如何在iOS目标C中使用openCV的凸函数？

Question

I am someone who is new to openCV and has been trying to use convexhull function in the openCV library for an app (objective-C being used), I need to know what is the input format of function arguments, it's pretty confusing. And does this function return the points in a sequence? Like, if I use addLineToPoint to draw a bezierpath of this hull, is it possible?

Answer 1

Some sample code for you:

std::vector<cv::Point> points;
//fill that vector with your points

std::vector<cv::Point> hull;
if (points.size()) {
    cv::convexHull(points, hull);
}

cv::Size size = cv::Size(w, h); 
//some size for the matrix where you will draw your convex hull

cv::Mat hullMask = Mat::zeros(size, CV_8UC1);
int hull_count = (int)hull.size();
if (hull_count) {
    const cv::Point* hull_pts = &hull[0];
    cv::fillPoly(hullMask, &hull_pts, &hull_count, 1, cv::Scalar(255));
}

This code will help you to create convex hull and draw it.

Here you can find complete documentation for that function. It will return points in a sequence according to the "clockwise" argument. By default it will be counter-clockwise.