point on line is computed properly

converter-sbml/src/main/java/lcsb/mapviewer/converter/model/sbml/reaction/SbmlReactionParser.java

@@ -514,9 +514,9 @@ public class SbmlReactionParser extends SbmlBioEntityParser {
     return getPointOnSegment(segment, 0.5);
   }
 
-  private Point getPointOnSegment(CurveSegment segment, double coef) {
-    double centerX = (segment.getStart().getX() + segment.getEnd().getX()) * coef;
-    double centerY = (segment.getStart().getY() + segment.getEnd().getY()) * coef;
+  Point getPointOnSegment(CurveSegment segment, double coef) {
+    double centerX = segment.getStart().getX() + (segment.getEnd().getX() - segment.getStart().getX()) * coef;
+    double centerY = segment.getStart().getY() + (segment.getEnd().getY() - segment.getStart().getY()) * coef;
     Point centerPoint = new Point(getSbmlModel().getLevel(), getSbmlModel().getVersion());
     centerPoint.setX(centerX);
     centerPoint.setY(centerY);

converter-sbml/src/test/java/lcsb/mapviewer/converter/model/sbml/reaction/SbmlReactionParserTest.java

@@ -6,9 +6,14 @@ import static org.junit.Assert.assertTrue;
 
 import java.io.FileNotFoundException;
 
-import org.apache.logging.log4j.*;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.junit.Test;
+import org.sbml.jsbml.ext.layout.CurveSegment;
+import org.sbml.jsbml.ext.layout.LineSegment;
+import org.sbml.jsbml.ext.layout.Point;
 
+import lcsb.mapviewer.common.Configuration;
 import lcsb.mapviewer.converter.ConverterParams;
 import lcsb.mapviewer.converter.InvalidInputDataExecption;
 import lcsb.mapviewer.converter.model.sbml.SbmlParser;
@@ -299,4 +304,22 @@ public class SbmlReactionParserTest extends SbmlTestFunctions {
     }
   }
 
+  @Test
+  public void testGetPointOnSegment() throws Exception {
+    try {
+      SbmlReactionParser parser = new SbmlReactionParser(new org.sbml.jsbml.Model(), null, null, null);
+      CurveSegment segment = new LineSegment(3, 2);
+      segment.setStart(new Point(12, 2, 0, 3, 2));
+      segment.setEnd(new Point(2, 8, 0, 3, 2));
+      Point p = parser.getPointOnSegment(segment, 0.4);
+
+      assertEquals(8, p.getX(), Configuration.EPSILON);
+      assertEquals(4.4, p.getY(), Configuration.EPSILON);
+
+    } catch (Exception e) {
+      e.printStackTrace();
+      throw e;
+    }
+  }
+
 }