Merge pull request #3827 from asmorkalov:as/gapi_migration

Migrate G-API module from main repo to opencv_contrib #3827

Related to https://github.com/opencv/opencv/pull/26469
Required https://github.com/opencv/opencv/pull/26527
CI: https://github.com/opencv/ci-gha-workflow/pull/201

TODO:
- [x]  Python types generator fix
- [x] CI update

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/gapi/test/common/gapi_render_tests.cpp

@@ -0,0 +1,97 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+//
+// Copyright (C) 2019 Intel Corporation
+
+
+#include "../test_precomp.hpp"
+#include "gapi_render_tests.hpp"
+
+namespace opencv_test
+{
+
+cv::Scalar cvtBGRToYUVC(const cv::Scalar& bgr)
+{
+    double y = bgr[2] *  0.299000 + bgr[1] *  0.587000 + bgr[0] *  0.114000;
+    double u = bgr[2] * -0.168736 + bgr[1] * -0.331264 + bgr[0] *  0.500000 + 128;
+    double v = bgr[2] *  0.500000 + bgr[1] * -0.418688 + bgr[0] * -0.081312 + 128;
+    return {y, u, v};
+}
+
+void drawMosaicRef(const cv::Mat& mat, const cv::Rect &rect, int cellSz)
+{
+    cv::Rect mat_rect(0, 0, mat.cols, mat.rows);
+    auto intersection = mat_rect & rect;
+
+    cv::Mat msc_roi = mat(intersection);
+
+    bool has_crop_x = false;
+    bool has_crop_y = false;
+
+    int cols = msc_roi.cols;
+    int rows = msc_roi.rows;
+
+    if (msc_roi.cols % cellSz != 0)
+    {
+        has_crop_x = true;
+        cols -= msc_roi.cols % cellSz;
+    }
+
+    if (msc_roi.rows % cellSz != 0)
+    {
+        has_crop_y = true;
+        rows -= msc_roi.rows % cellSz;
+    }
+
+    cv::Mat cell_roi;
+    for(int i = 0; i < rows; i += cellSz )
+    {
+        for(int j = 0; j < cols; j += cellSz)
+        {
+            cell_roi = msc_roi(cv::Rect(j, i, cellSz, cellSz));
+            cell_roi = cv::mean(cell_roi);
+        }
+        if (has_crop_x)
+        {
+            cell_roi = msc_roi(cv::Rect(cols, i, msc_roi.cols - cols, cellSz));
+            cell_roi = cv::mean(cell_roi);
+        }
+    }
+
+    if (has_crop_y)
+    {
+        for(int j = 0; j < cols; j += cellSz)
+        {
+            cell_roi = msc_roi(cv::Rect(j, rows, cellSz, msc_roi.rows - rows));
+            cell_roi = cv::mean(cell_roi);
+        }
+        if (has_crop_x)
+        {
+            cell_roi = msc_roi(cv::Rect(cols, rows, msc_roi.cols - cols, msc_roi.rows - rows));
+            cell_roi = cv::mean(cell_roi);
+        }
+    }
+}
+
+void blendImageRef(cv::Mat& mat, const cv::Point& org, const cv::Mat& img, const cv::Mat& alpha)
+{
+    auto roi = mat(cv::Rect(org, img.size()));
+    cv::Mat img32f_w;
+    cv::merge(std::vector<cv::Mat>(3, alpha), img32f_w);
+
+    cv::Mat roi32f_w(roi.size(), CV_32FC3, cv::Scalar::all(1.0));
+    roi32f_w -= img32f_w;
+
+    cv::Mat img32f, roi32f;
+    img.convertTo(img32f, CV_32F, 1.0/255);
+    roi.convertTo(roi32f, CV_32F, 1.0/255);
+
+    cv::multiply(img32f, img32f_w, img32f);
+    cv::multiply(roi32f, roi32f_w, roi32f);
+    roi32f += img32f;
+
+    roi32f.convertTo(roi, CV_8U, 255.0);
+}
+
+} // namespace opencv_test