[2053] Fix the ForkNode and JoinNode rendering

Bug: #2053
Signed-off-by: Guillaume Coutable <guillaume.coutable@obeo.fr>

Author: gcoutable

CHANGELOG.adoc

@@ -99,6 +99,7 @@ Now the _end_ keyword is not displayed anymore in the label of these graphical n
 - https://github.com/eclipse-syson/syson/issues/2057[#2057] [diagrams] Fix the support for removing the multiplicity using the direct edit.
 - https://github.com/eclipse-syson/syson/issues/1938[#1938] [diagrams] Fix an issue where the _New Flow (flow)_ tool between two parameters was broken.
 - https://github.com/eclipse-syson/syson/issues/2058[#2058] [diagrams] Fix error when importing SysML snippets referencing unknown units which could make the resluting model inconsistent
+- https://github.com/eclipse-syson/syson/issues/2053[#2053] [diagrams] Prevent incoming and outgoing graphical edges of a graphical `ForkNode` or `JoindNode` to point empty space.
 
 === Improvements
 
@@ -153,6 +154,8 @@ Tweak the diagnostic messages to help users understand where the erroneous eleme
 Make sure diagnostics are sorted according to their validated element and its containing document.
 - https://github.com/eclipse-syson/syson/issues/2042[#2042] [import] Improve error reporting while uploading a document.
 - https://github.com/eclipse-syson/syson/issues/2057[#2057] [diagrams] Add the support for empty value for multiplicity in the ANTLR grammar.
+- https://github.com/eclipse-syson/syson/issues/2053[#2053] [diagrams] The graphical `ForkNode` and `JoinNode` now use `RectangularNodeStyleDescription` and are restricted to horizontal resizing.
+Consequently, their entire footprint is filled with black, ensuring that all incoming and outgoing edges maintain a valid connection point.
 
 === New features
 

backend/application/syson-application/src/test/resources/scripts/database-content/GeneralView-IncludeUseCaseUsage.sql

@@ -25,6 +25,7 @@
 import org.eclipse.sirius.components.view.diagram.EdgeTool;
 import org.eclipse.sirius.components.view.diagram.NodeDescription;
 import org.eclipse.sirius.components.view.diagram.NodePalette;
+import org.eclipse.sirius.components.view.diagram.NodeStyleDescription;
 import org.eclipse.sirius.components.view.diagram.OutsideLabelDescription;
 import org.eclipse.sirius.components.view.diagram.OutsideLabelPosition;
 import org.eclipse.sirius.components.view.diagram.OutsideLabelStyle;
@@ -69,12 +70,7 @@ public AbstractControlNodeActionNodeDescriptionProvider(IColorProvider colorProv
      */
     protected abstract EClass getDomainType();
 
-    /**
-     * Implementers should provide the path of the image associated to the actual node description.
-     *
-     * @return The String representing the path to access the image associated to the node description.
-     */
-    protected abstract String getImagePath();
+    protected abstract NodeStyleDescription createNodeStyleDescription();
 
     /**
      * Implementers should provide the label used by the removal tool of the actual node description.
@@ -91,9 +87,7 @@ protected String getDefaultHeightExpression() {
         return "12";
     }
 
-    protected UserResizableDirection isNodeResizable() {
-        return UserResizableDirection.BOTH;
-    }
+    protected abstract UserResizableDirection isNodeResizable();
 
     @Override
     public NodeDescription create() {
@@ -107,7 +101,7 @@ public NodeDescription create() {
                 .name(this.descriptionNameGenerator.getNodeName(this.getNodeDescriptionName()))
                 .semanticCandidatesExpression(AQLUtils.getSelfServiceCallExpression("getExposedElements",
                         List.of(domainType, org.eclipse.sirius.components.diagrams.description.NodeDescription.ANCESTORS, IEditingContext.EDITING_CONTEXT, DiagramContext.DIAGRAM_CONTEXT)))
-                .style(this.createImageNodeStyleDescription(this.getImagePath()))
+                .style(this.createNodeStyleDescription())
                 .userResizable(this.isNodeResizable())
                 .synchronizationPolicy(SynchronizationPolicy.SYNCHRONIZED)
                 .build();

backend/application/syson-application/src/test/resources/scripts/database-content/SysON-Studio.sql

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2026 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -14,6 +14,7 @@
 
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.sirius.components.view.builder.providers.IColorProvider;
+import org.eclipse.sirius.components.view.diagram.NodeStyleDescription;
 import org.eclipse.sirius.components.view.diagram.UserResizableDirection;
 import org.eclipse.syson.sysml.SysmlPackage;
 import org.eclipse.syson.util.IDescriptionNameGenerator;
@@ -42,8 +43,8 @@ protected EClass getDomainType() {
     }
 
     @Override
-    protected String getImagePath() {
-        return "images/decision_action.svg";
+    protected NodeStyleDescription createNodeStyleDescription() {
+        return this.createImageNodeStyleDescription("images/decision_action.svg");
     }
 
     @Override

backend/views/syson-diagram-common-view/src/main/java/org/eclipse/syson/diagram/common/view/nodes/AbstractControlNodeActionNodeDescriptionProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2026 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -14,6 +14,8 @@
 
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.sirius.components.view.builder.providers.IColorProvider;
+import org.eclipse.sirius.components.view.diagram.NodeStyleDescription;
+import org.eclipse.sirius.components.view.diagram.UserResizableDirection;
 import org.eclipse.syson.sysml.SysmlPackage;
 import org.eclipse.syson.util.IDescriptionNameGenerator;
 
@@ -41,12 +43,22 @@ protected EClass getDomainType() {
     }
 
     @Override
-    protected String getImagePath() {
-        return "images/fork_action.svg";
+    protected String getRemoveToolLabel() {
+        return "Remove Fork";
     }
 
     @Override
-    protected String getRemoveToolLabel() {
-        return "Remove Fork";
+    protected UserResizableDirection isNodeResizable() {
+        return UserResizableDirection.HORIZONTAL;
+    }
+
+    @Override
+    protected NodeStyleDescription createNodeStyleDescription() {
+        return this.diagramBuilderHelper.newRectangularNodeStyleDescription()
+                .borderColor(this.colorProvider.getColor("transparent"))
+                .borderRadius(0)
+                .borderSize(0)
+                .background(this.colorProvider.getColor("black"))
+                .build();
     }
 }

backend/views/syson-diagram-common-view/src/main/java/org/eclipse/syson/diagram/common/view/nodes/DecisionActionNodeDescriptionProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2026 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -14,6 +14,8 @@
 
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.sirius.components.view.builder.providers.IColorProvider;
+import org.eclipse.sirius.components.view.diagram.NodeStyleDescription;
+import org.eclipse.sirius.components.view.diagram.UserResizableDirection;
 import org.eclipse.syson.sysml.SysmlPackage;
 import org.eclipse.syson.util.IDescriptionNameGenerator;
 
@@ -41,12 +43,22 @@ protected EClass getDomainType() {
     }
 
     @Override
-    protected String getImagePath() {
-        return "images/join_action.svg";
+    protected String getRemoveToolLabel() {
+        return "Remove Join";
     }
 
     @Override
-    protected String getRemoveToolLabel() {
-        return "Remove Join";
+    protected UserResizableDirection isNodeResizable() {
+        return UserResizableDirection.HORIZONTAL;
+    }
+
+    @Override
+    protected NodeStyleDescription createNodeStyleDescription() {
+        return this.diagramBuilderHelper.newRectangularNodeStyleDescription()
+                .borderColor(this.colorProvider.getColor("transparent"))
+                .borderRadius(0)
+                .borderSize(0)
+                .background(this.colorProvider.getColor("black"))
+                .build();
     }
 }

backend/views/syson-diagram-common-view/src/main/java/org/eclipse/syson/diagram/common/view/nodes/ForkActionNodeDescriptionProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2024 Obeo.
+ * Copyright (c) 2024, 2026 Obeo.
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v2.0
  * which accompanies this distribution, and is available at
@@ -14,6 +14,7 @@
 
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.sirius.components.view.builder.providers.IColorProvider;
+import org.eclipse.sirius.components.view.diagram.NodeStyleDescription;
 import org.eclipse.sirius.components.view.diagram.UserResizableDirection;
 import org.eclipse.syson.sysml.SysmlPackage;
 import org.eclipse.syson.util.IDescriptionNameGenerator;
@@ -42,8 +43,8 @@ protected EClass getDomainType() {
     }
 
     @Override
-    protected String getImagePath() {
-        return "images/merge_action.svg";
+    protected NodeStyleDescription createNodeStyleDescription() {
+        return this.createImageNodeStyleDescription("images/merge_action.svg");
     }
 
     @Override