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/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