Merge pull request #13030 from dmatveev:tutorial

* G-API: First steps with tutorial

* G-API Tutorial: First iteration

* G-API port of anisotropic image segmentation tutorial;
* Currently works via OpenCV only;
* Some new kernels have been required.

* G-API Tutorial: added chapters on execution code, inspection, and profiling

* G-API Tutorial: make Fluid kernel headers public

For some reason, these headers were not moved to the public
headers subtree during the initial development. Somehow it even
worked for the existing workloads.

* G-API Tutorial: Fix a couple of issues found during the work

* Introduced Phase & Sqrt kernels, OCV & Fluid versions
* Extended GKernelPackage to allow kernel removal & policies on include()

All the above stuff needs to be tested, tests will be added later

* G-API Tutorial: added chapter on running Fluid backend

* G-API Tutorial: fix a number of issues in the text

* G-API Tutorial - some final updates

- Fixed post-merge issues after Sobel kernel renaming;
- Simplified G-API code a little bit;
- Put a conclusion note in text.

* G-API Tutorial - fix build issues in test/perf targets

Public headers were refactored but tests suites were not updated in time

* G-API Tutorial: Added tests & reference docs on new kernels

* Phase
* Sqrt

* G-API Tutorial: added link to the tutorial from the main module doc

* G-API Tutorial: Added tests on new GKernelPackage functionality

* G-API Tutorial: Extended InRange tests to cover 32F

* G-API Tutorial: Misc fixes

* Avoid building examples when gapi module is not there
* Added a volatile API disclaimer to G-API root documentation page

* G-API Tutorial: Fix perf tests build issue

This change came from master where Fluid kernels are still used
incorrectly.

* G-API Tutorial: Fixed channels support in Sqrt/Phase fluid kernels

Extended tests to cover this case

* G-API Tutorial: Fix text problems found on team review

modules/gapi/test/cpu/gapi_core_tests_cpu.cpp

@@ -137,6 +137,21 @@ INSTANTIATE_TEST_CASE_P(Cart2PolarCPU, Cart2PolarTest,
 /*init output matrices or not*/ testing::Bool(),
                                 Values(cv::compile_args(CORE_CPU))));
 
+INSTANTIATE_TEST_CASE_P(PhaseCPU, PhaseTest,
+                        Combine(Values(CV_32F, CV_32FC3),
+                                Values(cv::Size(1280, 720),
+                                       cv::Size(640, 480),
+                                       cv::Size(128, 128)),
+                                testing::Bool(),
+                                Values(cv::compile_args(CORE_CPU))));
+
+INSTANTIATE_TEST_CASE_P(SqrtCPU, SqrtTest,
+                        Combine(Values(CV_32F, CV_32FC3),
+                                Values(cv::Size(1280, 720),
+                                       cv::Size(640, 480),
+                                       cv::Size(128, 128)),
+                                Values(cv::compile_args(CORE_CPU))));
+
 INSTANTIATE_TEST_CASE_P(CompareTestCPU, CmpTest,
                         Combine(Values(CMP_EQ, CMP_GE, CMP_NE, CMP_GT, CMP_LT, CMP_LE),
                                 testing::Bool(),
@@ -255,7 +270,7 @@ INSTANTIATE_TEST_CASE_P(ThresholdTestCPU, ThresholdOTTest,
 
 
 INSTANTIATE_TEST_CASE_P(InRangeTestCPU, InRangeTest,
-                        Combine(Values(CV_8UC1, CV_16UC1, CV_16SC1),
+                        Combine(Values(CV_8UC1, CV_16UC1, CV_16SC1, CV_32FC1),
                                 Values(cv::Size(1280, 720),
                                        cv::Size(640, 480),
                                        cv::Size(128, 128)),

modules/gapi/test/cpu/gapi_core_tests_fluid.cpp

@@ -7,7 +7,6 @@
 
 #include "../test_precomp.hpp"
 #include "../common/gapi_core_tests.hpp"
-#include "backends/fluid/gfluidcore.hpp"
 
 namespace opencv_test
 {
@@ -193,6 +192,21 @@ INSTANTIATE_TEST_CASE_P(Cart2PolarFluid, Cart2PolarTest,
                                 testing::Bool(),
                                 Values(cv::compile_args(CORE_FLUID))));
 
+INSTANTIATE_TEST_CASE_P(PhaseFluid, PhaseTest,
+                        Combine(Values(CV_32F, CV_32FC3),
+                                Values(cv::Size(1280, 720),
+                                       cv::Size(640, 480),
+                                       cv::Size(128, 128)),
+                                testing::Bool(),
+                                Values(cv::compile_args(CORE_FLUID))));
+
+INSTANTIATE_TEST_CASE_P(SqrtFluid, SqrtTest,
+                        Combine(Values(CV_32F, CV_32FC3),
+                                Values(cv::Size(1280, 720),
+                                       cv::Size(640, 480),
+                                       cv::Size(128, 128)),
+                                Values(cv::compile_args(CORE_FLUID))));
+
 INSTANTIATE_TEST_CASE_P(ThresholdTestFluid, ThresholdTest,
                         Combine(Values(CV_8UC3, CV_8UC1, CV_16UC1, CV_16SC1),
                                 Values(cv::Size(1920, 1080),
@@ -206,7 +220,7 @@ INSTANTIATE_TEST_CASE_P(ThresholdTestFluid, ThresholdTest,
                                 Values(cv::compile_args(CORE_FLUID))));
 
 INSTANTIATE_TEST_CASE_P(InRangeTestFluid, InRangeTest,
-                        Combine(Values(CV_8UC3, CV_8UC1, CV_16UC1, CV_16SC1),
+                        Combine(Values(CV_8UC3, CV_8UC1, CV_16UC1, CV_16SC1, CV_32FC1),
                                 Values(cv::Size(1920, 1080),
                                        cv::Size(1280, 720),
                                        cv::Size(640, 480),

modules/gapi/test/cpu/gapi_imgproc_tests_fluid.cpp

@@ -7,7 +7,6 @@
 
 #include "../test_precomp.hpp"
 #include "../common/gapi_imgproc_tests.hpp"
-#include "backends/fluid/gfluidimgproc.hpp"
 
 #define IMGPROC_FLUID cv::gapi::imgproc::fluid::kernels()
 

modules/gapi/test/cpu/gapi_operators_tests_fluid.cpp

@@ -7,9 +7,8 @@
 
 #include "test_precomp.hpp"
 #include "../common/gapi_operators_tests.hpp"
-#include "opencv2/gapi/cpu/core.hpp"
 
-#define CORE_FLUID cv::gapi::core::cpu::kernels()
+#define CORE_FLUID cv::gapi::core::fluid::kernels()
 
 namespace opencv_test
 {