Merge pull request #18332 from TolyaTalamanov:at/wrap-GIn-GOut

[G-API] Wrap GIn & GOut

* Wrap GIn & GOut into python

* Remove extra brackets

* Use reinterpret_cast

modules/gapi/misc/python/pyopencv_gapi.hpp

@@ -11,3 +11,35 @@ PyObject* pyopencv_from(const std::vector<GCompileArg>& value)
 {
     return pyopencv_from_generic_vec(value);
 }
+
+template <typename T>
+static PyObject* extract_proto_args(PyObject* py_args, PyObject* kw)
+{
+    using namespace cv;
+
+    GProtoArgs args;
+    Py_ssize_t size = PyTuple_Size(py_args);
+    for (int i = 0; i < size; ++i) {
+        PyObject* item = PyTuple_GetItem(py_args, i);
+        if (PyObject_TypeCheck(item, reinterpret_cast<PyTypeObject*>(pyopencv_GScalar_TypePtr))) {
+            args.emplace_back(reinterpret_cast<pyopencv_GScalar_t*>(item)->v);
+        } else if (PyObject_TypeCheck(item, reinterpret_cast<PyTypeObject*>(pyopencv_GMat_TypePtr))) {
+            args.emplace_back(reinterpret_cast<pyopencv_GMat_t*>(item)->v);
+        } else {
+            PyErr_SetString(PyExc_TypeError, "cv.GIn() supports only cv.GMat and cv.GScalar");
+            return NULL;
+        }
+    }
+
+    return pyopencv_from<T>(T{std::move(args)});
+}
+
+static PyObject* pyopencv_cv_GIn(PyObject* , PyObject* py_args, PyObject* kw)
+{
+    return extract_proto_args<GProtoInputArgs>(py_args, kw);
+}
+
+static PyObject* pyopencv_cv_GOut(PyObject* , PyObject* py_args, PyObject* kw)
+{
+    return extract_proto_args<GProtoOutputArgs>(py_args, kw);
+}