Fix CubicBezierCurve to handle single segment lines

locationtech · Nov 23, 2024 · 40b7b91 · 40b7b91
1 parent cb6a6b2
commit 40b7b91
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/modules/core/src/main/java/org/locationtech/jts/shape/CubicBezierCurve.java b/modules/core/src/main/java/org/locationtech/jts/shape/CubicBezierCurve.java
@@ -18,9 +18,9 @@
 import org.locationtech.jts.geom.GeometryFactory;
 import org.locationtech.jts.geom.LineString;
 import org.locationtech.jts.geom.LinearRing;
+import org.locationtech.jts.geom.MultiLineString;
 import org.locationtech.jts.geom.Polygon;
 import org.locationtech.jts.geom.util.GeometryMapper;
-import org.locationtech.jts.io.WKTWriter;
 
 /**
  * Creates a curved geometry by replacing the segments
@@ -176,6 +176,9 @@ public Geometry map(Geometry geom) {
   }
 
   private LineString bezierLine(LineString ls) {
+    //-- can't curve a single segment
+    if (ls.getNumPoints() <= 2)
+      return (LineString) ls.copy();
     Coordinate[] coords = ls.getCoordinates();
     CoordinateList curvePts = bezierCurve(coords, false);
     curvePts.add(coords[coords.length - 1].copy(), false);
@@ -202,8 +205,12 @@ private Polygon bezierPolygon(Polygon poly) {
   }
 
   private CoordinateList bezierCurve(Coordinate[] coords, boolean isRing) {
-    Coordinate[] control = controlPoints(coords, isRing);
     CoordinateList curvePts = new CoordinateList();
+    //-- can't curve a single segment
+    if (coords.length <= 2)
+      return curvePts;
+
+    Coordinate[] control = controlPoints(coords, isRing);
     for (int i = 0; i < coords.length - 1; i++) {
       int ctrlIndex = 2 * i;
       addCurve(coords[i], coords[i + 1], control[ctrlIndex], control[ctrlIndex + 1], curvePts);

diff --git a/modules/core/src/test/java/org/locationtech/jts/shape/CubicBezierCurveTest.java b/modules/core/src/test/java/org/locationtech/jts/shape/CubicBezierCurveTest.java
@@ -57,6 +57,11 @@ public void testCtrlRightZigzag() {
         "LINESTRING (10 10, 10.1 11, 10.3 12, 10.6 13, 11 13.9, 11.5 14.8, 12.1 15.7, 12.8 16.5, 13.5 17.2, 14.3 17.9, 15.2 18.5, 16.1 19, 17 19.4, 18 19.7, 19 19.9, 20 20, 21 19.9, 21.9 19.5, 22.8 19, 23.6 18.2, 24.4 17.4, 25.1 16.5, 25.8 15.5, 26.4 14.5, 27.1 13.5, 27.6 12.6, 28.2 11.8, 28.7 11, 29.1 10.5, 29.6 10.1, 30 10, 30.5 10.2, 31.1 10.7, 31.8 11.5, 32.6 12.5, 33.5 13.7, 34.4 15, 35.3 16.2, 36.2 17.5, 37.1 18.6, 37.9 19.6, 38.6 20.4, 39.2 20.9, 39.6 21, 39.9 20.7, 40 20)");
   }
 
+  public void testSingleSegment() {
+    checkCurve("LINESTRING (10 10, 20 20)",
+        1, "LINESTRING (10 10, 20 20)");
+  }
+
   private void checkCurve(String wkt, double alpha, String wktExpected) {
     Geometry geom = read(wkt);
     Geometry actual = CubicBezierCurve.bezierCurve(geom, alpha);