Merge pull request #15699 from TolyaTalamanov:at/graph-ocv-render-backend-skeleton

G-API: Implement OpenCV render backend

* Implement render opencv backend

* Fix comment to review

* Add comment

* Add wrappers for kernels

* Fix comments to review

* Fix comment to review

modules/gapi/include/opencv2/gapi/cpu/gcpukernel.hpp

@@ -28,6 +28,14 @@ namespace gimpl
 {
     // Forward-declare an internal class
     class GCPUExecutable;
+
+    namespace render
+    {
+    namespace ocv
+    {
+        class GRenderExecutable;
+    }
+    }
 } // namespace gimpl
 
 namespace gapi
@@ -98,6 +106,7 @@ protected:
     std::unordered_map<std::size_t, GRunArgP> m_results;
 
     friend class gimpl::GCPUExecutable;
+    friend class gimpl::render::ocv::GRenderExecutable;
 };
 
 class GAPI_EXPORTS GCPUKernel

modules/gapi/include/opencv2/gapi/render/render.hpp

@@ -23,13 +23,21 @@ namespace cv
 namespace gapi
 {
 
-namespace ocv { GAPI_EXPORTS cv::gapi::GKernelPackage kernels(); }
-
 namespace wip
 {
 namespace draw
 {
 
+/**
+ * A structure allows using freetype library for text rendering
+ */
+struct use_freetype
+{
+    /*@{*/
+    std::string path; //!< The path to font file (.ttf)
+    /*@{*/
+};
+
 /**
  * A structure to represent parameters for drawing a text string.
  */
@@ -131,6 +139,28 @@ using Prims     = std::vector<Prim>;
 using GMat2     = std::tuple<cv::GMat,cv::GMat>;
 using GMatDesc2 = std::tuple<cv::GMatDesc,cv::GMatDesc>;
 
+/** @brief The function renders on the input image passed drawing primitivies
+
+@param bgr input image: 8-bit unsigned 3-channel image @ref CV_8UC3.
+@param prims vector of drawing primitivies
+@param args graph compile time parameters
+*/
+void GAPI_EXPORTS render(cv::Mat& bgr,
+                         const Prims& prims,
+                         cv::GCompileArgs&& args = {});
+
+/** @brief The function renders on two NV12 planes passed drawing primitivies
+
+@param y_plane input image: 8-bit unsigned 1-channel image @ref CV_8UC1.
+@param uv_plane input image: 8-bit unsigned 2-channel image @ref CV_8UC2.
+@param prims vector of drawing primitivies
+@param args graph compile time parameters
+*/
+void GAPI_EXPORTS render(cv::Mat& y_plane,
+                         cv::Mat& uv_plane,
+                         const Prims& prims,
+                         cv::GCompileArgs&& args = {});
+
 G_TYPED_KERNEL_M(GRenderNV12, <GMat2(cv::GMat,cv::GMat,cv::GArray<wip::draw::Prim>)>, "org.opencv.render.nv12")
 {
      static GMatDesc2 outMeta(GMatDesc y_plane, GMatDesc uv_plane, GArrayDesc)
@@ -147,31 +177,39 @@ G_TYPED_KERNEL(GRenderBGR, <cv::GMat(cv::GMat,cv::GArray<wip::draw::Prim>)>, "or
      }
 };
 
-/** @brief The function renders on the input image passed drawing primitivies
+/** @brief Renders on 3 channels input
 
-@param bgr input image: 8-bit unsigned 3-channel image @ref CV_8UC3.
-@param prims vector of drawing primitivies
-@param pkg contains render kernel implementation
+Output image must be 8-bit unsigned planar 3-channel image
+
+@param src input image: 8-bit unsigned 3-channel image @ref CV_8UC3
+@param prims draw primitives
 */
-GAPI_EXPORTS void render(cv::Mat& bgr,
-                         const Prims& prims,
-                         const cv::gapi::GKernelPackage& pkg = ocv::kernels());
+GAPI_EXPORTS GMat render3ch(const GMat& src, const GArray<Prim>& prims);
 
-/** @brief The function renders on two NV12 planes passed drawing primitivies
+/** @brief Renders on two planes
 
-@param y_plane input image: 8-bit unsigned 1-channel image @ref CV_8UC1.
-@param uv_plane input image: 8-bit unsigned 2-channel image @ref CV_8UC2.
-@param prims vector of drawing primitivies
-@param pkg contains render kernel implementation
+Output y image must be 8-bit unsigned planar 1-channel image @ref CV_8UC1
+uv image must be 8-bit unsigned planar 2-channel image @ref CV_8UC2
+
+@param y  input image: 8-bit unsigned 1-channel image @ref CV_8UC1
+@param uv input image: 8-bit unsigned 2-channel image @ref CV_8UC2
+@param prims draw primitives
 */
-GAPI_EXPORTS void render(cv::Mat& y_plane,
-                         cv::Mat& uv_plane,
-                         const Prims& prims,
-                         const cv::gapi::GKernelPackage& pkg = ocv::kernels());
+GAPI_EXPORTS GMat2 renderNV12(const GMat& y,
+                              const GMat& uv,
+                              const GArray<Prim>& prims);
 
 } // namespace draw
 } // namespace wip
 
+namespace render
+{
+namespace ocv
+{
+    GAPI_EXPORTS cv::gapi::GKernelPackage kernels();
+
+} // namespace ocv
+} // namespace render
 } // namespace gapi
 } // namespace cv