Layered: Fix too much space between leftmost node and routing area. #734

Signed-off-by: le-cds <[email protected]>
(cherry picked from commit 8012eb5)

plugins/org.eclipse.elk.alg.layered/src/org/eclipse/elk/alg/layered/p5edges/OrthogonalEdgeRouter.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2010, 2015 Kiel University and others.
+ * Copyright (c) 2010, 2020 Kiel University and others.
  * 
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -50,10 +50,6 @@
  *   <dt>Postcondition:</dt><dd>each node is assigned a horizontal coordinate;
  *     the bend points of each edge are set; the width of the whole graph is set</dd>
  * </dl>
- *
- * @author msp
- * @author cds
- * @author jjc
  */
 public final class OrthogonalEdgeRouter implements ILayoutPhase<LayeredPhases, LGraph> {
 
@@ -262,18 +258,22 @@ public void process(final LGraph layeredGraph, final IElkProgressMonitor monitor
                     PolylineEdgeRouter.PRED_EXTERNAL_WEST_OR_EAST_PORT);
 
             if (slotsCount > 0) {
-                // The space between each pair of edge segments, and between nodes and edges
-                double increment =
-                        edgeNodeSpacing + (slotsCount - 1) * edgeEdgeSpacing;
+                // Compute routing area's width
+                double routingWidth = (slotsCount - 1) * edgeEdgeSpacing;
+
+                if (leftLayer != null) {
+                    routingWidth += edgeNodeSpacing;
+                }
+
                 if (rightLayer != null) {
-                    increment += edgeNodeSpacing;
+                    routingWidth += edgeNodeSpacing;
                 }
 
                 // If we are between two layers, make sure their minimal spacing is preserved
-                if (increment < nodeNodeSpacing && !isLeftLayerExternal && !isRightLayerExternal) {
-                    increment = nodeNodeSpacing;
+                if (routingWidth < nodeNodeSpacing && !isLeftLayerExternal && !isRightLayerExternal) {
+                    routingWidth = nodeNodeSpacing;
                 }
-                xpos += increment;
+                xpos += routingWidth;
             } else if (!isLeftLayerExternal && !isRightLayerExternal) {
                 // If all edges are straight, use the usual spacing 
                 xpos += nodeNodeSpacing;

test/org.eclipse.elk.alg.layered.test/src/org/eclipse/elk/alg/layered/issues/Issue734Test.java

@@ -0,0 +1,106 @@
+/*******************************************************************************
+ * Copyright (c) 2020 Kiel University and others.
+ * 
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.elk.alg.layered.issues;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.DoubleSummaryStatistics;
+import java.util.List;
+
+import org.eclipse.elk.alg.layered.intermediate.greedyswitch.TestGraphCreator;
+import org.eclipse.elk.alg.layered.options.LayeredOptions;
+import org.eclipse.elk.alg.test.framework.LayoutTestRunner;
+import org.eclipse.elk.alg.test.framework.annotations.Algorithm;
+import org.eclipse.elk.alg.test.framework.annotations.DefaultConfiguration;
+import org.eclipse.elk.alg.test.framework.annotations.GraphResourceProvider;
+import org.eclipse.elk.alg.test.framework.io.AbstractResourcePath;
+import org.eclipse.elk.alg.test.framework.io.FileNameFilter;
+import org.eclipse.elk.alg.test.framework.io.ModelResourcePath;
+import org.eclipse.elk.core.util.ElkUtil;
+import org.eclipse.elk.graph.ElkEdge;
+import org.eclipse.elk.graph.ElkNode;
+import org.eclipse.emf.common.util.EList;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import com.google.common.collect.Lists;
+
+@RunWith(LayoutTestRunner.class)
+@Algorithm(LayeredOptions.ALGORITHM_ID)
+public class Issue734Test extends TestGraphCreator {
+
+    //////////////////////////////////////////////////////////////////////////////////////////////////////////////
+    // Sources
+
+    @GraphResourceProvider
+    public List<AbstractResourcePath> testGraphs() {
+        return Lists.newArrayList(
+                new ModelResourcePath("tickets/layered/734_nodeEdgeSpacingFlat.elkt"),
+                new ModelResourcePath("tickets/layered/734_nodeEdgeSpacingFlatMoreComplex.elkt"),
+                new ModelResourcePath("tickets/layered/734_nodeEdgeSpacingHierarchical.elkt"));
+    }
+
+
+    //////////////////////////////////////////////////////////////////////////////////////////////////////////////
+    // Tests
+
+    @Test
+    public void testOrthogonalEdges(final ElkNode graph) {
+        // Compute the area occupied by nodes on the top level
+        CoordinateSpan nodeSpan = computeNodeCoordinateSpan(graph.getChildren());
+        CoordinateSpan edgeSpan = computeEdgeCoordinateSpan(graph.getContainedEdges());
+
+        // If the edge is routed properly, the edge span should have the same distance to the node span on both
+        // sides. In other words, their respective centres should be aligned
+        double nodeSpanCenter = (nodeSpan.min + nodeSpan.max) / 2;
+        double edgeSpanCenter = (edgeSpan.min + edgeSpan.max) / 2;
+
+        assertEquals(nodeSpanCenter, edgeSpanCenter, 0.5);
+    }
+
+    private CoordinateSpan computeNodeCoordinateSpan(EList<ElkNode> nodes) {
+        CoordinateSpan span = new CoordinateSpan();
+
+        span.min = nodes.stream()
+            .mapToDouble(node -> node.getX())
+            .min()
+            .orElse(0);
+        span.max = nodes.stream()
+            .mapToDouble(node -> node.getX() + node.getWidth())
+            .max()
+            .orElse(0);
+
+        return span;
+    }
+
+    private CoordinateSpan computeEdgeCoordinateSpan(EList<ElkEdge> containedEdges) {
+        DoubleSummaryStatistics stats = containedEdges.stream()
+            .flatMap(edge -> edge.getSections().stream())
+            .map(section -> ElkUtil.createVectorChain(section))
+            .flatMap(chain -> chain.stream())
+            .mapToDouble(vec -> vec.x)
+            .summaryStatistics();
+        return new CoordinateSpan(stats.getMin(), stats.getMax());
+    }
+
+    private static class CoordinateSpan {
+        private double min = Double.POSITIVE_INFINITY;
+        private double max = Double.NEGATIVE_INFINITY;
+
+        public CoordinateSpan() {
+        }
+
+        public CoordinateSpan(double min, double max) {
+            this.min = min;
+            this.max = max;
+        }
+    }
+
+}