Fix: calculate and test the rollLongitude result

Author: sebr72

core/src/main/java/org/mapfish/print/attribute/map/CenterScaleMapBounds.java

@@ -180,12 +180,19 @@ private ReferencedEnvelope computeGeodeticBBox(
     }
   }
 
-  private double rollLongitude(final double x) {
-    return x - (((int) (x + Math.signum(x) * 180)) / 360) * 360.0;
+  double rollLongitude(final double x) {
+    return modulo(x + 180, 360.0) - 180;
   }
 
-  private double rollLatitude(final double y) {
-    return y - (((int) (y + Math.signum(y) * 90)) / 180) * 180.0;
+  private static double modulo(double a, double b) {
+    return b - ((-a % b) + b) % b;
+  }
+
+  double rollLatitude(final double y) {
+    if (y > 90 || y < -90) {
+      throw new IllegalArgumentException("Latitude must be between -90 and 90");
+    }
+    return y;
   }
 
   @Override

core/src/test/java/org/mapfish/print/attribute/map/CenterScaleMapBoundsTest.java

@@ -1,6 +1,7 @@
 package org.mapfish.print.attribute.map;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
 
 import java.awt.Rectangle;
 import org.geotools.api.referencing.FactoryException;
@@ -111,4 +112,36 @@ public void testZoomOut() {
     assertEquals(envelope.getMinY() * 2, newEnvelope.getMinY(), delta);
     assertEquals(envelope.getMaxY() * 2, newEnvelope.getMaxY(), delta);
   }
+
+  @Test
+  public void testRollLongitude() {
+    final double denominator = 10000.0;
+    final CenterScaleMapBounds bounds =
+        new CenterScaleMapBounds(DefaultGeographicCRS.WGS84, 0.0, 0.0, denominator);
+
+    assertEquals(0.0, bounds.rollLongitude(0.0), 1e-6);
+    assertEquals(180.0, bounds.rollLongitude(-180.0), 1e-6);
+    assertEquals(180.0, bounds.rollLongitude(180.0), 1e-6);
+    assertEquals(-179.0, bounds.rollLongitude(181.0), 1e-6);
+    assertEquals(179.0, bounds.rollLongitude(-181.0), 1e-6);
+    assertEquals(1.0, bounds.rollLongitude(361.0), 1e-6);
+    assertEquals(-1.0, bounds.rollLongitude(-361.0), 1e-6);
+  }
+
+  @Test
+  public void testRollLatitude() {
+    final double denominator = 10000.0;
+    final CenterScaleMapBounds bounds =
+        new CenterScaleMapBounds(DefaultGeographicCRS.WGS84, 0.0, 0.0, denominator);
+
+    assertEquals(0.0, bounds.rollLatitude(0.0), 1e-6);
+    assertEquals(90.0, bounds.rollLatitude(90.0), 1e-6);
+    assertEquals(-90.0, bounds.rollLatitude(-90.0), 1e-6);
+    assertThrows(IllegalArgumentException.class, () -> bounds.rollLatitude(91.0));
+    assertThrows(IllegalArgumentException.class, () -> bounds.rollLatitude(-91.0));
+    assertThrows(IllegalArgumentException.class, () -> bounds.rollLatitude(180.0));
+    assertThrows(IllegalArgumentException.class, () -> bounds.rollLatitude(-180.0));
+    assertThrows(IllegalArgumentException.class, () -> bounds.rollLatitude(181.0));
+    assertThrows(IllegalArgumentException.class, () -> bounds.rollLatitude(-181.0));
+  }
 }