Draw relationships as diamonds

src/net/sourceforge/plantuml/svek/GeneralImageBuilder.java

@@ -101,6 +101,7 @@ import net.sourceforge.plantuml.svek.image.EntityImageAssociationPoint;
 import net.sourceforge.plantuml.svek.image.EntityImageBranch;
 import net.sourceforge.plantuml.svek.image.EntityImageChenAttribute;
 import net.sourceforge.plantuml.svek.image.EntityImageChenEntity;
+import net.sourceforge.plantuml.svek.image.EntityImageChenRelationship;
 import net.sourceforge.plantuml.svek.image.EntityImageCircleEnd;
 import net.sourceforge.plantuml.svek.image.EntityImageCircleStart;
 import net.sourceforge.plantuml.svek.image.EntityImageClass;
@@ -260,8 +261,7 @@ public final class GeneralImageBuilder {
 			return new EntityImageChenEntity(leaf, skinParam);
 
 		if (leaf.getLeafType() == LeafType.CHEN_RELATIONSHIP)
-			// TODO: custom image type
-			return new EntityImageChenEntity(leaf, skinParam);
+			return new EntityImageChenRelationship(leaf, skinParam);
 
 		if (leaf.getLeafType() == LeafType.CHEN_ATTRIBUTE)
 			return new EntityImageChenAttribute(leaf, skinParam);

src/net/sourceforge/plantuml/svek/image/EntityImageChenRelationship.java

@@ -0,0 +1,168 @@
+/* ========================================================================
+ * PlantUML : a free UML diagram generator
+ * ========================================================================
+ *
+ * (C) Copyright 2009-2024, Arnaud Roques
+ *
+ * Project Info:  https://plantuml.com
+ *
+ * If you like this project or if you find it useful, you can support us at:
+ *
+ * https://plantuml.com/patreon (only 1$ per month!)
+ * https://plantuml.com/paypal
+ *
+ * This file is part of PlantUML.
+ *
+ * PlantUML is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PlantUML distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA.
+ *
+ *
+ * Original Author:  Arnaud Roques
+ *
+ *
+ */
+package net.sourceforge.plantuml.svek.image;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+import net.sourceforge.plantuml.abel.Entity;
+import net.sourceforge.plantuml.klimt.UGroupType;
+import net.sourceforge.plantuml.klimt.UShape;
+import net.sourceforge.plantuml.klimt.UStroke;
+import net.sourceforge.plantuml.klimt.UTranslate;
+import net.sourceforge.plantuml.klimt.color.ColorType;
+import net.sourceforge.plantuml.klimt.color.Colors;
+import net.sourceforge.plantuml.klimt.color.HColor;
+import net.sourceforge.plantuml.klimt.creole.CreoleMode;
+import net.sourceforge.plantuml.klimt.drawing.UGraphic;
+import net.sourceforge.plantuml.klimt.font.FontConfiguration;
+import net.sourceforge.plantuml.klimt.font.StringBounder;
+import net.sourceforge.plantuml.klimt.geom.HorizontalAlignment;
+import net.sourceforge.plantuml.klimt.geom.XDimension2D;
+import net.sourceforge.plantuml.klimt.geom.XPoint2D;
+import net.sourceforge.plantuml.klimt.shape.TextBlock;
+import net.sourceforge.plantuml.klimt.shape.TextBlockInEllipse;
+import net.sourceforge.plantuml.klimt.shape.UPolygon;
+import net.sourceforge.plantuml.style.ISkinParam;
+import net.sourceforge.plantuml.style.PName;
+import net.sourceforge.plantuml.style.SName;
+import net.sourceforge.plantuml.style.Style;
+import net.sourceforge.plantuml.style.StyleSignatureBasic;
+import net.sourceforge.plantuml.svek.AbstractEntityImage;
+import net.sourceforge.plantuml.svek.ShapeType;
+import net.sourceforge.plantuml.url.Url;
+
+public class EntityImageChenRelationship extends AbstractEntityImage {
+
+	final private TextBlock title;
+	final private Url url;
+
+	public EntityImageChenRelationship(Entity entity, ISkinParam skinParam) {
+		super(entity, skinParam);
+
+		final FontConfiguration titleFontConfiguration = getStyleTitle(entity, skinParam)
+				.getFontConfiguration(getSkinParam().getIHtmlColorSet(), entity.getColors());
+
+		title = entity.getDisplay().create8(titleFontConfiguration, HorizontalAlignment.CENTER, skinParam, CreoleMode.FULL,
+				getStyle().wrapWidth());
+
+		url = entity.getUrl99();
+	}
+
+	private Style getStyle() {
+		return getStyle(getEntity(), getSkinParam());
+	}
+
+	private static Style getStyle(Entity group, ISkinParam skinParam) {
+		return StyleSignatureBasic.of(SName.root, SName.element, SName.chenEerDiagram, SName.chenRelationship)
+				.withTOBECHANGED(group.getStereotype()).getMergedStyle(skinParam.getCurrentStyleBuilder());
+	}
+
+	private static Style getStyleTitle(Entity group, ISkinParam skinParam) {
+		return StyleSignatureBasic.of(SName.root, SName.element, SName.chenEerDiagram, SName.chenRelationship, SName.title)
+				.withTOBECHANGED(group.getStereotype()).getMergedStyle(skinParam.getCurrentStyleBuilder());
+	}
+
+	@Override
+	public ShapeType getShapeType() {
+		return ShapeType.DIAMOND;
+	}
+
+	@Override
+	public XDimension2D calculateDimension(StringBounder stringBounder) {
+		final XDimension2D dimTitle = title.calculateDimension(stringBounder);
+
+		// Fit a diamond with aspect ratio 2 around the text
+		// diagonal = dimTitle dot ([1, 2] / sqrt(5)) + 2 * MARGIN
+		// dimTotal = diagonal * [sqrt(5), sqrt(5) / 2]
+
+		final double diagonal = (dimTitle.getWidth() + 2 * dimTitle.getHeight()) / Math.sqrt(5) + 2 * MARGIN;
+		return new XDimension2D(diagonal * Math.sqrt(5), diagonal * Math.sqrt(5) / 2);
+	}
+
+	@Override
+	public void drawU(UGraphic ug) {
+		ug.startGroup(Collections.singletonMap(UGroupType.ID, getEntity().getQuark().toStringPoint()));
+		if (url != null)
+			ug.startUrl(url);
+
+		final XDimension2D dimTotal = calculateDimension(ug.getStringBounder());
+		final XDimension2D dimTitle = title.calculateDimension(ug.getStringBounder());
+
+		final UStroke stroke = getStyle().getStroke(getEntity().getColors());
+		ug = applyColor(ug);
+		ug = ug.apply(stroke);
+		ug.draw(getShape(dimTotal));
+
+		final double xTitle = (dimTotal.getWidth() - dimTitle.getWidth()) / 2;
+		final double yTitle = (dimTotal.getHeight() - dimTitle.getHeight()) / 2;
+		title.drawU(ug.apply(new UTranslate(xTitle, yTitle)));
+
+		if (url != null)
+			ug.closeUrl();
+
+		ug.closeGroup();
+	}
+
+	final protected UGraphic applyColor(UGraphic ug) {
+		Colors colors = getEntity().getColors();
+
+		HColor border = colors.getColor(ColorType.LINE);
+		if (border == null)
+			border = getStyle().value(PName.LineColor).asColor(getSkinParam().getIHtmlColorSet());
+		ug = ug.apply(border);
+
+		HColor backcolor = colors.getColor(ColorType.BACK);
+		if (backcolor == null)
+			backcolor = getStyle().value(PName.BackGroundColor).asColor(getSkinParam().getIHtmlColorSet());
+		ug = ug.apply(backcolor.bg());
+
+		return ug;
+	}
+
+	private UShape getShape(XDimension2D dimTotal) {
+		final double width = dimTotal.getWidth();
+		final double height = dimTotal.getHeight();
+
+		final XPoint2D p1 = new XPoint2D(0, height / 2);
+		final XPoint2D p2 = new XPoint2D(width / 2, 0);
+		final XPoint2D p3 = new XPoint2D(width, height / 2);
+		final XPoint2D p4 = new XPoint2D(width / 2, height);
+
+		return new UPolygon(Arrays.asList(p1, p2, p3, p4));
+	}
+
+}