Recompute graph bounds after packing components in MrTree (#1142)

* Recompute graph bounds after packing components in MrTree

* add test for component packing in mrtree

Author: Eddykasp

plugins/org.eclipse.elk.alg.mrtree/src/org/eclipse/elk/alg/mrtree/ComponentsProcessor.java

@@ -22,11 +22,13 @@
 import org.eclipse.elk.alg.mrtree.graph.TEdge;
 import org.eclipse.elk.alg.mrtree.graph.TGraph;
 import org.eclipse.elk.alg.mrtree.graph.TNode;
+import org.eclipse.elk.alg.mrtree.intermediate.GraphBoundsProcessor;
 import org.eclipse.elk.alg.mrtree.options.InternalProperties;
 import org.eclipse.elk.alg.mrtree.options.MrTreeOptions;
 import org.eclipse.elk.core.math.ElkPadding;
 import org.eclipse.elk.core.math.KVector;
 import org.eclipse.elk.core.options.CoreOptions;
+import org.eclipse.elk.core.util.NullElkProgressMonitor;
 import org.eclipse.elk.graph.properties.IProperty;
 
 import com.google.common.collect.Lists;
@@ -258,6 +260,10 @@ public int compare(final TGraph graph1, final TGraph graph2) {
             }
         }
 
+        // We need to recompute the graphs bounds, since each component only knows its own bounds and the prop merge
+        // cannot catch this
+        GraphBoundsProcessor boundsProcessor = new GraphBoundsProcessor();
+        boundsProcessor.process(result, new NullElkProgressMonitor());
         // Move the resulting graph to 0,0 and apply padding
         applyPaddingAndNormalizePositions(result);
 

test/org.eclipse.elk.alg.mrtree.test/src/org/eclipse/elk/alg/mrtree/test/MrTreeGraphSizeTest.java

@@ -101,4 +101,38 @@ public void GraphSizeCalculationTest() {
         assertEquals(paddingLeft + nodeWidth + nodeNodeSpacing + nodeWidth + paddingRight, graph.getWidth(), DOUBLE_EQ_EPSILON);
         assertEquals(paddingTop + nodeHeight + nodeNodeSpacing + nodeHeight + paddingBottom, graph.getHeight(), DOUBLE_EQ_EPSILON);
     }
+    
+    /**
+     * Tests that the graph size is correct when the graph consists of disconnected components.
+     */
+    @Test
+    public void ComponentsGraphSizeCalculationTest() {
+        PlainJavaInitialization.initializePlainJavaLayout();
+        ElkNode graph = ElkGraphUtil.createGraph();
+        graph.setProperty(CoreOptions.ALGORITHM, MrTreeOptions.ALGORITHM_ID);
+        graph.setProperty(CoreOptions.PADDING, new ElkPadding(0));
+        graph.setProperty(CoreOptions.SPACING_NODE_NODE, 0.0);
+        // set aspect ratio to high value to force components to be laid out horizontally for the test
+        graph.setProperty(CoreOptions.ASPECT_RATIO, 1000.0);
+        
+        
+        ElkNode n1 = ElkGraphUtil.createNode(graph);
+        n1.setDimensions(nodeWidth, nodeHeight);
+        ElkNode n2 = ElkGraphUtil.createNode(graph);
+        n2.setDimensions(nodeWidth, nodeHeight);
+        
+        
+        // prepare layout engine
+        LayoutConfigurator config = new LayoutConfigurator();
+        ElkUtil.applyVisitors(graph, config, new LayoutAlgorithmResolver());
+        // call layout with layout engine
+        try {
+            new RecursiveGraphLayoutEngine().layout(graph, new BasicProgressMonitor());
+        } catch (UnsupportedGraphException exception) {
+            fail(exception.toString());
+        }
+        
+        assertEquals(nodeWidth + nodeWidth, graph.getWidth(), DOUBLE_EQ_EPSILON);
+        assertEquals(nodeHeight, graph.getHeight(), DOUBLE_EQ_EPSILON);
+    }
 }