Edge info labels on the edge

src/main/java/com/powsybl/nad/svg/EdgeInfo.java

@@ -17,14 +17,14 @@ public class EdgeInfo {
 
     private final String infoType;
     private final Direction arrowDirection;
-    private final String leftLabel;
-    private final String rightLabel;
+    private final String internalLabel;
+    private final String externalLabel;
 
-    public EdgeInfo(String infoType, Direction arrowDirection, String leftLabel, String rightLabel) {
+    public EdgeInfo(String infoType, Direction arrowDirection, String internalLabel, String externalLabel) {
         this.infoType = infoType;
         this.arrowDirection = arrowDirection;
-        this.leftLabel = leftLabel;
-        this.rightLabel = rightLabel;
+        this.internalLabel = internalLabel;
+        this.externalLabel = externalLabel;
     }
 
     public EdgeInfo(String infoType, double value) {
@@ -39,12 +39,12 @@ public Optional<Direction> getDirection() {
         return Optional.ofNullable(arrowDirection);
     }
 
-    public Optional<String> getLeftLabel() {
-        return Optional.ofNullable(leftLabel);
+    public Optional<String> getInternalLabel() {
+        return Optional.ofNullable(internalLabel);
     }
 
-    public Optional<String> getRightLabel() {
-        return Optional.ofNullable(rightLabel);
+    public Optional<String> getExternalLabel() {
+        return Optional.ofNullable(externalLabel);
     }
 
     public enum Direction {

src/main/java/com/powsybl/nad/svg/SvgParameters.java

@@ -21,7 +21,7 @@ public class SvgParameters {
     private int fixedWidth = -1;
     private int fixedHeight = -1;
     private double arrowShift = 0.3;
-    private double arrowLabelShift = 0.12;
+    private double arrowLabelShift = 0.19;
     private double converterStationWidth = 0.6;
     private double voltageLevelCircleRadius = 0.3;
     private double fictitiousVoltageLevelCircleRadius = 0.15;
@@ -35,6 +35,7 @@ public class SvgParameters {
     private double loopEdgesAperture = Math.toRadians(60);
     private double loopControlDistance = 0.4;
     private boolean textNodeBackground = true;
+    private boolean edgeInfoAlongEdge = true;
 
     public enum CssLocation {
         INSERTED_IN_SVG, EXTERNAL_IMPORTED, EXTERNAL_NO_IMPORT
@@ -243,4 +244,13 @@ public SvgParameters setTextNodeBackground(boolean textNodeBackground) {
         this.textNodeBackground = textNodeBackground;
         return this;
     }
+
+    public boolean isEdgeInfoAlongEdge() {
+        return edgeInfoAlongEdge;
+    }
+
+    public SvgParameters setEdgeInfoAlongEdge(boolean edgeInfoAlongEdge) {
+        this.edgeInfoAlongEdge = edgeInfoAlongEdge;
+        return this;
+    }
 }

src/main/java/com/powsybl/nad/svg/SvgWriter.java

@@ -298,18 +298,17 @@ private void drawEdgeInfo(XMLStreamWriter writer, List<EdgeInfo> edgeInfos, Poin
         writer.writeStartElement(GROUP_ELEMENT_NAME);
         writer.writeAttribute(CLASS_ATTRIBUTE, StyleProvider.EDGE_INFOS_CLASS);
         writer.writeAttribute(TRANSFORM_ATTRIBUTE, getTranslateString(infoCenter));
-        double textAngle = Math.sin(edgeAngle) > 0 ? -Math.PI / 2 + edgeAngle : Math.PI / 2 + edgeAngle;
         for (EdgeInfo info : edgeInfos) {
             writer.writeStartElement(GROUP_ELEMENT_NAME);
             addStylesIfAny(writer, styleProvider.getEdgeInfoStyles(info));
             drawInAndOutArrows(writer, edgeAngle);
-            Optional<String> rightLabel = info.getRightLabel();
-            if (rightLabel.isPresent()) {
-                drawLabel(writer, rightLabel.get(), svgParameters.getArrowLabelShift(), textAngle, "dominant-baseline:middle");
+            Optional<String> externalLabel = info.getExternalLabel();
+            if (externalLabel.isPresent()) {
+                drawLabel(writer, externalLabel.get(), edgeAngle, true);
             }
-            Optional<String> leftLabel = info.getLeftLabel();
-            if (leftLabel.isPresent()) {
-                drawLabel(writer, leftLabel.get(), -svgParameters.getArrowLabelShift(), textAngle, "dominant-baseline:middle; text-anchor:end");
+            Optional<String> internalLabel = info.getInternalLabel();
+            if (internalLabel.isPresent()) {
+                drawLabel(writer, internalLabel.get(), edgeAngle, false);
             }
             writer.writeEndElement();
         }
@@ -329,11 +328,37 @@ private void drawInAndOutArrows(XMLStreamWriter writer, double edgeAngle) throws
         writer.writeEndElement();
     }
 
-    private void drawLabel(XMLStreamWriter writer, String label, double labelShiftX, double angle, String style) throws XMLStreamException {
+    private void drawLabel(XMLStreamWriter writer, String label, double edgeAngle, boolean externalLabel) throws XMLStreamException {
+        if (svgParameters.isEdgeInfoAlongEdge()) {
+            drawLabelAlongEdge(writer, label, edgeAngle, externalLabel);
+        } else {
+            drawLabelPerpendicularToEdge(writer, label, edgeAngle, externalLabel);
+        }
+    }
+
+    private void drawLabelAlongEdge(XMLStreamWriter writer, String label, double edgeAngle, boolean externalLabel) throws XMLStreamException {
+        boolean textFlipped = Math.cos(edgeAngle) < 0;
+        String style = externalLabel == textFlipped ? "text-anchor:end" : null;
+        double textAngle = textFlipped ? edgeAngle - Math.PI : edgeAngle;
+        double shift = svgParameters.getArrowLabelShift() * (externalLabel ? 1 : -1);
+        drawLabel(writer, label, textFlipped ? -shift : shift, style, textAngle, X_ATTRIBUTE);
+    }
+
+    private void drawLabelPerpendicularToEdge(XMLStreamWriter writer, String label, double edgeAngle, boolean externalLabel) throws XMLStreamException {
+        boolean textFlipped = Math.sin(edgeAngle) > 0;
+        double textAngle = textFlipped ? -Math.PI / 2 + edgeAngle : Math.PI / 2 + edgeAngle;
+        double shift = svgParameters.getArrowLabelShift();
+        double shiftAdjusted = externalLabel == textFlipped ? shift * 1.15 : -shift; // to have a nice compact rendering, shift needs to be adjusted, because of dominant-baseline:middle (text is expected to be a number, hence not below the line)
+        drawLabel(writer, label, shiftAdjusted, "text-anchor:middle", textAngle, Y_ATTRIBUTE);
+    }
+
+    private void drawLabel(XMLStreamWriter writer, String label, double shift, String style, double textAngle, String shiftAxis) throws XMLStreamException {
         writer.writeStartElement(TEXT_ELEMENT_NAME);
-        writer.writeAttribute(TRANSFORM_ATTRIBUTE, getRotateString(angle));
-        writer.writeAttribute(X_ATTRIBUTE, getFormattedValue(labelShiftX));
-        writer.writeAttribute(STYLE_ELEMENT_NAME, style);
+        writer.writeAttribute(TRANSFORM_ATTRIBUTE, getRotateString(textAngle));
+        writer.writeAttribute(shiftAxis, getFormattedValue(shift));
+        if (style != null) {
+            writer.writeAttribute(STYLE_ELEMENT_NAME, style);
+        }
         writer.writeCharacters(label);
         writer.writeEndElement();
     }

src/main/resources/nominalStyle.css

@@ -2,7 +2,7 @@
 .nad-branch-edges circle {stroke: var(--nad-vl-color, lightgrey); stroke-width: 0.05; fill: white}
 .nad-3wt-edges polyline {stroke: var(--nad-vl-color, lightgrey); stroke-width: 0.05; fill: none}
 .nad-text-edges {stroke: black; stroke-width: 0.02; stroke-dasharray: .03,.05}
-.nad-disconnected {stroke-dasharray: .1,.1}
+.nad-branch-edges .nad-disconnected polyline {stroke-dasharray: .1,.1}
 .nad-vl-nodes circle {fill: var(--nad-vl-color, lightblue); stroke-width: 0.05; stroke: white}
 .nad-vl-nodes circle.nad-unknown-busnode {stroke: lightgrey; stroke-width: 0.05; stroke-dasharray: .05,.05; fill: none}
 .nad-vl-nodes path {fill: var(--nad-vl-color, lightblue); stroke-width: 0.05; stroke: white; stroke-linejoin:round;}
@@ -17,9 +17,9 @@
 .nad-reactive path {stroke: none; fill: #0277bd}
 .nad-text-background {flood-color: #90a4aeaa}
 .nad-text-nodes {font: 0.25px "Verdana"; fill: black}
-.nad-edge-infos {font: 0.2px "Verdana"}
-.nad-edge-infos .nad-state-in {fill: #b71c1c}
-.nad-edge-infos .nad-state-out {fill: #2e7d32}
+.nad-edge-infos text {font: 0.2px "Verdana"; dominant-baseline:middle; stroke: #FFFFFFAA; stroke-width: 0.1; stroke-linejoin:round; paint-order: stroke}
+.nad-edge-infos .nad-state-in text {fill: #b71c1c}
+.nad-edge-infos .nad-state-out text {fill: #2e7d32}
 .nad-vl0to30 {--nad-vl-color: #AFB42B}
 .nad-vl30to50 {--nad-vl-color: #EF9A9A}
 .nad-vl50to70 {--nad-vl-color: #9C27B0}

src/main/resources/topologicalStyle.css

@@ -2,7 +2,7 @@
 .nad-branch-edges circle {stroke: var(--nad-vl-color, lightgrey); stroke-width: 0.05; fill: white}
 .nad-3wt-edges polyline {stroke: var(--nad-vl-color, lightgrey); stroke-width: 0.05; fill: none}
 .nad-text-edges {stroke: black; stroke-width: 0.02; stroke-dasharray: .03,.05}
-.nad-branch-edges .nad-disconnected {stroke-dasharray: .1,.1}
+.nad-branch-edges .nad-disconnected polyline {stroke-dasharray: .1,.1}
 .nad-vl-nodes circle {fill: var(--nad-vl-color, lightgrey); stroke-width: 0.05; stroke: white}
 .nad-vl-nodes circle.nad-unknown-busnode {stroke: var(--nad-vl-color, #808080); stroke-width: 0.05; stroke-dasharray: .05,.05; fill: none}
 .nad-vl-nodes path {fill: var(--nad-vl-color, lightgrey); stroke-width: 0.05; stroke: white; stroke-linejoin:round;}
@@ -17,9 +17,9 @@
 .nad-reactive path {stroke: none; fill: #0277bd}
 .nad-text-background {flood-color: #90a4aeaa}
 .nad-text-nodes {font: 0.25px "Verdana"; fill: black}
-.nad-edge-infos {font: 0.2px "Verdana"}
-.nad-edge-infos .nad-state-in {fill: #b71c1c}
-.nad-edge-infos .nad-state-out {fill: #2e7d32}
+.nad-edge-infos text {font: 0.2px "Verdana"; dominant-baseline:middle; stroke: #FFFFFFAA; stroke-width: 0.1; stroke-linejoin:round; paint-order: stroke}
+.nad-edge-infos .nad-state-in text {fill: #b71c1c}
+.nad-edge-infos .nad-state-out text {fill: #2e7d32}
 .nad-disconnected {--nad-vl-color: #808080}
 .nad-vl0to30-0 {--nad-vl-color: #afb42b}
 .nad-vl0to30-1 {--nad-vl-color: #e6ee9c}
@@ -91,4 +91,3 @@
 .nad-vl300to500-7 {--nad-vl-color: #ef9a9a}
 .nad-vl300to500-8 {--nad-vl-color: #f44336}
 .nad-vl300to500-9 {--nad-vl-color: #c62828}
-

src/test/java/com/powsybl/nad/AbstractTest.java

@@ -32,9 +32,9 @@ public abstract class AbstractTest {
     protected boolean debugSvg = false;
     protected boolean overrideTestReferences = false;
 
-    protected abstract LayoutParameters getLayoutParameters();
+    private SvgParameters svgParameters;
 
-    protected abstract SvgParameters getSvgParameters();
+    private LayoutParameters layoutParameters;
 
     protected abstract StyleProvider getStyleProvider(Network network);
 
@@ -92,4 +92,20 @@ private static String normalizeLineSeparator(String str) {
         return str.replace("\r\n", "\n")
                 .replace("\r", "\n");
     }
+
+    protected LayoutParameters getLayoutParameters() {
+        return layoutParameters;
+    }
+
+    protected SvgParameters getSvgParameters() {
+        return svgParameters;
+    }
+
+    protected void setLayoutParameters(LayoutParameters layoutParameters) {
+        this.layoutParameters = layoutParameters;
+    }
+
+    protected void setSvgParameters(SvgParameters svgParameters) {
+        this.svgParameters = svgParameters;
+    }
 }

src/test/java/com/powsybl/nad/svg/EdgeInfoTest.java

@@ -0,0 +1,98 @@
+/**
+ * Copyright (c) 2022, RTE (http://www.rte-france.com)
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+package com.powsybl.nad.svg;
+
+import com.powsybl.iidm.network.Network;
+import com.powsybl.iidm.network.test.ThreeWindingsTransformerNetworkFactory;
+import com.powsybl.nad.AbstractTest;
+import com.powsybl.nad.layout.LayoutParameters;
+import com.powsybl.nad.model.BranchEdge;
+import com.powsybl.nad.model.Graph;
+import com.powsybl.nad.model.ThreeWtEdge;
+import com.powsybl.nad.svg.iidm.NominalVoltageStyleProvider;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * @author Florian Dupuy <florian.dupuy at rte-france.com>
+ */
+class EdgeInfoTest extends AbstractTest {
+
+    private String internalLabel;
+    private String externalLabel;
+
+    @BeforeEach
+    public void setup() {
+        setLayoutParameters(new LayoutParameters());
+        setSvgParameters(new SvgParameters()
+                .setSvgWidthAndHeightAdded(true)
+                .setFixedWidth(800));
+    }
+
+    @Override
+    protected StyleProvider getStyleProvider(Network network) {
+        return new NominalVoltageStyleProvider(network);
+    }
+
+    @Override
+    protected LabelProvider getLabelProvider(Network network) {
+        return new LabelProvider() {
+            @Override
+            public List<EdgeInfo> getEdgeInfos(Graph graph, BranchEdge edge, BranchEdge.Side side) {
+                return Collections.singletonList(new EdgeInfo("test", EdgeInfo.Direction.OUT, internalLabel, externalLabel));
+            }
+
+            @Override
+            public List<EdgeInfo> getEdgeInfos(Graph graph, ThreeWtEdge edge) {
+                return Collections.singletonList(new EdgeInfo("test", EdgeInfo.Direction.IN, internalLabel, externalLabel));
+            }
+
+            @Override
+            public String getArrowPathDIn() { // larger arrow
+                return "M-0.2 -0.1 H0.2 L0 0.1z";
+            }
+
+            @Override
+            public String getArrowPathDOut() { // thinner arrow
+                return "M-0.05 0.1 H0.05 L0 -0.1z";
+            }
+        };
+    }
+
+    @Test
+    void testMissingLabels() {
+        Network network = NetworkTestFactory.createTwoVoltageLevels();
+        getSvgParameters().setArrowShift(0.1);
+        assertEquals(toString("/edge_info_missing_label.svg"), generateSvgString(network, "/edge_info_missing_label.svg"));
+    }
+
+    @Test
+    void testPerpendicularLabels() {
+        Network network = NetworkTestFactory.createTwoVoltageLevels();
+        internalLabel = "int";
+        externalLabel = "ext";
+        getSvgParameters().setEdgeInfoAlongEdge(false)
+                .setArrowShift(0.5)
+                .setArrowLabelShift(0.25);
+        assertEquals(toString("/edge_info_perpendicular_label.svg"), generateSvgString(network, "/edge_info_perpendicular_label.svg"));
+    }
+
+    @Test
+    void testParallelLabels() {
+        Network network = ThreeWindingsTransformerNetworkFactory.create();
+        internalLabel = "243";
+        externalLabel = "145";
+        getSvgParameters().setArrowShift(0.6)
+                .setArrowLabelShift(0.2);
+        assertEquals(toString("/edge_info_double_labels.svg"), generateSvgString(network, "/edge_info_double_labels.svg"));
+    }
+}