Merge pull request #126 from Flashky/feature/57-add-multiply-by-scalar-to-vector2

feat: add Vector2 multiply by scalar method #57

Author: Flashky

src/main/java/com/adventofcode/flashk/common/Vector2.java

@@ -64,7 +64,15 @@ public static Vector2 transform(Vector2 start, Vector2 end) {
 
 		return new Vector2(x,y);
 	}
-	
+
+	/// Multiplies the given vector by a scalar, returning a new Vector2.
+	/// @param vector the vector to multiply
+	/// @param scalar the scalar value to multiply the vector by
+	/// @return a new Vector2 with the result of the scalar product.
+	public static Vector2 multiply(Vector2 vector, int scalar) {
+		return new Vector2(vector.x * scalar, vector.y * scalar);
+	}
+
 	/**
 	 * Substracts the right operand vector to the left operand vector, applying absolute value to the result.
 	 *  

src/test/java/com/adventofcode/flashk/common/Vector2Test.java

@@ -753,4 +753,20 @@ void testNormalizedOrigin() {
 		assertThrows(IllegalStateException.class, vector::normalized);
 
 	}
+
+	@Test
+	void multiply() {
+
+		Vector2 vector = new Vector2(2, 3);
+		Vector2 result = Vector2.multiply(vector, 5);
+
+		// The result is a new vector with the product of the vector by the scalar
+		assertNotSame(vector, result);
+		assertEquals(10, result.getX());
+		assertEquals(15, result.getY());
+
+		// Original vector is not modified
+		assertEquals(2, vector.getX());
+		assertEquals(3, vector.getY());
+	}
 }