Add python bindings for G-API onnx

modules/gapi/misc/python/pyopencv_gapi.hpp

@@ -14,6 +14,7 @@
 using gapi_GKernelPackage           = cv::GKernelPackage;
 using gapi_GNetPackage              = cv::gapi::GNetPackage;
 using gapi_ie_PyParams              = cv::gapi::ie::PyParams;
+using gapi_onnx_PyParams            = cv::gapi::onnx::PyParams;
 using gapi_wip_IStreamSource_Ptr    = cv::Ptr<cv::gapi::wip::IStreamSource>;
 using detail_ExtractArgsCallback    = cv::detail::ExtractArgsCallback;
 using detail_ExtractMetaCallback    = cv::detail::ExtractMetaCallback;

modules/gapi/misc/python/shadow_gapi.hpp

@@ -79,5 +79,6 @@ namespace streaming
 namespace detail
 {
     gapi::GNetParam GAPI_EXPORTS_W strip(gapi::ie::PyParams params);
+    gapi::GNetParam GAPI_EXPORTS_W strip(gapi::onnx::PyParams params);
 } // namespace detail
 } // namespace cv

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

@@ -0,0 +1,74 @@
+#!/usr/bin/env python
+
+import numpy as np
+import cv2 as cv
+import os
+import sys
+import unittest
+
+from tests_common import NewOpenCVTests
+
+
+try:
+
+    if sys.version_info[:2] < (3, 0):
+        raise unittest.SkipTest('Python 2.x is not supported')
+
+    CLASSIFICATION_MODEL_PATH = "onnx_models/vision/classification/squeezenet/model/squeezenet1.0-9.onnx"
+
+    testdata_required = bool(os.environ.get('OPENCV_DNN_TEST_REQUIRE_TESTDATA', False))
+
+    class test_gapi_infer(NewOpenCVTests):
+        def find_dnn_file(self, filename, required=None):
+            if not required:
+                required = testdata_required
+            return self.find_file(filename, [os.environ.get('OPENCV_DNN_TEST_DATA_PATH', os.getcwd()),
+                                            os.environ['OPENCV_TEST_DATA_PATH']],
+                                required=required)
+
+        def test_onnx_classification(self):
+            model_path = self.find_dnn_file(CLASSIFICATION_MODEL_PATH)
+
+            if model_path is None:
+                raise unittest.SkipTest("Missing DNN test file")
+
+            in_mat = cv.imread(
+                self.find_file("cv/dpm/cat.png",
+                [os.environ.get('OPENCV_TEST_DATA_PATH')]))
+
+            g_in = cv.GMat()
+            g_infer_inputs = cv.GInferInputs()
+            g_infer_inputs.setInput("data_0", g_in)
+            g_infer_out = cv.gapi.infer("squeeze-net", g_infer_inputs)
+            g_out = g_infer_out.at("softmaxout_1")
+
+            comp = cv.GComputation(cv.GIn(g_in), cv.GOut(g_out))
+
+            net = cv.gapi.onnx.params("squeeze-net", model_path)
+            try:
+                out_gapi = comp.apply(cv.gin(in_mat), cv.gapi.compile_args(cv.gapi.networks(net)))
+            except cv.error as err:
+                if err.args[0] == "G-API has been compiled without ONNX support":
+                    raise unittest.SkipTest("G-API has been compiled without ONNX support")
+                else:
+                    raise
+
+            self.assertEqual((1, 1000, 1, 1), out_gapi.shape)
+
+
+except unittest.SkipTest as e:
+
+    message = str(e)
+
+    class TestSkip(unittest.TestCase):
+        def setUp(self):
+            self.skipTest('Skip tests: ' + message)
+
+        def test_skip():
+            pass
+
+    pass
+
+
+if __name__ == '__main__':
+    NewOpenCVTests.bootstrap()