Merge pull request #23702 from dkurt:py_rotated_rect

Python binding for RotatedRect #23702

### Pull Request Readiness Checklist

related: https://github.com/opencv/opencv/issues/23546#issuecomment-1562894602

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/core/include/opencv2/core/types.hpp

@@ -527,23 +527,23 @@ The sample below demonstrates how to use RotatedRect:
 
 @sa CamShift, fitEllipse, minAreaRect, CvBox2D
 */
-class CV_EXPORTS RotatedRect
+class CV_EXPORTS_W_SIMPLE RotatedRect
 {
 public:
     //! default constructor
-    RotatedRect();
+    CV_WRAP RotatedRect();
     /** full constructor
     @param center The rectangle mass center.
     @param size Width and height of the rectangle.
     @param angle The rotation angle in a clockwise direction. When the angle is 0, 90, 180, 270 etc.,
     the rectangle becomes an up-right rectangle.
     */
-    RotatedRect(const Point2f& center, const Size2f& size, float angle);
+    CV_WRAP RotatedRect(const Point2f& center, const Size2f& size, float angle);
     /**
     Any 3 end points of the RotatedRect. They must be given in order (either clockwise or
     anticlockwise).
      */
-    RotatedRect(const Point2f& point1, const Point2f& point2, const Point2f& point3);
+    CV_WRAP RotatedRect(const Point2f& point1, const Point2f& point2, const Point2f& point3);
 
     /** returns 4 vertices of the rotated rectangle
     @param pts The points array for storing rectangle vertices. The order is _bottomLeft_, _topLeft_, topRight, bottomRight.
@@ -552,16 +552,19 @@ public:
     rectangle.
     */
     void points(Point2f pts[]) const;
+
+    CV_WRAP void points(CV_OUT std::vector<Point2f>& pts) const;
+
     //! returns the minimal up-right integer rectangle containing the rotated rectangle
-    Rect boundingRect() const;
+    CV_WRAP Rect boundingRect() const;
     //! returns the minimal (exact) floating point rectangle containing the rotated rectangle, not intended for use with images
     Rect_<float> boundingRect2f() const;
     //! returns the rectangle mass center
-    Point2f center;
+    CV_PROP_RW Point2f center;
     //! returns width and height of the rectangle
-    Size2f size;
+    CV_PROP_RW Size2f size;
     //! returns the rotation angle. When the angle is 0, 90, 180, 270 etc., the rectangle becomes an up-right rectangle.
-    float angle;
+    CV_PROP_RW float angle;
 };
 
 template<> class DataType< RotatedRect >

modules/core/src/types.cpp

@@ -186,6 +186,11 @@ void RotatedRect::points(Point2f pt[]) const
     pt[3].y = 2*center.y - pt[1].y;
 }
 
+void RotatedRect::points(std::vector<Point2f>& pts) const {
+    pts.resize(4);
+    points(pts.data());
+}
+
 Rect RotatedRect::boundingRect() const
 {
     Point2f pt[4];

modules/python/src2/cv2_convert.cpp

@@ -728,6 +728,26 @@ PyObject* pyopencv_from(const Rect2d& r)
 
 // --- RotatedRect
 
+static inline bool convertToRotatedRect(PyObject* obj, RotatedRect& dst)
+{
+    PyObject* type = PyObject_Type(obj);
+    if (getPyObjectAttr(type, "__module__") == MODULESTR &&
+        getPyObjectNameAttr(type) == "RotatedRect")
+    {
+        struct pyopencv_RotatedRect_t
+        {
+            PyObject_HEAD
+            cv::RotatedRect v;
+        };
+        dst = reinterpret_cast<pyopencv_RotatedRect_t*>(obj)->v;
+
+        Py_DECREF(type);
+        return true;
+    }
+    Py_DECREF(type);
+    return false;
+}
+
 template<>
 bool pyopencv_to(PyObject* obj, RotatedRect& dst, const ArgInfo& info)
 {
@@ -735,6 +755,12 @@ bool pyopencv_to(PyObject* obj, RotatedRect& dst, const ArgInfo& info)
     {
         return true;
     }
+    // This is a workaround for compatibility with an initialization from tuple.
+    // Allows import RotatedRect as an object.
+    if (convertToRotatedRect(obj, dst))
+    {
+        return true;
+    }
     if (!PySequence_Check(obj))
     {
         failmsg("Can't parse '%s' as RotatedRect."

modules/python/src2/pycompat.hpp

@@ -98,10 +98,10 @@ static inline bool getUnicodeString(PyObject * obj, std::string &str)
 }
 
 static inline
-std::string getPyObjectNameAttr(PyObject* obj)
+std::string getPyObjectAttr(PyObject* obj, const char* attrName)
 {
     std::string obj_name;
-    PyObject* cls_name_obj = PyObject_GetAttrString(obj, "__name__");
+    PyObject* cls_name_obj = PyObject_GetAttrString(obj, attrName);
     if (cls_name_obj && !getUnicodeString(cls_name_obj, obj_name)) {
         obj_name.clear();
     }
@@ -117,6 +117,12 @@ std::string getPyObjectNameAttr(PyObject* obj)
     return obj_name;
 }
 
+static inline
+std::string getPyObjectNameAttr(PyObject* obj)
+{
+    return getPyObjectAttr(obj, "__name__");
+}
+
 //==================================================================================================
 
 #define CV_PY_FN_WITH_KW_(fn, flags) (PyCFunction)(void*)(PyCFunctionWithKeywords)(fn), (flags) | METH_VARARGS | METH_KEYWORDS

modules/python/test/test_misc.py

@@ -482,6 +482,27 @@ class Arguments(NewOpenCVTests):
             self.assertEqual(expected, actual,
                              msg=get_conversion_error_msg(convertible, expected, actual))
 
+
+    def test_wrap_rotated_rect(self):
+        center = (34.5, 52.)
+        size = (565.0, 140.0)
+        angle = -177.5
+        rect1 = cv.RotatedRect(center, size, angle)
+        self.assertEqual(rect1.center, center)
+        self.assertEqual(rect1.size, size)
+        self.assertEqual(rect1.angle, angle)
+
+        pts = [[ 319.7845, -5.6109037],
+               [ 313.6778, 134.25586],
+               [-250.78448, 109.6109],
+               [-244.6778, -30.25586]]
+        self.assertLess(np.max(np.abs(rect1.points() - pts)), 1e-4)
+
+        rect2 = cv.RotatedRect(pts[0], pts[1], pts[2])
+        _, inter_pts = cv.rotatedRectangleIntersection(rect1, rect2)
+        self.assertLess(np.max(np.abs(inter_pts.reshape(-1, 2) - pts)), 1e-4)
+
+
     def test_parse_to_rotated_rect_not_convertible(self):
         for not_convertible in ([], (), np.array([]), (123, (45, 34), 1), {1: 2, 3: 4}, 123,
                                 np.array([[123, 123, 14], [1, 3], 56], dtype=object), '123'):