Merge pull request #20 from lsst/tickets/DM-19409

DM-19409: Add Box2I.getCenter()
lsst · Apr 23, 2019 · b9095d2 · b9095d2
2 parents fd17674 + 796d531
commit b9095d2
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Showing 4 changed files with 25 additions and 38 deletions.
diff --git a/include/lsst/geom/Box.h b/include/lsst/geom/Box.h
@@ -176,6 +176,17 @@ class Box2I final {
     int getArea() const { return getWidth() * getHeight(); }
     //@}
 
+    /**
+     *  @name Center Accessors
+     *
+     *  Return the center coordinate of the box.
+     */
+    //@{
+    Point2D const getCenter() const noexcept;
+    double getCenterX() const noexcept { return this->getCenter().getX(); }
+    double getCenterY() const noexcept { return this->getCenter().getY(); }
+    //@}
+
     /// Return slices to extract the box's region from an ndarray::Array.
     ndarray::View<boost::fusion::vector2<ndarray::index::Range, ndarray::index::Range> > getSlices() const;
 

diff --git a/python/lsst/geom/_Box.cc b/python/lsst/geom/_Box.cc
@@ -76,6 +76,9 @@ void wrapBox(utils::python::WrapperCollection & wrappers) {
             cls.def("getWidth", &Box2I::getWidth);
             cls.def("getHeight", &Box2I::getHeight);
             cls.def("getArea", &Box2I::getArea);
+            cls.def("getCenter", &Box2I::getCenter);
+            cls.def("getCenterX", &Box2I::getCenterX);
+            cls.def("getCenterY", &Box2I::getCenterY);
             cls.def("isEmpty", &Box2I::isEmpty);
             cls.def("contains", (bool (Box2I::*)(Point2I const &) const) & Box2I::contains);
             cls.def("contains", (bool (Box2I::*)(Box2I const &) const) & Box2I::contains);

diff --git a/src/Box.cc b/src/Box.cc
@@ -93,6 +93,10 @@ Box2I::Box2I(Box2D const& other, EdgeHandlingEnum edgeHandling) : _minimum(), _d
     }
 }
 
+Point2D const Box2I::getCenter() const noexcept {
+    return Box2D(*this).getCenter();
+}
+
 Box2I Box2I::makeCenteredBox(Point2D const& center, Box2I::Extent const& size) {
     if (!std::isfinite(center[0]) || !std::isfinite(center[1])) {
         throw LSST_EXCEPT(pex::exceptions::InvalidParameterError, "Cannot make Box2I with non-finite center");

diff --git a/tests/test_box.py b/tests/test_box.py
@@ -194,6 +194,10 @@ def testAccessors(self):
         self.assertEqual(box.getHeight(), (ymax - ymin + 1))
         self.assertAlmostEqual(box.getArea(), box.getWidth() * box.getHeight(),
                                places=14)
+        self.assertEqual(box.getCenterX(), 0.5*(pmax.getX() + pmin.getX()))
+        self.assertEqual(box.getCenterY(), 0.5*(pmax.getY() + pmin.getY()))
+        self.assertEqual(box.getCenter().getX(), box.getCenterX())
+        self.assertEqual(box.getCenter().getY(), box.getCenterY())
         corners = box.getCorners()
         self.assertEqual(corners[0], box.getMin())
         self.assertEqual(corners[1].getX(), box.getMaxX())
@@ -561,50 +565,15 @@ def _checkBoxConstruction(self, boxClass, size, center, precision):
         if all(np.isfinite(center)):
             box = boxClass.makeCenteredBox(center, size)
             if all(size.gt(0)):
-                self._checkBoxProperties(box, size, center, precision, msg)
+                self.assertIsNotNone(box, msg=msg)
+                self.assertPairsAlmostEqual(box.getCenter(), center, maxDiff=precision, msg=msg)
+                self.assertPairsAlmostEqual(box.getDimensions(), size, msg=msg)
             else:
                 self.assertTrue(box.isEmpty(), msg=msg)
         elif boxClass == geom.Box2I:
             with self.assertRaises(lsst.pex.exceptions.InvalidParameterError, msg=msg):
                 boxClass.makeCenteredBox(center, size)
 
-    def _checkBoxProperties(self, box, size, center, precision, msg):
-        """Test whether a box has the desired size and position.
-
-        Parameters
-        ----------
-        box : `lsst.geom.Box2I` or `lsst.geom.Box2D`
-            The box to test.
-        size : ``box.Extent``
-            The expected dimensions of ``box``.
-        center : `lsst.geom.Point2D`
-            The expected center of ``box``.
-        precision : `float`
-            The maximum distance between the center of ``box`` and ``center``.
-        msg : `str`
-            An error message suffix describing test parameters.
-        """
-        newCenter = self._getBoxCenter(box)
-        self.assertIsNotNone(box, msg=msg)
-        self.assertPairsAlmostEqual(newCenter, center, maxDiff=precision, msg=msg)
-        self.assertPairsAlmostEqual(box.getDimensions(), size, msg=msg)
-
-    def _getBoxCenter(self, box):
-        """Return the coordinates of a Box's center.
-
-        Parameters
-        ----------
-        box : `lsst.geom.Box2I` or `lsst.geom.Box2D`
-            The box whose center is desired.
-
-        Returns
-        -------
-        center : `lsst.geom.Point2D`
-            The position at the center of ``box``. If ``box`` is a ``Box2I``,
-            this will always have integer or half-integer coordinates.
-        """
-        return geom.Box2D(box).getCenter()
-
 
 class MemoryTester(lsst.utils.tests.MemoryTestCase):
     pass