Merge pull request #17493 from TolyaTalamanov:at/python-bindings-gapi

* Implement G-API python bindings

* Fix hdr_parser

* Drop initlization with brackets using regexp

* Handle bracket initilization another way

* Add test for core operations

* Declaration and definition of View constructor now in different files

* Refactor tests

* Remove combine decorator from tests

* Fix comment to review

* Fix test

* Fix comments to review

* Remove GCompilerArgs implementation from python

Co-authored-by: Pinaev <danil.pinaev@intel.com>

modules/gapi/misc/python/pyopencv_gapi.hpp

@@ -0,0 +1,13 @@
+using gapi_GKernelPackage = cv::gapi::GKernelPackage;
+
+template<>
+bool pyopencv_to(PyObject* obj, std::vector<GCompileArg>& value, const ArgInfo& info)
+{
+    return pyopencv_to_generic_vec(obj, value, info);
+}
+
+template<>
+PyObject* pyopencv_from(const std::vector<GCompileArg>& value)
+{
+    return pyopencv_from_generic_vec(value);
+}

modules/gapi/misc/python/shadow_gapi.hpp

@@ -0,0 +1,7 @@
+#error This is a shadow header file, which is not intended for processing by any compiler. \
+       Only bindings parser should handle this file.
+
+namespace cv
+{
+   GAPI_EXPORTS_W GCompileArgs compile_args(gapi::GKernelPackage pkg);
+} // namespace cv

modules/gapi/misc/python/test/test_gapi_core.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+import numpy as np
+import cv2 as cv
+
+from tests_common import NewOpenCVTests
+
+
+# Plaidml is an optional backend
+pkgs = [
+         cv.gapi.core.ocl.kernels(),
+         cv.gapi.core.cpu.kernels(),
+         cv.gapi.core.fluid.kernels()
+         # cv.gapi.core.plaidml.kernels()
+       ]
+
+
+class gapi_core_test(NewOpenCVTests):
+
+    def test_add(self):
+        # TODO: Extend to use any type and size here
+        sz = (1280, 720)
+        in1 = np.random.randint(0, 100, sz).astype(np.uint8)
+        in2 = np.random.randint(0, 100, sz).astype(np.uint8)
+
+        # OpenCV
+        expected = in1 + in2
+
+        # G-API
+        g_in1 = cv.GMat()
+        g_in2 = cv.GMat()
+        g_out = cv.gapi.add(g_in1, g_in2)
+        comp = cv.GComputation(g_in1, g_in2, g_out)
+
+        for pkg in pkgs:
+            actual = comp.apply(in1, in2, args=cv.compile_args(pkg))
+            # Comparison
+            self.assertEqual(0.0, cv.norm(expected, actual, cv.NORM_INF))
+
+
+if __name__ == '__main__':
+    NewOpenCVTests.bootstrap()