Merge branch 4.x

modules/imgproc/include/opencv2/imgproc.hpp

@@ -4061,6 +4061,19 @@ A program using pyramid scaling, Canny, contours and contour simplification to f
 squares in the input image.
 */
 
+//! @brief Find contours using link runs algorithm
+//!
+//! This function implements an algorithm different from cv::findContours:
+//! - doesn't allocate temporary image internally, thus it has reduced memory consumption
+//! - supports CV_8UC1 images only
+//! - outputs 2-level hierarhy only (RETR_CCOMP mode)
+//! - doesn't support approximation change other than CHAIN_APPROX_SIMPLE
+//! In all other aspects this function is compatible with cv::findContours.
+CV_EXPORTS_W void findContoursLinkRuns(InputArray image, OutputArrayOfArrays contours, OutputArray hierarchy);
+
+//! @overload
+CV_EXPORTS_W void findContoursLinkRuns(InputArray image, OutputArrayOfArrays contours);
+
 /** @brief Approximates a polygonal curve(s) with the specified precision.
 
 The function cv::approxPolyDP approximates a curve or a polygon with another curve/polygon with less

modules/imgproc/include/opencv2/imgproc/detail/legacy.hpp

@@ -0,0 +1,30 @@
+// 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
+
+#ifndef OPENCV_IMGPROC_DETAIL_LEGACY_HPP
+#define OPENCV_IMGPROC_DETAIL_LEGACY_HPP
+
+#include "opencv2/imgproc.hpp"
+
+namespace cv {
+
+#ifdef __OPENCV_BUILD
+
+CV_EXPORTS void findContours_legacy(InputArray _image,
+                                    OutputArrayOfArrays _contours,
+                                    OutputArray _hierarchy,
+                                    int mode,
+                                    int method,
+                                    Point offset = Point());
+CV_EXPORTS void findContours_legacy(InputArray image,
+                                    OutputArrayOfArrays contours,
+                                    int mode,
+                                    int method,
+                                    Point offset = Point());
+
+#endif
+
+}  // namespace cv
+
+#endif  // OPENCV_IMGPROC_DETAIL_LEGACY_HPP