutParameters));
-        }
+    protected int getScale() {
+        return SCALE;
     }
 
-    private void setInitialPositions(ForceAtlas2Layout<Node, Edge> forceLayout, Graph graph) {
-        Map<Node, com.powsybl.diagram.util.forcelayout.Point> initialPoints = getInitialNodePositions().entrySet().stream()
-                // Only accept positions for nodes in the graph
-                .filter(nodePosition -> graph.getNode(nodePosition.getKey()).isPresent())
-                .collect(Collectors.toMap(
-                    nodePosition -> graph.getNode(nodePosition.getKey()).orElseThrow(),
-                    nodePosition -> new com.powsybl.diagram.util.forcelayout.Point(
-                            nodePosition.getValue().getX() / SCALE,
-                            nodePosition.getValue().getY() / SCALE)
-                ));
-        forceLayout.setInitialPoints(initialPoints);
+    @Override
+    protected AbstractForceLayout<Node, Edge> getForceLayoutAlgorithm(org.jgrapht.Graph<Node, Edge> jgraphtGraph, LayoutParameters layoutParameters) {
+        // We could complete the ForceAtlas2 object created here
+        // setting additional parameters received through the layout parameters
+        return new ForceAtlas2Layout<>(jgraphtGraph);
     }
 }

network-area-diagram/src/main/java/com/powsybl/nad/layout/BasicForceLayoutSpringy.java

@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) 2021, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package com.powsybl.nad.layout;
+
+import com.powsybl.diagram.util.forcelayout.AbstractForceLayout;
+import com.powsybl.diagram.util.forcelayout.ForceLayoutSpringy;
+import com.powsybl.nad.model.Edge;
+import com.powsybl.nad.model.Node;
+
+/**
+ * @author Florian Dupuy {@literal <florian.dupuy at rte-france.com>}
+ */
+public class BasicForceLayoutSpringy extends AbstractBasicForceLayout {
+
+    private static final int SCALE = 100;
+
+    @Override
+    protected int getScale() {
+        return SCALE;
+    }
+
+    @Override
+    protected AbstractForceLayout<Node, Edge> getForceLayoutAlgorithm(org.jgrapht.Graph<Node, Edge> jgraphtGraph, LayoutParameters layoutParameters) {
+        ForceLayoutSpringy<Node, Edge> forceLayout = new ForceLayoutSpringy<>(jgraphtGraph);
+        forceLayout.setSpringRepulsionFactor(layoutParameters.getSpringRepulsionFactorForceLayout());
+        return forceLayout;
+    }
+
+}

network-area-diagram/src/main/java/com/powsybl/nad/layout/BasicForceLayoutFactory.java → network-area-diagram/src/main/java/com/powsybl/nad/layout/BasicForceLayoutSpringyFactory.java

@@ -9,9 +9,9 @@
 /**
  * @author Florian Dupuy {@literal <florian.dupuy at rte-france.com>}
  */
-public class BasicForceLayoutFactory implements LayoutFactory {
+public class BasicForceLayoutSpringyFactory implements LayoutFactory {
     @Override
     public Layout create() {
-        return new BasicForceLayout();
+        return new BasicForceLayoutSpringy();
     }
 }

network-area-diagram/src/test/java/com/powsybl/nad/AbstractTest.java

@@ -11,7 +11,7 @@
 import com.powsybl.iidm.network.VoltageLevel;
 import com.powsybl.nad.build.iidm.NetworkGraphBuilder;
 import com.powsybl.nad.build.iidm.VoltageLevelFilter;
-import com.powsybl.nad.layout.BasicForceLayoutFactory;
+import com.powsybl.nad.layout.BasicForceLayoutSpringyFactory;
 import com.powsybl.nad.layout.LayoutFactory;
 import com.powsybl.nad.layout.LayoutParameters;
 import com.powsybl.nad.model.Graph;
@@ -35,7 +35,7 @@ public abstract class AbstractTest {
 
     protected boolean debugSvg = false;
     protected boolean overrideTestReferences = false;
-    protected LayoutFactory defaultLayoutFactory = new BasicForceLayoutFactory();
+    protected LayoutFactory defaultLayoutFactory = new BasicForceLayoutSpringyFactory();
 
     private SvgParameters svgParameters;
 

network-area-diagram/src/test/java/com/powsybl/nad/layout/LayoutWithInitialPositionsTest.java

@@ -150,7 +150,7 @@ private Map<String, Point> layoutResult(Network network,
                                             Map<String, Point> fixedNodePositions,
                                             Predicate<VoltageLevel> voltageLevelFilter
     ) {
-        LayoutFactory delegateLayoutFactory = new BasicForceLayoutFactory();
+        LayoutFactory delegateLayoutFactory = new BasicForceLayoutSpringyFactory();
         PositionsLayoutFactory positionsLayoutFactory = new PositionsLayoutFactory(
                 delegateLayoutFactory,
                 initialNodePositions,