Added visualization of relations, transparent selection and attribute backgrounds

README.md

@@ -7,8 +7,9 @@ This program is distributed as an executable **jar** file. You can find the late
 Simply double-click on the jar file, or execute `java -jar <jar file>` from the command line (where `<jar file>` is replaced with the path to your actual jar file).
 
 ![window screenshot](https://raw.githubusercontent.com/andrewlalis/EntityRelationMappingEditor/main/design/main_interface.PNG)
+> The above image shows the application's user-interface.
 
-## How to Use
+## Instructions
 The interface and menus should be pretty self-explanatory, but here are some tips to get you started:
 * Click on a relation to select it.
 * You can CTRL + click to select multiple relations.
@@ -16,7 +17,7 @@ The interface and menus should be pretty self-explanatory, but here are some tip
 * Right-click on different areas to access context menus with some helpful actions.
 * When exporting the model to an image, be sure to add the desired image file extension (`.png`, `.jpg`, `.bmp`, etc.), or the application will default to `.png`.
 
-## Sample Exported Image
+## Contributing
-Here's a sample of an exported diagram.
+This is an open-source project, and gladly accepts contributions in terms of new features, bug fixes, suggestions, bug reports, and more.
-
+* [Create a new issue](https://github.com/andrewlalis/EntityRelationMappingEditor/issues) if you'd like to make a suggestion, or report a bug.
-![sample diagram export](https://raw.githubusercontent.com/andrewlalis/EntityRelationMappingEditor/main/design/sample_export.png)
+* Fork the repository, make your changes, and submit them as a pull request.

src/main/java/nl/andrewlalis/erme/control/actions/VisualizeReferencesAction.java

@@ -0,0 +1,37 @@
+package nl.andrewlalis.erme.control.actions;
+
+import lombok.Getter;
+import lombok.Setter;
+import nl.andrewlalis.erme.view.DiagramPanel;
+
+import javax.swing.*;
+import java.awt.event.ActionEvent;
+
+public class VisualizeReferencesAction extends AbstractAction {
+	private static VisualizeReferencesAction instance;
+
+	public static VisualizeReferencesAction getInstance() {
+		if (instance == null) {
+			instance = new VisualizeReferencesAction();
+		}
+		return instance;
+	}
+
+	@Getter
+	@Setter
+	private boolean referenceVisualizationEnabled = false;
+
+	@Setter
+	private DiagramPanel diagramPanel;
+
+	public VisualizeReferencesAction() {
+		super("Toggle Reference Visualization");
+		this.putValue(SHORT_DESCRIPTION, "Shows/hides visualization of the references between attributes.");
+	}
+
+	@Override
+	public void actionPerformed(ActionEvent e) {
+		referenceVisualizationEnabled = ((AbstractButton)e.getSource()).getModel().isSelected();
+		diagramPanel.repaint();
+	}
+}

src/main/java/nl/andrewlalis/erme/view/DiagramPanel.java

@@ -135,6 +135,7 @@ public class DiagramPanel extends JPanel implements ModelChangeListener {
 		RemoveAttributeAction.getInstance().setDiagramPanel(this);
 		LoadSampleModelAction.getInstance().setDiagramPanel(this);
 		LolcatAction.getInstance().setDiagramPanel(this);
+		VisualizeReferencesAction.getInstance().setDiagramPanel(this);
     	AutoPositionAction.getInstance().setDiagramPanel(this);
 		AutoPositionAction.getInstance().setModel(this.model);
 		OrderableListPanel.getInstance().setModel(this.model);

src/main/java/nl/andrewlalis/erme/view/EditorMenuBar.java

@@ -15,6 +15,7 @@ public class EditorMenuBar extends JMenuBar {
 	public EditorMenuBar() {
 		this.add(this.buildFileMenu());
 		this.add(this.buildEditMenu());
+		this.add(this.buildViewMenu());
 		this.add(this.buildHelpMenu());
 	}
 
@@ -36,7 +37,6 @@ public class EditorMenuBar extends JMenuBar {
 		menu.add(RemoveRelationAction.getInstance());
 		menu.add(AddAttributeAction.getInstance());
 		menu.add(RemoveAttributeAction.getInstance());
-		menu.add(new JCheckBoxMenuItem(LolcatAction.getInstance()));
 		menu.add(AutoPositionAction.getInstance());
 		menu.addSeparator();
 		menu.add(UndoAction.getInstance());
@@ -44,6 +44,13 @@ public class EditorMenuBar extends JMenuBar {
 		return menu;
 	}
 
+	private JMenu buildViewMenu() {
+		JMenu menu = new JMenu("View");
+		menu.add(new JCheckBoxMenuItem(LolcatAction.getInstance()));
+		menu.add(new JCheckBoxMenuItem(VisualizeReferencesAction.getInstance()));
+		return menu;
+	}
+
 	private JMenu buildHelpMenu() {
 		JMenu menu = new JMenu("Help");
 		menu.add(InstructionsAction.getInstance());

src/main/java/nl/andrewlalis/erme/view/view_models/AttributeViewModel.java

@@ -16,7 +16,7 @@ import java.text.AttributedString;
 public class AttributeViewModel implements ViewModel {
 	public static final int PADDING_X = 5;
 	public static final int PADDING_Y = 5;
-	public static final Color BACKGROUND_COLOR = Color.LIGHT_GRAY;
+	public static final Color BACKGROUND_COLOR = new Color(192, 192, 192, 127);
 	public static final Color FONT_COLOR = Color.BLACK;
 	public static final float FK_FONT_SIZE = 11.0f;
 	private static final float LOLCAT_SAT = 0.75f;

src/main/java/nl/andrewlalis/erme/view/view_models/MappingModelViewModel.java

@@ -1,5 +1,8 @@
 package nl.andrewlalis.erme.view.view_models;
 
+import nl.andrewlalis.erme.control.actions.VisualizeReferencesAction;
+import nl.andrewlalis.erme.model.Attribute;
+import nl.andrewlalis.erme.model.ForeignKeyAttribute;
 import nl.andrewlalis.erme.model.MappingModel;
 import nl.andrewlalis.erme.model.Relation;
 
@@ -17,11 +20,34 @@ public class MappingModelViewModel implements ViewModel {
 
 	@Override
 	public void draw(Graphics2D g) {
+		if (VisualizeReferencesAction.getInstance().isReferenceVisualizationEnabled()) {
+			visualizeReferences(g);
+		}
 		for (Relation r : this.model.getRelations()) {
 			r.getViewModel().draw(g);
 		}
 	}
 
+	private void visualizeReferences(Graphics2D g) {
+		Graphics2D g2 = (Graphics2D) g.create();
+		g2.setColor(Color.BLUE);
+		Stroke dashedStroke = new BasicStroke(2, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND, 0, new float[]{5}, 0);
+		g2.setStroke(dashedStroke);
+		for (Relation r : this.model.getRelations()) {
+			for (Attribute a : r.getAttributes()) {
+				if (a instanceof ForeignKeyAttribute) {
+					ForeignKeyAttribute fk = (ForeignKeyAttribute) a;
+					Rectangle sourceBounds = fk.getViewModel().getBounds(g);
+					Rectangle targetBounds = fk.getReference().getViewModel().getBounds(g);
+					Point sourcePoint = new Point(sourceBounds.x + sourceBounds.width / 2, sourceBounds.y);
+					Point targetPoint = new Point(targetBounds.x + targetBounds.width / 2, targetBounds.y + targetBounds.height);
+					g2.drawLine(sourcePoint.x, sourcePoint.y, targetPoint.x, targetPoint.y);
+				}
+			}
+		}
+		g2.dispose();
+	}
+
 	@Override
 	public Rectangle getBounds(Graphics2D g) {
 		int minX = Integer.MAX_VALUE;

src/main/java/nl/andrewlalis/erme/view/view_models/RelationViewModel.java

@@ -27,7 +27,7 @@ public class RelationViewModel implements ViewModel {
 	 */
 	public static final int ATTRIBUTE_SEPARATION = 10;
 
-	public static final Color SELECTED_COLOR = new Color(204, 224, 255);
+	public static final Color SELECTED_COLOR = new Color(204, 224, 255, 127);
 	public static final Color NAME_COLOR = Color.BLACK;
 
 	private final Relation relation;