Merge pull request #18762 from TolyaTalamanov:at/support-garray

[G-API] Wrap GArray

* Wrap GArray for output

* Collect in/out info in graph

* Add imgproc tests

* Add cv::Point2f

* Update test_gapi_imgproc.py

* Fix comments to review

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

@@ -0,0 +1,79 @@
+#!/usr/bin/env python
+
+import numpy as np
+import cv2 as cv
+import os
+
+from tests_common import NewOpenCVTests
+
+
+# Plaidml is an optional backend
+pkgs = [
+           ('ocl'    , cv.gapi.core.ocl.kernels()),
+           ('cpu'    , cv.gapi.core.cpu.kernels()),
+           ('fluid'  , cv.gapi.core.fluid.kernels())
+           # ('plaidml', cv.gapi.core.plaidml.kernels())
+       ]
+
+
+class gapi_imgproc_test(NewOpenCVTests):
+
+    def test_good_features_to_track(self):
+        # TODO: Extend to use any type and size here
+        img_path = self.find_file('cv/face/david2.jpg', [os.environ.get('OPENCV_TEST_DATA_PATH')])
+        in1 = cv.cvtColor(cv.imread(img_path), cv.COLOR_RGB2GRAY)
+
+        # NB: goodFeaturesToTrack configuration
+        max_corners         = 50
+        quality_lvl         = 0.01
+        min_distance        = 10
+        block_sz            = 3
+        use_harris_detector = True
+        k                   = 0.04
+        mask                = None
+
+        # OpenCV
+        expected = cv.goodFeaturesToTrack(in1, max_corners, quality_lvl,
+                                          min_distance, mask=mask,
+                                          blockSize=block_sz, useHarrisDetector=use_harris_detector, k=k)
+
+        # G-API
+        g_in = cv.GMat()
+        g_out = cv.gapi.goodFeaturesToTrack(g_in, max_corners, quality_lvl,
+                                            min_distance, mask, block_sz, use_harris_detector, k)
+
+        comp = cv.GComputation(cv.GIn(g_in), cv.GOut(g_out))
+
+        for pkg_name, pkg in pkgs:
+            actual = comp.apply(cv.gin(in1), args=cv.compile_args(pkg))
+            # NB: OpenCV & G-API have different output shapes:
+            # OpenCV - (num_points, 1, 2)
+            # G-API  - (num_points, 2)
+            # Comparison
+            self.assertEqual(0.0, cv.norm(expected.flatten(), actual.flatten(), cv.NORM_INF),
+                             'Failed on ' + pkg_name + ' backend')
+
+
+    def test_rgb2gray(self):
+        # TODO: Extend to use any type and size here
+        img_path = self.find_file('cv/face/david2.jpg', [os.environ.get('OPENCV_TEST_DATA_PATH')])
+        in1 = cv.imread(img_path)
+
+        # OpenCV
+        expected = cv.cvtColor(in1, cv.COLOR_RGB2GRAY)
+
+        # G-API
+        g_in = cv.GMat()
+        g_out = cv.gapi.RGB2Gray(g_in)
+
+        comp = cv.GComputation(cv.GIn(g_in), cv.GOut(g_out))
+
+        for pkg_name, pkg in pkgs:
+            actual = comp.apply(cv.gin(in1), args=cv.compile_args(pkg))
+            # Comparison
+            self.assertEqual(0.0, cv.norm(expected, actual, cv.NORM_INF),
+                             'Failed on ' + pkg_name + ' backend')
+
+
+if __name__ == '__main__':
+    NewOpenCVTests.bootstrap()