From 931af518d9a179b469265d70fdc417faf62a0d1b Mon Sep 17 00:00:00 2001
From: Gianluca Nordio <96429106+GianlucaNordio@users.noreply.github.com>
Date: Tue, 25 Mar 2025 07:30:56 +0100
Subject: [PATCH] Merge pull request #27139 from GianlucaNordio:patch-4

Fix minAreaRect and boxPoints docs (#26799) #27139

As requested from issue #26799 the docs regarding minAreaRect and boxPoints are extended specifying the order of the corners for boxPoints and the way the angle is computed for the rotated rect returned by minAreaRect
---
 modules/imgproc/include/opencv2/imgproc.hpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/modules/imgproc/include/opencv2/imgproc.hpp b/modules/imgproc/include/opencv2/imgproc.hpp
index cf222b9edd..14f07e78ad 100644
--- a/modules/imgproc/include/opencv2/imgproc.hpp
+++ b/modules/imgproc/include/opencv2/imgproc.hpp
@@ -4160,7 +4160,11 @@ CV_EXPORTS_W double contourArea( InputArray contour, bool oriented = false );
 /** @brief Finds a rotated rectangle of the minimum area enclosing the input 2D point set.
 
 The function calculates and returns the minimum-area bounding rectangle (possibly rotated) for a
-specified point set. Developer should keep in mind that the returned RotatedRect can contain negative
+specified point set. The angle of rotation represents the angle between the line connecting the starting
+and ending points (based on the clockwise order with greatest index for the corner with greatest \f$y\f$)
+and the horizontal axis. This angle always falls between \f$[-90, 0)\f$ because, if the object
+rotates more than a rect angle, the next edge is used to measure the angle. The starting and ending points change
+as the object rotates.Developer should keep in mind that the returned RotatedRect can contain negative
 indices when data is close to the containing Mat element boundary.
 
 @param points Input vector of 2D points, stored in std::vector\<\> or Mat
@@ -4169,7 +4173,9 @@ CV_EXPORTS_W RotatedRect minAreaRect( InputArray points );
 
 /** @brief Finds the four vertices of a rotated rect. Useful to draw the rotated rectangle.
 
-The function finds the four vertices of a rotated rectangle. This function is useful to draw the
+The function finds the four vertices of a rotated rectangle. The four vertices are returned
+in clockwise order starting from the point with greatest \f$y\f$. If two points have the
+same \f$y\f$ coordinate the rightmost is the starting point. This function is useful to draw the
 rectangle. In C++, instead of using this function, you can directly use RotatedRect::points method. Please
 visit the @ref tutorial_bounding_rotated_ellipses "tutorial on Creating Bounding rotated boxes and ellipses for contours" for more information.