Merge pull request opencv#19322 from TolyaTalamanov:at/python-callbacks

[G-API] Introduce cv.gin/cv.descr_of for python

* Implement cv.gin/cv.descr_of

* Fix macos build

* Fix gcomputation tests

* Add test

* Add using to a void exceeded length for windows build

* Add using to a void exceeded length for windows build

* Fix comments to review

* Fix comments to review

* Update from latest master

* Avoid graph compilation to obtain in/out info

* Fix indentation

* Fix comments to review

* Avoid using default in switches

* Post output meta for giebackend

Author: TolyaTalamanov

modules/gapi/include/opencv2/gapi/core.hpp

@@ -1909,14 +1909,14 @@ kmeans(const GMat& data, const int K, const GMat& bestLabels,
  - Function textual ID is "org.opencv.core.kmeansNDNoInit"
  - #KMEANS_USE_INITIAL_LABELS flag must not be set while using this overload.
  */
-GAPI_EXPORTS std::tuple<GOpaque<double>,GMat,GMat>
+GAPI_EXPORTS_W std::tuple<GOpaque<double>,GMat,GMat>
 kmeans(const GMat& data, const int K, const TermCriteria& criteria, const int attempts,
        const KmeansFlags flags);
 
 /** @overload
 @note Function textual ID is "org.opencv.core.kmeans2D"
  */
-GAPI_EXPORTS std::tuple<GOpaque<double>,GArray<int>,GArray<Point2f>>
+GAPI_EXPORTS_W std::tuple<GOpaque<double>,GArray<int>,GArray<Point2f>>
 kmeans(const GArray<Point2f>& data, const int K, const GArray<int>& bestLabels,
        const TermCriteria& criteria, const int attempts, const KmeansFlags flags);
 
@@ -1935,7 +1935,7 @@ namespace streaming {
 @param src Input tensor
 @return Size (tensor dimensions).
 */
-GAPI_EXPORTS GOpaque<Size> size(const GMat& src);
+GAPI_EXPORTS_W GOpaque<Size> size(const GMat& src);
 
 /** @overload
 Gets dimensions from rectangle.

modules/gapi/include/opencv2/gapi/garg.hpp

@@ -249,6 +249,30 @@ template<typename... Ts> inline GRunArgsP gout(Ts&... args)
     return GRunArgsP{ GRunArgP(detail::wrap_host_helper<Ts>::wrap_out(args))... };
 }
 
+struct GTypeInfo;
+using GTypesInfo = std::vector<GTypeInfo>;
+
+// FIXME: Needed for python bridge, must be moved to more appropriate header
+namespace detail {
+struct ExtractArgsCallback
+{
+    cv::GRunArgs operator()(const cv::GTypesInfo& info) const { return c(info); }
+    using CallBackT = std::function<cv::GRunArgs(const cv::GTypesInfo& info)>;
+    CallBackT c;
+};
+
+struct ExtractMetaCallback
+{
+    cv::GMetaArgs operator()(const cv::GTypesInfo& info) const { return c(info); }
+    using CallBackT = std::function<cv::GMetaArgs(const cv::GTypesInfo& info)>;
+    CallBackT c;
+};
+
+void constructGraphOutputs(const cv::GTypesInfo &out_info,
+                           cv::GRunArgs         &args,
+                           cv::GRunArgsP        &outs);
+} // namespace detail
+
 } // namespace cv
 
 #endif // OPENCV_GAPI_GARG_HPP

modules/gapi/include/opencv2/gapi/garray.hpp

@@ -368,8 +368,6 @@ template<typename T> class GArray
     detail::GArrayU m_ref;
 };
 
-using GArrayP2f = GArray<cv::Point2f>;
-
 /** @} */
 
 } // namespace cv

modules/gapi/include/opencv2/gapi/gcomputation.hpp

@@ -258,7 +258,8 @@ class GAPI_EXPORTS_W GComputation
     void apply(GRunArgs &&ins, GRunArgsP &&outs, GCompileArgs &&args = {});       // Arg-to-arg overload
 
     /// @private -- Exclude this function from OpenCV documentation
-    GAPI_WRAP GRunArgs apply(GRunArgs &&ins, GCompileArgs &&args = {});
+    GAPI_WRAP GRunArgs apply(const cv::detail::ExtractArgsCallback  &callback,
+                                   GCompileArgs                    &&args = {});
 
     /// @private -- Exclude this function from OpenCV documentation
     void apply(const std::vector<cv::Mat>& ins,                                   // Compatibility overload
@@ -436,7 +437,11 @@ class GAPI_EXPORTS_W GComputation
      *
      * @sa @ref gapi_compile_args
      */
-    GAPI_WRAP GStreamingCompiled compileStreaming(GMetaArgs &&in_metas, GCompileArgs &&args = {});
+    GStreamingCompiled compileStreaming(GMetaArgs &&in_metas, GCompileArgs &&args = {});
+
+    /// @private -- Exclude this function from OpenCV documentation
+    GAPI_WRAP GStreamingCompiled compileStreaming(const cv::detail::ExtractMetaCallback &callback,
+                                                        GCompileArgs                   &&args = {});
 
     /**
      * @brief Compile the computation for streaming mode.

modules/gapi/include/opencv2/gapi/gkernel.hpp

@@ -30,6 +30,7 @@ struct GTypeInfo
 {
     GShape                 shape;
     cv::detail::OpaqueKind kind;
+    detail::HostCtor       ctor;
 };
 
 using GShapes    = std::vector<GShape>;

modules/gapi/include/opencv2/gapi/gproto.hpp

@@ -135,7 +135,7 @@ GRunArg value_of(const GOrigin &origin);
 // Transform run-time computation arguments into a collection of metadata
 // extracted from that arguments
 GMetaArg  GAPI_EXPORTS descr_of(const GRunArg  &arg );
-GMetaArgs GAPI_EXPORTS_W descr_of(const GRunArgs &args);
+GMetaArgs GAPI_EXPORTS descr_of(const GRunArgs &args);
 
 // Transform run-time operation result argument into metadata extracted from that argument
 // Used to compare the metadata, which generated at compile time with the metadata result operation in run time

modules/gapi/include/opencv2/gapi/gstreaming.hpp

@@ -180,7 +180,10 @@ class GAPI_EXPORTS_W_SIMPLE GStreamingCompiled
      * @param ins vector of inputs to process.
      * @sa gin
      */
-    GAPI_WRAP void setSource(GRunArgs &&ins);
+    void setSource(GRunArgs &&ins);
+
+    /// @private -- Exclude this function from OpenCV documentation
+    GAPI_WRAP void setSource(const cv::detail::ExtractArgsCallback& callback);
 
     /**
      * @brief Specify an input video stream for a single-input
@@ -251,6 +254,7 @@ class GAPI_EXPORTS_W_SIMPLE GStreamingCompiled
     bool pull(cv::GRunArgsP &&outs);
 
     // NB: Used from python
+    /// @private -- Exclude this function from OpenCV documentation
     GAPI_WRAP std::tuple<bool, cv::GRunArgs> pull();
 
     /**

modules/gapi/include/opencv2/gapi/imgproc.hpp

@@ -1158,7 +1158,7 @@ if there are 2 channels, or have 2 columns if there is a single channel. Mat sho
 @param src Input gray-scale image @ref CV_8UC1; or input set of @ref CV_32S or @ref CV_32F
 2D points stored in Mat.
  */
-GAPI_EXPORTS GOpaque<Rect> boundingRect(const GMat& src);
+GAPI_EXPORTS_W GOpaque<Rect> boundingRect(const GMat& src);
 
 /** @overload
 

modules/gapi/include/opencv2/gapi/infer/parsers.hpp

@@ -85,11 +85,11 @@ the larger side of the rectangle.
 @param filterOutOfBounds If provided true, out-of-frame boxes are filtered.
 @return a vector of detected bounding boxes.
 */
-GAPI_EXPORTS GArray<Rect> parseSSD(const GMat& in,
-                                   const GOpaque<Size>& inSz,
-                                   const float confidenceThreshold = 0.5f,
-                                   const bool alignmentToSquare = false,
-                                   const bool filterOutOfBounds = false);
+GAPI_EXPORTS_W GArray<Rect> parseSSD(const GMat& in,
+                                     const GOpaque<Size>& inSz,
+                                     const float confidenceThreshold = 0.5f,
+                                     const bool alignmentToSquare = false,
+                                     const bool filterOutOfBounds = false);
 
 /** @brief Parses output of Yolo network.