Radial layout: center on root option (#941)

* Add option to control the initial angle of a radial layout Signed-off-by: Max Kasperowski <[email protected]> * Adds option to center a radial layout on its root node This is done by increasing the overall size of the layout and shifting the entire layout such that the root node is positioned exactly in the center. Signed-off-by: Max Kasperowski <[email protected]> * PR feedback Signed-off-by: Max Kasperowski <[email protected]> * Add tests project for radial layout and add tests for center on root option Signed-off-by: Max Kasperowski <[email protected]> * fix years and names --------- Signed-off-by: Max Kasperowski <[email protected]>
eclipse · Jul 6, 2023 · e878d4c · e878d4c
1 parent d154b63
commit e878d4c
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diff --git a/plugins/org.eclipse.elk.alg.radial/src/org/eclipse/elk/alg/radial/Radial.melk b/plugins/org.eclipse.elk.alg.radial/src/org/eclipse/elk/alg/radial/Radial.melk
@@ -43,9 +43,18 @@ algorithm radial(RadialLayoutProvider) {
     supports radius
     supports sorter
     supports wedgeCriteria
+    supports centerOnRoot
 }
 
 /////////////////////////////////Options///////////////////////////////
+option centerOnRoot: boolean {
+    label "Center On Root"
+    description 
+        "Centers the layout on the root of the tree i.e. so that the central node is also the center node of the
+         final layout. This introduces additional whitespace."
+    default = false
+    targets parents
+}
 option orderId: int {
     label "Order ID "
     description

diff --git a/...clipse.elk.alg.radial/src/org/eclipse/elk/alg/radial/intermediate/CalculateGraphSize.java b/...clipse.elk.alg.radial/src/org/eclipse/elk/alg/radial/intermediate/CalculateGraphSize.java
@@ -9,6 +9,8 @@
  *******************************************************************************/
 package org.eclipse.elk.alg.radial.intermediate;
 
+import org.eclipse.elk.alg.radial.InternalProperties;
+import org.eclipse.elk.alg.radial.options.RadialOptions;
 import org.eclipse.elk.core.alg.ILayoutProcessor;
 import org.eclipse.elk.core.math.ElkMargin;
 import org.eclipse.elk.core.math.ElkPadding;
@@ -48,6 +50,45 @@ public void process(final ElkNode graph, final IElkProgressMonitor progressMonit
 
         ElkPadding padding = graph.getProperty(CoreOptions.PADDING);
         KVector offset = new KVector(minXPos - padding.getLeft(), minYPos - padding.getTop());
+
+
+        double width = maxXPos - minXPos + padding.getHorizontal();
+        double height = maxYPos - minYPos + padding.getVertical();
+
+        if (graph.getProperty(RadialOptions.CENTER_ON_ROOT)) {
+            ElkNode root = graph.getProperty(InternalProperties.ROOT_NODE);
+            ElkMargin rootMargins = root.getProperty(CoreOptions.MARGINS);
+            // calculate the current midpoint of the root, taking into account the defined margins and the already
+            // calculated offset necessary to shift the graph into the positive quadrant of the coordinate system
+            double rootX = root.getX() + root.getWidth()/2 + (rootMargins.left + rootMargins.right)/2 - offset.x;
+            double rootY = root.getY() + root.getHeight()/2 + (rootMargins.top + rootMargins.bottom)/2 - offset.y;
+
+            double dx = width - rootX;
+            double dy = height - rootY;
+
+            if (dx < width / 2) {
+                // need to add additional space on the left
+                double additionalX = dx - rootX;
+                width += additionalX;
+                offset.x -= additionalX;
+            } else {
+                // add addtional space on the right
+                double additionalX = rootX - dx;
+                width += additionalX;
+            }
+
+            if (dy < height / 2) {
+                //need to add additional space on the top
+                double additionalY = dy - rootY;
+                height += additionalY;
+                offset.y -= additionalY;
+            } else {
+                // add addtional space on the bottom
+                double additionalY = rootY - dy;
+                height += additionalY;
+            }
+
+        }
 
         // process the nodes
         for (ElkNode node : graph.getChildren()) {
@@ -57,12 +98,12 @@ public void process(final ElkNode graph, final IElkProgressMonitor progressMonit
         }
 
         // set up the graph
-        double width = maxXPos - minXPos + padding.getHorizontal();
-        double height = maxYPos - minYPos + padding.getVertical();
         if (!graph.getProperty(CoreOptions.NODE_SIZE_FIXED_GRAPH_SIZE)) {
             graph.setWidth(width);
             graph.setHeight(height);
         }
+
+        // store child area info
         graph.setProperty(CoreOptions.CHILD_AREA_WIDTH, width - padding.getHorizontal());
         graph.setProperty(CoreOptions.CHILD_AREA_HEIGHT, height - padding.getVertical());
         progressMonitor.logGraph(graph, "After");

diff --git a/test/org.eclipse.elk.alg.radial.test/.classpath b/test/org.eclipse.elk.alg.radial.test/.classpath
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8"/>
+	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
+	<classpathentry kind="src" path="src/">
+		<attributes>
+			<attribute name="test" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="output" path="target/classes"/>
+</classpath>
diff --git a/test/org.eclipse.elk.alg.radial.test/.project b/test/org.eclipse.elk.alg.radial.test/.project
@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>org.eclipse.elk.alg.radial.test</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.pde.ManifestBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.pde.SchemaBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>net.sf.eclipsecs.core.CheckstyleBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.m2e.core.maven2Builder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.m2e.core.maven2Nature</nature>
+		<nature>org.eclipse.pde.PluginNature</nature>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>net.sf.eclipsecs.core.CheckstyleNature</nature>
+	</natures>
+</projectDescription>