Math: added Range*::center*() convenience functions.

src/Math/Range.h

@@ -125,10 +125,19 @@ template<UnsignedInt dimensions, class T> class Range {
          *
          * @see @ref min(), @ref max(), @ref Range2D::sizeX(),
          *      @ref Range2D::sizeY(), @ref Range3D::sizeX(),
-         *      @ref Range3D::sizeY(), @ref Range3D::sizeZ()
+         *      @ref Range3D::sizeY(), @ref Range3D::sizeZ(), @ref center()
          */
         VectorType size() const { return _max - _min; }
 
+        /**
+         * @brief Range center
+         *
+         * @see @ref Range2D::centerX(), @ref Range2D::centerY(),
+         *      @ref Range3D::centerX(), @ref Range3D::centerY(),
+         *      @ref Range3D::centerZ(), @ref size()
+         */
+        VectorType center() const { return (_min + _max)/T(2); }
+
         /**
          * @brief Translated range
          *
@@ -242,6 +251,24 @@ template<class T> class Range2D: public Range<2, T> {
             return Range<2, T>::max().y() - Range<2, T>::min().y();
         }
 
+        /**
+         * @brief %Range center on X axis
+         *
+         * @see @ref center()
+         */
+        T centerX() const {
+            return (Range<2, T>::min().x() + Range<2, T>::max().x())/T(2);
+        }
+
+        /**
+         * @brief %Range center on Y axis
+         *
+         * @see @ref center()
+         */
+        T centerY() const {
+            return (Range<2, T>::min().y() + Range<2, T>::max().y())/T(2);
+        }
+
         MAGNUM_RANGE_SUBCLASS_IMPLEMENTATION(2, Range2D, Vector2)
 };
 
@@ -362,6 +389,34 @@ template<class T> class Range3D: public Range<3, T> {
             return Range<3, T>::max().z() - Range<3, T>::min().z();
         }
 
+        /**
+         *
+         * @brief %Range center on X axis
+         *
+         * @see @ref center()
+         */
+        T centerX() const {
+            return (Range<3, T>::min().x() + Range<3, T>::max().x())/T(2);
+        }
+
+        /**
+         * @brief %Range center on Y axis
+         *
+         * @see @ref center()
+         */
+        T centerY() const {
+            return (Range<3, T>::min().y() + Range<3, T>::max().y())/T(2);
+        }
+
+        /**
+         * @brief %Range center on Z axis
+         *
+         * @see @ref center()
+         */
+        T centerZ() const {
+            return (Range<3, T>::min().z() + Range<3, T>::max().z())/T(2);
+        }
+
         MAGNUM_RANGE_SUBCLASS_IMPLEMENTATION(3, Range3D, Vector3)
 };
 

src/Math/Test/RangeTest.cpp

@@ -47,6 +47,7 @@ class RangeTest: public Corrade::TestSuite::Tester {
         void access();
         void compare();
         void size();
+        void center();
 
         void translated();
 
@@ -76,6 +77,7 @@ RangeTest::RangeTest() {
               &RangeTest::access,
               &RangeTest::compare,
               &RangeTest::size,
+              &RangeTest::center,
 
               &RangeTest::translated,
 
@@ -255,6 +257,23 @@ void RangeTest::size() {
     CORRADE_COMPARE(cube.sizeZ(), 29);
 }
 
+void RangeTest::center() {
+    const Range1Di line(34, 47);
+    const Range2Di rect({34, 23}, {47, 30});
+    const Range3Di cube({34, 23, -17}, {47, 30, 12});
+
+    CORRADE_COMPARE(line.center(), 40);
+    CORRADE_COMPARE(rect.center(), Vector2i(40, 26));
+    CORRADE_COMPARE(cube.center(), Vector3i(40, 26, -2));
+
+    CORRADE_COMPARE(rect.centerX(), 40);
+    CORRADE_COMPARE(rect.centerY(), 26);
+
+    CORRADE_COMPARE(cube.centerX(), 40);
+    CORRADE_COMPARE(cube.centerY(), 26);
+    CORRADE_COMPARE(cube.centerZ(), -2);
+}
+
 void RangeTest::translated() {
     Range2Di a({34, 23}, {47, 30});
     Range2Di b({17, 63}, {30, 70});