Merge pull request #17493 from TolyaTalamanov:at/python-bindings-gapi

* Implement G-API python bindings

* Fix hdr_parser

* Drop initlization with brackets using regexp

* Handle bracket initilization another way

* Add test for core operations

* Declaration and definition of View constructor now in different files

* Refactor tests

* Remove combine decorator from tests

* Fix comment to review

* Fix test

* Fix comments to review

* Remove GCompilerArgs implementation from python

Co-authored-by: Pinaev <danil.pinaev@intel.com>

modules/gapi/CMakeLists.txt

@@ -24,6 +24,8 @@ ocv_add_module(gapi
       opencv_imgproc
     OPTIONAL
       opencv_video
+    WRAP
+      python
 )
 
 if(MSVC)

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

@@ -528,7 +528,7 @@ Supported matrix data types are @ref CV_8UC1, @ref CV_8UC3, @ref CV_16UC1, @ref
 @param ddepth optional depth of the output matrix.
 @sa sub, addWeighted
 */
-GAPI_EXPORTS GMat add(const GMat& src1, const GMat& src2, int ddepth = -1);
+GAPI_EXPORTS_W GMat add(const GMat& src1, const GMat& src2, int ddepth = -1);
 
 /** @brief Calculates the per-element sum of matrix and given scalar.
 

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

@@ -16,7 +16,7 @@ namespace gapi {
 namespace core {
 namespace cpu {
 
-GAPI_EXPORTS GKernelPackage kernels();
+GAPI_EXPORTS_W cv::gapi::GKernelPackage kernels();
 
 } // namespace cpu
 } // namespace core

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

@@ -13,7 +13,7 @@
 
 namespace cv { namespace gapi { namespace core { namespace fluid {
 
-GAPI_EXPORTS GKernelPackage kernels();
+GAPI_EXPORTS_W cv::gapi::GKernelPackage kernels();
 
 }}}}
 

modules/gapi/include/opencv2/gapi/fluid/gfluidbuffer.hpp

@@ -56,8 +56,6 @@ public:
         }
     };
 
-    View() = default;
-
     const inline uint8_t* InLineB(int index) const // -(w-1)/2...0...+(w-1)/2 for Filters
     {
         return m_cache->linePtr(index);
@@ -80,6 +78,7 @@ public:
     Priv& priv();               // internal use only
     const Priv& priv() const;   // internal use only
 
+    View();
     View(std::unique_ptr<Priv>&& p);
     View(View&& v);
     View& operator=(View&& v);

modules/gapi/include/opencv2/gapi/gcommon.hpp

@@ -93,9 +93,12 @@ namespace detail {
  * passed in (a variadic template parameter pack) into a vector of
  * cv::GCompileArg objects.
  */
-struct GAPI_EXPORTS GCompileArg
+struct GAPI_EXPORTS_W_SIMPLE GCompileArg
 {
 public:
+    // NB: Required for pythnon bindings
+    GCompileArg() = default;
+
     std::string tag;
 
     // FIXME: use decay in GArg/other trait-based wrapper before leg is shot!

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

@@ -118,7 +118,7 @@ namespace I {
  *
  * @sa GCompiled
  */
-class GAPI_EXPORTS GComputation
+class GAPI_EXPORTS_W GComputation
 {
 public:
     class Priv;
@@ -191,7 +191,7 @@ public:
      * @param in2 second input GMat of the defined binary computation
      * @param out output GMat of the defined binary computation
      */
-    GComputation(GMat in1, GMat in2, GMat out);        // Binary overload
+    GAPI_WRAP GComputation(GMat in1, GMat in2, GMat out);        // Binary overload
 
     /**
      * @brief Defines a binary (two inputs -- one output) computation
@@ -275,7 +275,7 @@ public:
      * @param args compilation arguments for underlying compilation
      * process.
      */
-    void apply(cv::Mat in, cv::Mat &out, GCompileArgs &&args = {});               // Unary overload
+    void apply(cv::Mat in, cv::Mat &out, GCompileArgs &&args = {}); // Unary overload
 
     /**
      * @brief Execute an unary computation (with compilation on the fly)
@@ -286,7 +286,7 @@ public:
      * @param args compilation arguments for underlying compilation
      * process.
      */
-    void apply(cv::Mat in, cv::Scalar &out, GCompileArgs &&args = {});            // Unary overload (scalar)
+    void apply(cv::Mat in, cv::Scalar &out, GCompileArgs &&args = {}); // Unary overload (scalar)
 
     /**
      * @brief Execute a binary computation (with compilation on the fly)
@@ -298,7 +298,7 @@ public:
      * @param args compilation arguments for underlying compilation
      * process.
      */
-    void apply(cv::Mat in1, cv::Mat in2, cv::Mat &out, GCompileArgs &&args = {}); // Binary overload
+    GAPI_WRAP void apply(cv::Mat in1, cv::Mat in2, CV_OUT cv::Mat &out, GCompileArgs &&args = {}); // Binary overload
 
     /**
      * @brief Execute an binary computation (with compilation on the fly)

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

@@ -445,7 +445,7 @@ namespace gapi {
      * Finally, two kernel packages can be combined into a new one
      * with function cv::gapi::combine().
      */
-    class GAPI_EXPORTS GKernelPackage
+    class GAPI_EXPORTS_W_SIMPLE GKernelPackage
     {
 
         /// @private
@@ -712,6 +712,7 @@ namespace detail
         static const char* tag() { return "gapi.use_only"; }
     };
 } // namespace detail
+
 } // namespace cv
 
 #endif // OPENCV_GAPI_GKERNEL_HPP

modules/gapi/include/opencv2/gapi/gmat.hpp

@@ -46,10 +46,10 @@ struct GOrigin;
  *    `cv::GArray<T>`    | std::vector<T>
  *    `cv::GOpaque<T>`   | T
  */
-class GAPI_EXPORTS GMat
+class GAPI_EXPORTS_W_SIMPLE GMat
 {
 public:
-    GMat();                                 // Empty constructor
+    GAPI_WRAP GMat();                       // Empty constructor
     GMat(const GNode &n, std::size_t out);  // Operation result constructor
 
     GOrigin& priv();                        // Internal use only

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

@@ -16,7 +16,7 @@ namespace gapi {
 namespace core {
 namespace ocl {
 
-        GAPI_EXPORTS GKernelPackage kernels();
+        GAPI_EXPORTS_W cv::gapi::GKernelPackage kernels();
 
 } // namespace ocl
 } // namespace core

modules/gapi/include/opencv2/gapi/own/exports.hpp

@@ -11,8 +11,15 @@
 #   if defined(__OPENCV_BUILD)
 #       include <opencv2/core/base.hpp>
 #       define GAPI_EXPORTS CV_EXPORTS
+        /* special informative macros for wrapper generators */
+#       define GAPI_WRAP CV_WRAP
+#       define GAPI_EXPORTS_W_SIMPLE CV_EXPORTS_W_SIMPLE
+#       define GAPI_EXPORTS_W CV_EXPORTS_W
 #   else
+#       define GAPI_WRAP
 #       define GAPI_EXPORTS
+#       define GAPI_EXPORTS_W_SIMPLE
+#       define GAPI_EXPORTS_W
 
 #if 0  // Note: the following version currently is not needed for non-OpenCV build
 #       if defined _WIN32

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

@@ -13,7 +13,7 @@
 
 namespace cv { namespace gapi { namespace core { namespace plaidml {
 
-GAPI_EXPORTS GKernelPackage kernels();
+GAPI_EXPORTS cv::gapi::GKernelPackage kernels();
 
 }}}}
 

modules/gapi/misc/python/pyopencv_gapi.hpp

@@ -0,0 +1,13 @@
+using gapi_GKernelPackage = cv::gapi::GKernelPackage;
+
+template<>
+bool pyopencv_to(PyObject* obj, std::vector<GCompileArg>& value, const ArgInfo& info)
+{
+    return pyopencv_to_generic_vec(obj, value, info);
+}
+
+template<>
+PyObject* pyopencv_from(const std::vector<GCompileArg>& value)
+{
+    return pyopencv_from_generic_vec(value);
+}

modules/gapi/misc/python/shadow_gapi.hpp

@@ -0,0 +1,7 @@
+#error This is a shadow header file, which is not intended for processing by any compiler. \
+       Only bindings parser should handle this file.
+
+namespace cv
+{
+   GAPI_EXPORTS_W GCompileArgs compile_args(gapi::GKernelPackage pkg);
+} // namespace cv

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

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+import numpy as np
+import cv2 as cv
+
+from tests_common import NewOpenCVTests
+
+
+# Plaidml is an optional backend
+pkgs = [
+         cv.gapi.core.ocl.kernels(),
+         cv.gapi.core.cpu.kernels(),
+         cv.gapi.core.fluid.kernels()
+         # cv.gapi.core.plaidml.kernels()
+       ]
+
+
+class gapi_core_test(NewOpenCVTests):
+
+    def test_add(self):
+        # TODO: Extend to use any type and size here
+        sz = (1280, 720)
+        in1 = np.random.randint(0, 100, sz).astype(np.uint8)
+        in2 = np.random.randint(0, 100, sz).astype(np.uint8)
+
+        # OpenCV
+        expected = in1 + in2
+
+        # G-API
+        g_in1 = cv.GMat()
+        g_in2 = cv.GMat()
+        g_out = cv.gapi.add(g_in1, g_in2)
+        comp = cv.GComputation(g_in1, g_in2, g_out)
+
+        for pkg in pkgs:
+            actual = comp.apply(in1, in2, args=cv.compile_args(pkg))
+            # Comparison
+            self.assertEqual(0.0, cv.norm(expected, actual, cv.NORM_INF))
+
+
+if __name__ == '__main__':
+    NewOpenCVTests.bootstrap()

modules/gapi/src/backends/fluid/gfluidbuffer.cpp

@@ -694,6 +694,8 @@ fluid::View::View(std::unique_ptr<Priv>&& p)
     : m_priv(std::move(p)), m_cache(&m_priv->cache())
 { /* nothing */ }
 
+
+fluid::View::View() = default;
 fluid::View::View(View&&) = default;
 fluid::View& fluid::View::operator=(View&&) = default;
 fluid::View::~View() = default;

modules/python/src2/gen2.py

@@ -27,14 +27,14 @@ gen_template_check_self = Template("""
 gen_template_call_constructor_prelude = Template("""new (&(self->v)) Ptr<$cname>(); // init Ptr with placement new
         if(self) """)
 
-gen_template_call_constructor = Template("""self->v.reset(new ${cname}${args})""")
+gen_template_call_constructor = Template("""self->v.reset(new ${cname}${py_args})""")
 
 gen_template_simple_call_constructor_prelude = Template("""if(self) """)
 
-gen_template_simple_call_constructor = Template("""new (&(self->v)) ${cname}${args}""")
+gen_template_simple_call_constructor = Template("""new (&(self->v)) ${cname}${py_args}""")
 
 gen_template_parse_args = Template("""const char* keywords[] = { $kw_list, NULL };
-    if( PyArg_ParseTupleAndKeywords(args, kw, "$fmtspec", (char**)keywords, $parse_arglist)$code_cvt )""")
+    if( PyArg_ParseTupleAndKeywords(py_args, kw, "$fmtspec", (char**)keywords, $parse_arglist)$code_cvt )""")
 
 gen_template_func_body = Template("""$code_decl
     $code_parse
@@ -362,6 +362,7 @@ class ArgInfo(object):
         self.inputarg = True
         self.outputarg = False
         self.returnarg = False
+        self.isrvalueref = False
         for m in arg_tuple[3]:
             if m == "/O":
                 self.inputarg = False
@@ -377,6 +378,8 @@ class ArgInfo(object):
             elif m.startswith("/CA"):
                 self.isarray = True
                 self.arraycvt = m[2:].strip()
+            elif m == "/RRef":
+                self.isrvalueref = True
         self.py_inputarg = False
         self.py_outputarg = False
 
@@ -529,14 +532,14 @@ class FuncInfo(object):
     def get_wrapper_prototype(self, codegen):
         full_fname = self.get_wrapper_name()
         if self.isconstructor:
-            return "static int {fn_name}(pyopencv_{type_name}_t* self, PyObject* args, PyObject* kw)".format(
+            return "static int {fn_name}(pyopencv_{type_name}_t* self, PyObject* py_args, PyObject* kw)".format(
                     fn_name=full_fname, type_name=codegen.classes[self.classname].name)
 
         if self.classname:
             self_arg = "self"
         else:
             self_arg = ""
-        return "static PyObject* %s(PyObject* %s, PyObject* args, PyObject* kw)" % (full_fname, self_arg)
+        return "static PyObject* %s(PyObject* %s, PyObject* py_args, PyObject* kw)" % (full_fname, self_arg)
 
     def get_tab_entry(self):
         prototype_list = []
@@ -682,6 +685,10 @@ class FuncInfo(object):
 
                 if not code_args.endswith("("):
                     code_args += ", "
+
+                if a.isrvalueref:
+                    a.name = 'std::move(' + a.name + ')'
+
                 code_args += amp + a.name
 
             code_args += ")"
@@ -695,7 +702,7 @@ class FuncInfo(object):
                     templ = gen_template_call_constructor
 
                 code_prelude = templ_prelude.substitute(name=selfinfo.name, cname=selfinfo.cname)
-                code_fcall = templ.substitute(name=selfinfo.name, cname=selfinfo.cname, args=code_args)
+                code_fcall = templ.substitute(name=selfinfo.name, cname=selfinfo.cname, py_args=code_args)
                 if v.isphantom:
                     code_fcall = code_fcall.replace("new " + selfinfo.cname, self.cname.replace("::", "_"))
             else:
@@ -744,7 +751,7 @@ class FuncInfo(object):
                     parse_arglist = ", ".join(["&" + all_cargs[argno][1] for aname, argno in v.py_arglist]),
                     code_cvt = " &&\n        ".join(code_cvt_list))
             else:
-                code_parse = "if(PyObject_Size(args) == 0 && (!kw || PyObject_Size(kw) == 0))"
+                code_parse = "if(PyObject_Size(py_args) == 0 && (!kw || PyObject_Size(kw) == 0))"
 
             if len(v.py_outlist) == 0:
                 code_ret = "Py_RETURN_NONE"

modules/python/src2/hdr_parser.py

@@ -111,6 +111,11 @@ class CppHeaderParser(object):
         if npos >= 0:
             modlist.append("/C")
 
+        npos = arg_str.find("&&")
+        if npos >= 0:
+            arg_str = arg_str.replace("&&", '')
+            modlist.append("/RRef")
+
         npos = arg_str.find("&")
         if npos >= 0:
             modlist.append("/Ref")
@@ -715,6 +720,8 @@ class CppHeaderParser(object):
                     return stmt_type, classname, True, decl
 
             if stmt.startswith("enum") or stmt.startswith("namespace"):
+                # NB: Drop inheritance syntax for enum
+                stmt = stmt.split(':')[0]
                 stmt_list = stmt.rsplit(" ", 1)
                 if len(stmt_list) < 2:
                     stmt_list.append("<unnamed>")
@@ -812,6 +819,15 @@ class CppHeaderParser(object):
 
             l = l0.strip()
 
+            # G-API specific aliases
+            l = self.batch_replace(l, [
+                    ("GAPI_EXPORTS", "CV_EXPORTS"),
+                    ("GAPI_EXPORTS_W", "CV_EXPORTS_W"),
+                    ("GAPI_EXPORTS_W_SIMPLE","CV_EXPORTS_W_SIMPLE"),
+                    ("GAPI_WRAP", "CV_WRAP"),
+                    ('defined(GAPI_STANDALONE)', '0'),
+                ])
+
             if state == SCAN and l.startswith("#"):
                 state = DIRECTIVE
                 # fall through to the if state == DIRECTIVE check
@@ -867,7 +883,12 @@ class CppHeaderParser(object):
                 sys.exit(-1)
 
             while 1:
-                token, pos = self.find_next_token(l, [";", "\"", "{", "}", "//", "/*"])
+                # NB: Avoid parsing '{' for case:
+                # foo(Obj&& = {});
+                if re.search(r'=\s*\{\s*\}', l):
+                    token, pos = ';', len(l)
+                else:
+                    token, pos = self.find_next_token(l, [";", "\"", "{", "}", "//", "/*"])
 
                 if not token:
                     block_head += " " + l