Function opencv::imgproc::convex_hull

pub fn convex_hull(
    points: &dyn ToInputArray, 
    hull: &mut dyn ToOutputArray, 
    clockwise: bool, 
    return_points: bool
) -> Result<()>

Finds the convex hull of a point set.

The function cv::convexHull finds the convex hull of a 2D point set using the Sklansky's algorithm Sklansky82 that has O(N logN) complexity in the current implementation.

Parameters

• points: Input 2D point set, stored in std::vector or Mat.
• hull: Output convex hull. It is either an integer vector of indices or vector of points. In the first case, the hull elements are 0-based indices of the convex hull points in the original array (since the set of convex hull points is a subset of the original point set). In the second case, hull elements are the convex hull points themselves.
• clockwise: Orientation flag. If it is true, the output convex hull is oriented clockwise. Otherwise, it is oriented counter-clockwise. The assumed coordinate system has its X axis pointing to the right, and its Y axis pointing upwards.
• returnPoints: Operation flag. In case of a matrix, when the flag is true, the function returns convex hull points. Otherwise, it returns indices of the convex hull points. When the output array is std::vector, the flag is ignored, and the output depends on the type of the vector: std::vector<int> implies returnPoints=false, std::vector<Point> implies returnPoints=true.

Note: points and hull should be different arrays, inplace processing isn't supported.

Check @ref tutorial_hull "the corresponding tutorial" for more details.

useful links:

https://www.learnopencv.com/convex-hull-using-opencv-in-python-and-c/

C++ default parameters

• clockwise: false
• return_points: true