Merge pull request #11703 from alalek:c_api_calib3d_chessboard_detector

modules/core/include/opencv2/core/types_c.h

@@ -409,6 +409,11 @@ IplConvKernelFP;
 #define CV_MAT_MAGIC_VAL    0x42420000
 #define CV_TYPE_NAME_MAT    "opencv-matrix"
 
+#ifdef __cplusplus
+typedef struct CvMat CvMat;
+CV_INLINE CvMat cvMat(const cv::Mat& m);
+#endif
+
 /** Matrix elements are stored row by row. Element (i, j) (i - 0-based row index, j - 0-based column
 index) of a matrix can be retrieved or modified using CV_MAT_ELEM macro:
 
@@ -531,6 +536,16 @@ inline CvMat::CvMat(const cv::Mat& m)
     step = (int)m.step[0];
     type = (type & ~cv::Mat::CONTINUOUS_FLAG) | (m.flags & cv::Mat::CONTINUOUS_FLAG);
 }
+
+inline CvMat cvMat(const cv::Mat& m)
+{
+    CvMat self;
+    CV_DbgAssert(m.dims <= 2);
+    self = cvMat(m.rows, m.dims == 1 ? 1 : m.cols, m.type(), m.data);
+    self.step = (int)m.step[0];
+    self.type = (self.type & ~cv::Mat::CONTINUOUS_FLAG) | (m.flags & cv::Mat::CONTINUOUS_FLAG);
+    return self;
+}
 #endif
 
 
@@ -916,6 +931,15 @@ CV_INLINE  CvPoint2D32f  cvPoint2D32f( double x, double y )
     return p;
 }
 
+#ifdef __cplusplus
+template<typename _Tp>
+CvPoint2D32f cvPoint2D32f(const cv::Point_<_Tp>& pt)
+{
+    CvPoint2D32f p((float)pt.x, (float)pt.y);
+    return p;
+}
+#endif
+
 /** converts CvPoint to CvPoint2D32f. */
 CV_INLINE  CvPoint2D32f  cvPointTo32f( CvPoint point )
 {